209 results about "Voltage control loop" patented technology

A system and a method provide a photovoltaic system which regenerates the output characteristics of the photovoltaic at different ambient condition with high precision under all environmental conditions. The photovoltaic system includes a photovoltaic array, a buck / boost converter, a DC link capacitor to connect the buck / booster converter to a load / inverter, an adaptive network-based fuzzy inference maximum power point tracking controller, a voltage control loop, a proportional integral controller to maintain the output voltage of the photovoltaic array to the reference voltage by adjusting the duty ratio of buck / boost converter.

A controller for controlling a reactive series compensator serially inserted at compensator terminals into a power transmission line for controlling the line current. The controller includes a current control loop and a voltage control loop. A current controller outputs a control voltage (cc.sub.out) indicating a desired compensator terminal output voltage (u.sub.c). A control method selector means generates, in a low output voltage region, a constant reference voltage (u.sub.DC.sup.ref) for the voltage control loop and a variable modulation index mq of a modulation signal m=m.sub.d cos (.omega.t) -m.sub.q sin (.omega.t). In a high output voltage range, the control method selector outputs a constant modulation index m.sub.q and a variable reference voltage (u.sub.DC.sup.ref). The voltage controller outputs the modulation index m.sub.d of the modulation signal m. Furthermore, the control method selector can include a rate limiter for limiting the change rate of the reference voltage (u.sub.DC.sup.ref). In connection with the control method selection and / or the rate limiter, a decoupling control for making the voltage and current control loops independent from each other can be used. The controllers find particular application in transformerless reactive series compensators for single-phase or three-phase control.

A buck switching regulator implements a fixed frequency feedback control circuit including a voltage control loop and a frequency control loop to regulate the switching frequency of the buck switching regulator to a fixed or nearly fixed frequency. The voltage control loop, implementing ripple mode control, is configured to control the power switches in response to the switching regulator output voltage or a signal related to the switching regulator output voltage. The frequency control loop, implementing a phase-locked loop control scheme, is configured to adjust the on-time of the high-side switch so as to regulate the switching frequency to be equal to or be proportional to the reference frequency.

In addition to an output voltage control loop, a dead-time optimization loop is provided for a digital synchronous switching converter to dynamically adjust the dead-time for the power switches of the converter. It is extracted a minimal feedback signal at a steady state while the output voltage remains under a specification, and a maximal efficiency of the digital synchronous switching converter is thus obtained.

The invention discloses a primary side single-phase bridge-subsidiary side three-phase bridge high frequency chain inverter, a digital control system of the primary side single-phase bridge-subsidiary side three-phase bridge high frequency chain inverter and a method for the primary side single-phase bridge-subsidiary side three-phase bridge high frequency chain inverter and belongs to the field of a power electronic converter and control of the power electronic converter. The primary side single-phase bridge-subsidiary side three-phase bridge high frequency chain inverter comprises input voltage Uin, a single-phase bridge type circuit, a high frequency isolation transformer, a three-phase bridge type circuit, an LC filter, a voltage sensor, a current sensor and a DSP digital controller. The single-phase bridge type circuit is composed of four electricity MOSFETs. A primary side of the high frequency isolation transformer is a single winding and a subsidiary side of the high frequency isolation transformer is a winding with a center tap. The three-phase bridge type circuit is composed of six electricity MOSFETs. The LC filter is composed of an inductor L and a capacitor C. TMS320F28335 is adopted by the DSP digital controller and the functions of the DSP digital controller comprises outputting a voltage control loop, an inductive current control loop, a signal conditioner and a drive signal selective switch. Two-stage power conversion is adopted, so that electrical insulation of an input side and an output side is achieved, size is small, weight is light, efficiency is high, energy flows in two directions, soft switching is achieved, heat emission of devices is dispersed, and the requirement for heat dissipation is low.

A method of detecting an interruption of grid electrical power at an output of an inverter power train coupled to an electrical grid includes generating a reference waveform representing a power train output current waveform with a current control loop. An out-of-phase control signal is generated, which is synchronized and out-of-phase with a grid voltage waveform, with a voltage control loop coupled to the output of the inverter power train, the voltage control loop having a gain proportional to an inverter power train load impedance. The reference waveform and the out-of-phase control signal are combined to generate a power train control signal for producing a small phase difference between the inverter power train output current waveform and the grid voltage waveform. The inverter power train output is monitored for a change and the inverter power train is turned off in response to a change in the inverter power train output caused by an increase in inverter power train load impedance resulting from an interruption in the grid electrical power.

The invention discloses a resonant converter device and a use method thereof. The resonant converter device comprises a plurality of resonant converters and a control module, wherein the plurality of resonant converters are connected in parallel; the control module outputs a pulse-width modulation control signal and comprises a voltage control loop and a current control loop; the voltage control loop compares sensed output voltage with a preset reference voltage, and outputs the pulse-width modulation control signal to one of the plurality of converters so as to enable the output voltage of the converter to be equal to the preset reference voltage; and the current control loop takes the sensed output current of the converter as a reference current, compares the reference current with sensed output currents of other converters in the plurality of converters except one converter, generates frequency adjusting variable and calculates respective pulse-width modulation control signals for each of the other converters so as to enable the output currents of all the converters to be equal. Therefore, the invention provides a current balance mechanism for the converter device.

This invention relates to an optimized pulse crossover modulation switch regulated supply controller composed of a voltage control loop, a current control loop and a primary control gate, in which, the voltage control loop is composed of a voltage comparator, a voltage primary source, an AND gate, a state register, a zero state judgment device, a counter and a decoder to realize the ordinary PSM modulation, the current control loop is composed of a resistor network, the voltage comparator and the voltage primary source to generate different current limit values by controlling the resistor network based on the voltage comparator signals of the local and the last clock periods to realize the conversion of three kinds of duty ratios, said primary control gate is composed of a vibrator, OR gate, a RS trigger, a NAND gate and an AND gate to generate the control signals for conducting or stopping power switch tubes.

The invention provides a back-to-back flexible direct current transmission system and a double-loop additional frequency control method. The back-to-back flexible direct current transmission system comprises a back-to-back converter body, a basic controller, an active additional controller and a reactive additional controller, wherein the basic controller is used for enabling DC-side voltage of the back-to-back converter body, the transmitted active power and reactive power absorbed or sent to a power grid to keep constant according to an instruction of a constant active power control loop, aninstruction of a constant reactive power control loop, an instruction of a constant DC voltage control loop and an instruction of a constant AC voltage control loop; the active additional controlleris used for performing proportional-integral control on a frequency deviation input signal to output an active power additional reference instruction value; and the reactive additional controller is used for performing differential control on the frequency deviation input signal to output a reactive power additional reference instruction value. According to the invention, frequency support for a disturbed alternating current system is realized through changing the active power instruction value and the reactive power instruction value.

A power converter provides current limit / current share functionality, allowing use in a point-of-load architecture and / or in parallel with one or more other power converters. An inner current control loop may sense output current over only a portion of a duty cycle, for example at a low side active switch. The resulting signal is compensated, and may be level shifted, for example via a resistor divider network, and supplied to a current control amplifier. An outer voltage control loop may sense output voltage, and provide a voltage error signal from a voltage error amplifier to the resistor divider network. Power converters are operable as masters or slaves, and include sense input and trim input terminals.

This invention relates to a mixed digital pulse modulator used in digital supply controllers composed of an adaptive offset voltage generation circuit, a 8-stage voltage-controlled loop oscillator and a digital control part, in which, the adaptive offset voltage generation circuit generates an offset voltage compensated by temperature technology to control the loop oscillator and a 16-phase clock C0-C15 not influenced by outside temperature or technical offset, and the digital control part generates a modulated pulse with the resolution of n-bit according to the clock staggered for 1 / 16 period orderly and n-bit duty ratio input from outside d[n-1 :0].

A power converter module is disclosed, which is an all-digital module. The power converter module includes a reference voltage generation unit, a voltage loop control unit, a current loop control unit, an input voltage compensation unit, and a pulse width modulation generation unit, to transfer input power to stable output power for providing power to an external loading device through driving bridge switch unit with external driver. The voltage loop control unit and the current loop control unit contain a proportion-integral-differentiation controller for receiving signal related to voltage and current of loading device to form voltage control loop and current control loop. The pulse width modulation generation unit contains function of deciding necessary stop time to improve quality of output power and decrease the effect of input power and loading variation, and to provide stable sine-waveform output power to the external loading device.

The invention relates to a control method and system based on a virtual synchronous generator. In the grid-connected pre-synchronization stage, phase-locked loop control is performed on grid voltage to obtain a grid voltage amplitude; the phase-locked loop control is conducted on the terminal voltage of a virtual synchronous generator, and the amplitude of the terminal voltage is obtained; the grid voltage amplitude is taken as a given value, the terminal voltage amplitude is taken as a feedback value, closed-loop control is conducted, the amplitude synchronization amount is obtained, and theamplitude synchronization amount is superimposed on a voltage control loop of an excitation controller. When the phase-locked loop control is performed on the grid voltage, the frequency adjustment amount is obtained, and the frequency adjustment amount is superimposed on a power frequency controller. The method adaptively compensates the deviation of bridge arm voltage phase and terminal voltagephase caused by an LC / LCL filter, thereby achieving the synchronization of the terminal voltage phase and the grid voltage phase and amplitude synchronization.

The invention discloses an active power filter (APF) control method based on fuzzy neural network PID. The method comprises the steps that a non-linear dynamic model of an APF inverter is established according to power electronics; a PIC controller of a current control loop is designed according to the established non-linear dynamic model; a fuzzy neural network compensating controller is designed and used for improving the dynamic response of the current control loop of the inverter; a PI controller of a voltage control loop of the inverter is designed, and a reference current value which needs to be tracked by the output current of the inverter is solved. According to the method, PID control and fuzzy neural network control are combined, the design process is simple, engineering realization is easy, and the response performance of the output current of the inverter is further improved.

A method of controlling a power converter having at least one switching device for supplying an output voltage and a load current to a load is disclosed. The method includes sensing the output voltage and sensing the load current. The method further includes controlling a duty cycle of the switching device according to the sensed output voltage and a voltage control loop when a rate of change of the load current does not exceed a threshold level. The method also includes adjusting the duty cycle of the switching device set by the voltage control loop when the rate of change of the load current exceeds the threshold level.

The invention provides a control apparatus and control method for maintaining stable voltage of a conflux DC bus in a distributed power generation system. In order to enable the current transformers of multiple power generation devices to realize parallel operation under the condition that there is no interconnection line communication, voltage instruction signals are obtained through calculation according to a preset sagging characteristic by actual output currents, current instruction signals are given according to actual conditions by an MPPT algorithm or a system, two control signals obtained through operation of a voltage control loop and a current control loop are sent to the minimum taking link of CPU control software, and the output of the link is used for PWM to ensure no overvoltage in case of a current control mode and ensure no overcurrent in case of a voltage control mode, such that smooth switching of multiple electric power converting devices between the current control mode and the voltage control mode is realized, and under the condition that there are no interconnection communication lines, multiple converters can realize stable parallel output according to power which can be obtained by themselves.

The invention provides a constant conduction time type boosting voltage stabilizer. The constant conduction time type boosting voltage stabilizer comprises an output circuit, a voltage feedback circuit, a voltage feedback compensation circuit, a ripple generation circuit, a signal addition and subtraction circuit, an output voltage control circuit, a self-adaptive conduction time trigger circuit, a self-adaptive conduction time production circuit, a frequency locking circuit and a driving output circuit. The voltage feedback circuit is used for sampling output voltage to obtain feedback voltage. The voltage feedback compensation circuit is used for sampling output voltage to obtain feedback compensation voltage; a ripple production circuit is used for sampling inductive current in the output circuit to generate ripple voltage; the signal addition and subtraction circuit is used for using the feedback voltage to add the ripple voltage and to subtract the feedback compensation voltage to obtain a feedback resultant signal; the output voltage control circuit obtains a trigger enabled signal on the basis of the feedback resultant signal; the self-adaptive conduction time trigger circuit obtains the conductive trigger signal on the basis of the trigger enabled signal; the self-adaptive conduction time generation circuit and the frequency locking circuit are used for obtaining a quasi-fixed conduction time on the basis of the conduction trigger signal; and the driving output circuit generates a driving signal according to the quasi-fixed conduction time in order to drive the output circuit. The constant conduction time type boosting voltage stabilizer solves problem that a load end needs to use a electrolytic capacitor of a large parasitic resistor.

A resonant power conversion apparatus and a controlling method of the resonant power conversion apparatus are provided. The resonant power conversion apparatus includes a switch-based resonant converter and a controller. The switch-based resonant converter is configured to supply power to a load. The controller is coupled to the switch-based resonant converter and the load and configured to control switching of the switch-based resonant converter to regulate power conversion of the switch-based resonant converter. The controller has a voltage control loop and a current control loop. The controller detects a driving state of the load and enables one of the voltage control loop and the current control loop according to the detection result to adjust a switching frequency of the switch-based resonant converter.

The invention discloses a method for controlling DC (Direct-Current)-side voltage ripple of a railway power regulator. According to the power balance principle for the DC side of the railway power regulator, a situation that a secondary ripple voltage exists at the DC side of the railway power regulator can be extrapolated, and the value of voltage ripple is related to the fluctuation of the power at an AC (Alternating Current) side; if the secondary ripple voltage is introduced into a voltage control loop at the DC side, a command signal of triple-frequency harmonics can be output, so that the railway power regulator outputs a current of triple-frequency harmonics, and the abnormal operation of a device can be caused. According to the method for controlling the DC-side voltage ripple provided by the invention, by virtue of the analysis on the power balance model of the railway power regulator, the value of the secondary voltage ripple at the DC side can be extrapolated, so that a reverse secondary voltage ripple component can be superposed on the voltage control loop, the influence is eliminated, and the normal stable operation of the device is realized.

A method and system for controlling a tuning voltage of a phase-locked loop circuit to an optimal value are disclosed. Minimum and maximum bias current values are defined for a bias current from the linear control loop circuit. The linear control loop circuit is coupled to the phase-locked loop circuit. The linear control loop circuit infinitely varies a current value for a current-controlled oscillator of the phase-locked loop circuit. The current value is based on a tuning current of the phase-locked loop circuit and the bias current. The bias current infinitely varies in value between the minimum bias current value and the maximum bias current value to direct the tuning voltage to an optimal value. The phase-locked loop circuit includes a phase detector, a filter, a voltage-to-current converter, a current adder, and the current-controlled oscillator coupled together in series. The linear control loop circuit is an analog, voltage control loop that has a voltage summer, another filter, and another voltage-to-current converter coupled together in series. A reference voltage and the tuning voltage are inputted into the voltage summer, and a bias current is outputted and injected from the other voltage-to-current converter into the tuning current. The other voltage-to-current converter has a sufficient gain to provide the bias current between the minimum bias current value and the maximum bias current value. The linear control loop circuit is designed with a time constant characteristic that is slower than another time constant characteristic of the phase-locked loop circuit.

In addition to an output voltage control loop, a dead-time optimization loop is provided for a digital synchronous switching converter to dynamically adjust the dead-time for the power switches of the converter. It is extracted a minimal feedback signal at a steady state while the output voltage remains under a specification, and a maximal efficiency of the digital synchronous switching converter is thus obtained.

The invention belongs to the technical field of power electronic device control, and relates to a power decoupling control method and system for a virtual synchronous generator based on voltage feedforward compensation. The method comprises the steps of firstly, acquiring output power Pvsg and Qvsg of the virtual synchronous generator; giving a reactive power reference value Qref, subtracting thereactive power Qvsg output by the virtual synchronous generator from the reactive power reference value Qref to obtain d-axis initial reference voltage V<d><ref'> through an inertia equation of a reactive power loop, setting the q-axis initial reference voltage V<q><ref'> to be 0 at the same time, then presetting voltage feedforward equivalent inductive reactance Xv, and generating feedforward voltage Xviod; and obtaining a voltage control loop reference instruction V<d><ref> according to the d-axis initial reference voltage V<d><ref'>, subtracting the feedforward voltage Xviod from the q-axisinitial reference voltage V<q><ref'> to obtain a voltage control loop reference instruction V<q><ref>, and finally generating an SVPWM control instruction through a voltage control loop and a currentcontrol loop according to the voltage control loop reference instruction. According to the invention, the coupling problem between active power output and reactive power output is significantly improved, and the capacity requirement of the inverter is reduced.

The invention relates to the field of distributed power generation, and aims at providing an impedance adaptive power decoupling control method considering the virtual synchronous machine power angleinfluence. The method comprises the steps that the fluctuating quantity Deltadelta of the power angle is estimated by using the output active power of a virtual synchronous machine, and then the virtual resistance value Rv and the virtual inductance value Xv of virtual impedance are calculated; and then the virtual impedance values Rv and Lv are added to an inverter voltage control loop, the obtained voltage given value EO* acts as the given signal of the internal loop voltage control loop, finally the output signal of internal loop control acts as the control signal of the inverter, and the internal loop is double closed loop control of voltage and current. The problem of power coupling caused by increasing of the power angle is considered, and the size of the virtual impedance value is autonomously changed when the output power angle fluctuates so as to realize power decoupling of the virtual synchronous machine. The influence of the power angle, i.e. the active power loop, on the reactive power control loop can be relieved, and the method has the stable, accurate and excellent control effect.

An LED driver circuit is disclosed that can drive a plurality of LED strings that are arranged in parallel, each LED string having a plurality of component LEDs that are series-connected. The LED strings can be the same type of LEDs in each string, or have different types of LEDs from one string to another. The LED driver includes a voltage control loop that dynamically regulates the output voltage across the parallel arrangement of LED strings. The output voltage is dynamically adjusted to accommodate the LED string with the largest operational voltage drop. This enables LED displays to constructed using different types of LEDs strings, but still supply the LED strings in a power efficient manner. Further, each LED string also includes its own individual current regulation loop so that the current, and therefore brightness, of each LED string can be individually adjusted.

The invention relates to a control method for improving power grid frequency stability of a flexible DC system converter. The method is implemented according to FLC control and virtual synchronous control of a DC frequency limiter, in FLC control link, active power adjustment increment Delta PFLC required by frequency support of an MMC is obtained by detecting AC power grid frequency changing quantity and additive frequency feedback control loop. The method is characterized in that a frequency reference and a phase reference of an MMC output voltage are obtained by a virtual synchronous control-based active power control loop, a voltage amplitude reference of the MMC output voltage is obtained by a reactive power or AC voltage control loop, and AC voltage closed-loop tracing control is achieved by a voltage-current dual-loop control strategy after the phase reference and the amplitude reference of the output voltage are obtained.

The invention discloses a storage battery charging control method based on MPPT (Maximum Power Point Tracking) control. The storage battery charging control method comprises the steps that a central control unit is used for judging the charging state of a storage battery by acquiring the voltage of the storage battery; the central control unit is used for selecting one of a MPPT control loop, an electric current control loop and a voltage control loop in a charge controller to calculate so as to obtain a charging control result at different charging states; the central control unit is used for transmitting PWM (Pulse-Width Modulation) signals with corresponding duty ratios at different charging states according to the charging control result of the charge controller, and the charging currents or the charging voltages at different charging stages are adjusted through a DC-DC (direct current-direct current) converter so as to realize the charging of the storage battery. The storage battery charging control method has the advantages that the charging intelligence is realized, the prolonging of the service life of the storage battery is facilitated, the central control unit is provided with various peripherals and has rapid data processing capacity, and peripheral devices of hardware are greatly reduced, and thus the structure of a charging control circuit is simplified, and the lowering of the control difficulty and the realization cost is facilitated.

The invention discloses a combined control method for obtaining optimal efficiency of an electric automobile wireless charging system. The method comprises the following steps of adjusting the phase shift angle of a secondary side rectifier by using a charging voltage control loop and a charging current control loop so as to control the charging voltage and the charging current of a battery; adjusting the power angle of the secondary side rectifier by using a secondary side ZVS phase angle control loop so as to control the ZVS phase angle of the secondary side rectifier; adjusting the phase shift angle of a primary side inverter by using a primary side ZVS phase angle control loop so as to control the ZVS phase angle of the primary side inverter; and determining the current working condition of the system, and adjusting the ZVS phase angle of the primary side inverter and the ZVS phase angle of the secondary side rectifier through the perturbation and observation method so as to automatically search for a working point of optimal charging efficiency. According to the method, ZVS of the inverter and ZVS of the rectifier are realized on the premise of keeping stable charging voltageand charging current, and the method is capable of automatically searching for the working point of optimal transmission efficiency according to the current working condition.

The invention discloses an MMC frequency coupling impedance modeling method under model prediction AC voltage control. An MMC under AC voltage control is predicted by using a model to serve as a modeling object; through circuit equation frequency domain small signal modeling and model prediction AC voltage control loop frequency domain small signal modeling, an MMC small signal impedance model isobtained through derivation, and the model is composed of MMC positive sequence impedance, MMC negative sequence impedance and positive sequence impedance and negative sequence impedance frequency coupling terms caused by MMC internal complex harmonic dynamic characteristics. The accuracy of the small signal impedance model established by the method is verified by simulation, and the method and the basis can be provided for MMC small signal impedance modeling and stability analysis based on an MMC system.

An LED driver for at least one light emitting diode including an input for receiving an input voltage, an output comprising at least one light emitting diode, a current limiting loop for regulating an output current supplied to the at least one light emitting diode, a voltage control loop for monitoring a feedback voltage from the at least one light emitting diode, and a junction including a first diode for closing the current limiting loop and a second diode for closing the voltage control loop, wherein the junction enables the voltage control loop to communicate with the current limiting loop such that the feedback voltage is taken into account by the current limiting loop in regulating the out current.

The invention discloses a method and a device for restraining power-frequency ripple current. The device comprises an energy power supply, a bidirectional DC / DC (direct current / direct current) converter, a filter capacitor C3, an energy buffer capacitor C4 and a low-pass filter circuit, for sampling voltage, of the energy buffer capacitor, an energy power supply current detecting unit and a low-pass filter circuit of the detecting unit, a voltage reference Vref of C4, a current ripple restraining error amplifier EA1, a voltage control loop error amplifier EA2 of C4, a summing circuit of EA1 and EA2, and loads. By the device, restraining of energy power supply power-frequency ripple current is achieved under single-point current sampling, the defect that power-frequency ripples cannot be filtered effectively when large-capacity capacitors are used is overcome, and system cost is lowered while sampling lose is reduced and system efficiency is increased.