48results about How to "Reduce switch stress" patented technology

The present invention provides an electrical isolation apparatus having independently controllable contactors. The isolation apparatus includes a contactor for each phase or pole of an electrical device as well as each phase or pole of a load. Each contactor is constructed so that each includes multiple contact assemblies that may be independently controlled to open and close. Moreover, the contactors within a single contactor assembly or housing can be independently controlled so that the contacts of one contactor can be opened without opening the contacts of the other contactors in the contactor assembly. Additionally, the contactors are constructed and controlled such that a single line side contactor and a single load contactor open simultaneously when an open circuit condition is desired.

The invention discloses a system and a method for modularizing a battery pack balancer based on multi-winding transformers. Through anti-parallel connection of secondary sides of an odd number and an even number of the multi-winding transformers, balancing in modules and between the odd / even number of modules is realized based on forward conversion; the balancing between the odd number and the even number of the modules and the automatic demagnetization of the multi-winding transformers are realized based on flyback conversion; during control, direct, automatic and synchronous balancing from any battery monomer to any battery monomer in a battery pack can be realized just by a pair of control signals which are complementary in states, so that the balancing efficiency and the balancing speed are greatly increased, and the inconsistency between battery monomers can be effectively improved. The system and the method, disclosed by the invention, have the advantages that the balancing efficiency is high, the balancing speed is fast, the volume is small, the cost is low, the reliability is high, modularization is easy, the control is simple, a voltage detection circuit and a demagnetization circuit are not required, and the like.

A method of and apparatus for protecting a MEMS switch is provided. The method and apparatus improve the integrity of MEMS switches by reducing their vulnerability to current flow through them during switching of the MEMS switch between on and off or vice versa. The protection circuit provides for a parallel path, known as a shunt, around the MEMS component. However, components within the shunt circuit can themselves be removed from the shunt when they are not required. This improves the electrical performance of the shunt when the switch is supposed to be in an off state.

The present invention discloses a double closed-loop control of a VIENNA rectifier with neutral point potential balance control. A VIENNA rectifier is high in power factor, low in input current THD, few in switching devices and low in switching stress and has no switching dead zone, is high in reliability, and is especially suitable for medium and high power occasions of energy one-way flow. The double closed-loop control of a VIENNA rectifier with neutral point potential balance control can realize neutral point voltage balance control at a direct current side through regulation of a direct current offset, and a three-level SVPWM algorithm based on a two-level space vector plane is provided by the invention, so that neutral point voltage balance control is realized while a rectifier system has a good input performance and a direct current voltage stabilization performance.

The invention discloses a same-phase power supply system based on a single-phase full-bridge diode clamping multilevel back-to-back converter. A secondary winding of an alpha-phase step-down transformer (2) is parallelly connected with an input end of a diode clamping multilevel rectifier through a connecting reactor (5), an output end of the diode clamping multilevel rectifier is parallelly connected with a second winding of a beta-phase step-down transformer (3) through a connecting reactor (5), and parallel output is connected in a traction network to power a load; a signal controller (7) mainly collects load current I load, phase signals of alpha-phase voltage and beta-phase voltage and voltage Vdc of a direct-current side capacitor, and current I alpha and I beta is controlled to be equal through a control circuit, so that balance of three-phase current on a network side is guaranteed. When the same-phase power supply system is applied in high-voltage high-power places, switch stress borne by devices can be lowered, switch loss of the devices is reduced, du / dt, di / dt and output waveform harmonic content during circuit running are lowered, capacity, grade and efficiency of the circuit are improved, and functions of the circuit are enabled to be more advantageous; the whole system is enabled to be small in loss and long in service life, so that maintenance frequency is lowered greatly.

The invention discloses a PWM plus double phase shift control method for a bidirectional DC / DC converter, comprising: collecting the port voltage of the bidirectional DC / DC in real time, and calculating the duty ratio of the control signal when the leakage inductance voltage is re-matched ; Obtain the external phase angle j output by the closed-loop controller of the circuit; calculate the internal phase angle acting on the second bridge arm of the improved H bridge when the circuit power circulation is completely eliminated according to the obtained duty cycle and the external phase angle j 0 ; The three parameters of external phase angle, duty cycle and internal phase angle are used to generate the control signal of the circuit. The beneficial effects of the present invention are: the present invention is applicable to a bidirectional DC / DC topology structure in which one side of the converter is an improved H-bridge, and the other side is a buck, boost or its derivative circuit, which can reduce the current stress of the circuit switching device , expand the soft switching range of the circuit, and can completely eliminate the circulating power in the circuit when the circuit works in different working conditions such as light load or heavy load, and improve the working efficiency of the circuit.

The invention discloses a satisfaction optimization prediction fault-tolerant control method for a double-three-level inverter. A stator winding of the motor is opened; two ends of the stator windingare powered by two same inverters; the two inverters share the same set of direct-current bus to form a common-bus double-three-level topology; when an open-circuit fault occurs in a certain switchingdevice, the maximum output voltage of the inverter is reduced to half of the original output voltage; the voltage jump range is controlled to be set within Vdc / 2 through the inverter; a reference voltage vector is synthesized by using the available switching state of the inner hexagon of the common-bus double-three-level topology; the current following performance is taken as a main control target of the double-inverter system and a three-phase current satisfaction error function is established for optimizing the reference voltage vector; and the neutral point potential balance is taken as afinal control target, a neutral point potential satisfaction judgment function is established, and further the reference voltage vector is optimized through a comprehensive satisfaction error function.

The invention discloses an active clamp non-electrolytic capacitor LED driving power supply, comprising an AC input power supply, an input filter part, a rectifier part, a clamp circuit, a flyback converter, an output filter capacitor Co, a parallel absorption circuit and an LED load; The input filter part is composed of input filter inductor and input filter capacitor; the rectifier part is composed of four switch tubes; the clamping circuit is composed of switch tubes S 2 and the clamping capacitor C aux The flyback converter consists of a flyback transformer, a switch tube S 1 and diode D s Composition; the flyback transformer includes the primary winding and the secondary winding, and the primary winding includes the main inductance L m and leakage inductance L r , the primary winding is connected to the input, and the secondary winding is connected to the output; the parallel absorption loop includes the boost inductor L b , switch tube S 3 , switch tube S 4 and storage capacitor C ds . The present invention introduces an active clamp circuit to reduce the switch tube S 1 switch stress; switch tube S 1 and switch tube S 2 Both realize soft switching, reducing switching loss; at the same time, leakage inductance energy can be fed back.

The invention discloses a non-transformer isolated DC-DC converter with a large step-down ratio. The positive pole of the input power supply is connected to the positive pole of the first capacitor and one end of the first switch tube, and the other end of the first switch tube is connected to the first switch tube. One end of the second switch tube is connected to the positive pole of the third capacitor, the negative pole of the third capacitor is connected to one end of the first inductor and one end of the fourth switch tube, the other end of the first inductor is connected to one end of the load resistor and the second inductor One end of the first capacitor is connected, the negative pole of the first capacitor is connected with the positive pole of the second capacitor, the other end of the second switch tube, the other end of the second inductor and one end of the fifth switch tube, the negative pole of the second capacitor, the input power supply Both the negative pole and one end of the third switching tube are grounded, and the other end of the third switching tube is connected to the other end of the fifth switching tube, the other end of the fourth switching tube and the other end of the load resistor, and the converter has low loss. At the same time, it has the characteristics of high efficiency, small size, light weight, and large voltage change ratio.

The invention relates to a Z source inverter double loop grid-connected control method based on repetitive proportional resonant control. The method is used for an LC type Z source inverter grid-connected system. The method comprises the steps of 1, obtaining circuit reference values at an alpha and beta axis according to acquired capacitor and voltage in a Z source inverter; 2, obtaining circuit feedback values at the alpha and beta axis according to acquired grid side inductive current; 3, adding difference values of the circuit reference values and the circuit values after the circuit reference values and the circuit values pass through a repetitive controller and a proportional resonant controller respectively to obtain circuit values of repetitive proportional resonant control, and inputting the obtained circuit values into an SPWM module. Compared with the prior art, waveform quality of grid-connected circuit and voltage under the LC type filter is improved, harmonic distortion rate is reduced, pressure raising effect is drastically improved, system structure is simplified, and use of related materials is saved.

The invention discloses a control circuit for a three-phase high power factor rectifier, and belongs to the field of electrical control. The control circuit comprises an input high-frequency filter circuit, a three-phase input inductor, a three-phase rectifier circuit, a switch tube power circuit, an output rectifier filter circuit, a voltage-dividing detection circuit, an input current detection unit, a single cycle controller and a switch tube driving circuit. A three-phase high power factor can be rectified, high-precision stable output voltage can be obtained, and interference resistance is high.

The invention discloses a direct current charger based on a single-phase II type three-level pseudo totem pole. The direct current charger comprises a pseudo totem pole bridge arm, a filter circuit and a single-phase II type rectifier bridge; the pseudo totem pole bridge arm comprises switch tubes S1 and S2 and diodes D3 and D4; the filter circuit comprises filter inductors L1 and L2; the single-phase II-type rectifier bridge comprises diodes D1 and D2, a pair of bidirectional switching tubes, capacitors C1 and C2 and a load RL; and the pair of bidirectional switch tubes comprises switch tubes S3-S6. According to the direct current charger based on the single-phase II type three-level pseudo totem pole, the pseudo totem pole rectification technology and the three-level topology technology are fused, and compared with a traditional boost power factor correction type two-level direct current charger, the stress of a switch tube can be effectively reduced, the conduction loss of the switch tube is small, and the bridge arm direct connection phenomenon does not exist; meanwhile, due to the fact that an II-type two-switch-tube series-connection type bidirectional switch branch exists in the circuit, the reliability of the direct-current charging circuit is greatly improved.

The invention discloses a distribution transformer integrated cascaded static compensator, which includes a distribution transformer, a cascaded static compensation module, an output filter and a control platform, and is set at the center of each phase winding on the high voltage side of the distribution transformer The connection tap is used as the injection point of the compensation current, and the connection tap is connected to the AC output terminal of the cascaded static compensation module through the output filter, and the control input terminal of the cascaded static compensation module is connected to the control platform, and the control platform is used to collect distribution transformers Based on the voltage and current information at the high and low voltage sides and the connection taps, the tracking command current signal is generated based on the information, and the output of the cascaded static compensation module is controlled by the tracking command current signal to achieve compensation. The invention integrates the cascaded multi-level structure and the distribution transformer, increases the capacity of the static compensator of the distribution network, and improves the power quality of the distribution network.

A single-phase three-switch tube pseudo-totem-pole three-level rectifier comprises a single-phase pseudo-totem-pole structure, a filter, and a single-phase rectifier bridge with two-way switch tubes. Among them: the single-phase pseudo-totem pole structure consists of two fully-controlled power switch tubes and two ordinary diodes to form two asymmetric bridge arms; A group of bidirectional switch tubes, 2 identical capacitors and a load, the bidirectional switch tube structure is composed of 4 diodes and 1 fully controlled switch tube to realize the bidirectional flow of current. The single-phase three-switch tube pseudo-totem-pole three-level rectifier combines traditional totem-pole rectification technology and three-level topology technology. Compared with the traditional boost power factor correction rectifier, it can effectively reduce the stress of the switch tube. The conduction loss is small, and there is no bridge arm through phenomenon.