Series-parallel redundancy WPT system based on dual-channel current sharing and charging control method

Abstract

The invention discloses a series-parallel redundancy WPT system based on dual-channel current sharing and a charging control method, and relates to the field of power control, and in the system, a direct current voltage source VIN is connected with a dual-channel magnetic coupling mechanism through a dual-channel inverter and a dual-channel LCC compensation network; the dual-channel magnetic coupling mechanism is connected with the load resistor RL through the S compensation network and the series-parallel semi-active rectifier; a series-parallel connection change-over switch SSP1 and a series-parallel connection change-over switch SSP2 in the series-parallel connection semi-active rectifier are used for switching working modes of the series-parallel connection semi-active rectifier, and output control of different voltage levels is achieved. According to the invention, different charging requirements of 400V and 800V electrical architecture electric vehicles can be met, and the maximum charging power can be achieved under two voltage levels while the power balance between two channels is ensured.

Description

Technical Field

[0001] The present application relates to the field of power control, and in particular to a series-parallel redundant WPT system based on dual-channel current sharing and a charging control method. Background Art

[0002] At present, electric vehicles mainly use 400V and 800V electrical architecture systems, and 800V or even higher voltage electrical architecture systems have obvious advantages in high-power fast charging and electrical system efficiency improvement, which has become the current development trend. In order to meet the charging needs of different models, the wireless charging system output is required to be compatible with 400V and 800V voltage level battery packs.

[0003] How to meet the different charging requirements of electric vehicles with 400V and 800V electrical architectures and achieve maximum charging power at both voltage levels while ensuring power balance between the two channels is a difficult problem that needs to be solved urgently. Summary of the invention

[0004] The purpose of this application is to provide a series-parallel redundant WPT system and a charging control method based on dual-channel current sharing, which can meet the different charging requirements of electric vehicles with 400V and 800V electrical architectures, and while ensuring the power balance between the two channels, the maximum charging power can be achieved at both voltage levels.

[0005] To achieve the above objectives, this application provides the following solutions:

[0006] In a first aspect, the present application provides a series-parallel redundant WPT system based on dual-channel current sharing, the series-parallel redundant WPT system based on dual-channel current sharing includes: a DC voltage source V IN , dual-channel inverter, dual-channel LCC compensation network, S compensation network, dual-channel magnetic coupling mechanism, transmitting end current sharing channel, receiving end current sharing channel, series-parallel semi-active rectifier, filter capacitor C O and load resistance R L ;

[0007] At the sending end, the DC voltage source V IN The dual-channel inverter, the dual-channel LCC compensation network and the dual-channel magnetic coupling mechanism are connected; the transmitting end current sharing channel is located between the dual-channel LCC compensation network and the dual-channel magnetic coupling mechanism;

[0008] At the receiving end, the dual-channel magnetic coupling mechanism is connected through the S compensation network, the series-parallel semi-active rectifier and the load resistor R L Connection: Filter capacitor C O and load resistance R LParallel connection; the current sharing channel at the transmitting end is located between the dual-channel magnetic coupling mechanism and the S compensation network;

[0009] The series-parallel semi-active rectifier comprises: MOSFET tube Q S5 , MOSFET tube Q S6 , MOSFET tube Q S7 , diode D1, diode D2, diode D3, series-parallel switch S SP1 And series-parallel switch S SP2 MOSFET tube Q S5 The first branch composed of diode D1 and MOSFET tube Q S6 The second branch composed of diode D2 and MOSFET tube Q S7 The first branch and the output end of the S compensation network of the first channel of the receiving end are connected in parallel with the third branch composed of the diode D3; the intersection of the first branch and the output end of the S compensation network of the first channel of the receiving end and the series-parallel switching switch S SP2 One end of the series-parallel switch S SP2 The other end of the first branch is connected to the third branch; the intersection of the first branch and the output end of the S compensation network of the second channel of the receiving end is connected to the series-parallel switching switch S SP1 One end of the series-parallel switch S SP2 The other end is connected to the second branch;

[0010] Series-parallel switch S SP1 And series-parallel switch S SP2 Used to switch the working mode of series-parallel semi-active rectifiers to achieve output control of different voltage levels.

[0011] Optionally, the operating modes of the series-parallel semi-active rectifier include: a parallel operating mode and a series operating mode;

[0012] In the parallel working mode, the two channel outputs of the receiving end are connected in parallel, and the load resistance R L Charging, charging current I O The current I of the two channels output REC1 and current I REC2 sum;

[0013] In the series operation mode, the two channels of the receiving end are output in series, and the load resistance R L Charging, charging voltage V O is the input voltage V of the series-parallel semi-active rectifier REC1 and input voltage V REC2 sum.

[0014] Optionally, the series-parallel switch S SP1 Including: MOSFET tube Q connected in reverse series S1and MOSFET tube Q S2 ;

[0015] The series-parallel switch S SP2 Including: MOSFET tube Q connected in reverse series S3 and MOSFET tube Q S4 .

[0016] Optionally, the current parameter determination process of the parallel working mode and the series working mode specifically includes:

[0017]

[0018] Among them, the current parameters include: the output current of the dual-channel inverter and output current Transmitter coil current and coil current Coil current at the receiving end and coil current Input current of series-parallel semi-active rectifier and input current Transmitter current sharing channel current Share channel with receiving current L F The inductance and resistance of the dual-channel LCC compensation network are R EP is the resistance in parallel working mode, R ES is the resistance in the series working mode, α is the conduction angle of the series-parallel semi-active rectifier, according to αT S / 2π determines the on-time of the rectifier working mode, T S is the switching duty cycle of the system, ω is the system angular frequency, j is a complex number, L T is the coil inductance at the transmitting end, where the current and parameters σ are: L R is the coil inductance at the receiving end, V IN is a DC voltage source, M 11 and M 22 It is the mutual inductance between two coaxially placed coils on both sides.

[0019] Optionally, the output power P of the dual-channel inverter INV1 And the output power P INV2 for:

[0020] Optionally, a series-parallel semi-active rectifier input current and input current for:

[0021] Input voltage of series-parallel semi-active rectifier and input voltage for:

[0022] Input power P of series-parallel semi-active rectifier REC1 and input power P REC2 for:

[0023] Optionally, the coil current at the sending end and coil current The coil current at the receiving end and coil current satisfy

[0024] The transmitting coil transmits power P LT1 and coil transmission power P LT2 The power P transmitted to the receiving coil LR1 and coil transmission power P LR2 for:

[0025] Optionally, the voltage gain G VV for:

[0026] Among them, G VV_EP is the voltage gain in parallel operation mode, G VV_ES is the voltage gain in series operation mode, It is known that the output voltage level of 400V or 800V is determined by using a determined working mode; and the output voltage control at different voltage levels is achieved by controlling the conduction angle α of the series-parallel semi-active rectifier.

[0027] Optionally, the transmitting end of the dual-channel magnetic coupling mechanism uses two orthogonally placed DD-type coils L T1 and coil L T2 , the receiving coil L R1 and coil L R2 Has a symmetrical structure.

[0028] In a second aspect, the present application provides a charging control method for a series-parallel redundant WPT system based on dual-channel current sharing, which is applied to the series-parallel redundant WPT system based on dual-channel current sharing, and the charging control method includes:

[0029] Start the dual-channel inverter at the sending end;

[0030] Sampling the input current of the series-parallel semi-active rectifier to obtain a current sampling signal;

[0031] According to the obtained current sampling signal, a rectangular wave signal is obtained through a zero-crossing comparator;

[0032] The output voltage V of the series-parallel redundant WPT system O and output current I O Sampling is performed to obtain an output voltage sampling signal and an output current sampling signal of the series-parallel redundant WPT system;

[0033] According to the external input battery pack voltage level signal S MOD Determine the operating mode of the series-parallel semi-active rectifier;

[0034] Compare the output voltage sampling signal and the output current sampling signal with the target voltage and current to obtain a comparison result;

[0035] According to the comparison result, the conduction angle α of the series-parallel semi-active rectifier is controlled by using the PI control method, and a control signal is obtained;

[0036] Perform synchronous correction on the control signal and output PWM control signal;

[0037] The PWM driver outputs a driving pulse according to the PWM control signal, and controls the series-parallel switching switch S according to the driving pulse. SP1 And series-parallel switch S SP2 And the MOSFET tube in the series-parallel semi-active rectifier completes the output control of the series-parallel redundant WPT system.

[0038] According to the specific embodiments provided in this application, this application discloses the following technical effects:

[0039] The present application provides a series-parallel redundant WPT system based on dual-channel current sharing and a charging control method, based on a series-parallel semi-active rectifier (SPSAR) at the receiving end through a series-parallel switching switch S SP1 And series-parallel switch S SP2 Switch the working mode of the series-parallel semi-active rectifier to achieve output control at different voltage levels; this application can meet the different charging needs of electric vehicles with 400V and 800V electrical architectures at the same time through the series-parallel combination of two channels. At the same time, the proposed current sharing mechanism can ensure the power balance between the two channels and achieve the designed maximum charging power at both voltage levels. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0041] Figure 1 This is a structural diagram of a series-parallel redundant WPT system based on dual-channel current sharing in one embodiment of the present application;

[0042] Figure 2 It is the current path diagram of the working mode;

[0043] Figure 3 This is the waveform diagram of the rectifier operation;

[0044] Figure 4 is the equivalent circuit diagram;

[0045] Figure 5 It is the simulation waveform of system voltage and current in parallel working mode @ alignment condition, and the schematic diagram of no current sharing channel;

[0046] Figure 6 It is the voltage and current simulation waveform of the system in parallel working mode @ alignment condition, with a schematic diagram of the current sharing channel;

[0047] Figure 7 This is the voltage and current simulation waveform of the system in parallel working mode @Δx=10cm, without current sharing channel schematic diagram;

[0048] Figure 8 The voltage and current simulation waveforms of the system in parallel working mode @Δx=10cm, with a schematic diagram of the current sharing channel;

[0049] Fig. 9 It is the simulation waveform of system voltage and current in series working mode @ alignment condition, and the schematic diagram of no current sharing channel;

[0050] Fig.10 It is the system voltage and current simulation waveform in the series working mode @ alignment condition, with a current sharing channel schematic diagram;

[0051] Fig.11 This is the voltage and current simulation waveform of the system in the series working mode @Δx=10cm condition, without the current sharing channel schematic diagram;

[0052] Fig.12 The voltage and current simulation waveforms of the system in the series working mode @Δx=10cm, with a schematic diagram of the current sharing channel;

[0053] Fig.13This is the current path diagram for the freewheeling working mode:

[0054] Fig.14 This is a schematic diagram of the working waveform of the freewheeling working mode;

[0055] Fig.15 It is a flow chart of the control method;

[0056] Fig.16 Schematic diagram of the electrical parameter design process for compatible 400V / 800V voltage level systems. DETAILED DESCRIPTION

[0057] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0058] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0059] In an exemplary embodiment, Figure 1 As shown, a series-parallel redundant WPT system based on dual-channel current sharing is provided, and the system includes: a DC voltage source V IN , dual-channel inverter, dual-channel LCC compensation network, S compensation network, dual-channel magnetic coupling mechanism, transmitting end current sharing channel, receiving end current sharing channel, series-parallel semi-active rectifier, filter capacitor C O and load resistance R L ;

[0060] At the sending end, the DC voltage source V IN The dual-channel inverter, the dual-channel LCC compensation network and the dual-channel magnetic coupling mechanism are connected; the transmitting end current sharing channel is located between the dual-channel LCC compensation network and the dual-channel magnetic coupling mechanism;

[0061] At the receiving end, the dual-channel magnetic coupling mechanism is connected through the S compensation network, the series-parallel semi-active rectifier and the load resistor R L Connection: Filter capacitor C O and load resistance R L Parallel connection; the current sharing channel at the transmitting end is located between the dual-channel magnetic coupling mechanism and the S compensation network;

[0062] The series-parallel semi-active rectifier comprises: MOSFET tube Q S5 , MOSFET tube Q S6 , MOSFET tube QS7 , diode D1, diode D2, diode D3, series-parallel switch S SP1 And series-parallel switch S SP2 MOSFET tube Q S5 The first branch composed of diode D1 and MOSFET tube Q S6 The second branch composed of diode D2 and MOSFET tube Q S7 The first branch and the output end of the S compensation network of the first channel of the receiving end are connected in parallel with the third branch composed of the diode D3; the intersection of the first branch and the output end of the S compensation network of the first channel of the receiving end and the series-parallel switching switch S SP2 One end of the series-parallel switch S SP2 The other end of the first branch is connected to the third branch; the intersection of the first branch and the output end of the S compensation network of the second channel of the receiving end is connected to the series-parallel switching switch S SP1 One end of the series-parallel switch S SP2 The other end is connected to the second branch;

[0063] Series-parallel switch S SP1 And series-parallel switch S SP2 Used to switch the working mode of series-parallel semi-active rectifiers to achieve output control of different voltage levels.

[0064] Among them, MOSFET tubes Q1 to Q4 and MOSFET tubes Q5 to Q8 respectively form a dual-channel inverter connected in parallel at the sending end. F1 , capacitor C F1 and capacitor C P1 With inductance L F2 , capacitor C F2 and capacitor C P2 The dual-channel LCC compensation network at the transmitting end is composed of capacitors C S1 and capacitor C S2 The dual-channel S compensation network capacitance at the receiving end. The transmitting end of the dual-channel magnetic coupling mechanism uses two orthogonally placed DD-type coils L T1 and coil L T2 , receiving coil L R1 and coil L R2 Has a symmetrical structure. 11 and M 22 The mutual inductance between two coaxially placed coils on both sides. PS , capacitor C PS The transmitting end current sharing channel, inductor L SS , capacitor C SS It is a receiving end current sharing channel; the transmitting end current sharing channel and the receiving end current sharing channel provide a path for the power balancing current.

[0065] The series-parallel switch S SP1 Including: MOSFET tube Q connected in reverse series S1 and MOSFET tube Q S2 ;

[0066] The series-parallel switch S SP2 Including: MOSFET tube Q connected in reverse series S3 and MOSFET tube Q S4 .

[0067] In order to simplify the analysis, all MOSFET tubes, diodes, inductors, capacitors and other components are ideal devices, and the dual-channel inverter at the sending end is driven by the same control pulse; according to the series-parallel switching switch S SP1 And series-parallel switch S SP2 The switching state of the series-parallel semi-active rectifier divides the working mode into parallel working mode and series working mode; the circuit working principle of the working mode, such as Figure 2 shown.

[0068] Parallel working mode:

[0069] The SPSAR input voltage V REC1 , voltage V REC2 The positive half cycle (V REC1 >0,V REC2 >0), and simultaneously close the series-parallel switch S SP1 And series-parallel switch S SP2 , turn on the MOSFET tube Q S6 and MOSFET tube Q S7 , turn off MOSFET tube Q S5 Current I REC1 Through diode D1 and MOSFET tube Q S6 Give the load resistor R L Charging, current I REC2 Through diode D1 and MOSFET tube Q S7 Give the load resistor R L Charging, the current path is as follows Figure 2 part (a) of the

[0070] Input voltage V of series-parallel semi-active rectifier REC1 and input voltage V REC2 In the negative half cycle, the series-parallel switching switch S SP1 And series-parallel switch S SP2 Turn off and turn on MOSFET tube Q S5 , turn off MOSFET tube Q S6 and MOSFET tube Q S7; Current I REC1 Through diode D2 and MOSFET tube Q S5 Give the load resistor R L Charging, current I REC2 Through diode D3 and MOSFET tube Q S5 Give the load resistor R L Charging; the current path is as follows Figure 2 part (b) of the

[0071] In the parallel working mode, the two channel outputs of the receiving end are connected in parallel, and the load resistance R L Charging, charging current I O The current I of the two channels output REC1 and current I REC2 sum;

[0072] Series working mode:

[0073] The SPSAR input voltage V REC1 , voltage V REC2 The positive half cycle (V REC1 >0,V REC2 >0), turn on the series-parallel switch S SP1 , turn off the series-parallel switch S SP2 , turn on MOSFET tube Q S7 , turn off MOSFET tube Q S5 and MOSFET tube Q S6 The series current of the two channels I REC1 =I REC2 Through diode D1, MOSFET tube Q S7 And series-parallel switch S SP1 Give the load resistor R L Charging, the current path is as follows Figure 2 As shown in part (c) of .

[0074] The SPSAR input voltage V REC1 , voltage V REC2 The negative half cycle (V REC1 <0, V REC2 <0), turn on the series-parallel switch S SP2 , turn off the series-parallel switch S SP1 , turn on MOSFET tube Q S5 , turn off MOSFET tube Q S6 and MOSFET tube Q S7 The series current of the two channels I REC1 =I REC2 Through diode D2, MOSFET tube Q S5 And series-parallel switch SSP2 Give the load resistor R L Charging, the current path is as follows Figure 2 As shown in part (d) of .

[0075] In the series operation mode, the two channels of the receiving end are output in series, and the load resistance R L Charging, charging voltage V O is the input voltage V of the series-parallel semi-active rectifier REC1 and input voltage V REC2 sum.

[0076] To further elaborate on the working mode, Figure 3 The rectifier working waveform is shown.

[0077] According to the series-parallel switching switch (S SP1 , S SP2 ) working state, the system can work in series or parallel working mode. In the parallel working mode, the series-parallel switching switch S SP1 And series-parallel switch S SP2 At the same time, it is always turned off, and the two channels are output in parallel. In the series operation mode, the input voltage of the receiving end rectifier bridge V REC1 and voltage V REC2 In the positive half cycle, the series-parallel switch S SP1 Open, series-parallel switch S SP2 Shutdown, voltage V REC1 and voltage V REC2 In the negative half cycle, the series-parallel switch S SP1 Shutdown, series-parallel switching switch S SP2 The fundamental wave equivalent circuit of the system series and parallel working modes is as follows: Figure 4 As shown in Figure 1, all current and voltage variables are represented by fundamental phasors.

[0078] like Figure 4 As shown, the parallel and series working modes of the system can be represented as matrices by applying KVL:

[0079]

[0080] Among them, the output voltage amplitude and phase of the dual-channel inverter are the same, which can be expressed as:

[0081] The impedance of the above matrix can be expressed as:

[0082] When the system operates in a known resonant state, all impedances are zero.

[0083] In order to simplify the parameter design of the system, the same circuit parameters are selected for the two channels:

[0084]

[0085] Furthermore, the current parameter determination process of the parallel working mode and the series working mode specifically includes:

[0086]

[0087] Among them, the current parameters include: the output current of the dual-channel inverter and output current Transmitter coil current and coil current Coil current at the receiving end and coil current Input current of series-parallel semi-active rectifier and input current Transmitter current sharing channel current Share channel with receiving current L F The inductance and resistance of the dual-channel LCC compensation network are R EP is the resistance in parallel working mode, R ES is the resistance in the series working mode, α is the conduction angle of the series-parallel semi-active rectifier, according to αT S / 2π determines the on-time of the rectifier working mode, T S is the switching duty cycle of the system, ω is the system angular frequency, j is a complex number, L T is the coil inductance at the transmitting end, where the current and parameters σ are: L R is the coil inductance at the receiving end, V IN is a DC voltage source, M 11 and M 22 It is the mutual inductance between two coaxially placed coils on both sides.

[0088] The voltage gain G of the system in parallel and series working modes can be obtained by determining the current parameter formula. VV for:

[0089]

[0090] Among them, the input voltage V REC =V REC1 =V REC2 , G VV_EP and G VV_ESThey are the system voltage gains in parallel and series working modes respectively. It can be seen that the system voltage gain in the series working mode is twice that in the parallel working mode.

[0091] The output power P of the dual-channel inverter INV1 And the output power P INV2 for:

[0092] Regardless of the series or parallel working mode, the input current of the series-parallel semi-active rectifier and input current for:

[0093] Input voltage of series-parallel semi-active rectifier and input voltage for:

[0094] It can be seen that the input voltage and current of the series-parallel semi-active rectifiers are equal, which can ensure that the proposed system can simultaneously realize series and parallel operations at the output end.

[0095] Input power P of series-parallel semi-active rectifier REC1 and input power P REC2 for:

[0096] Transmitter coil current and coil current The coil current at the receiving end and coil current satisfy

[0097] and So it can be approximately considered and The transmitting coil transmits power P LT1 and coil transmission power P LT2 The power P transmitted to the receiving coil LR1 and coil transmission power P LR2 for:

[0098] In order to illustrate the advantages of the proposed current sharing method in balancing the dual-channel transmission power of the system, a simulation study of the system is carried out based on the simulation parameters in Table 1. Under different mutual inductance values ​​of the dual channels, with or without current sharing channels, the system inverter output voltage and current (V INV1 ,V INV2 ,I INV1 ,I INV2 ), rectifier input voltage and current (V REC1 ,VREC2 ,I REC1 ,I REC2 ) and the shared channel current (I PS ,I SS ) waveform, and also compared the power balance performance of the system in series-parallel working mode. The corresponding simulation analysis results in the series working mode are as follows Figure 9-12 As shown, in this working mode, sharing the channel can also ensure the power balance of the two channels when the mutual inductances are inconsistent.

[0099] Table 1

[0100]

[0101]

[0102] Figure 5-Figure 8 The simulation waveforms of the system with and without shared channels under different mutual inductance conditions in parallel working mode are shown. Figure 9-12 is the corresponding simulation waveform in the series working mode. In the parallel working mode, when the dual-channel magnetic coupling mechanism is fully aligned (M 11 =M 22 ), with or without current sharing channels, the output current of the dual-channel inverter (I INV1 ,I INV2 ), series-parallel semi-active rectifier input current (I REC1 ,I REC2 ) are equal, such as Figure 5 and Figure 6 As shown, the transmission power of the two channels is balanced, and the shared channel current (I PS ,I SS ) is 0. However, when the dual-channel magnetic coupling mechanism is offset by 15 cm along the x-axis direction (M 11 ≠M 22 ), in the case of no current sharing channel, the channel with larger mutual inductance bears almost all the transmission power, while the other channel has almost no transmission power. The output voltage and current (V INV1 ,V INV2 ,I INV1 ,I INV2 ), series-parallel semi-active rectifier input voltage and current (V REC1 ,V REC2 ,I REC1 ,I REC2 )'s simulation waveform is as follows Figure 7 Under this condition, the proposed current sharing channel is added. Under the action of bilateral current sharing, the transmission power of the two channels is restored to balance, and the output voltage and current of the dual-channel inverter (V INV1 ,V INV2 ,IINV1 ,I INV2 ), series-parallel semi-active rectifier input voltage and current (V REC1 ,V REC2 ,I REC1 ,I REC2 ) and the shared channel current (I PS ,I SS ) has a waveform such as Fig. 9 shown.

[0103] Through the above analysis, it can be seen that the present application can simultaneously achieve the power balance of the dual-channel inverter, the transmitting and receiving coils, and the series-parallel semi-active rectifier, and it can simultaneously complete the series-parallel operation of the two channels. The above power balance can be achieved in the series-parallel working mode. This feature provides important support for the high efficiency and high power transmission of the proposed system.

[0104] On the basis of the receiving end SPSAR series-parallel working mode, a series-parallel freewheeling working mode is added to adjust the output voltage, thereby realizing the output control of the system. The circuit working principles of the series-parallel freewheeling working mode are introduced below. The current path diagram is as follows Fig.13 shown.

[0105] Parallel freewheeling working mode:

[0106] The SPSAR input voltage V REC1 , V REC2 The positive half cycle (V REC1 >0,V REC2 >0), and simultaneously close the series-parallel switch S SP1 and S SP2 , and turn on MOSFET Q S5 , Q S6 and Q S7 Current I REC1 Q S5 (forward conduction) and Q S6 (Reverse conduction) only at L R1 and C S1 Between the continuous flow work, I REC1 No flow to load R L , output capacitor C O For load R L Charging. Current I REC2 Q S5 (forward conduction) and Q S7 (Reverse conduction) only at L R2 and C S2 Between the continuous flow work, I REC2 No flow to load R L , output capacitor C O For load R LCharging. The above current path is as follows Fig.13 As shown in part (a) of .

[0107] The SPSAR input voltage V REC1 , V REC2 The negative half cycle (V REC1 <0, V REC2 <0), and simultaneously close the series-parallel switch S SP1 and S SP2 , and turn on MOSFET Q S5 , Q S6 and Q S7 Current I REC1 Q S6 (forward conduction) and Q S5 (Reverse conduction) only at L R1 and C S1 Between the continuous flow work, I REC1 No flow to load R L , output capacitor C O For load R L Charging. Current I REC2 Q S7 (forward conduction) and Q S5 (Reverse conduction) only at L R2 and C S2 Between the continuous flow work, I REC2 No flow to load R L , output capacitor C O is the load resistance R L Charging. The above current path is as follows Fig.13 As shown in part (b) of .

[0108] In the parallel freewheeling mode, the output power of the two channels is in the form of reactive power in coil L R1 Resonant capacitor C S1 , and coil L R2 , resonant capacitor C S2 flows between the load R L Provides power, at this time by the output capacitor C O is the load resistance R L Charge.

[0109] Series freewheeling working mode:

[0110] The SPSAR input voltage V REC1 , V REC2 The positive half cycle (V REC1 >0,V REC2 >0), turn on the series-parallel switch S at the same time SP1 and S SP2 , and turns off MOSFET QS5 , Q S6 and Q S7 The series current of the two channels I REC1 =I REC2 S SP1 and S SP2 Only in L R1 , L R2 and C S1 , C S2 The current does not flow to the load R L , output capacitor C O For load R L Charging. The above current path is as follows Fig.13 As shown in part (c) of .

[0111] The SPSAR input voltage V REC1 , V REC2 The negative half cycle (V REC1 <0, V REC2 <0), S SP1 and S SP2 , and turns off MOSFET Q S5 , Q S6 and Q S7 The switching state of the positive half cycle is the same as that of the positive half cycle, except that the current direction is opposite to that of the positive half cycle. Similarly, the series current I REC1 =I REC2 S SP1 and S SP2 Only in L R1 , L R2 and C S1 , C S2 The current does not flow to the load R L , output capacitor C O is the load resistance R L Charging. The above current path is as follows Fig.13 As shown in part (d) of .

[0112] Similarly, in the series continuous flow mode, the output power of the two channels is in the form of reactive power in the coil L R1 , L R2 and resonant capacitor C S1 , C S2 The current flows between the series circuits and not to the load R L Provides power, at this time by the output capacitor C O is the load resistance R L Charge.

[0113] pass Fig.14 The operating waveform shown further explains the freewheeling operating mode in detail.

[0114] According to the above working principle and system working waveform analysis, the rectifier input voltage V REC1 , V REC2 It can be expressed as:

[0115]

[0116] Define the on-time of the working mode as αT S / 2π, where α is the conduction angle of the series-parallel semi-active rectifier, T S is the switching duty cycle of the system, then V REC1 , V REC2 It can be expressed as:

[0117]

[0118] The system output voltage V O It can be expressed as:

[0119]

[0120] Among them, V REC =V REC1 =V REC2 .

[0121] In parallel and series operation modes,

[0122] By adjusting α only R E The size of , which is always a pure resistor, provides guarantee for the ZPA and ZVS operation of the system.

[0123] Voltage gain G VV for:

[0124]

[0125] Among them, G VV_EP is the voltage gain in parallel operation mode, G VV_ES is the voltage gain in series operation mode, V O is the output voltage.

[0126] When other system parameters remain unchanged, the voltage gain G VV It is only related to the conduction angle α of the series-parallel semi-active rectifier. Therefore, the output control of the proposed WPT system can be achieved by adjusting the value of α, and the output requirements of different voltage levels of 400V / 800V can be adapted by switching the series-parallel working mode of the rectifier. It does not require bilateral communication between the transmitter and the receiver, which reduces the complexity of the system and improves reliability.

[0127] like Fig.15 As shown, the charging control method includes:

[0128] S1, start the dual-channel inverter at the sending end;

[0129] The sending end controller DSP generates a PWM control signal S P1 ~S P8 Input PWM driver, PWM driver outputs two sets of drive pulses Q with the same frequency and phase P1 ~Q P4 and Q P5 ~Q P8 Drive dual-channel inverters separately;

[0130] S2, input current I to the series-parallel semi-active rectifier S1 and I S2 Sampling is performed to obtain the current sampling signal I′ S1 and I′ S2 ;

[0131] S3, according to the current sampling signal I' S1 and I′ S2 , obtain the rectangular wave signal S through the zero-crossing comparator S1 and S S2 ;

[0132] S4 uses differential resistor voltage division and high-precision sampling resistor to respectively measure the output voltage V of the series-parallel redundant WPT system. O and output current I O Sampling is performed to obtain the output voltage sampling signal and output current sampling signal V′ of the series-parallel redundant WPT system O and I′ O ;

[0133] S5, in the receiving end controller DSP, according to the external input battery pack voltage level signal S MOD Determine the operating mode of the series-parallel semi-active rectifier;

[0134] S6, comparing the output voltage sampling signal and the output current sampling signal with the target voltage and current to obtain a comparison result;

[0135] S7, according to the comparison result, using the PI control method to control the conduction angle α of the series-parallel semi-active rectifier and obtain a control signal;

[0136] S8, perform synchronous correction on the control signal and output PWM control signal S S1 ~S S8 ;

[0137] S9, the PWM driver controls the PWM signal S S1 ~S S8 Output drive pulse Q S1 ~QS4 and Q S5 ~Q S7 , according to the driving pulse Q S1 ~Q S4 and Q S5 ~Q S7 Control series-parallel switch S SP1 And series-parallel switch S SP2 And the MOSFET tube in the series-parallel semi-active rectifier completes the output control of the series-parallel redundant WPT system.

[0138] like Fig.16 As shown, in order to simultaneously meet the charging needs of electric vehicles with 400V and 800V electrical architectures, it is usually necessary to design different compensation network parameters or circuit topologies for the WPT system to ensure the system's power output capacity and output voltage range. This application, without changing the system's compensation network parameters and circuit topology, controls the series-parallel operating mode switching of the SPSAR and the conduction angle of the series-parallel semi-active rectifier, and is compatible with the charging needs of electric vehicles with 400V and 800V electrical architectures, and can achieve the designed 30kW power output at both 400V and 800V voltage levels. The specific electrical parameter design method and compatibility analysis are shown below. Fig.16 As shown, it is divided into the following 4 steps.

[0139] Step 1: Determine the voltage level of the battery pack and determine the series-parallel operating mode.

[0140] The voltage range of the 400V voltage level battery pack is designed to be 320-425V, and the two-channel parallel working mode is adopted at the receiving end. The voltage range of the 800V voltage level battery pack is designed to be 640-850V, and the two-channel series working mode is adopted at the receiving end. Both working modes meet the system maximum output power of 30kW.

[0141] Step 2: Configure the resonant compensation network parameters.

[0142] Under the condition of system rated working condition and magnetic coupling alignment, determine the maximum mutual inductance value M of the two channels 11_max and M 22_max According to M 11_max , M 22_max And the low output voltage 320V and 640V configuration resonant compensation network parameters in two working modes, and according to G in formula (5.20) VV Verify that the output voltage ranges of the two systems must meet 320-425V and 640-850V respectively.

[0143] Step 3: Verify the system output capability at maximum excursion.

[0144] Under the condition of maximum magnetic coupling offset, the minimum mutual inductance values ​​M11_min and M22_min of the two channels are determined. 11_min and M 22_min and G VV Verify that the output voltage ranges of the two systems must meet 320-425V and 640-850V respectively, to ensure that the system can achieve the designed power and voltage output range under the maximum deviation.

[0145] Step 4: Evaluate system performance indicators to guide component selection.

[0146] Under the worst working conditions of the system, evaluate the voltage and current stress of the switching devices, resonant capacitors, inductors, coils and other components in the system to determine their selection basis. For example, determine the type and quantity of MOSFET tubes and diodes based on voltage, current and dissipated power, determine the withstand voltage value and quantity of resonant capacitors based on voltage and current, and determine the wire diameter of resonant inductors and coils. Finally, evaluate the system's transmission power and efficiency and other performance indicators through loss calculation.

[0147] This application can simultaneously meet the high-power wireless charging needs of electric vehicles with different electrical architectures of 400V and 800V. First, the series-parallel working mode analysis was carried out for the power topology of the proposed system, and on this basis, the equivalent circuit models of the two working modes were established respectively. The system characteristics such as system output performance, power balance performance, and the impact of shared channels on the system were analyzed. Then, according to the SPSAR working mode of the receiving end and the conduction angle of the series-parallel semi-active rectifier, the control mechanism and system voltage gain were determined, and a series-parallel redundant output charging control method was formulated; a series-parallel redundant output control method was formulated based on SPSAR, and an electrical parameter design method compatible with 400V / 800V voltage level systems was proposed. Finally, a 30kW principle prototype was established to verify the feasibility and effectiveness of the proposed system. The results show that the proposed SPR WPT system is compatible with the wireless charging needs of electric vehicles with 400V and 800V voltage levels, and can achieve the designed maximum charging power under both voltage level output conditions. At the same time, it can also solve the power imbalance problem caused by the inconsistent mutual inductance of the dual-channel coils.

[0148] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0149] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. A series-parallel redundant WPT system based on dual-channel current sharing, characterized in that: The series-parallel redundant WPT system based on dual-channel current sharing includes: a DC voltage source V IN , dual-channel inverter, dual-channel LCC compensation network, S compensation network, dual-channel magnetic coupling mechanism, transmitting end current sharing channel, receiving end current sharing channel, series-parallel semi-active rectifier, filter capacitor C O and load resistance R L ; At the sending end, the DC voltage source V IN The dual-channel inverter, the dual-channel LCC compensation network and the dual-channel magnetic coupling mechanism are connected; the transmitting end current sharing channel is located between the dual-channel LCC compensation network and the dual-channel magnetic coupling mechanism; At the receiving end, the dual-channel magnetic coupling mechanism is connected through the S compensation network, the series-parallel semi-active rectifier and the load resistor R L Connection: Filter capacitor C O and load resistance R L Parallel connection; the current sharing channel at the transmitting end is located between the dual-channel magnetic coupling mechanism and the S compensation network; The series-parallel semi-active rectifier comprises: MOSFET tube Q S5 , MOSFET tube Q S6 , MOSFET tube Q S7 , diode D1, diode D2, diode D3, series-parallel switch S SP1 And series-parallel switch S SP2 MOSFET tube Q S5 The first branch composed of diode D1 and MOSFET tube Q S6 The second branch composed of diode D2 and MOSFET tube Q S7 The first branch and the output end of the S compensation network of the first channel of the receiving end are connected in parallel with the third branch composed of the diode D3; the intersection of the first branch and the output end of the S compensation network of the first channel of the receiving end and the series-parallel switching switch S SP2 One end of the series-parallel switch S SP2 The other end of the first branch is connected to the third branch; the intersection of the first branch and the output end of the S compensation network of the second channel of the receiving end is connected to the series-parallel switching switch S SP1 One end of the series-parallel switch S SP2 The other end is connected to the second branch; Series-parallel switch S SP1 And series-parallel switch S SP2 Used to switch the working mode of series-parallel semi-active rectifiers to achieve output control of different voltage levels.

2. The series-parallel redundant WPT system based on dual-channel current sharing according to claim 1 is characterized in that: The working modes of the series-parallel semi-active rectifier include: parallel working mode and series working mode; In the parallel working mode, the two channel outputs of the receiving end are connected in parallel, and the load resistance R L Charging, charging current I O The current I of the two channels output REC1 and current I REC2 sum; In the series operation mode, the two channels of the receiving end are output in series, and the load resistance R L Charging, charging voltage V O is the input voltage V of the series-parallel semi-active rectifier REC1 and input voltage V REC2 sum.

3. The series-parallel redundant WPT system based on dual-channel current sharing according to claim 2 is characterized in that: The series-parallel switch S SP1 Including: MOSFET tube Q connected in reverse series S1 and MOSFET tube Q S2 ; The series-parallel switch S SP2 Including: MOSFET tube Q connected in reverse series S3 and MOSFET tube Q S4 .

4. The series-parallel redundant WPT system based on dual-channel current sharing according to claim 2 is characterized in that: The current parameter determination process of the parallel working mode and the series working mode specifically includes: Among them, the current parameters include: the output current of the dual-channel inverter and output current Transmitter coil current and coil current Coil current at the receiving end and coil current Input current of series-parallel semi-active rectifier and input current Transmitter current shares channel current Share channel with receiving current L F The inductance and resistance of the dual-channel LCC compensation network are R EP is the resistance in parallel working mode, R ES is the resistance in the series working mode, α is the conduction angle of the series-parallel semi-active rectifier, according to αT S / 2π determines the on-time of the rectifier working mode, T S is the switching duty cycle of the system, ω is the system angular frequency, j is a complex number, L T is the coil inductance at the transmitting end, where the current and parameters σ are: L R is the coil inductance at the receiving end, VIN is the DC voltage source, M 11 and M 22 It is the mutual inductance between two coaxially placed DD type coils on both sides.

5. The series-parallel redundant WPT system based on dual-channel current sharing according to claim 4 is characterized in that: The output power P of the dual-channel inverter INV1 And the output power P INV2 for:

6. The series-parallel redundant WPT system based on dual-channel current sharing according to claim 4 is characterized in that: Input current of series-parallel semi-active rectifier and input current for: Input voltage of series-parallel semi-active rectifier and input voltage for: Input power P of series-parallel semi-active rectifier REC1 and input power P REC2 for:

7. The series-parallel redundant WPT system based on dual-channel current sharing according to claim 4 is characterized in that: Transmitter coil current and coil current The coil current at the receiving end and coil current satisfy The transmitting coil transmits power P LT1 and coil transmission power P LT2 The power P transmitted to the receiving coil LR1 and coil transmission power P LR2 for:

8. The series-parallel redundant WPT system based on dual-channel current sharing according to claim 4 is characterized in that: Voltage gain G VV for: Among them, G VV_EP is the voltage gain in parallel operation mode, G VV_ES is the voltage gain in series operation mode, V O is the output voltage; according to It is known that the output voltage level of 400V or 800V is determined by using a determined working mode; and the output voltage control at different voltage levels is achieved by controlling the conduction angle α of the series-parallel semi-active rectifier.

9. The series-parallel redundant WPT system based on dual-channel current sharing according to claim 1 is characterized in that: The transmitting end of the dual-channel magnetic coupling mechanism uses two orthogonally placed DD-type coils L T1 and coil L T2 , the receiving coil L R1 and coil L R2 Has a symmetrical structure.

10. A charging control method for a series-parallel redundant WPT system based on dual-channel current sharing, applied to the series-parallel redundant WPT system based on dual-channel current sharing according to any one of claims 1-9, characterized in that: The charging control method comprises: Start the dual-channel inverter at the sending end; Sampling the input current of the series-parallel semi-active rectifier to obtain a current sampling signal; According to the obtained current sampling signal, a rectangular wave signal is obtained through a zero-crossing comparator; The output voltage V of the series-parallel redundant WPT system O and output current I O Perform sampling to obtain an output voltage sampling signal and an output current sampling signal of the series-parallel redundant WPT system; According to the external input battery pack voltage level signal S MOD Determine the operating mode of the series-parallel semi-active rectifier; Compare the output voltage sampling signal and the output current sampling signal with the target voltage and current to obtain a comparison result; According to the comparison result, the conduction angle α of the series-parallel semi-active rectifier is controlled by using the PI control method, and a control signal is obtained; Perform synchronous correction on the control signal and output PWM control signal; The PWM driver outputs a driving pulse according to the PWM control signal, and controls the series-parallel switching switch S according to the driving pulse. SP1 And series-parallel switch S SP2 And the MOSFET tube in the series-parallel semi-active rectifier completes the output control of the series-parallel redundant WPT system.

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