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60results about How to "Stabilize bus voltage" patented technology

Mixed micro-grid system based on power electronic transformer and power control method of system

The invention provides an AC and DC mixed micro-grid system based on a power electronic transformer and a power control method of the system. The system comprises a main grid, an AC micro grid, a DC micro grid and the power electronic transformer. According to the operation states and power requirements of the AC micro grid and the DC micro grid, the power electronic transformer adjusts the power of the AC micro grid and the DC micro grid in a mixed sagging method. Thus, the power of the main grid, the AC micro grid and the DC micro grid can be rapidly and accurately adjusted, it is ensured that the frequency of the AC micro grid and the bus voltage of the DC micro grid are stable, and stable operation of the AC and DC mixed micro-grid after access of distributed energy is realized.
Owner:HUNAN UNIV

Energy management control method of photovoltaic energy storage system

InactiveCN105576677AConvenient global controlConvenient local controlPV power plantsEnergy storageControl mannerSystem configuration
The invention discloses an energy management control method of a photovoltaic energy storage system. The energy management control method comprises a photovoltaic energy storage system configuration method, a concentrated energy storage system control method and a distributed energy storage system control method. Compared with a mixed energy storage structure, the energy management control method adopts a concentrated energy storage and distributed energy storage layered control manner, and global control and partial control can be conveniently and effectively carried out on the photovoltaic energy storage system; a control circuit and a control process are simplified and the control efficiency is improved; by optimizing the concentrated energy storage and distributed energy storage control methods, the photovoltaic utilization rate can be effectively improved and bus voltage is stabilized; and with the adoption of a storage battery grouped control manner, the problems that the data volume is great and an electric charge state of each storage battery is difficult to reasonably determine when single control is adopted are solved. The energy management control method can be widely applied to the distributed photovoltaic energy storage system; and a control manner is simplified, the control efficiency is improved and the photovoltaic utilization rate and the power supply quality are improved, so that the energy management control method has very important application prospects.
Owner:HUAZHONG UNIV OF SCI & TECH +3

Bi-directional DCDC converter

The invention provides a bi-directional DCDC converter. The bi-directional DCDC converter comprises a transformer, an inductor, a diode, a relay, a controller, a current detection module, a voltage detection module and a field-effect tube, wherein the current detection module is connected with an external first direct-current voltage, and the current detection module is connected to the transformer by virtue of the field-effect tube; the transformer is connected with the relay, and the transformer is connected to an external second direct-current voltage by virtue of the field-effect tube; the second direct-current voltage is connected to an alternating-current load by virtue of an inverter; the relay, the current detection module, the voltage detection module and the field-effect tube are connected with the controller; when direct-current power is transferred by the second direct-current voltage to the first direct-current voltage, the relay is controlled to be turned off, and the pulse width of a PWM signal transmitted by the second direct-current voltage is adjusted; when the direct-current power is transferred by the first direct-current voltage to the second direct-current voltage, the relay is controlled to be turned on, and the pulse width of a PWM signal transmitted by the first direct-current voltage is adjusted.
Owner:SHENZHEN KSTAR SCI & TECH

Multi-mode coordination control method of annular AC/DC hybrid microgrid system

The invention discloses a multi-mode coordination control method of an annular AC / DC hybrid microgrid system. The annular AC / DC hybrid microgrid system is characterized in that an AC side and a DC side form a looped network structure through two AC / DC bidirectional converters, and the AC side and the DC side are radiation type networks respectively; in the annular AC / DC hybrid microgrid system, the voltage class of a medium-voltage alternating-current bus is 10 kV, the voltage class of the medium-voltage direct-current bus is + / -1.5 kV, the alternating-current side is connected with a large power grid and comprises a wind driven generator, a micro gas turbine, an alternating-current load and an alternating-current side energy storage system, and the distributed power supply and the load are connected with the medium-voltage alternating-current bus through an alternating-current transformer, the direct-current side comprises a photovoltaic power generation system, a direct-current loadand a direct-current side energy storage system, and the distributed power supply and the load are connected with a medium-voltage direct-current bus through a direct-current transformer.
Owner:NORTH CHINA ELECTRIC POWER UNIV (BAODING)

Semiconductor device test system and test method thereof

The invention discloses a semiconductor device test system and a test method thereof. The test system comprises an upper computer, an oscilloscope, a main control system PLC, a circuit control moduleand a test box body. An automatic tool is arranged in the test box body, a tested piece is placed on the automatic tool, and a test fixture is arranged right above the tested piece. The automatic toolcomprises a driving device, the driving device drives the automatic tool to move so as to drive the tested piece to be connected with the test fixture, and the main control system PLC is connected with the test box body, the test fixture, a main circuit unit and a gate pole driving unit. The upper computer is connected with the oscilloscope, and the oscilloscope is connected with the test box body. The advantages of the present invention are that the semiconductor device test system with a specific testing circuit and a testing system structure is designed, the theory is combined with the practice, and all devices in the system are matched with one another to test the semiconductor device.
Owner:HEFEI KEWELL POWER SYST CO LTD

Large-scale energy storage SOC balance coordination control system and method

The invention provides a large-scale energy storage SOC balance coordination control system and method. The system comprises a first bus, a second bus, a third bus, a fourth bus, at least one photovoltaic power generation unit, at least one wind power generation unit, at least two loads, a first line impedance, a second line impedance, a third line impedance, a fourth line impedance and N lithiumbattery boxes. In order to adjust the charging and discharging power of each battery according to the properties of the batteries with different capacities, the system achieves the purpose that the SOC tends to be consistent, has certain resistance to power grid disturbance caused by frequent load switching, and maintains the stability of each bus voltage. Different reference voltage regulation coefficients are distributed to batteries with different capacities, and the corresponding change ranges are given, thereby achieving the reasonable distribution of the charging and discharging power, reducing the loss of the battery and prolonging the service life of the battery. Meanwhile, the SOC can be kept consistent for a long time through reference adjustment coefficient adjustment when all batteries reach the same SOC.
Owner:NORTHEASTERN UNIV

A railway engine AC traction one-phase power supply device based on YN,vd wiring transformer

The utility model relates to an A.C. co-phase traction supply device of railway locomotive based on YN, vd wiring transformer; wherein, the traction transformer is a three-phase to two-phase balancing transformer (T), the wiring method of which is YN, vd. A rectifying inverter (Z) is connected between two outputs (b', c') of the line voltage of the transformer (T) and two outputs (a, x) of the phase voltage of the transformer (T), and the outputs (b', c') of the line voltage and the outputs (a, x) of the phase voltage are the supply ends (V1, V2) of the traction locomotive. Meanwhile, a control device of the rectifying inverter (Z) is connected with the two supply ends (V1, V2) of the traction locomotive. The utility model has the advantages of achieving the co-phase power supply in the whole line of the railway without dividing phases, being stable voltage in each section of the traction transforming station, ensuring that the locomotives can move at high speed when the locomotives are overloading, getting the power in three-phase from the public power network of the power supply system of the traction load of the railway, and eliminating the effect of the traction load of the railway to the power quality of the public power network can be eliminate, which can also be made by the prior traction transformer with low cost and convenient implementation.
Owner:SOUTHWEST JIAOTONG UNIV

Uninterrupted standby power system

The invention discloses an uninterrupted standby power system comprising an uninterrupted power supply, an inversion distribution box, a charge-discharge protection unit and a double-power control cabinet, wherein the inversion distribution box is electrically connected with a load; the charge-discharge protection unit and the double-power control cabinet are electrically connected with an uninterrupted power supply; the double-power control cabinet is electrically connected with a generating set and a commercial power incoming line device; the generating set and the charge-discharge protection unit are in electric connection; and an automatic oil supply device is arranged on one side of the generating set. The power for the load is provided by the uninterrupted power supply when the commercial power is cut or goes wrong, and when the voltage of the uninterrupted power supply is lowered to a protection voltage, the charge-discharge protection unit controls the generating set to charge the uninterrupted power supply, so as to guarantee stable power supply for users; besides, the uninterrupted standby power system has the advantages of small volume of the entire equipment, flexibility in use, light weight, and convenience in both operation and maintenance.
Owner:广东康菱动力科技有限公司

Adaptive interference compensation passive control method of micro-grid hybrid energy storage system

The invention relates to an adaptive interference compensation passive control method of a micro-grid hybrid energy storage system. The micro-grid hybrid energy storage system comprises a super capacitor and a storage battery, the super capacitor and the storage battery are connected in parallel to a direct current bus through a bidirectional DC-DC converter to form an energy bidirectional loop. The control method concretely comprises the steps of: acquiring a control signal of a bidirectional DC-DC converter by employing a dual-ring control mode of inner ring current passive control and outerring voltage passive control to stabilize the voltage of the direct current bus, wherein theoretical reference current values of charge and discharge of the energy storage system are generated through the outer ring voltage passive control, the inner ring current passive control allows the charge-discharge current of the energy storage system to reach a current reference value and generates the control signal of the converter, and the current reference value is obtained based on adaptive interference compensation correction. Compared to the prior art, the adaptive interference compensation passive control method of the micro-grid hybrid energy storage system can have good robustness in the conditions that the modeling parameters are not accurate of the micro-grid comprising the energy storage system and the parameters of the system are changed and interfered by the outside.
Owner:SHANGHAI UNIVERSITY OF ELECTRIC POWER

Electric vehicle hybrid energy management system based on adaptive wavelet transformation and control method thereof

The invention discloses an electric vehicle hybrid energy management system based on adaptive wavelet transformation and a control method thereof. The electric vehicle hybrid energy management systembased on adaptive wavelet transformation comprises a super capacitor, a lithium battery, two DC / DC converters, a drive module, an acquisition circuit and a control module. The control method comprisesthe following steps that firstly, a total reference current required by the load is obtained through voltage loop control; then the adaptive wavelet transform algorithm is used for performing wavelettransform on the total reference current required by the load to obtain a high-frequency current component and a low-frequency current component, wherein the low-frequency current component is takenas a reference current of the lithium battery, and the high-frequency current component is taken as the reference current of the super capacitor; then, a current loop of the control module tracks thereference current of the lithium battery and the super capacitor in real time to realize the real-time distribution of the load demand power. According to the electric vehicle hybrid energy managementsystem based on adaptive wavelet transformation and the control method thereof, the super capacitor is fully utilized, and the lithium battery is effectively protected.
Owner:CENT SOUTH UNIV +1

Adjusting method for dynamic reactive compensation controller

The invention discloses an adjusting method for a dynamic reactive compensation controller. The adjusting method comprises the following steps: firstly, collecting the busbar current of a three-phase system, the busbar voltage of the three-phase system and the current of a three-phase thyristor controlled reactor in real time; then carrying out closed loop proportional-integral-differential (PID)adjustment on the current of the three-phase thyristor controlled reactor according to the compensated admittance of each parallel branch, and outputting the triggering angle of the thyristor controlled reactor; simultaneously, carrying out closed loop PID adjustment on the busbar voltage of the three-phase system, and outputting the triggering angle of the thyristor controlled reactor; and finally, according to whether each phase of voltage is in a specific range or not, judging whether to adopt the closed loop PID adjustment of the second step or the third step, and outputting the actual triggering angle of the thyristor controlled reactor. The method provided by the invention can increase the power factor, reduce the reactive power, decrease the line loss, improve the transmission capacity of the active power of a power transmission line, stabilize the busbar voltage, and inhibit the voltage fluctuation and flicker.
Owner:GUANGDONG MINGYANG LONGYUAN POWER ELECTRONICS

Independent power coordination control method applicable for AC/DC hybrid microgrid

The invention discloses an independent power coordination control method applicable for an AC / DC hybrid microgrid. The power exchange of subnets on two sides of the AC / DC hybrid microgrid is coordinated through an independent power coordination control strategy of BICs, so that mutual acid of energy is realized in AC / DC subnets, and the stability of busbar voltage and frequency inside each subnet is maintained; and moreover, due to the fact that the power coordination control method based on droop control is adopted by the BICs, power equipartition control among the BICs is effectively realized. The method can be widely applied to the AC / DC hybrid microgrid system.
Owner:HUNAN UNIV

Power supply structure for stratospheric aerostat

ActiveCN107681762AMeet the center of gravity adjustment requirementsImplement redundant backupBatteries circuit arrangementsElectric powerEngineeringSolar cell
The invention discloses a power supply structure for a stratospheric aerostat. The power supply structure comprises a first power supply unit and a second power supply unit, wherein the first power supply unit comprises a first solar cell array, a first unidirectional DC converter, a first bidirectional DC converter and a first energy storage battery which are electrically connected in sequence; and the second power supply unit adopts an electric connection structure which is the same as the first power supply unit. The power supply structure for the stratospheric aerostat comprises two independent power supply units, and a distributed installation method is adopted to meet the requirement for center-of-gravity regulation of the aerostat; the redundant backup is realized through a controllable parallel connection of the same components of the two independent power supply units, a fault isolation function of a component level and a component backup function between the two power supplyunits are realized, and the reliability of system operation is improved; the power supply structure has various working modes, and bus voltage is guaranteed to remain stable always.
Owner:BEIHANG UNIV

Reactive compensation method for electrified railway V/V transformer

The invention discloses a reactive compensation method for an electrified railway V / V transformer. A reactive compensation device for the electrified railway V / V transformer is adopted. The reactive compensation method comprises the specific steps that a bus voltage, a bus current and the current of a compensation network are detected; the bus voltage, the bus current and fundamental signals of the compensation network are extracted and converted into digital signals through an ADC circuit to be transmitted to a controller; the controller processes the digit value bus voltage, the digit value bus current and the digit value fundamental signals of the compensation network through a symmetrical component method and a balance compensation method in sequence, and all phase compensation admittance of the compensation network is obtained; a fuzzy PI regulator is used for obtaining a thyristor firing angle of the compensation network according to the relation of the compensation admittance and the thyristor firing angle; the controller sends out trigger pulses which are sent to the gate pole of a thyristor through a driving circuit. By means of the reactive compensation method for the electrified railway V / V transformer, reactive power can be completely compensated for, negative-sequence currents are thoroughly eliminated, and the compensation capacity is not limited.
Owner:XIAN UNIV OF TECH

Wind power converter main circuit topological structure with two units of direct-current bus connected in series

The invention discloses a wind power converter main circuit topological structure with two units of a direct-current bus connected in series. The wind power converter main circuit topological structure with two units of the direct-current bus connected in series comprises a power generator, a positive bus, a negative bus, a transformer connected with an external power grid, a rectification module through which the positive bus and the negative bus are connected, a boosting module and an inversion module. The positive bus and the negative bus are connected in series after being processed by the rectification module, the boosting module and the inversion module, and a neural point is grounded. By means of the design, the wind power converter main circuit topological structure can bear higher outlet voltage of the power generator, the voltage level of the direct-current bus is improved, bus current is reduced under the same power, the wind power converter main circuit topological structure is applicable to a high-power direct-drive type wind power converter, a control mode is flexible, meanwhile, insulating difficulty is reduced, the whole structure is more compact compared with the situation that an IGBT power device or a bus parallel-connection circuit is purely replaced, the occupied area of the converter is reduced, and design and type selection and systematic configuration can be achieved easily.
Owner:GUANGDONG MINGYANG WIND POWER IND GRP CO LTD

Operating resonant load circuit, dimming circuit and dimming method

The invention discloses an operating resonant load circuit, a dimming circuit and a dimming method. The operating resonant load circuit comprises an input unit, a rectifier and a controller, wherein the input unit comprises a plurality of input terminals and is used for receiving alternating current voltage; the rectifier is used for converting the alternating current voltage received by the input unit into direct current bus voltage; and the controller is used for dividing the direct current bus voltage according to the communication state of the input terminal for outputting corresponding direct current reference voltage.
Owner:OSRAM SYLVANIA INC

Photovoltaic system maximum power point tracing method

The invention provides a photovoltaic system maximum power point tracing method. The method comprises the steps that 1, the power value P of a photovoltaic system is obtained in real time; 2, a limit marking value M is obtained according to the current MPPT disturbance period system power value P(k), the set limit power value PLimit and the limit power dead zone PStep; 3, the disturbance direction DFlag is determined according to the current MPPT disturbance period system power value P(k), the previous MPPT disturbance period system power value P(k-1) and the maximum power tracking dead zone PDead; 4, according to the formula: Vmmpt(k)=Vmppt(k-1)+M*DFlag*VStep, the maximum power disturbance voltage Vmppt (k) is obtained for maximum power tracking. By the adoption of the technical scheme, the photovoltaic system maximum power point tracing method has the advantages that full load and limiting output power of a photovoltaic inverter are smooth; the full-load power and limit power of the photovoltaic system are accurate, and the output power is stable; bus voltage is more stable, and a system loop is more reliable.
Owner:厦门科华数能科技有限公司

Energy management method of marine DC hybrid power system

The invention relates to the technical field of energy management, in particular to an energy management technology aiming at a marine direct current hybrid power system, and particularly relates to an energy management method aiming at the marine direct current hybrid power system composed of multiple groups of fuel cells, multiple groups of lithium batteries and a super capacitor. By monitoring information such as bus voltage and residual electric quantity of each power supply, each power supply DC / DC converter in the marine direct-current hybrid power system is controlled, so that the hybrid power system is switched among 11 working modes, flow of energy in the hybrid power supply is timely allocated, the stability of the direct-current bus is ensured, and the service life of the hybrid power supply is prolonged. The hybrid power supply system rapidly tracks load changes, and stable and reliable operation of the whole DC hybrid power system is realized.
Owner:SHENYANG INST OF AUTOMATION - CHINESE ACAD OF SCI

Non-communication bus voltage zero-deviation control method

The invention relates to a non-communication bus voltage zero-deviation control method. Bus voltage stability and accurate load current allocation are used as control targets, accurate line impedanceinformation is acquired by an active measurement method and is introduced to a droop coefficient so as to make up influence of line impedance inconsistency on current allocation, and a load current can be accurately allocated during the steady-state and dynamic process. Moreover, virtual bus voltage information is introduced, a bus voltage stably runs at a rated value according to a translation compensation principle, and current allocation is not affected. With the control method proposed by the invention, the defect of traditional droop control is overcome, interconnection communication is not needed, the plug and play requirement is met, the capacity expansion of the system is facilitated, and the system reliability is greatly improved.
Owner:SHANGHAI UNIVERSITY OF ELECTRIC POWER

Flexible power tracking control method of photovoltaic power generation unit and application thereof

The invention discloses a flexible power tracking control method of a photovoltaic power generation unit and application thereof. The photovoltaic power generation unit is connected to the DC bus through the DC-DC converter, and the load is connected to the DC bus. According to the control method, the reference power and the output power of the photovoltaic power generation unit are judged, the working state of the photovoltaic power generation unit is selected as an MPPT mode or a constant power tracking mode, the output of the photovoltaic power generation unit is controlled in real time, and the DC bus voltage is adjusted. The method is suitable for occasions where the illumination intensity and the load power change continuously. When the photovoltaic power generation unit is applied to a traction power supply system and a micro-grid system, the use of a brake resistor and a heat dissipation device can be reduced, the cost is reduced, the capacity of other voltage stabilizing devices such as an energy storage device can be reduced, and the service life of the energy storage device is prolonged.
Owner:SOUTHWEST JIAOTONG UNIV

Three-port direct-current energy router power coordination control method

PendingCN111224392AImprove the ability to deal with risksStabilize bus voltageDc source parallel operationPower controllerTelecommunications
The invention discloses a three-port direct-current energy router power coordination control method, which comprises the following steps that: a port power controller collects a direct-current bus voltage value of each microgrid, and performs per-unit processing on the active power droop characteristic of the bus voltage value to obtain a voltage per-unit value of each port; therefore, different droop characteristics of the three direct-current micro-grids can be unified, and the direct-current micro-grids can be analyzed and power transmission of each port of the three-port direct-current energy router can be controlled under the same coordinate system. The transmission power deviation of each energy router port is calculated according to the voltage per unit value of each port; and a TABinternal controller converts the transmission power deviation of each energy router port into an adjustment amount of a phase shift angle between the energy router ports. Driving pulses of all switches of the TAB converter are obtained through continuous phase modulation, and power coordination control over the three-port direct-current energy router is achieved. The bus voltage stability can bemaintained, and the risk coping capacity of a power grid system is improved.
Owner:YUNNAN POWER GRID CO LTD ELECTRIC POWER RES INST

A railway engine AC traction in-phase power supply device based on YN,vd wiring transformer

A kind of railway locomotive AC traction co-phase power supply device based on YN, vd connection transformer, wherein the traction transformer is a three-phase-two-phase balance transformer (T) with YN, vd connection, the line voltage output end of the transformer (T) (T) A rectifier inverter (Z) is connected between b', c') and the phase voltage output terminals (a, x), and the line voltage output terminals (b', c') or the phase voltage output terminals (a, x) are used as The power supply terminals (V1, V2) of the traction locomotive; at the same time, the control device of the rectifier inverter (Z) is connected with the power supply terminals (V1, V2) of the traction locomotive. The device can realize the same-phase power supply for the entire railway line without the need for phase separation, and the power supply voltage of each traction substation section is stable, ensuring the high-speed and heavy-load operation of the locomotive; the power supply system of the railway traction load draws power from the three-phase power grid, eliminating the need for railway Influence of traction load on power quality of utility grid. In addition, the device can be transformed by using the existing traction transformer, with low cost and easy implementation.
Owner:SOUTHWEST JIAOTONG UNIV

Sine wave inverter with switchable output voltages

The invention relates to a sine wave inverter with switchable output voltages. The sine wave inverter comprises a push-pull boosting main circuit, a full bridge inversion main circuit, a fore-level drive protecting circuit and a back-level drive protecting circuit. A 24-volt storage battery is electrically connected with the push-pull boosting main circuit. The push-pull boosting main circuit is in signal connection with the fore-level drive protecting circuit, the back-level drive protecting circuit and the full bridge inversion main circuit. The full bridge inversion main circuit is in signal connection with the back-level drive protecting circuit. When the 24-volt storage battery is connected to the inverter, two kinds of different amplitudes of alternating voltages can be output, and immediate switching of the two kinds of output voltages can be achieved through a switch. The output alternating voltages are pure sine waves, the harmonic content is small, the interference on the load is small, and the overall conversion efficiency can reach to more than 90 percent.
Owner:HANGZHOU DIANZI UNIV

Control method and device of permanent magnet synchronous motor and related assembly

InactiveCN111342721AAvoid problems that affect the effectiveness of brake controlCurb riseElectronic commutation motor controlAC motor controlOvercurrentPermanent magnet synchronous motor
The invention discloses a control method of a permanent magnet synchronous motor, and the method comprises the following steps: acquiring an actual bus voltage, and acquiring an initial electrical angle adjustment amount according to the actual bus voltage when the actual bus voltage meets a control condition; calculating a current electrical angle adjustment gradient, and obtaining an actual electrical angle adjustment amount by using the current electrical angle adjustment gradient and the initial electrical angle adjustment amount; and controlling the motor to operate through the current loop controller according to the actual electrical angle adjustment amount and the actual angle so as to suppress the rise of the bus voltage. By means of the scheme of software control, bus voltage rise during motor braking can be effectively restrained, bus voltage stability is guaranteed; meanwhile, the problem that the braking control effect is affected when rotational inertia is too large can be avoided, it is guaranteed that rapid braking can be achieved under any condition, and the stability and robustness of the system are improved. The invention further discloses a control device, electronic equipment and a computer readable storage medium, which have the above beneficial effects.
Owner:ZHEJIANG ZOBOW MECHANICAL & ELECTRICAL TECH

Magnetically-controlled static var compensator

The invention discloses a magnetically-controlled static var compensator, which mainly solves the defects that in the prior art, the existing reactive compensation is stepped and low in accuracy, and cannot provide inductive reactive power or capacitive reactive power synchronously; the switching operation is frequent; the higher requirements of the electrical power system and users cannot be met. The magnetically-controlled static var compensator comprises a digital signal processor, a power supply, a capacitor bank or a filter bank, a keyboard, a liquid crystal displayer, a programmable logic controller, a reactive compensation unit, CSR (Controllable Shunt Reactors), and an AD (Analog-to-Digital) sampling circuit, wherein the output ends of the power supply, the capacitor bank or the filter bank and the keyboard are all connected with the digital signal processor; the input ends of the liquid crystal displayer, the programmable logic controller and the reactive compensator are all connected with the digital signal processor; the controllable shunt reactors are connected with the reactive compensation unit and the programmable logic controller; the input end of the AD sampling circuit is connected with the controllable shunt reactors, while the output end is connected with the digital signal processor. By virtue of the scheme, the magnetically-controlled static var compensator can reach the target of high cost performance and meet the actual demand, and is of high practical value and promotion value.
Owner:成都星宇融科电力电子股份有限公司

Multi-diode series connection type back-to-back bridgeless three-level rectifier

A multi-diode series connection type back-to-back bridgeless three-level rectifier comprises two bridge arms, namely a multi-diode rectifier bridge arm and a traditional rectifier bridge arm. Compared with the traditional rectifier bridge arm, the rectifier reduces the voltage stress borne by the MOS transistor through series connection of the multiple diodes. Meanwhile, an additional power branch is provided to be directly connected to the midpoint of the series capacitor. According to the rectifier, an extra power channel is provided, and meanwhile, a new diode structure is added, so that the stability and the reliability of a circuit are improved. Except the power input end back-to-back MOS transistor group, each MOS transistor is provided with an additional diode to share voltage stress, so that the switching loss is relatively small, the circuit heating is reduced, and the circuit efficiency is improved. Compared with a traditional two-level rectifier, the rectifier has the advantages that the number of levels of phase voltage on the alternating current side can be three, and the capacitance value can be remarkably reduced; the voltage stress of the device is reduced; the circuit size and cost are reduced; output voltage ripples are reduced; and the volume and the cost of the capacitor and the semiconductor device are reduced.
Owner:CHINA THREE GORGES UNIV

Direct-current microgrid power and voltage regulation method considering line impedance and local load

ActiveCN111327042AEliminate the effects of power distributionStabilize bus voltageDc source parallel operationMicrogridDistribution control
The invention relates to a direct-current microgrid power and voltage regulation method considering line impedance and a local load. The method is used for an island operation mode of the direct-current microgrid. A plurality of groups of DGs and different types of loads are contained in the direct-current microgrid. Theh DGs are connected in parallel to a common DC bus through the corresponding converter. According to the method, an improved droop control strategy is adopted, so that each DG distributes load power according to the rated capacity of the DG, the influence of line impedance andlocal load on power distribution is eliminated, and the voltage stability of the bus is maintained. Compared with the prior art, the island direct-current microgrid power distribution control and voltage recovery control strategy provided by the invention can effectively improve the load power distribution precision among multiple parallel distributed power supplies in the island direct-current microgrid, improves the efficiency of the distributed power supplies, and gives full play to the plug-and-play characteristic of the DG. And meanwhile, the DC bus voltage is maintained, so that the microgrid system can stably operate.
Owner:SHANGHAI UNIVERSITY OF ELECTRIC POWER

Hybrid microgrid system and power control method based on power electronic transformer

The invention provides an AC and DC mixed micro-grid system based on a power electronic transformer and a power control method of the system. The system comprises a main grid, an AC micro grid, a DC micro grid and the power electronic transformer. According to the operation states and power requirements of the AC micro grid and the DC micro grid, the power electronic transformer adjusts the power of the AC micro grid and the DC micro grid in a mixed sagging method. Thus, the power of the main grid, the AC micro grid and the DC micro grid can be rapidly and accurately adjusted, it is ensured that the frequency of the AC micro grid and the bus voltage of the DC micro grid are stable, and stable operation of the AC and DC mixed micro-grid after access of distributed energy is realized.
Owner:HUNAN UNIV

High voltage cascading four-quadrant frequency converter unit controller

InactiveCN105720797AStable jobNot susceptible to interference from strong magnetic fieldsAC motor controlPower conversion systemsFour quadrantsClosed loop
The invention discloses a high voltage cascading four-quadrant frequency converter unit controller which is less susceptible to the interference of a peripheral high-intensity magnetic field and relatively low in cost, and results in more stable voltage of a bus and unlikeliness in over-current fault. The high voltage cascading four-quadrant frequency converter unit controller comprises a sampling circuit, a DSP chip and a CPLD chip, wherein the DSP chip and the CPLD chip are powered by a single power supply; the sampling circuit is completed by a drive plate and then inputted to the DSP chip; the DSP chip is operated in a dual-closed-loop control initiative front-end AFE manner; and the CPLD chip is communicated with a main control box by virtue of an optical fiber, so that the state conversion of units, interaction with the state of an operation box, generation of an IGBT drive signal and the protection logic are realized.
Owner:SENYUAN DONGBIAO ELECTRIC CO LTD

Adjusting method for dynamic reactive compensation controller

The invention discloses an adjusting method for a dynamic reactive compensation controller. The adjusting method comprises the following steps: firstly, collecting the busbar current of a three-phase system, the busbar voltage of the three-phase system and the current of a three-phase thyristor controlled reactor in real time; then carrying out closed loop proportional-integral-differential (PID) adjustment on the current of the three-phase thyristor controlled reactor according to the compensated admittance of each parallel branch, and outputting the triggering angle of the thyristor controlled reactor; simultaneously, carrying out closed loop PID adjustment on the busbar voltage of the three-phase system, and outputting the triggering angle of the thyristor controlled reactor; and finally, according to whether each phase of voltage is in a specific range or not, judging whether to adopt the closed loop PID adjustment of the second step or the third step, and outputting the actual triggering angle of the thyristor controlled reactor. The method provided by the invention can increase the power factor, reduce the reactive power, decrease the line loss, improve the transmission capacity of the active power of a power transmission line, stabilize the busbar voltage, and inhibit the voltage fluctuation and flicker.
Owner:GUANGDONG MINGYANG LONGYUAN POWER ELECTRONICS
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