78results about How to "Achieve zero voltage turn-on" patented technology

The invention discloses a super-wide output voltage range charger based on LLC topology and a control method. The super-wide output voltage range charger comprises an LLC resonant converter and a control circuit. The LLC resonant converter comprises a switch network composed of an MOSFET full-bridge conversion circuit, the input end of the switch network is connected with the input end of a power source, the output end of the switch network is connected with the input end of a resonant network, the output end of the resonant network is connected with a leakage inductor of a transformer, and a secondary side coil of the transformer is connected with a rectifying and filtering network; the control circuit comprises a control unit, the control unit controls MOS tubes of the MOSFET full-bridge conversion circuit to be connected or disconnected according to received signals at the input end and the output end of the LLC resonant converter, and therefore the LLC resonant converter can achieve no-voltage connection of a primary side switch tube and no-current disconnection of a secondary side rectifying diode within a full voltage range. The super-wide output voltage range charger is wide in output voltage, free of limitation of the input voltage range of a charged object and capable of charging various new energy electric vehicles.

The invention provides a soft switching conversion device based on a flyback converter. On the basis of the conventional Flyback converter power topology, a clamp branch consisting of a controllable power clamper tube and a clamp capacitor is connected to a drain end of a main power tube in series; a primary side chip of the conversion device receives information such as the peak excitation current, the valley bottom excitation current and the maximum voltage of switching nodes of a converter power loop and generates ideal drive dead time varying with an input voltage and a load condition to control the main power tube and the clamper tube, so that the voltage oscillation of the drain end of the power tube caused by leakage inductance can be completely eliminated. Owing to the basically loss-free soft switching technology of the MOS tube active clamp, the stable clamp voltage value and the primary-side and auxiliary-side full working conditions, the device can work at a high frequency(> 1MHz) and can greatly increase the power density of a power adapter when being applied to the adapter.

The invention discloses a soft switching high-efficiency wireless charging method based on bilateral phase shifting and frequency adjusting. The DC side of a sending end converter and the DC side of areceiving end converter of a wireless charging system are each connected with a soft switching auxiliary branch circuit, by reasonably controlling the on and off of an auxiliary switching tube and resonating the voltage of a bridge arm into zero before the switching tube is switched on, the zero-voltage on of all sending end switching devices and receiving end switching devices is realized. Meanwhile, according to the soft switching bilateral phase shifting control system, by means of the frequency adjusting method, the switching frequency is the same as the resonating frequency all the time,the loss problem caused by the idle work under detuning can be avoided, and efficiency is further improved. The method is simple in structure and convenient to implement, the soft switching work of the power converters of the wireless charging system is ensured, the partial efficiency of the converters is improved, and the low-reactive loss of original side coils and auxiliary side coils is realized through the frequency adjusting and phase shifting control mode.

The invention discloses a non-isolated soft switching DC-DC converter with low input current ripple and high output voltage gain, which is composed of a high-gain boosted circuit and a soft switchingauxiliary circuit, wherein the high-gain boosted circuit comprises a first boosted circuit and a second boosted circuit, the first boosted circuit and the second boosted circuit are each composed of amain inductor, a capacitor, a diode and a main switching tube, the input ends of the first boosted circuit and the second boosted circuit are connected in parallel by adopting a two-phase staggered structure, the output ends of the first boosted circuit and the second boosted circuit are connected in series in a two-phase mode through a switched capacitor structure, the soft switching auxiliary circuit is composed of an auxiliary inductor and an auxiliary switching tube, the soft switching auxiliary circuit is connected with one phase in parallel, and zero-voltage conduction of the main switching tubes of the two boosted circuits is achieved; and the inductors of the first boosted circuit and the second boosted circuit and the auxiliary inductor are integrated in one magnetic core.

The present invention provides a zero-voltage switching synchronous rectification Boost circuit, a zero-voltage switching Boost circuit and a control method thereof. An auxiliary resonance circuit isconnected in series with a rectifying circuit of a main power circuit, when a main power switch tube is switched off, the current of a Boost inductor is employed to achieve zero-voltage conduction ofan auxiliary switch tube, resonances of a resonance capacitor and a resonance inductor are employed to achieve rapid increasing of the current of the resonance inductor and prompt the current of the resonance inductor to be larger than the current of the Boost inductor, a diode connected in parallel with the resonance capacitor is employed to perform follow current of the current of the resonanceinductor to ensure that the voltage of the resonance capacitor cannot be inversed and the current of the resonance inductor cannot be rapidly reduced after reaching the maximum value. After the auxiliary switch tube is switched off, the difference of the resonance current and the Boost inductor current is employed to achieve zero-voltage opening of the main switch tube.

The invention discloses a resonance boost DC / DC converter and a control method thereof suitable for high-voltage and high-power occasions. The converter is connected with a direct-current input power source and a load and comprises two primary-side diodes, a first switching tube, a second switching tube, a third switching tube, a fourth switching tube, a resonance unit, a first rectifier diode, a second rectifier diode and two filter capacitors. The resonance boost DC / DC converter is characterized in that the resonance unit is connected with a bridge arm composed of the four switching tubes and a rectifier unit composed of the two rectifier diodes and the two filter capacitors. According to the resonance boost DC / DC converter and the control method thereof, approximate zero voltage switching-off of the switching tubes and zero current switching-off of the rectifier diodes can be achieved, losses can be greatly reduced, and meanwhile the voltage stress of all switching devices is not larger than one second of the output voltage. A resonance circuit can be used for the high-power boost occasions.

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 tri-level double-end active bridge DC (Direct Current) conversion device and a control method. According to the tri-level double-end active bridge DC conversion device and the control method disclosed by the invention, a low-voltage rating switch tube can be adopted for realizing high-voltage high-power input and output, two-way real-time conversion of occasion demands can be realized by high-frequency electrical isolation energy, and the dynamic property is high, thereby being beneficial for reducing cost and improving power density and reliability; voltage sharing of a flying capacitor, a series switch device and a voltage-dividing capacitor under the working condition of the whole load and voltage variation range can be realized, thereby ensuring the safety of the device; and inner and outer pipes are decoupled, so as to realize zero-voltage-switching of the switch tube more easily, lower the switch loss of the device greatly and improve the efficiency and the electromagnetic compatibility.

The invention discloses a control method of a power conversion circuit and an apparatus thereof. By using the method and the apparatus of the invention, zero voltage opening of a high frequency bridge arm switch tube can be realized, circuit losses are reduced and circuit efficiency is increased. The control method comprises the following steps of for each input inductor in the power conversion circuit, detecting a current of the input inductor; when a current zero crossing point of the input inductor is detected, making a main switch tube on a high frequency bridge arm connected to the input inductor be in a conduction state for a first time length and making a follow-current switch tube on the high frequency bridge arm connected to the input inductor be in a disconnected state; and after the main switch tube is controlled to be in the conduction state for the first time length, making the main switch tube be in a disconnected state and making the follow-current switch tube be in a conduction state for a second time length.

The invention discloses a topological conversion type multi-resonance element resonance soft switch direct current converter. The topological conversion type multi-resonance element resonant soft switch direct current converter consists of a bridge type inversion circuit, a topological conversion type multi-element resonance circuit and a diode rectifying circuit which are connected in sequence; the converter is input from the bridge type inversion circuit, passes through the topological conversion type multi-element resonance circuit and then is output from the diode rectifying circuit; the bridge type inversion circuit can realize switching of half bridge and full bridge according to the switching of a switching tube; the topological conversion type multi-element resonance circuit comprises two transformers, so that the power transmission performance of the converter can be expanded effectively; by virtue of the topological conversion type multi-element resonance circuit, switching of an LCLCL resonance circuit and a CLTCL resonance circuit can be realized through an auxiliary switch; meanwhile, zero-voltage switch-on of the switching tube and zero-current switch-off (ZCS) of a back-stage rectifying circuit diode can be realized, ring current can be reduced, and efficiency and capacity of the converter can be improved; and the direct current converter has the advantages of wide range adjustment of the input and output voltages and overcurrent protection.

The invention provides a high-gain Boost converter based on a three-winding coupled inductor and a working method of the high-gain Boost converter. The high-gain Boost converter comprises a Boost unit, an auxiliary Boost unit, a voltage doubling unit and a low ripple unit; the Boost unit comprises a primary winding, a first switching tube, a second switching tube and a fourth capacitor and a fifthcapacitor which are connected in series; the positive electrode of a power supply is connected with the non-dotted terminal of the first winding; the dotted terminal of the primary winding is connected with the drain electrode of the first switching tube and the source electrode of the second switching tube; the source electrode of the first switching tube and the source electrode of the second switching tube are connected to the two ends of the fifth capacitor respectively; and the negative electrode of the power supply is connected with the source electrode of the first switching tube. Theproblem of low efficiency of the Boost converter in the prior art is solved.

A staggered and parallel soft switch Buck converter comprises two synchronous rectification Buck circuits, a driving control circuit and an auxiliary zero-voltage circuit, wherein the auxiliary zero-voltage circuit is connected in series with a capacitor by an auxiliary inductor, the driving control circuit is used for acquiring an output voltage Vo and generating a feedback voltage signal, the driving control circuit outputs a first driving signal, a first complementary driving signal, a second driving signal and a second complementary driving signal, the first driving signal is complement tothe first complementary driving signal and is used for controlling the first synchronous rectification Buck circuit, the second driving signal is complement to the second complementary driving signaland is used for controlling a second synchronous rectification Buck circuit, the first synchronous rectification Buck circuit and the second synchronous rectification Buck circuit are conducted in astaggered way, power is continuously supplied to a subsequent load, and a zero-voltage switch current required by the zero-voltage switch is obtained according to node potential difference formed by working of the two Buck circuits in a staggered way. The staggered and parallel soft switch Buck converter is simple to control, and zero-voltage conduction of all switch tubes also can be achieved under the condition that circuit parameters are not consistent.

The invention discloses a complex forward DC converter which belongs to the field of DC converters. The converter comprises an original edge circuit, a first high frequency transformer, a second high frequency transformer and an auxiliary edge circuit, wherein the original edge circuit comprises a DC power supply, two voltage-dividing capacitors, four power switch pipes and three magnetic reset diodes; both the first high frequency transformer and the second high frequency transformer comprise original edge windings and auxiliary edge windings; and the auxiliary edge circuit comprises two rectifying diodes, a following current diode, a filter inductor, a filter capacitor and a load. The two-path interlaced parallel connection output structure of the original edge of the converter is beneficial to reducing the voltage stress of the rectifying diodes and the size and the volume of an output wave filter and improving equivalent duty ratio and equivalent switching frequency. The invention has high reliability and conversion efficiency and is suitable for a middle and high voltage power conversion occasion.

The invention discloses an isolation three-port DC-DC converter. The isolation three-port DC-DC converter comprises a three-winding transformer, a DC-isolation capacitor, two full-bridge circuits, a full-wave rectification circuit and two LC resonant cavities, wherein the two LC resonant cavities respectively comprises a first resonant inductor, a first resonant capacitor, a second resonant inductor and a second resonant capacitor, a DC bus-side winding is connected with a DC bus port by the DC-isolation capacitor and a first full-bridge circuit, a high-voltage battery-side winding is connected with a high-voltage battery port by the first resonant inductor, the first resonant capacitor and a second full-bridge circuit, and a low-voltage battery-side winding is connected with a low-voltagebattery port by the second resonant inductor, the second resonant capacitor and the full-wave rectification circuit. The isolation three-port DC-DC converter employs a three-winding structure, the numbers of rectification diodes and transformers are reduced, the power loss is reduced, and the circuit conversion efficiency is improved.

An active clamping flyback switching power supply circuit is provided. Based on a LCL flyback converter, the NP1 corresponding terminal in a transformer B is connected with a power supply, a second primary winding NP2 corresponding terminal is connected to ground, the NP1 and the NP2 are both wound by two wires. One end of a capacitor C1 is connected to the NP1 non-corresponding terminal, and the other end of the capacitor C1 is connected to the NP2 corresponding terminal. The NP2 corresponding terminal is connected to the power supply via a field-effect transistor Q2 and a clamping network 400 connected with a C3 in series. Thus, when the Q1 is in saturated conduction, the NP1 and the NP2 are both excited. When the Q1 is switched off, a secondary side outputs energy, a primary side presents a state that a voltage source is connected in series with leakage inductance, the Q2 is switched on, the C3 and leakage inductance resonate so as to switch on the Q1 at zero voltage. In a light load state, the Q2 is switched on at intervals of a few cycles during which the voltage of the C3 increases step by step. When the Q2 is switched on, the C3 and leakage inductance resonate so as to switch on the Q1 at zero voltage, and further reduce the power consumption of driving the Q2 at the light load state, and achieve a duty cycle greater than 0.5, energy recovery of a demagnetization circuit, especially at the light load state, the conversion efficiency is improved.

The invention discloses a control method and device of an I-type three-level circuit. With the control method and device adopted, the zero-voltage switching on of the switching tubes of a high-frequency bridge arm can be realized, the loss of the circuit can be reduced, and the efficiency of the circuit can be improved. The control method comprises the following steps that: the inductance current of an inductor which is connected with each high-frequency bridge arm in an operating state in the I-type three-level circuit is detected; in the positive half cycle of the voltage of the alternating current wiring end of the I-type three-level circuit, when the freewheel switching tube of the high-frequency bridge arm connected with the inductor is in an on state, and the main switching tube of the high-frequency bridge arm is in an off state, if it is detected that the inductance current does not reach preset negative current, the freewheel switching tube in the on state is controlled to be in the on state continuously, and the main switching tube in the off state is controlled to be in the off state continuously; and if it is detected that the inductance current reaches the preset negative current, the freewheel switching tube in the on state is controlled to be switched off, and the main switching tube in the off state is controlled to be switched on.

The invention relates to a topological structure of an asymmetrical half-bridge converter. A PWM control chip generates two phase-complementary driving pulses, and generates two driving signals VGS1 and VGS2 through an isolated driving circuit. With dead time, VGS1 drives power transistor Q1, and VGS2 drives power transistor Q2; power transistors Q1 and Q2 are connected in series to form a half-bridge bridge arm, and the midpoint A of the bridge arm is connected to The primary side coil of the power transformer T1; the secondary side coil of the power transformer T1 is connected with a full-wave rectification filter circuit, followed by a filter capacitor Cf to output a stable DC voltage Vo. The asymmetrical half-bridge converter of the present invention can conveniently realize DC voltage conversion through the resonant inductance, the parasitic capacitance of the power device, and the leakage inductance of the power transformer, and realize the high-voltage and low-current output of the power device. Zero-voltage conduction improves power conversion efficiency, is convenient to control, and has remarkable effects.

The invention provides a half-bridge LLC resonant converter staggered parallel circuit and a current sharing control method thereof. Two phase half-bridge LLC resonant converters are staggered and connected in parallel. Two capacitors connected in series are on the direct current input side of each phase half-bridge LLC resonant converter, and a resonant cavity is connected through a T-switch network. The secondary side of a transformer is connected with a rectifier circuit, an output capacitor and a load. According to the invention, the insertion of the Vin / 2 state in the input voltage of theresonant cavity is realized by adding an auxiliary path and MOS tubes, so as to reduce the effective value of the fundamental wave of the input voltage of the resonant cavity; the gain of the LLC resonant converters can be reduced while the switching frequency remains unchanged; in the case of parallel interleaving at the same frequency, the resonance current of each phase can be compared with the average value of the resonance current of a parallel system; the gain of each phase LLC resonant converter is adjusted to achieve current sharing control; and all MOS tubes on the primary side can achieve zero voltage turn-on.

The invention discloses an all-digital soft switching control circuit of a four-switch buck-boost bidirectional converter, and belongs to the technical field of control of power electronic converters. According to the invention, the converter works in a critical conduction mode, and zero-voltage conduction of the switch tube can be realized in a full-load range. During boost operation, a PI controller forming a current regulator and a voltage regulator calculates the turn-off time of a switch tube, and keeps the turn-on time constant; during step-down operation, the PI controller calculates the conduction time of the switch tube and keeps the conduction time constant for a short time; on the basis, the dead time is dynamically adjusted according to the input and output voltage of the converter, so that zero-voltage conduction of all switching tubes is realized. According to the invention, a high-cost zero-cross detection circuit is omitted, the control is simple and easy to realize, the power density of the converter is improved, and the method has a wide application prospect in the field of power electronic converters.

The invention relates to a novel compound switch for high-voltage capacitor switching and a working method of the novel compound switch. The compound switch comprises a compound switch control system, diode strings and mechanical switches, wherein each of A and C two phases is provided with two mechanical switches, namely a primary switch and an auxiliary switch; each primary switch is connected with one diode string in parallel; only one auxiliary mechanical switch is arranged on a B phase for playing an isolating role; and the compound switch control system comprises a voltage and current detection circuit, mechanical switch drive circuits, an operating mechanism energy-storage capacitor charging control circuit, a compound switch state display circuit and a digital control system. By the novel compound switch, voltage zero point turn-on and current zero point turn-off of the compound switch can be achieved; switching inrush current and breaking overvoltage in the switching process are eliminated; and non-arc operation of the mechanical switches can also be achieved. Meanwhile, a thyristor string is replaced with the diode strings; and compared with a traditional compound switch, the novel compound switch has the advantages that complicated trigger circuit is not needed and the problem of the damage caused by over-voltage conduction by mistake of a lightning stroke and the like is solved.

Disclosed is an active clamping forward switching power supply circuit. On the basis of an LCL forward converter, the N<P1> dotted terminal of a transformer B is connected with a power supply, and the N<P2> dotted terminal is grounded; the N<P1> and N<P2> are in double-wire parallel winding; one end of a capacitor C1 is connected with the non-dotted terminal of the N<P1> while the other end is connected with the non-dotted terminal of the N<P2>; the dotted terminal of the N<P2> and a clamping network 400 which is connected with a C3 in series are connected with the power supply through a field effect transistor Q2, so that the conditions are realized as follows: when a Q1 is in a saturation switch-on state, N<P1> and N<P2> both can be excited, and a secondary side NS outputs energy; when the Q1 is switched off, an L1 outputs energy based on follow current, a D2 is synchronously switched off, the energy generated by exciting is clamped through the N<P2> via 400, the primary side is in an inductive state, the Q2 is switched on, the C3 and the primary side inductor are in resonance, and zero-voltage switching on of the Q1 is realized; in a light load state, the Q2 is switched on after several periods, and during the period, the end voltage of the C3 is increased in a step manner; when the Q2 is re-switched-on, the C3 and the primary side inductor are in resonance, and the zero-voltage switching on of the Q1 is realized, so that power consumption in driving the Q2 in the light load state is lowered; and consequently, the duty ratio can be greater than 0.5, demagnetized energy recycling can be realized, and the efficiency is improved in the light load state.

The invention provides a dual-motor drive inverter. The dual-motor drive inverter comprises a direct-current power supply, six switching tube bridge arms and two motors; each switching tube bridge arm is connected between the positive pole and negative pole of the direct-current power supply; each switching tube bridge arm is compose of a transistor and a diode which are in series connection; and the first center line of the first motor is connected with the positive bus of the direct-current power supply, the second center line of the second motor is connected with the negative bus of the direct-current power supply, and the three phases of each motor are connected with the middle points of the switching tube bridge arms, and therefore, control on the three-phase voltage of the two motors can be realized. The dual-motor drive inverter of the invention has the advantages of simple structure and few used electronic components. According to the dual-motor drive inverter adopted, the zero-voltage switching on of the switching devices can be realized, and the efficiency of the dual-motor drive inverter can be improved.

The invention discloses a phase-shifted full-bridge converter frequency conversion control method based on load current. The switching frequency of a switching tube is adjusted according to the magnitude of the load current obtained by ADC sampling, so that the equivalent resonant inductance value changes. When the load current Io is greater than a high critical value IoB, the switching frequencyfs is set to be a low frequency value fsmin; when the load current Io is smaller than a low critical value IoS, the switching frequency fs is set to be a high frequency value fsmax; and when Io is greater than IoS and smaller than IoB, the frequency remains unchanged. According to the method disclosed by the invention, the lagging leg can be increased to realize a zero-voltage-switching (ZVS) loadrange, and the duty ratio loss is limited, so that the voltage regulating range of a phase-shifted full-bridge converter is broadened, and the efficiency of the converter is promoted. Moreover, any additional device does not need to be added, the structure is simple, and the implementation method is convenient.

The invention discloses an active clamping LED driving power supply without an electrolytic capacitor. The active clamping LED driving power supply comprises an AC input power supply, an input filtering part, a rectification part, a clamping circuit, a flyback converter, an output filtering capacitor Co, a parallel absorption loop and an LED load. The input filtering part is composed of an input filtering inductor and an input filtering capacitor. The rectification part is composed of four switch tubes. The clamping circuit is composed of a switching tube S2 and a clamping capacitor Caux; theflyback converter is composed of a flyback transformer, a switching tube S1 and a diode Ds. The flyback transformer comprises a primary side winding and a secondary side winding, the primary side winding comprises a main inductor Lm and a leakage inductor Lr, the primary side winding is connected with the input, and the secondary side winding is connected with the output; the parallel absorption circuit comprises a boost inductor Lb, a switching tube S3, a switching tube S4 and an energy storage capacitor Cds. According to the invention, the active clamping circuit is introduced, so that the switching stress of the switching tube S1 is reduced; both the switching tube S1 and the switching tube S2 realize soft switching, so that the switching loss is reduced; meanwhile, leakage inductance energy can be fed back.

The invention discloses an efficiency optimization control method for a wireless power transmission system. The efficiency optimization control method comprises the following steps: step 1, a control system is accessed to the wireless power transmission system based on a bilateral LCC compensation network; 2, according to the detected voltage and current values of the secondary side direct current side and a duty ratio value beta s obtained by sampling an input voltage vcd duty ratio detection circuit, a phase update value in a main control PWM module is obtained, and phase locking and output voltage and current control are achieved; the input current irs is ahead of the input voltage vcd through a phase-locked link, so that the input impedance of the rectifier is capacitive, and zero-voltage switching-on of the secondary side rectifier is realized; and the duty ratio beta s of the input voltage vcd is controlled through the voltage loop controlled rectifier, so that the output voltage V2 and the current I2 are controlled; and step 3, the working mode of an inverter is adjusted according to the adjustable range of the input voltage of the inverter. According to the invention, the output voltage and current control of the system is simplified without depending on communication and control.

The invention discloses a soft switching control circuit of a coupled inductor interleaved four-switch buck-boost bidirectional converter, belongs to the technical field of control of power electronic converters, and can enable the converter to work in a critical state under the condition of considering nonlinearity of coupled inductors. Zero-voltage conduction of the switch tube can be realized under the conditions of different loads and input and output voltages; according to the invention, a method for calculating the turn-off time and the dead time by considering the influence of the coupling inductance is provided, so that zero-voltage conduction of all switching tubes is realized; by adopting the interleaving parallel structure, the inductive current flowing through each switching tube can be effectively reduced, the on-state loss is reduced, the control is simple and easy to realize, the high power density of the converter is facilitated, and the interleaving parallel structure has a wide application prospect in the field of low-voltage large-current lithium battery charging and discharging.

The invention relates to a current control power converter, and belongs to the motor control field. The problem is solved that in a present power converter, a switching frequency is raised while switching loss is increased. The power converter is mainly composed of a power supply, a main circuit, an auxiliary switching circuit and a filtering circuit. The main circuit is an H-bridge-shaped main circuit composed of two bridge arms. Each bridge arm is composed of two semiconductor switching elements in series connection. Each semiconductor switching element is in parallel connection with a capacitor. The two bridge arms of the main circuit are in parallel connection between the positive busbar and the negative busbar of the power supply. An auxiliary switch and an auxiliary inductor are in series connection to form an auxiliary switch circuit. Each of the two ends of the auxiliary switch circuit is connected with the connection point of two semiconductor switching elements in series connection of each bridge arm of the main circuit respectively. The current control power converter is mainly used for control of the motor.

The invention provides a bidirectional isolation type resonant power converter control method based on a virtual synchronous motor to solve the problems of lack of rotational inertia in the charging and discharging process of an electric vehicle, low voltage stability of a power electronic converter, efficiency reduction caused by large reactive power in the operation process and the like. The bidirectional power converter is composed of a DC / DC stage and a DC / AC stage. According to the structural similarity of a three-phase synchronous motor model and a three-phase converter, the DC / AC-levelthree-phase converter can be equivalent to a synchronous motor, the whole electric vehicle charging pile is equivalent to a synchronous motor at the grid-connected point, and the motor can respond tovoltage and frequency disturbance of a power grid in a self-adaptive mode and provide necessary inertia and damping for the power grid. In order to overcome the defect of power loss caused by large reactive current of a traditional DAB converter, a resonance module is added, zero-voltage connection and zero-current disconnection of an interface converter switching device are achieved, and the overall operation efficiency of the converter is improved.

The invention discloses an inverter power source device used for converting a direct current output by a direct-current power source into an alternating current. The inverter power source device comprises a preceding-stage current feed circuit and a posterior-stage inverter circuit. The current feed circuit comprises a full-bridge converter, an isolation transformer and a rectifying circuit, wherein the full-bridge converter, the isolation transformer and the rectifying circuit are connected in series in sequence. The posterior-stage inverter circuit comprises a tank circuit and a bipolar full-bridge high-frequency inverter circuit, wherein the tank circuit is connected between two output ends of the current feed circuit, and the bipolar full-bridge high-frequency inverter circuit is used for converting direct voltage output by the current feed circuit into alternating voltage. Due to the inverter power source device, under the condition that energy conversion efficiency is ensured, complexity of control can be reduced, and reactive power adjusting and power expansion are convenient.

The invention discloses a control method and device of a Vienna-like three-level circuit. With the control method and device adopted, zero-voltage switching on of a high-frequency bridge arm switching tube can be realized, and circuit loss can be reduced. The control method comprises the following steps that: the inductance current of an inductor which is connected with each high-frequency bridge arm in an operating state in the Vienna-like three-level circuit is detected in the positive half cycle of the alternating current input voltage of the Vienna-like three-level circuit; when the freewheel switching tube of the high-frequency bridge arm connected with the inductor is in an on state, and the main switching tube of the high-frequency bridge arm is in an off state, if it is detected that the inductance current does not reach preset negative current, the freewheel switching tube in the on state is controlled to be in the on state continuously, and the main switching tube in the off state is controlled to be in the off state continuously; and if it is detected that the inductance current reaches the preset negative current, the freewheel switching tube in the on state is controlled to be switched off, and the main switching tube in the off state is controlled to be switched on.