A single-phase isolated integrated vehicle charging system topology without electrolytic capacitor and a control method thereof

Abstract

The application discloses a kind of no electrolytic capacitor single-phase isolation type integrated vehicle-mounted charging system topological structure and its control method, the system is based on the open-winding drive system of electric vehicle, reuse drive motor stator winding, when system is switched from drive operation mode to charging operation mode, open-winding permanent magnet motor drive system is reconstructed into a kind of isolated AC / DC converter without electrolytic capacitor by switching switch, including synchronous rectifier, double active bridge converter and active filter device, by the matching control of transmission power and net side input power, realize power factor correction, by winding inductance current control, filter out inherent secondary power ripple to realize active filtering, realize torque ripple suppression to multiplex motor winding by flux balance method, so as to obtain the integrated vehicle-mounted charging system of vehicle-mounted power battery with isolation charging characteristics, realize the integration design of drive charging function, and improve the reliability and safety of integrated charging system.

Description

Technical Field

[0001] This invention relates to the fields of power electronics and electric drive technology, and in particular to a topology and control method of an electrolytic capacitor-free single-phase isolated integrated on-board charging system. Background Technology

[0002] Currently, common on-board chargers for electric vehicles charge battery packs by converting AC power from the grid. However, because they are installed on electric vehicles, they increase vehicle weight, reduce interior space, and decrease driving range, contradicting the goal of lightweighting the entire vehicle. An integrated on-board charging solution that reuses the electric vehicle's motor windings and drive system power devices addresses this by changing the motor winding connection method during charging via a switching switch. This reconfigures the motor windings and drive system into an AC / DC converter, transforming the grid AC power into DC power that meets the charging voltage level of electric vehicles, thus achieving integration of the drive and charging system. Compared to traditional on-board chargers, this integrated on-board charging system, through time-division multiplexing of the drive system and motor windings, saves space and weight while achieving the same charging effect as an on-board charger, making it highly practical.

[0003] Currently, integrated on-board charging systems typically lack electrical isolation, requiring additional power frequency transformers or DAB converters in practical applications to achieve this. Furthermore, the inherent secondary pulsation power during rectification in single-phase power grids usually necessitates the addition of electrolytic capacitors or other passive components for filtering. This contradicts the goal of highly integrated charging systems, limiting their large-scale development and application.

[0004] Therefore, achieving an isolated, integrated on-board charging system without electrolytic capacitors without adding extra power devices, power frequency transformers, and passive components is an urgent problem to be solved. Summary of the Invention

[0005] Purpose of the invention: This invention provides a topology and control method for an electrolytic capacitor-free single-phase isolated integrated on-board charging system, which achieves electrical isolation of the integrated on-board charging system and improves the reliability and safety of charging.

[0006] Technical Solution: The present invention discloses a capacitor-free, single-phase isolated integrated on-board charging system topology, comprising: an open-winding permanent magnet synchronous motor, a dual three-phase inverter, a power battery, a bus capacitor, a high-frequency transformer, winding switching switches K1, K2, K3, and a single-phase grid switching switch G1; the three-phase windings of the open-winding permanent magnet synchronous motor have center taps, dividing them into L... a1 L a2 L b1 L b2 Lc1 , L c2 six segments winding; the winding switch is a double-pole double-throw switch, which is switched according to the driving mode or the charging mode.

[0007] Further, in the driving mode, the three-phase single-phase grid switch G1 is opened, the winding switches K1, K2 and K3 connect the two segments of each phase winding in series and connect the double three-phase inverter, the power battery and the bus capacitor and the double three-phase inverter of the isolation bus drive the open winding permanent magnet synchronous motor; in the charging mode, the winding switches K1, K2 and K3 and the single-phase grid switch G1 are closed, the two segments of the motor winding of each phase are connected in parallel, the system topology is reconstructed into an isolated single-stage AC / DC converter without electrolytic capacitor, the single-phase grid alternating current is outputted through the isolated converter with secondary pulsating power, and the secondary pulsating power is filtered through the active filter circuit to charge the power battery.

[0008] Further, in the charging mode, the system topology is reconstructed into an isolated single-stage AC / DC converter without electrolytic capacitor, the three-phase inverter 1 is reconstructed into a transformer primary side bridge arm, wherein the switch tubes S1, S2, S5 and S6 and the parallel winding L a1 , L a2 are reconstructed into a synchronous rectifier, the switch tubes S5 and S6 are reused, the switch tubes S3 and S4 are reconstructed into a primary side full-bridge circuit, and the parallel winding L c1 , L c2 is connected to the primary side of the high-frequency transformer; the three-phase inverter 2 is reconstructed into a transformer secondary side bridge arm, wherein the switch tubes S7, S8, S 11 , S 12 are reconstructed into a secondary side full-bridge circuit, the high-frequency transformer is connected to the secondary side, the switch tubes S7 and S8 are reused, the switch tubes S9 and S 10 and the parallel winding L b1 , L b2 are reconstructed into an H-bridge active filter circuit; the primary side full-bridge circuit, the secondary side full-bridge circuit and the high-frequency transformer constitute a double active bridge converter; the synchronous rectifier converts the single-phase grid alternating current into a pulsating DC bus voltage, outputs the DC through the double active bridge converter in the rear stage, filters the secondary pulsating power through the H-bridge active filter circuit, realizes the isolation type single-phase integrated charging of the battery pack; in the topology, the current of the parallel winding is equal in size and direction during the charging process, the magnetic flux generated is offset, the magnetic flux generated in the three-phase winding of the motor is zero, the magnetic flux balance is realized, and the electromagnetic torque generated by the reused motor winding is eliminated.

[0009] Further, in the synchronous rectifier, the switch tubes S1 and S2 are power frequency switch bridge arms, and the switch tubes S5 and S6 are high-frequency switch bridge arms with a duty ratio of 0.5, so that the AC side voltage is boosted to a pulsed DC bus voltage with a double amplitude; the switch tubes of the dual active bridge converter are high-frequency switches, and the pulsed DC bus voltage is regarded as a constant voltage in a switching period; the primary side full-bridge circuit uses the switch tubes S5 and S6, and the switch tubes S4 and S5 and the switch tubes S3 and S6 are complementary conduction with a duty ratio of 0.5; the secondary side full-bridge circuit uses the switch tubes S7 and S 12 and the switch tubes S 11 are complementary conduction; the switch tubes S3, S4, S5, S6 and the switch tubes S7, S8, S 11 , and S 12 are controlled to transmit power of the phase-shifted angle-regulated dual active bridge converter; the H-bridge active filter circuit uses the switch tubes S7 and S8, and the switch tubes S7 and S8 are high-frequency switch bridge arms with a duty ratio of 0.5; the switch tubes S9 and S 10 are controlled to control the parallel B-phase winding current for filtering secondary power pulsation.

[0010] Correspondingly, a control method of a single-phase isolated integrated vehicle charging system topology without electrolytic capacitor comprises the following steps:

[0011] Step 1, collecting the single-phase power grid side voltage instantaneous value u g , the current instantaneous value i g , the B-phase parallel winding current instantaneous value i b , and the output voltage U o ;

[0012] Step 2, calculating the phase angle θ g of the single-phase power grid side voltage instantaneous value u g by using a phase-locked loop, and determining that the switch tube S2 is turned on when the single-phase power grid side voltage instantaneous value u g is positive, and the switch tube S1 is turned on when the single-phase power grid side voltage instantaneous value u g is negative;

[0013] Step 3, calculating the difference between the given value of the charging voltage of the power battery and the actual output voltage U o , filtering the secondary pulsation component by using a notch filter, and outputting a phase-shifted ratio coefficient k by using a proportional-integral controller;

[0014] Step 4, calculating the phase-shifted ratio D by using the phase-shifted ratio coefficient k and the power grid side voltage phase angle θ g in the phase-shifted ratio calculation module;

[0015] Step 5, set the constant duty ratio of the switching signal to 0.5, drive the switching tubes S3, S4, S5, S6, the switching tubes S3, S6 are respectively complementary to S4, S5, drive the switching tubes S7, S8, S 11 , S 12 , the switching tubes S7, S 12 are respectively complementary to S8, S 11 ;

[0016] Step 6, calculate the given value of the parallel winding current of the B phase, subtract the current instantaneous value i b from the given value , subtract 0.5 after passing through the proportional-integral controller, to obtain the duty ratio of the switching tube S9, S9, S 10 are complementary.

[0017] Further, in step 4, the phase shift ratio D is calculated according to the formula:

[0018]

[0019] Further, in step 6, the given value of the current flowing through the B phase winding is calculated according to the formula:

[0020]

[0021] Where, P r is the required pulsating power component to be filtered out, L b is the inductance value of the B phase parallel inductor, L a is the inductance value of the A phase parallel inductor, ω is the power frequency electrical angular velocity, U g is the grid side voltage amplitude, I g is the grid input current amplitude.

[0022] Advantages: compared with the prior art, the present application has the following remarkable advantages: the present application realizes the electrical isolation of the integrated vehicle-mounted charging system without increasing additional power devices and power frequency transformers, improves the reliability and safety of charging, filters out the inherent secondary pulsating power of the single-phase power grid without increasing additional passive devices such as electrolytic capacitors, and improves the integration of the system. On the basis of the open-winding drive system of the electric vehicle, the stator winding of the drive motor is reused, when the system is switched from the drive operation mode to the charging operation mode, the open-winding permanent magnet motor drive system is reconstructed into an electrolytic capacitor-free isolated AC / DC converter through the switching switch, so that the integrated vehicle-mounted power battery of the vehicle-mounted power battery is obtained, the integrated design of the drive and charging functions is realized, and the reliability and safety of the integrated charging system are improved. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 The topology diagram of the single-phase isolated integrated vehicle charging system without electrolytic capacitor of the application.

[0024] Figure 2 The system topology in the driving state of the application.

[0025] Figure 3 The system topology in the charging state of the application.

[0026] Figure 4 The equivalent circuit of the system in the charging mode of the application.

[0027] Figure 5 The control block diagram of the system in the charging mode of the application.

[0028] Figure 6 The grid-side voltage and current waveform comparison diagram before and after adding the power factor correction of the application.

[0029] Figure 7 The grid-side current harmonic analysis result comparison diagram before and after adding the active filter circuit of the application.

[0030] Figure 8 The output voltage and current ripple comparison waveform diagram before and after adding the active filter circuit of the application.

[0031] Figure 9 The main waveform diagram of the transformer voltage and current during charging of the application.

[0032] Figure 10 The main input and output voltage and current waveform diagram during charging of the application. DETAILED DESCRIPTION

[0033] As shown in Figure 1 , a topology structure of a single-phase isolated integrated vehicle charging system without electrolytic capacitor, comprising: an open-winding permanent magnet synchronous motor, a double three-phase inverter, a power battery, a bus capacitor, a high-frequency transformer, winding switching switches K1, K2 and K3, and a single-phase grid switching switch G1; the open-winding permanent magnet synchronous motor has a three-phase winding leading center tap, which is divided into six segments of L a1 , L a2 , L b1 , L b2 , L c1 , L c2 ; the winding switching switch is a double-pole double-throw switch, which is switched according to the driving mode or the charging mode.

[0034] As shown in Figure 2As shown, when the electric vehicle operates in the driving mode, the three-phase single-phase grid switch G1 is opened, the winding switch K1, K2, K3 connects two sections of winding of each phase in series and connects the double three-phase inverter, the power battery and the bus capacitor and the double three-phase inverter of the isolation bus drive the open winding permanent magnet synchronous motor.

[0035] As shown, Figure 3 when the electric vehicle operates in the charging mode, the winding switch K1, K2, K3 and the single-phase grid switch G1 are closed, two sections of winding of each phase of the motor are connected in parallel, the system topology is reconstructed into an isolated single-stage AC / DC converter without electrolytic capacitor, the single-phase grid AC power is outputted through the isolated converter to obtain DC power with secondary pulsating power, and the secondary pulsating power is filtered through the active filter circuit to charge the power battery.

[0036] As shown, Figure 4 the system equivalent circuit of the isolated single-stage AC / DC converter without electrolytic capacitor in the charging mode, characterized in that the three-phase inverter 1 is reconstructed into a transformer primary side bridge arm, wherein the switch tubes S1, S2, S5, S6 and the parallel windings L a1 , L a2 are reconstructed into a synchronous rectifier, the switch tubes S5, S6 are reused, and the switch tubes S3, S4 are reconstructed into a primary side full-bridge circuit connected with the parallel windings L c1 , L c2 and the primary side of the high-frequency transformer; the three-phase inverter 2 is reconstructed into a transformer secondary side bridge arm, wherein the switch tubes S7, S8, S 11 , S 12 are reconstructed into a secondary side full-bridge circuit connected with the secondary side of the high-frequency transformer, the switch tubes S7, S8 are reused, and the switch tubes S9, S 10 and the parallel windings L b1 , L b2 are reconstructed into an H-bridge active filter circuit.

[0037] The primary side full-bridge circuit, the secondary side full-bridge circuit and the high-frequency transformer constitute a double active bridge converter; the synchronous rectifier converts the single-phase grid AC power into pulsating DC bus voltage, outputs DC power through the double active bridge converter in the rear stage, filters the secondary pulsating power through the H-bridge active filter circuit, and realizes the isolated single-phase integrated charging of the battery pack.

[0038] In the topology, the current of the parallel winding of each phase winding is equal in size and direction during the charging process, the magnetic flux generated is offset, the magnetic flux generated in the three-phase winding of the motor is zero, the magnetic flux balance is realized, and the electromagnetic torque generated by the reused motor winding is eliminated.

[0039] In the topology, the current of the two inductors is equal in size and direction during the charging process, the magnetic flux generated by the two inductors is offset, the magnetic flux generated in the three-phase winding is zero, the magnetic flux balance is achieved, and no electromagnetic torque is generated, so that the motor rotor can be kept stationary during the charging process.

[0040] As shown in Figure 5 , the application also provides a charging control method of a single-phase isolated integrated vehicle-mounted charging system without electrolytic capacitor, characterized in that, in the synchronous rectifier, the switch tubes S1 and S2 are power frequency switch bridge arms, and the switch tubes S5 and S6 are high-frequency switch bridge arms with a duty ratio of 0.5, so that the AC side voltage is boosted to a pulse DC bus voltage with a double amplitude.

[0041] The switch tubes of the dual active bridge converter are high-frequency switch tubes, and the pulse DC bus voltage is regarded as a constant voltage in a switching period, the primary side full-bridge circuit uses the switch tubes S5 and S6, the switch tubes S4 and S5 and the switch tubes S3 and S6 are complementary conduction, the duty ratio is 0.5, the secondary side full-bridge circuit uses the switch tubes S7 and S 12 and the switch tubes S8 and S 11 are complementary conduction, the transmission power of the phase-shifted angle regulation dual active bridge converter is controlled by controlling the switch tubes S3, S4, S5, S6 and the switch tubes S7, S8, S 11 , S 12 .

[0042] The switch tubes S7 and S8 of the H-bridge active filter circuit are high-frequency switch bridge arms with a duty ratio of 0.5, the duty ratio of the switch tubes S9 and S 10 is controlled to control the parallel B-phase winding current for filtering the secondary power pulsation.

[0043] The switch tubes S1 and S2 control the switching state by judging the voltage direction of the grid side, the phase-shifted angle of the switch tubes S3, S4, S5, S6 and the switch tubes S7, S8, S 11 , S 12 is controlled by the power factor control and the voltage regulator, and the duty ratio of the switch tubes S9 and S 10 is determined by the active filter control strategy, and the realization steps are as follows:

[0044] (1) collect the instantaneous value u g of the single-phase grid side voltage, the instantaneous value i g of the current, the instantaneous value i b of the parallel B-phase winding current, and the output voltage U o ;

[0045] (2) calculate the phase angle θ g of the single-phase grid side voltage instantaneous value u gSimultaneously determine the grid-side voltage instantaneous value u g When positive, switch S2 is turned on, and the grid-side voltage instantaneous value u g When negative, switch S1 is turned on.

[0046] (3) Calculate the difference between the given value of the charging voltage of the power battery and the actual output voltage U o , filter out the secondary ripple component through the notch filter, pass through the proportional-integral controller, and output the phase-shifting ratio coefficient k.

[0047] (4) In the phase-shifting ratio calculation module, the phase-shifting ratio D is calculated by the phase-shifting ratio coefficient k and the grid-side voltage phase angle θ g .

[0048] (5) Set the constant duty ratio of the switching signal to 0.5, drive switches S3, S4, S5, and S6, switches S3 and S6 are respectively complementary to S4 and S5, and drive switches S7, S8, S 11 , and S 12 after the switching signal is phase-shifted according to the calculated phase-shifting ratio D, switches S7 and S 12 are respectively complementary to S8 and S 11 .

[0049] (6) Calculate the given value of the B-phase parallel winding current, subtract the current instantaneous value i b from the given value , subtract 0.5 after passing through the proportional-integral controller, and obtain the duty ratio of switch S9, S9 and S 10 are complementary.

[0050] In step (4) of the above control strategy, the phase-shifting ratio D calculation step is as follows:

[0051] The voltage expression of the grid side is:

[0052] u g = U g sin(ωt),

[0053] i g = I g sin(ωt)

[0054] Where U g and I g are the amplitudes of the voltage and current, respectively, and the grid-side power is obtained by multiplying the two:

[0055] p g = U g I g sin(ωt)sin(ωt)

[0056] The synchronous rectifier, switch S1, S2 is the frequency switching bridge arm, switch S5, S6 is the duty ratio of 0.5 high frequency switching bridge arm, so that the AC side voltage boost conversion into two times the amplitude of the pulsed DC bus voltage, therefore the DC bus voltage U in For:

[0057] U in =2U g |sin(ωt)

[0058] Under the single phase shift control, the system transmission power of the dual active bridge converter is:

[0059]

[0060] Where, U o is the output voltage, f is the system operating frequency, L is the C phase winding parallel inductance, n is the transformer turns ratio; In order to realize the function of power factor correction, the grid side power and the converter system transmission power should be equal, so:

[0061]

[0062] Further simplified as:

[0063]

[0064] Therefore, the phase shift ratio calculation formula is as follows:

[0065]

[0066] The calculation formula of the phase shift ratio coefficient k is:

[0067]

[0068] Because the system operating frequency f, C phase winding parallel inductance L and transformer turns ratio n are constant, when the system works stably, U o is the output voltage fixed, so the phase shift ratio coefficient k determines the size of the system input current amplitude, thereby determining the system input power, so the calculation formula of the phase shift ratio is as follows:

[0069]

[0070] In step (6) of the above control strategy, the B phase current given value The calculation steps are as follows:

[0071] The power of the grid side:

[0072]

[0073] And the input side winding A phase inductance consumption power is:

[0074]

[0075] where L a is the parallel equivalent inductance of the A phase winding, the input power of the converter is:

[0076]

[0077] It can be seen that the input power of the rectifier has a DC component and a twice power frequency pulsating component, if the twice power frequency pulsating power is to be eliminated, the pulsating component should be completely applied to the B phase winding inductance, and the power on the B phase winding inductance is:

[0078]

[0079] In order to filter out the twice power frequency pulsating component, the pulsating component in p in should be equal to p r , and the given value of the B phase winding inductance current should be:

[0080]

[0081] Based on the above-mentioned isolated single-phase integrated vehicle charging system topology for electric vehicles and its control strategy, an isolated single-phase integrated vehicle charging system is built in Matlab / Simulink software, mainly including a mathematical model of an open-winding permanent magnet synchronous motor with a center tap, a double three-phase inverter model, a single-phase PWM rectifier control model, and a double active bridge converter control model. The key parameter settings in the simulation verification process are shown in Table 1:

[0082] Table 1 Simulation setting parameters

[0083]

[0084] As shown in Figure 6 and Figure 7 , the simulation time is set to 0.12s, and the power factor correction is added at 0.06s, Figure 6 are the voltage and current waveforms of the grid side before and after the power factor correction is added. It can be seen that before the power factor correction is added, the current sinusoidal degree is poor and there is zero-crossing distortion, and after the power factor correction is added, the current sinusoidal degree is high and the phase is basically consistent with the voltage, and there is no current distortion, realizing the PFC function and meeting the power requirements of the grid. Figure 7 is a comparison chart of grid side current harmonic analysis results before and after the power factor correction is added. It can be seen that there are harmonics after the power factor correction is added, and the THD is 41.52%, and after the power factor correction is added, there is basically no current harmonic, and the THD is 2.65%, meeting the harmonic requirements of the grid.

[0085] As Figure 8 shown, the simulation time is set to 0.8s, and the active filter control is added at 0.4s, Figure 8 For the charging voltage waveform and current waveform of the power battery before and after adding the active filter control, it can be seen that the peak-to-peak value of the second harmonic of the charging voltage of the power battery before adding the active filter reaches 65.2V, and the peak-to-peak value of the second harmonic after adding the active filter reduces to 21.5V, compared with the second harmonic before filtering, the second harmonic content is reduced by 67.02%, and the average charging voltage is always stable at 800V.

[0086] As Figure 9 shown, after adding the power factor correction and active filter control strategy, the simulation time is set to 0.5s, and the steady-state waveforms of 0.2s-0.3s and 0.215s-0.21505s are intercepted, which are the voltage difference of the transformer primary and secondary sides and the inductor current waveform of the transformer, it can be seen that the inductor current can be controlled by phase shift control, and the electrical isolation and energy transmission are realized by high-frequency transformer.

[0087] As Figure 10 shown, the steady-state waveforms of 0.2s-0.3s are intercepted, and the waveforms of the input voltage, the front bus capacitor voltage, the power battery charging voltage and the power battery charging current are shown, it can be seen that the voltage fluctuation is small in steady state, and it has good steady-state performance.

[0088] Through the above specific embodiments, the feasibility of the single-phase isolated integrated vehicle charging system topology without electrolytic capacitor and the control method thereof proposed by the application is verified. Based on the open-winding drive system of the electric vehicle, the stator winding of the drive motor is reused. When the system is switched from the drive operation mode to the charging operation mode, the open-winding permanent magnet motor drive system is reconstructed into an isolated AC / DC converter without electrolytic capacitor by switching the switch, including a synchronous rectifier, a dual active bridge converter and an active filter device. Through the matching control of the transmission power and the input power of the grid side, the phase shift ratio is realized to realize power factor correction. Through winding inductor current control, the inherent second power pulsation is filtered to realize active filtering. Through the magnetic flux balance method, the torque ripple suppression of the reused motor winding is realized, so as to obtain an integrated vehicle charging system of the vehicle power battery with isolation charging characteristics, realize the integrated design of the drive and charging functions, and improve the reliability and safety of the integrated charging system.

Claims

1. A single phase isolated integrated on-board charging system topology without electrolytic capacitor, characterized in that, In the driving mode, the three-phase single-phase grid switch G1 is disconnected, the winding switch K1, K2, K3 connects two winding sections of each phase in series and connects the double three-phase inverter, the power battery and the bus capacitor and the double three-phase inverter of the isolated bus drive the open winding permanent magnet synchronous motor; in the charging mode, the winding switch K1, K2, K3 and the single-phase grid switch G1 are closed, two winding sections of each phase of the motor are connected in parallel, the system topology is reconstructed into an isolated single-stage AC / DC converter without electrolytic capacitor, the single-phase grid AC power is outputted as DC power with secondary pulsating power through the isolated converter, and the power with secondary pulsating power is filtered through the active filter circuit to charge the power battery. Open-winding permanent magnet synchronous motor, double three-phase inverter, power battery, bus capacitor, high-frequency transformer, winding switching switches K1, K2, K3 and single-phase grid switching switch G1; the open-winding permanent magnet synchronous motor three-phase winding leads out the center tap, which is divided into L a1 , L a2 , L b1 , L b2 , L c1 , L c2 six sections of winding; the winding switching switch is a double-pole double-throw switch, which is switched according to the driving mode or the charging mode; in the charging mode, the system topology is reconstructed into an electrolytic capacitor-free isolated single-stage AC / DC converter, the three-phase inverter 1 is reconstructed into a transformer primary side bridge arm, wherein the switching tubes S1, S2, S5, S6 and the parallel winding L a1 , L a2 are reconstructed into a synchronous rectifier, the multiplexing switching tubes S5, S6 are reconstructed into a primary side full-bridge circuit with the switching tubes S3, S4, and the parallel winding L c1 , L c2 is connected to the primary side of the high-frequency transformer; the three-phase inverter 2 is reconstructed into a transformer secondary side bridge arm, wherein the switching tubes S7, S8, S 11 , S 12 are reconstructed into a secondary side full-bridge circuit, the multiplexing switching tubes S7, S8 are reconstructed into an H-bridge active filter circuit with the switching tubes S9, S 10 and the parallel winding L b1 , L b2 ; the primary side full-bridge circuit, the secondary side full-bridge circuit and the high-frequency transformer constitute a double active bridge converter; the synchronous rectifier converts single-phase grid alternating current into pulsating direct bus voltage, outputs direct current through the double active bridge converter in the rear stage, filters out secondary pulsating power through the H-bridge active filter circuit, and realizes isolated single-phase integrated charging of the battery pack; in the topology, the current of the parallel winding is equal in size and direction in the charging process, the magnetic flux generated is offset, the magnetic flux generated in the motor three-phase winding is zero, the magnetic flux balance is realized, and the electromagnetic torque generated by the multiplexing motor winding is eliminated.

2. The electrolytic capacitorless single-phase isolated integrated vehicle charging system topology of claim 1, wherein, The method comprises the following steps:

3. The electrolytic capacitorless single-phase isolated integrated vehicle charging system topology of claim 1, wherein, In the synchronous rectifier, switches S1 and S2 are power frequency switching bridge arms, while switches S5 and S6 are high-frequency switching bridge arms with a duty cycle of 0.5, enabling the AC side voltage to be boosted and converted into a pulsating DC bus voltage with twice the amplitude. The high-frequency switches of the dual active bridge converter treat the pulsating DC bus voltage as a constant voltage during the switching cycle. Its primary-side full-bridge circuit reuses switches S5 and S6, while switches S4 and S5 are complementary to switches S3 and S6 with a duty cycle of 0.

5. Its secondary-side full-bridge circuit uses switches S7 and S8. 12 With switching transistors S8 and S 11 Complementary conduction is achieved by controlling switches S3, S4, S5, S6 and S7, S8, S... 11 S 12 The phase shift angle adjusts the transmission power of the dual active bridge converter; the H-bridge active filter circuit multiplexes switches S7 and S8, and switches S7 and S8 are high-frequency switching bridge arms with a duty cycle of 0.

5. The power is adjusted by controlling switches S9 and S8. 10 The duty cycle controls the current of the parallel B-phase winding to filter out secondary power pulsations.

4. The control method of the electrolytic capacitorless single-phase isolated integrated vehicle charging system topology according to claim 1, characterized in that, In step 4, the phase shift ratio D is calculated according to the following formula: Step 1, collect single-phase power grid side voltage instantaneous value u g , current instantaneous value i g , B-phase parallel winding current instantaneous value i b , output voltage U o ; Step 2: Calculate the instantaneous voltage u of a single-phase grid side using a phase-locked loop. g phase angle θ g Simultaneously determine the instantaneous value u of the grid-side voltage. g When the positive condition is met, switch S2 is turned on, and the instantaneous voltage value u on the grid side is... g When the value is negative, switch S1 is turned on; Step 3, calculate the difference between the given value of the charging voltage of the power battery and the actual output voltage U, filter the secondary pulsation component through a notch filter, pass through a proportional-integral controller, and output a phase shift ratio coefficient k; o Step 3, calculate the difference between the given value of the charging voltage of the power battery and the actual output voltage U, filter the secondary pulsation component through a notch filter, pass through a proportional-integral controller, and output a phase shift ratio coefficient k; Step 4, in the phase shift ratio calculation module, the phase shift ratio D is calculated by the phase shift ratio coefficient k and the grid-side voltage phase angle θ g . Step 5, set the constant duty ratio of the switching signal to 0.5, drive the switching tubes S3, S4, S5, S6, the switching tubes S3, S6 are respectively complementary to S4, S5, and the switching signal is shifted according to the calculated phase shift ratio D to drive the switching tubes S7, S8, S 11 , S 12 , the switching tubes S7, S 12 are respectively complementary to S8, S 11 . Step 6, calculate the given value of the B-phase parallel winding current, subtract the current instantaneous value i b from the given value , pass through a proportional-integral controller, and subtract 0.5 to obtain the duty ratio of the switch S9, S9, S 10 complementary conduction.

5. The control method of the one-phase isolated integrated vehicle charging system topology without an electrolytic capacitor according to claim 4, wherein ​ 6. The control method of the one-phase isolated integrated vehicle charging system topology without an electrolytic capacitor according to claim 4, wherein In step 6, the B-phase winding flows a given value of current The calculation formula is: where P r is the desired pulsating power component to be filtered out, L b is the B-phase parallel inductance, L a is the A-phase parallel inductance, ω is the power frequency electrical angular velocity, U g is the grid-side voltage amplitude, I g is the grid input current amplitude.

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