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

The invention discloses a mixed micro-grid system of a large-scale energy recycling power battery pack test device. The mixed micro-grid system comprises a tested power battery pack and an alternating-current grid, and further comprises a test unit, a direct-current voltage-variable unit, an alternating-current voltage-variable unit, a direct-current bus and an energy storage unit. The test unit is connected between the power battery pack and the direct-current bus and comprises a bidirectional DC/DC conversion assembly which is used for enabling the voltage in the power battery pack to be matched with the voltage in the direct-current bus. The mixed micro-grid system has the advantages that a power battery pack test grid-connected alternating-current micro-grid power generation system generally adopted in current power battery pack manufacturers is changed through the mentioned components of the system; the design of a test device converter is facilitated, in other words, the test device converter is mainly composed of a one-stage converter instead of a two-stage converter and a filter in the prior art; meanwhile, the energy storage battery pack and a super-capacitor set are arranged, and therefore stability of the voltage of the direct-current bus of the high and low voltage side in a direct-current micro-grid is ensured, and energy supplementing and supporting are achieved.

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 provides a novel zero-sequence current compensator. An inverter bridge is connected between a neutral point and a neutral line of a zigzag transformer; and a current output by the inverter bridge is injected into a system through a low-impedance zero-sequence current channel which is provided by the zigzag transformer so as to compensate for a neutral current. A controllable rectifier module is connected with the secondary side of the zigzag transformer to supply a direct-current power supply to the inverter bridge, and thus, the two-way flow of energy is realized and the problem of direct-current voltage rise caused when the compensator absorbs active power is solved. The novel zero-sequence current compensator has a series of advantages of good compensation effect, low direct-current voltage, small switching stress, few influences of system parameters, flexible control, few influences on system operation and the like.

In the DC/DC converter, a switching part has first and second switches serially connected from a power supply to a ground. The first and second switches switch on/off in response to first and second switching signals having a fixed frequency. The first switching signal has a phase level that does not overlap a corresponding phase level of the second switching signal. A transformer transforms a voltage applied to a first winding into a second winding in response to switching operation of the switching part, and resonates by an inductor and a capacitor of the first winding. Also, a rectifier includes a rectifying diode for rectifying the voltage from the transformer into a direct voltage. A feedback circuit detects the voltage outputted via the rectifier. Additionally, a controller controls pulse width of the first and second switching signals in a PWM mode according to the voltage detected by the feedback circuit.

The invention relates to a high-frequency high-transformation-ratio bidirectional DC/DC converter based on coupled inductors, belongs to the technical field of power electronics and solves the problems that an existing non-isolated bidirectional DC/DC converter is high in switching stress and low in system efficiency. The DC/DC converter comprises a first filter unit, a boost-buck unit and a second filter unit. The first filter unit and the second filter unit are used for input filtering and output filtering of the boost-buck unit. The boost-buck unit comprises a coupled inductor L1, a coupledinductor L2, a resonant capacitor Cr, a switching tube S1, a switching tube S2 and a switching tube S3, and the switching tube S1, the switching tube S2 and the switching tube S3 are respectively provided with a body diode. The coupled inductor L1, the coupled inductor L2, the switching tube S1 and the switching tube S3 form a coupled inductor type boost circuit. The resonant capacitor Cr and leakage inductances of the two coupled inductors form an LC series resonant unit, and the LC series resonant unit, the switching tube S2 and the switching tube S3 form a half-bridge converter topology structure.

The invention discloses a deadbeat current control method for adding a zero vector for a grid-connected inverter. A single-phase photovoltaic grid-connecting inversion system is composed of a photovoltaic array, a voltage-type invertible PWM (pulse-width modulation) rectifier, a maximum power point tracking unit (MPPT) and an invertible variable flow control system based on a DSP (digital signal processor. The deadbeat current tracking control method for adding zero vector modulation is used for inhibiting the current change rate in the PWM control and reducing a power tube switch stress so that a network-side current can track an order current within a switch period so as to achieve an electric energy high-quality control function; the method comprises the following steps: tracking the current within a PWM control period; controlling the on-off of the V1-V4 power tube switches shown in a figure; and limiting the change rate of the current, therefore, the actual current can catch up with the order current within the PWM period so as to achieve the deadbeat current tracking control.

The invention discloses a method for logically controlling combined chopped waves of power switch devices of a switched reluctance motor. A combined chopped wave logical control circuit adopted in the method comprises a signal feedback circuit, a logical processing chip and a power drive circuit, wherein the logical processing chip and the power drive circuit are connected in sequence. A power switch tube set in the power drive circuit is of an asymmetric bridge type topological circuit structure. Each phase is of a structure of an upper bridge arm and a lower bridge arm, wherein the structure is composed of two power switch tubes, two diodes and a motor winding in series connection. When the current of the switched reluctance motor is increased, the power switch tubes of the upper bridge arm and the lower bridge arm are switched on simultaneously; when the current is reduced, one power switch tube is switched off and the other power switch tube is switched on. According to the method for logically controlling the combined chopped waves of the power switch devices of the switched reluctance motor, consumption of a switch is evenly distributed to the two switch devices on one phase, the use frequency of the switch devices is balanced, so that the problem that the power switch devices emit heat unevenly is solved, the switching stress of the power switch devices is reduced, and the service life of the power switch tubes is prolonged.

The invention provides a self-balancing non-isolated modular multilevel DC-DC converter, which comprises a power main circuit and a power balance circuit which are connected to each other, wherein thepower balance circuit comprises a plurality of air core inductors and a diode; the air core inductors are sequentially connected with the diode in series; the power main circuit is formed by sequentially connecting an input filter inductor, an output buffer inductor and a plurality of submodules through a series chain in series; and when the submodules are in a removal state, a bus capacitor of one submodule and the bus capacitor of the adjacent submodule carry out energy transfer through the power balance circuit. AC running through a bridge arm of the converter is avoided, the switching loss is reduced and the DC side filter inductance is reduced.

The invention discloses an active clamping, boosting and isolating series miniature converter control method and a device. The device comprises an acquisition circuit used to acquire an input direct voltage and current signal and an output direct voltage signal, a controller used to track the maximum power of the input direct voltage and current signal and form a switching drive signal, a drive circuit used to control on-off of a main switch and an auxiliary switch of an active clamping and boosting circuit according to the switching drive signal, the active clamping and boosting circuit used to actively clamp and boost the high side of the input direct voltage signal, and an isolation circuit used to isolate the direct voltage signal after high-side active clamping and boosting and output a boosted high-frequency direct voltage. By adopting the active clamping, boosting and isolating series miniature converter control method and the device of the invention, on the premise of ensuring the safety performance of voltage conversion, the number of the switches is reduced, the stress of the switches is lowered, the size of the device is reduced, and the cost is lowered.

The invention relates to the technical field of power electronics, in particular to a bidirectional DC-DC converter and a control method thereof. For the problems that a constant speed area and a constant power area need to be frequently switched because the running conditions of a permanent magnet motor driving system are generally large in random fluctuation and are relatively complicated, and the torque output capacity and the high-speed power output capacity of a driving motor are poor due to the influence of output fluctuation of a storage battery of an electric automobile, the interleaved bidirectional DC-DC converter and the control method thereof are provided. The dynamic direct current bus voltage regulation is realized, and the direct current bus voltage gain is improved, so thatthe turning speed of the motor is increased, and the overload capacity of the motor is indirectly improved; a constant torque area is expanded to improve the torque output capacity of the motor; andmeanwhile, a weak magnetic area is delayed to be accessed, so that the loss of the driving system is reduced, and the temperature rise of the system is reduced.

A single-phase three-switch-tube pseudo totem pole type three-level rectifier comprises a single-phase pseudo totem pole structure, a filter and a single-phase rectifier bridge with a bidirectional switch tubes. According to the single-phase pseudo totem pole structure, two asymmetric bridge arms are formed by two full-control power switch tubes and two common diodes; the single-phase rectification branch with the bidirectional switch tubes is composed of a bridge arm composed of two diodes, a group of bidirectional switch tubes, two identical capacitors and a load; and the bidirectional switch tube structure is composed of four diodes and a full-control switch tube, and bidirectional flow of current is achieved. The single-phase three-switch-tube pseudo totem pole type three-level rectifier integrates a traditional totem pole rectification technology and a three-level topology technology, and compared with a traditional boost power factor correction rectifier, the single-phase three-switch-tube pseudo totem pole type three-level rectifier can effectively reduce stress of the switch tubes, conduction loss of the switch tubes is small, and meanwhile the bridge arm direct connection phenomenon does not exist.

The invention provides a five-level single phase photovoltaic gird-connected inverter, which comprises an alternating current access port, an electric reactor, a power switch circuit, a first photovoltaic battery module and a second photovoltaic battery module, wherein the alternating current access port is provided with an end a and an end b, the power switch circuit comprises eight power switches, the first photovoltaic battery module and the second photovoltaic battery module are respectively provided with a positive end and a negative end, one end of the electric reactor is connected with the end a of the alternating current port, and the other end of the electric reactor and the end b of the alternating current port are respectively and electrically connected with the power switch circuit. The five-level single phase photovoltaic gird-connected inverter has the advantages that the power switches are few, the structure is simple, the dependence of the inverter on a controller is reduced, the stability of the whole system can be improved, in the practical application, the switching stress of each switch is smaller, the self energy consumption of the inverter can be reduced, the size of a heat radiator is effectively reduced, and the overall benefits of the inverter are increased.