Integrated charging system and control method thereof

Abstract

The application discloses an integrated charging system and a control method thereof, and belongs to the technical field of new energy automobile charging. The integrated charging system comprises the following steps: performing double-port voltage independent control, controlling the integrated charging system to realize grid-side power factor correction in a charging process, performing motor torque ripple suppression in the charging process, and controlling the integrated charging system to realize double-port power distribution. The integrated charging system and the control method thereof can construct a multi-port integrated charging system without increasing winding switching switches, power devices and magnetic elements, and realize decoupling control of energy of each channel, thereby improving the reliability and safety of charging.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle charging technology, and in particular to an integrated charging system and its control method. Background Technology

[0002] With the rapid development of the new energy vehicle industry, higher demands are being placed on the driving range of electric vehicles. Traditional on-board chargers, as one of the main forms of electric vehicle charging, can be used as independent functional modules directly connected to the AC power grid, and have received widespread attention and research. However, because on-board chargers require dedicated power devices and passive components, they are typically installed on the vehicle, leading to hardware redundancy in the vehicle's electrical system, encroaching on interior space, and increasing overall vehicle manufacturing costs.

[0003] Therefore, many researchers have focused on on-board integrated charging systems that reuse electric vehicle motor windings and their drive systems. By deeply integrating the charging system with the drive system, the overall system integration is improved. The integrated charging system reconfigures the motor and its drive system into a charging system by reusing the power devices and motor windings of the motor drive system, converting the grid-side AC power into DC power to charge the battery. Compared to traditional stand-alone on-board chargers, the integrated solution significantly reduces the redundant configuration of power devices and magnetic components, reducing system complexity while improving system integration.

[0004] However, during the charging process, the current flowing through the reusable motor windings in an integrated charging system generates a magnetic field, which can cause the motor to vibrate or rotate, affecting the safety of the integrated charging system. Furthermore, to meet the energy exchange requirements of multi-battery systems in vehicles, electric vehicle electrical systems typically include multiple energy sources such as high-voltage power battery packs, low-voltage battery packs, and auxiliary power supplies. Traditional solutions rely on multi-stage converters to achieve energy transfer, leading to a significant increase in system size and cost. Summary of the Invention

[0005] The present invention aims to provide a multi-port integrated charging system and its control method without adding additional power devices, magnetic components, passive devices and switching switches, and to achieve decoupled control of energy in each channel, while simultaneously suppressing torque ripple during charging.

[0006] To achieve the above objectives, the technical solution of the present invention is as follows:

[0007] A control method for an integrated charging system includes performing independent dual-port voltage control. Specifically, this includes adjusting the output voltage of two independent channels using a voltage and outer-loop proportional-integral controller to output the DC component of a given input active current; adjusting the output voltage difference of the two independent channels using a voltage difference outer-loop proportional-integral controller to output the given amplitude of the AC component in the current vector; calculating the given two-phase current values ​​of the two independent channels based on the given amplitude of the DC component of the given input active current and the AC component in the current vector; subtracting these values ​​from the two-phase currents of the two independent channels; and passing the subtraction values ​​of the subtraction values ​​from the two-phase currents of the two independent channels to a proportional resonant controller. The output of the proportional resonant controller is then used to generate a switching signal through space vector pulse width modulation to drive the switches in the integrated charging system.

[0008] Furthermore, the control method for the aforementioned integrated charging system also includes controlling the integrated charging system to achieve grid-side power factor correction during the charging process, specifically including controlling the sum of the active currents of the dual rectifier units to be twice the DC component of the input active current; and controlling the sum of the reactive currents of the dual rectifier units to be zero.

[0009] Furthermore, the control method of the aforementioned integrated charging system also includes suppressing motor torque ripple during the charging process. Specifically, this includes controlling the DC component of the active current of the dual rectifier unit to be equal; when the AC component in the current vector of the dual rectifier unit transmits unbalanced power through the motor armature winding, the AC component in the current vector is distributed in the three-phase winding to make the q-axis current in the motor coordinate system cancel each other out, and the unbalanced power is transmitted through the d-axis current in the motor coordinate system.

[0010] Furthermore, the control method for the aforementioned integrated charging system also includes controlling the integrated charging system to achieve dual-port power distribution. Specifically, this includes controlling the DC components of the active current in the dual rectifier units to be equal, with a magnitude equal to the DC component of the given input active current; when the battery charging power in the two independent channels is not equal, by controlling the amplitude of the AC components in the current vectors of the two rectifier units, the difference in output power between the two channels is transmitted through the three-phase winding from the side with lower battery power requirement to the side with higher battery power requirement.

[0011] Furthermore, the control method for the aforementioned integrated charging system specifically includes the following steps: sampling the instantaneous value e of the three-phase grid voltage. a e b e c The instantaneous value of the three-phase current i of the first three-phase winding module a1 i b1 i c1 The instantaneous value of the three-phase current i of the second three-phase winding module a2 i b2 i c2The output voltage U of the first rectifier unit dc1 The output voltage U of the second rectifier unit dc2 ;

[0012] Using a grid-side voltage phase-locked loop, the fundamental frequency ω and phase angle ωt of the grid voltage are calculated; the two-phase current i of the first three-phase winding module and the second three-phase winding module in a synchronous rotating coordinate system oriented towards the grid voltage is also calculated. d1 i q1 i d2 i q2 ;

[0013] Calculate the output voltage U of the first rectifier unit. dc1 The output voltage U of the second rectifier unit dc2 The sum ΣU dc With the given output voltage U of the first rectifier unit dc1 * The given output voltage U of the second rectifier unit dc2 * The sum ΣU dc * Subtracting the two, the DC component I of the given input active current is output by the voltage and outer loop proportional-integral controller. g * ;

[0014] Calculate the output voltage U of the first rectifier unit. dc1 The output voltage U of the second rectifier unit dc2 The difference ΔU dc With the given output voltage U of the first rectifier unit dc1 * The given output voltage U of the second rectifier unit dc2 * The difference ΔU dc * Subtracting the two, the AC component of the output current vector from the voltage difference outer loop proportional-integral controller is given an amplitude I. m * ;

[0015] The AC component i in the current vector is calculated based on the phase angle ωt of the grid voltage and the rotor position angle θ of the motor. m * The expression is:

[0016] i m * =I m * cos(ωt-θ);

[0017] Calculate the given value i of the AC component in the current vector. m* The given value i of the d-axis component in the synchronous rotating coordinate system oriented by grid voltage. d_m * q-axis component given value i q_m * The expression is:

[0018]

[0019] Calculate the two-phase current setpoint i of the first three-phase winding module and the second three-phase winding module in a synchronous rotating coordinate system oriented by grid voltage. d1 * i q1 * i d2 * i q2 * The expression is as follows:

[0020]

[0021] Among them, i d1 * The given value for the d-axis current of the first three-phase winding module in the synchronous rotating coordinate system is i. q1 * The given value for the q-axis current of the first three-phase winding module in the synchronous rotating coordinate system is i. d2 * The given value for the d-axis current of the second and third phase winding modules in the synchronous rotating coordinate system is i. q2 * The given value for the q-axis current of the second and third phase winding modules in the synchronous rotating coordinate system;

[0022] The two-phase currents i of the first three-phase winding module and the second three-phase winding module in a synchronous rotating coordinate system oriented towards grid voltage are considered. d1 i q1 i d2 i q2 With the two-phase current given value i d1 * i q1 * i d2 * i q2 * The corresponding difference is input to the proportional resonant controller to realize closed-loop control of the two-phase current. The output of the proportional resonant controller is generated into a switching signal through space vector pulse width modulation to drive the switch in the integrated charging system.

[0023] Furthermore, the current value in the motor windings is:

[0024] imotor_d =i m

[0025] i motor_q =0

[0026] Among them, i motor_d This refers to the current vector in the rotor direction, i.e., the d-axis current in the motor coordinate system; i motor_q i is the q-axis current in the motor coordinate system; m This represents the AC component in the current vector.

[0027] This invention also provides an integrated charging system, applying the control method of the aforementioned integrated charging system. The integrated charging system includes an open-winding motor unit, a first rectifier unit, a second rectifier unit, a charging control unit, a first battery, and a second battery. A three-phase power grid is connected to the first end of the open-winding motor unit. The second end of the open-winding motor unit is connected to the first end of the first rectifier unit. The second end of the first rectifier unit is connected to the first battery. The third end of the open-winding motor unit is connected to the first end of the second rectifier unit. The second end of the second rectifier unit is connected to the second battery. The charging control unit outputs drive signals for the switches in the first rectifier unit and the second rectifier unit.

[0028] Furthermore, the open-winding motor unit includes a first three-phase winding module and a second three-phase winding module. The first end of the first three-phase winding module and the first end of the second three-phase winding module are connected to form the first end of the open-winding motor unit. The second end of the first three-phase winding module is the second end of the open-winding motor unit, and the second end of the second three-phase winding module is the third end of the open-winding motor unit.

[0029] Furthermore, the open-winding motor unit is an open-winding permanent magnet synchronous motor.

[0030] Furthermore, the first rectifier unit and the second rectifier unit are three-phase rectifier units.

[0031] Beneficial effects: This invention provides an integrated charging system and its control method. Based on the open-winding motor drive system of an electric vehicle, the drive system is reconfigured into a common-input dual-rectifier unit to charge the power battery of two channels. By controlling the sum of the active current and reactive current of the dual-rectifier unit, grid-side power factor correction is achieved during the charging process. By controlling the magnitude of the DC component and the difference between the AC components of the active current of the dual-rectifier unit, the sum of active power and unbalanced power at both ports are controlled, realizing an output power distribution strategy for the independent channels at both ports. The output voltage of the two independent channels is adjusted by voltage and outer loop and voltage difference outer loop, achieving independent voltage control at both ports. By controlling the DC component of the active current in the dual-rectifier unit to be equal, magnetic flux balance is achieved, eliminating electromagnetic torque pulsation during the charging process. By distributing the AC component in the current vector in the three-phase windings, torque balance is achieved, suppressing the pulsating torque generated during the unbalanced power transfer process, thereby suppressing motor torque pulsation. This invention constructs a multi-port integrated charging system without adding winding switching switches, power devices, and magnetic components, and achieves decoupled control of energy in each channel, thereby improving the reliability and safety of charging.

[0032] To make the above-mentioned features and advantages of the invention more apparent and understandable, specific embodiments are described below, and detailed descriptions are provided in conjunction with the accompanying drawings. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of an integrated charging system according to the present invention.

[0034] Figure 2 for Figure 1 A circuit diagram of a specific embodiment of the open-circuit winding motor unit and rectifier unit.

[0035] Figure 3 This is a simulation waveform diagram of an integrated charging system according to the present invention. Detailed Implementation

[0036] To make the objectives and technical solutions of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the described embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0037] Figure 1 This is a schematic diagram of an integrated charging system according to the present invention. Figure 1As shown, the integrated charging system of the present invention includes an open-winding motor unit 1, a first rectifier unit 2, a second rectifier unit 3, a charging control unit 4, a first battery 5, and a second battery 6. A three-phase power grid is connected to the first end of the open-winding motor unit 1. The second end of the open-winding motor unit 1 is connected to the first end of the first rectifier unit 2. The second end of the first rectifier unit 2 is connected to the first battery 5. The third end of the open-winding motor unit 1 is connected to the first end of the second rectifier unit 3. The second end of the second rectifier unit 3 is connected to the second battery 6. The charging control unit 4 outputs drive signals for the switches in the first rectifier unit 2 and the second rectifier unit 3.

[0038] More specifically, the open-winding motor unit 1 includes a first three-phase winding module 11 and a second three-phase winding module 12. The first end of the first three-phase winding module 11 and the first end of the second three-phase winding module 12 are connected to form the first end of the open-winding motor unit 1. The second end of the first three-phase winding module 11 is the second end of the open-winding motor unit 1, and the second end of the second three-phase winding module 12 is the third end of the open-winding motor unit 1.

[0039] More specifically, the open-winding motor unit 1 is an open-winding permanent magnet synchronous motor, and the first end of the open-winding motor unit 1 is the center tap of the three-phase winding.

[0040] More specifically, the first rectifier unit 2 and the second rectifier unit 3 are three-phase rectifier units.

[0041] Optionally, the first rectifier unit 2 and the second rectifier unit 3 are pulse width modulation (PWM) rectifier units.

[0042] More specifically, during charging, the three-phase grid is connected to the center tap of the three-phase winding of the open-winding motor unit 1. Without the need for a winding switching switch, the dual three-phase rectifier unit and the two sets of three-phase winding modules are reconfigured into a common-input dual-pulse-width modulation (PWM) rectifier, charging the batteries for two channels respectively. The charging control unit 4 controls the common-input dual three-phase rectifier unit using the control method of this integrated charging system, achieving grid-side power factor correction, dual-port power distribution, independent dual-port voltage control, and motor torque ripple suppression during the charging process.

[0043] Please continue to refer to this. Figure 1 In one specific embodiment, the first three-phase winding module 11 includes a first A-phase winding L a1 First B-phase winding L b1 First C-phase winding L c1 The first A-phase winding L a1 The first terminal is connected to the A-phase grid voltage e a The first B-phase winding L b1 The first terminal is connected to the B-phase grid voltage e b The first C-phase winding Lc1 The first terminal is connected to the C-phase grid voltage e c The first A-phase winding L a1 The second end, the first B-phase winding L b1 The second end, the first C-phase winding L c1 The second end is connected to the first rectifier unit 2.

[0044] Furthermore, the second three-phase winding module 12 includes a second A-phase winding L a2 Second phase B winding L b2 Second C-phase winding L c2 The second phase A winding L a2 The first terminal is connected to phase A of the power grid. a The second phase B winding L b2 The first terminal is connected to the B-phase power grid. b The second C-phase winding L c2 The first end is connected to the C-phase power grid e c The second phase A winding L a2 The second end, the second B-phase winding L b2 The second end, the second C-phase winding L c2 The second end is connected to the second rectifier unit 3.

[0045] Please refer to Figure 2 In one specific embodiment, the first rectifier unit 2 includes a first A-phase bridge arm 21, a first B-phase bridge arm 22, and a first C-phase bridge arm 23. The first A-phase bridge arm 21, the first B-phase bridge arm 22, and the first C-phase bridge arm 23 are connected in parallel. The midpoint of the bridge arm 21 of the first A-phase bridge arm is connected to the first A-phase winding L. a1 At the second end, the midpoint of the first B-phase bridge arm 22 is connected to the first B-phase winding L. b1 At the second end, the midpoint of the first C-phase bridge arm 23 is connected to the first C-phase winding L. c1 The second end, the two ends of the first A-phase bridge arm 21, the first B-phase bridge arm 22, and the first C-phase bridge arm 23 connected in parallel, are connected in parallel with the two ends of the first battery 5.

[0046] Furthermore, the first A-phase bridge arm 21 includes switch S1 and switch S2, which are connected in series; the first B-phase bridge arm 22 includes switch S3 and switch S4, which are connected in series; and the first C-phase bridge arm 23 includes switch S5 and switch S6, which are connected in series.

[0047] Please continue to refer to this. Figure 2 In one specific embodiment, the second rectifier unit 3 includes a second A-phase bridge arm 31, a second B-phase bridge arm 32, and a second C-phase bridge arm 33, which are connected in parallel. The midpoint of the bridge arm 31 of the second A-phase bridge arm is connected to the second A-phase winding L.a2 At the second end, the midpoint of the bridge arm 32 of the second B phase is connected to the second B phase winding L. b2 At the second end, the midpoint of the bridge arm 33 of the second C-phase bridge is connected to the second C-phase winding L. c2 The second end of the second phase bridge arm 31, the second phase bridge arm 32, and the second phase bridge arm 33 are connected in parallel to the two ends of the second battery 6.

[0048] Furthermore, the second phase A bridge arm 31 includes switch S 11 With switch S 12 Switch S 11 With switch S 12 Series connection; the second phase B bridge arm 32 includes switch S9 and switch S 10 Switch S9 and switch S 10 The second C-phase bridge arm 33 includes switch S7 and switch S8, which are connected in series.

[0049] Optionally, the integrated charging system of the present invention further includes a capacitor C. bus1 Capacitor C bus1 They are connected in parallel across the two ends of the first battery 5.

[0050] Optionally, the integrated charging system of the present invention further includes a capacitor C. bus2 Capacitor C bus2 It is connected in parallel across the two ends of the second battery 6.

[0051] The present invention also provides a control method for an integrated charging system, including controlling the integrated charging system to achieve grid-side power factor correction during the charging process.

[0052] Furthermore, the integrated charging system is controlled to achieve grid-side power factor correction during the charging process. Specifically, this includes controlling the sum of the active currents of the dual rectifier units to be twice the DC component I of the input active current. g This enables the control of instantaneous active power on the grid side, thereby controlling the total power of dual-port charging. By controlling the sum of reactive currents of the dual rectifier units to zero, the instantaneous reactive power on the grid side is controlled to zero, allowing the integrated charging system to operate in a unity power factor state, thus enabling the integrated charging system to achieve grid-side power factor correction during the charging process.

[0053] More specifically, in a grid voltage-oriented synchronous rotating coordinate system, the instantaneous active power p on the grid side of the integrated charging system... g and grid-side instantaneous reactive power q g It can be represented as:

[0054]

[0055] Among them, e dThe voltage along the d-axis in a synchronously rotating coordinate system; e q The voltage across the q-axis in a synchronously rotating coordinate system; i d This refers to the d-axis current in a synchronously rotating coordinate system, i.e., the active current; q This refers to the q-axis current in the synchronously rotating coordinate system, i.e., the reactive current.

[0056] When based on grid voltage orientation, e q =0, therefore the above expression can be further simplified to:

[0057]

[0058] Therefore, the instantaneous active power p on the grid side g With the d-axis current i in the synchronous rotating coordinate system d Related to the instantaneous reactive power q on the grid side g With the q-axis current i in the synchronous rotating coordinate system q related.

[0059] When the transmission power of the two ports in the integrated charging system is equal, the current of the two three-phase winding modules in the synchronous rotating coordinate system oriented by the grid voltage can be further expressed as follows:

[0060]

[0061] Where p1 is the instantaneous active power on the grid side of the first rectifier unit 2, p2 is the instantaneous active power on the grid side of the second rectifier unit 3, q1 is the instantaneous reactive power on the grid side of the first rectifier unit 2, and q2 is the instantaneous reactive power on the grid side of the second rectifier unit 3; i d1 This refers to the d-axis current of the first three-phase winding module 11 in the synchronous rotating coordinate system, i.e., the active current of the first three-phase winding module 11; q1 i represents the q-axis current of the first three-phase winding module 11 in the synchronous rotating coordinate system, i.e., the reactive current of the first three-phase winding module 11; d2 This refers to the d-axis current of the second three-phase winding module 12 in the synchronous rotating coordinate system, i.e., the active current of the second three-phase winding module 12; q2 This refers to the q-axis current of the second three-phase winding module 12 in the synchronous rotating coordinate system, which is the reactive current of the second three-phase winding module 12.

[0062] Therefore, the instantaneous active power p on the grid side g It is related to the sum of the d-axis currents of the two three-phase winding modules and must be a DC quantity; the instantaneous reactive power q on the grid side. g Since it relates to the sum of the q-axis currents of the two three-phase winding modules, it must be zero. Therefore, the following expression holds:

[0063]

[0064] Among them, I g The sum of the d-axis currents of the two three-phase winding modules is a constant and is a DC component of the input active current.

[0065] In summary, the above control methods enable the integrated charging system to achieve grid-side power factor correction during charging, meaning it only receives active power from the grid. Therefore, by controlling the sum of the active currents of the dual rectifier units to be twice the DC component of the input active current, I... g It can control the instantaneous active power on the grid side, thereby controlling the total power of dual-port charging; by controlling the sum of the reactive currents of the dual rectifier units to be zero, the instantaneous reactive power on the grid side is controlled to be zero, so that the integrated charging system operates in a unity power factor state.

[0066] The present invention provides a control method for an integrated charging system, which further includes suppressing motor torque ripple during the charging process.

[0067] Furthermore, the suppression of motor torque ripple during the charging process specifically includes: controlling the DC component of the active current in the dual rectifier unit to be equal, thereby ensuring that the three-phase currents flowing through the two corresponding three-phase winding modules are equal in magnitude and opposite in direction, thus canceling out the magnetic flux generated and eliminating electromagnetic torque ripple during the charging process; when the AC component in the current vector of the dual rectifier unit transmits unbalanced power through the motor armature winding, the components of the AC component in the current vector in the three-phase winding are distributed to make the q-axis current in the motor coordinate system cancel out each other, and the unbalanced power is transmitted through the d-axis current in the motor coordinate system, suppressing the pulsating torque during the charging process, thereby achieving suppression of motor torque ripple during the charging process.

[0068] Furthermore, when the AC component of the current vector in the dual rectifier unit transmits unbalanced power through the motor armature winding, in order to cancel each other out in the q-axis current in the motor coordinate system and transmit unbalanced power through the d-axis current in the motor coordinate system, it is necessary to control the current value in the motor winding to be:

[0069] i motor_d =i m

[0070] i motor_q =0

[0071] Among them, i motor_d This refers to the current vector in the rotor direction, i.e., the d-axis current in the motor coordinate system; i motor_q i is the q-axis current in the motor coordinate system; m This represents the AC component of the current vector. In the motor coordinate system, since the DC component is canceled out, the current vector has no DC component and only an AC component. Therefore, in the motor coordinate system, i m That is, the current vector.

[0072] Furthermore, the current vector i m Transforming to a synchronous rotating coordinate system oriented by grid voltage, the expression is as follows:

[0073]

[0074] Among them, i d_m Let i be the d-axis component of the AC component in the current vector in a synchronous rotating coordinate system oriented towards the grid voltage. q_m Let ωt be the q-axis component of the AC component in the current vector in a synchronous rotating coordinate system oriented towards the grid voltage, and θ be the phase angle of the grid voltage.

[0075] The present invention provides a control method for an integrated charging system, which further includes controlling the integrated charging system to achieve dual-port power distribution.

[0076] Furthermore, the integrated charging system is controlled to achieve dual-port power distribution, specifically by controlling the DC components of the active current in the dual rectifier units to be equal, with a magnitude equal to the DC component I of the given input active current. g * This enables control of the average power value at both ports, thereby controlling the total active power input to the grid side. When the battery charging power of the two independent channels is unequal, the amplitude I of the AC component in the current vector of the two rectifier units is controlled. m This allows the power difference between the two channels to be transferred from the side with lower power requirement to the side with higher power requirement through the three-phase winding, thereby achieving the control of unbalanced power at both ports. Thus, by controlling the sum of active power and unbalanced power at both ports, a charging power allocation strategy for independent channels at both ports can be achieved.

[0077] More specifically, in the grid voltage-oriented synchronous rotating coordinate system, the instantaneous active power and instantaneous reactive power on the grid side can be further expressed as:

[0078]

[0079] Among them, by controlling the d-axis current i of the first three-phase winding module 11 in the synchronous rotating coordinate system d1 DC component I d1 The d-axis current i of the second three-phase winding module 12 in the synchronous rotating coordinate system d2 DC component I d2 They are equal, and both are the DC component I of the given input active current. g * This enables control of the average power value at both ports, thereby controlling the total active power input to the grid side.

[0080] Id1 =I d2 =I g * .

[0081] Furthermore, when the battery charging power of the two independent channels is unequal, it is necessary to control the AC component in the current vector to achieve the transmission of unbalanced power. Considering the AC component, the expressions for the d-axis current and q-axis current of the first three-phase winding module 11 and the second three-phase winding module 12 in the synchronous rotating coordinate system are as follows:

[0082] i d1 =I d1 +i m cos(ωt-θ)

[0083] i d2 =I d2 -i m cos(ωt-θ)

[0084] i q1 =-i m sin(ωt-θ)

[0085] i q2 =i m sin(ωt-θ)

[0086] Among them, the d-axis current i of the first three-phase winding module 11 in the synchronous rotating coordinate system d1 DC component I d1 The d-axis current i of the second three-phase winding module 12 in the synchronous rotating coordinate system d2 DC component I d2 Equal in magnitude to the DC component I of the given input active current. g * i m This is the AC component of the current vector, which is the current vector in the direction of the motor rotor.

[0087] Therefore, we can obtain the following expression:

[0088]

[0089] The active power difference is Δp:

[0090] Δp=p1-p2=3e d i m cos(ωt-θ)

[0091] In order to transmit the charging power difference between the two channels from the lower charging power side to the higher charging power side through the three-phase windings, it is necessary to control the AC component i in the current vector. mThis results in a DC component in the active power difference Δp, and therefore an AC component i in the current vector. m The expression is as follows:

[0092] i m =I m cos(ωt-θ),

[0093] Among them, I m This represents the magnitude of the AC component in the current vector.

[0094] At this time, the active power difference Δp is:

[0095]

[0096] The DC component in the active power difference Δp is:

[0097]

[0098] Therefore, by controlling the amplitude I of the AC component in the current vector m That is, the difference in the amplitude of the AC component in the current vector, which in turn controls the difference in active power Δp, so that the difference in output power of the dual channels is transmitted from the side with lower charging power required by the battery to the side with higher charging power required by the battery through the three-phase winding.

[0099] Therefore, by controlling the sum of active power and unbalanced power at both ports, a charging power allocation strategy for independent channels at both ports can be achieved.

[0100] The present invention provides a control method for an integrated charging system, comprising performing independent control of dual-port voltage.

[0101] Furthermore, independent dual-port voltage control is implemented, specifically by adjusting the output voltages of the two independent channels using a voltage and an outer-loop proportional-integral (PI) controller, and outputting the DC component I of the given input active current. g * The output voltage difference between the two independent channels is adjusted by a voltage difference outer-loop proportional-integral (PI) controller, and the AC component in the output current vector is given an amplitude I. m * Based on the DC component I of the given input active current g * Given the magnitude I of the AC component in the current vector m *The two-phase current setpoints of the two independent channels are calculated, and the difference between the two-phase currents of the two independent channels is calculated. The two-phase currents are then controlled in a closed loop by a proportional resonant (PR) controller. The output of the PR controller is used to generate a switching signal through space vector pulse width modulation (SVPWM) to drive the switch in the integrated charging system, thereby achieving independent control of the output voltage of the two channels.

[0102] More specifically, through closed-loop control of the voltage and outer loop proportional-integral (PI) controllers and the voltage difference outer loop proportional-integral (PI) controller, independent voltage control of the two ports can be achieved even when the output voltage settings of the two ports are unequal and the charging of the two ports is unbalanced.

[0103] For further information, please continue to refer to [link / reference]. Figure 1 In one specific embodiment, the control method of the integrated charging system of the present invention specifically includes steps S1 to S8.

[0104] Step S1: Sample the instantaneous value e of the three-phase grid voltage. a e b e c The instantaneous value of the three-phase current i of the first three-phase winding module 11 a1 i b1 i c1 The instantaneous value of the three-phase current i of the second three-phase winding module 12 a2 i b2 i c2 The output voltage U of the first rectifier unit 2 dc1 The output voltage U of the second rectifier unit 3 dc2 .

[0105] Step S2: Calculate the fundamental frequency ω and phase angle ωt of the grid voltage using a grid-side voltage phase-locked loop; calculate the two-phase current i of the first three-phase winding module 11 and the second three-phase winding module 12 in a synchronous rotating coordinate system oriented towards grid voltage. d1 i q1 i d2 i q2 .

[0106] Among them, i d1 i represents the d-axis current of the first three-phase winding module 11 in the synchronous rotating coordinate system. q1 i represents the q-axis current of the first three-phase winding module 11 in the synchronous rotating coordinate system. d2 For the d-axis current of the second three-phase winding module 12 in the synchronous rotating coordinate system, i q2 This refers to the q-axis current of the second three-phase winding module 12 in the synchronous rotating coordinate system.

[0107] Optionally, the instantaneous value i of the three-phase current of the first three-phase winding module 11 can be... a1 i b1 i c1 The instantaneous value of the three-phase current i of the second three-phase winding module 12 a2 i b2 i c2 The two-phase current i in the synchronous rotating coordinate system oriented by grid voltage is obtained by successively performing Clark transformation and Park transformation. d1 i q1 i d2 i q2 .

[0108] Step S3: Calculate the output voltage U of the first rectifier unit 2. dc1 The output voltage U of the second rectifier unit 3 dc2 The sum ΣU dc With the given output voltage U of the first rectifier unit 2 dc1 * The given output voltage U of the second rectifier unit 3 dc2 * The sum ΣU dc * Subtracting the two, the DC component I of the given input active current is output by the voltage and outer-loop proportional-integral (PI) controller. g * .

[0109] Step S4: Calculate the output voltage U of the first rectifier unit 2. dc1 The output voltage U of the second rectifier unit 3 dc2 The difference ΔU dc With the given output voltage U of the first rectifier unit 2 dc1 * The given output voltage U of the second rectifier unit 3 dc2 * The difference ΔU dc * Subtracting the two, the AC component of the output current vector from the voltage difference outer loop proportional-integral (PI) controller is given an amplitude I. m * .

[0110] Step S5: Calculate the AC component setpoint i in the current vector based on the phase angle ωt of the grid voltage and the rotor position angle θ of the motor. m * The expression is:

[0111] i m * =I m * cos(ωt-θ).

[0112] Step S6: Calculate the given value i of the AC component in the current vector. m * The given value i of the d-axis component in the synchronous rotating coordinate system oriented by grid voltage. d_m * q-axis component given value i q_m * The expression is:

[0113]

[0114] Step S7: Calculate the two-phase current setpoint i of the first three-phase winding module 11 and the second three-phase winding module 12 in the synchronous rotating coordinate system oriented by the grid voltage. d1 * i q1 * i d2 * i q2 * The expression is as follows:

[0115]

[0116] Among them, i d1 * The given value for the d-axis current of the first three-phase winding module 11 in the synchronous rotating coordinate system is i. q1 * The given value for the q-axis current of the first three-phase winding module 11 in the synchronous rotating coordinate system is i. d2 * The given value for the d-axis current of the second three-phase winding module 12 in the synchronous rotating coordinate system is i. q2 * The given value for the q-axis current of the second three-phase winding module 12 in the synchronous rotating coordinate system.

[0117] Step S8: The two-phase currents i of the first three-phase winding module 11 and the second three-phase winding module 12 in a synchronous rotating coordinate system oriented by grid voltage are... d1 i q1 i d2 i q2 With the two-phase current given value i d1 * i q1 * i d2 * i q2 *The corresponding differential input proportional resonant (PR) controller realizes closed-loop control of the two-phase current. The output of the proportional resonant controller is used to generate a switching signal through space vector pulse width modulation (SVPWM) to drive the switch in the integrated charging system.

[0118] More specifically, the d-axis current i of the first three-phase winding module 11 in the synchronous rotating coordinate system d1 The d-axis current setpoint i of the first three-phase winding module 11 in the synchronous rotating coordinate system d1 * The differential input proportional resonant controller will control the q-axis current i of the first three-phase winding module 11 in the synchronous rotating coordinate system. q1 The q-axis current setpoint i of the first three-phase winding module 11 in the synchronous rotating coordinate system q1 * The differential input proportional resonant controller will control the d-axis current i of the second three-phase winding module 12 in the synchronous rotating coordinate system. d2 The d-axis current setpoint i of the second three-phase winding module 12 in the synchronous rotating coordinate system d2 * The differential input proportional resonant controller will control the q-axis current i of the second three-phase winding module 12 in the synchronous rotating coordinate system. q2 The q-axis current setpoint i of the second three-phase winding module 12 in the synchronous rotating coordinate system q2 * The differential input proportional resonant controller.

[0119] More specifically, as shown in step S7, the two-phase current setpoint i of the first three-phase winding module 11 and the second three-phase winding module 12 is set in a synchronous rotating coordinate system oriented by the grid voltage. d1 * i q1 * i d2 * i q2 * Then, through step S8, the two-phase currents i of the first three-phase winding module 11 and the second three-phase winding module 12 are made to rotate in a synchronous coordinate system oriented by the grid voltage. d1 i q1 i d2 i q2 Each of these values ​​is followed to control the sum of the active currents of the dual rectifier units to be twice the DC component of the input active current, I. g This enables the control of instantaneous active power on the grid side, thereby controlling the total power of dual-port charging; and controls the sum of reactive currents of the dual rectifier units to be zero, controlling the instantaneous reactive power on the grid side to be zero, so that the integrated charging system operates in a unity power factor state.

[0120] Furthermore, it can simultaneously control the DC component of the active current in the dual rectifier units to be equal, thereby eliminating electromagnetic torque ripple during charging; and control the DC component of the active current in the dual rectifier units to be equal, with a magnitude equal to the DC component I of the given input active current. g * This enables control of the average power value at both ports, thereby controlling the total active power input to the grid side. Simultaneously, it controls the amplitude of the AC component in the current vector of the two rectifier units, allowing the power difference between the two channels to be transmitted through the three-phase windings from the side with lower power requirement of the battery to the side with higher power requirement of the battery, thus achieving control of the unbalanced power at both ports.

[0121] To verify the control method of the integrated charging system of the present invention, an integrated charging system was built in Matlab / Sumink software, mainly including a mathematical model of an open-winding permanent magnet synchronous motor and a dual three-phase inverter model. The key parameters were set during the simulation verification process as follows:

[0122] Simulation setting parameters

[0123]

[0124] Please see Figure 3As shown, the simulation time is set to 0.4s. At 0s, the output power of the two channels is equal, the load ratio is 1:1, and the output voltage is 800V. At 0.1s, the load on the two channels is increased and decreased respectively, and the load ratio becomes 1:1.5. At 0.2s, the given output voltage values ​​of the two channels are changed, the output voltage of channel 1 is 850V, and the output voltage of channel 2 is 750V, the voltage ratio is 1:1.13, and the load ratio remains 1:1.5. In the period of 0-0.1s, the output power of the two channels is equal, the grid-side input current is in phase with the grid-side voltage, the current of the two rectifier units is equal, the output voltage of the two channels is 800V, the output current is 5A, and the total power is 8kW. Furthermore, the charging torque is offset by magnetic flux balance, and no torque pulsation is generated. During the 0.1s-0.2s interval, the dual-channel load ratio is 1:1.5, and the grid-side input current and grid-side voltage remain in phase. The current carrying unbalanced power is superimposed on the current of the dual rectifier units. The dual-channel output voltage is 800V, and the output currents are 4.17A and 6.25A, respectively. The charging torque is offset by flux balance and torque balance, resulting in no torque ripple. During the 0.2s interval, the dual-channel load ratio is 1:1.5, and the dual-channel voltage setpoints are 850V and 750V, respectively. The system enters steady state within 0.1s. During the 0.3s-0.4s interval, the system enters steady state with a dual-channel load ratio of 1:1.5 and dual-channel voltages of 850V and 750V, respectively. The grid-side input current and grid-side voltage remain in phase, and the current carrying unbalanced power is superimposed on the current of the dual inverters. The output currents are 3.91A and 6.8A, respectively. The charging torque is offset by flux balance and torque balance, resulting in no torque ripple. Throughout the process, the system exhibits good dynamic and steady-state performance, with motor torque pulsation not exceeding 0.6 Nm. Therefore, it can realize a multi-port integrated charging system, achieve decoupled control of energy in each channel, suppress torque pulsation during charging, and improve the safety of the charging process.

[0125] In summary, the integrated charging system and its control method of this invention, based on the open-winding motor drive system of an electric vehicle, reconfigures the drive system into a common-input dual-rectifier unit to charge the power battery of two channels. By controlling the sum of the active current and the sum of the reactive current of the dual-rectifier unit, grid-side power factor correction is achieved during the charging process; by controlling the magnitude of the DC component and the difference between the AC components of the active current of the dual-rectifier unit, the sum of active power and unbalanced power at both ports are controlled, realizing an output power distribution strategy for the independent channels at both ports; by adjusting the output voltage of the two independent channels through voltage and outer loops and voltage difference outer loops, independent voltage control at both ports is achieved; by controlling the DC component in the active current of the dual-rectifier unit to be equal, magnetic flux balance is achieved, eliminating electromagnetic torque pulsation during the charging process; by distributing the AC component in the current vector in the three-phase windings, torque balance is achieved, suppressing the pulsating torque generated during the unbalanced power transfer process, thereby suppressing motor torque pulsation. This invention constructs a multi-port integrated charging system without adding winding switching switches, power devices, and magnetic components, and achieves decoupled control of energy in each channel, thereby improving the reliability and safety of charging.

[0126] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Anyone skilled in the art can make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A control method for an integrated charging system, characterized in that, This includes performing independent dual-port voltage control, specifically including adjusting the output voltage of the two independent channels through a voltage and an outer loop proportional-integral controller, and outputting the DC component of the given input active current. The output voltage difference between the two independent channels is adjusted by a voltage difference outer loop proportional-integral controller, and the amplitude of the AC component in the output current vector is given. The two-phase current given values ​​of the two independent channels are calculated based on the given amplitude of the DC component of the given input active current and the AC component in the current vector. After being subtracted from the two-phase currents of the two independent channels, they are passed through proportional resonant controllers. The output of the proportional resonant controllers is generated into switching signals through space vector pulse width modulation to drive the switches in the integrated charging system. The control method for the integrated charging system specifically includes the following steps: Sampling the instantaneous value of the three-phase grid voltage e a , e b , e c Instantaneous value of three-phase current in the first three-phase winding module i a1 , i b1 , i c1 Instantaneous values ​​of three-phase currents of the second and third phase winding modules i a2 , i b2 , i c2 The output voltage of the first rectifier unit U dc1 The output voltage of the second rectifier unit U dc2 ; The fundamental frequency of the grid voltage is calculated using a grid-side voltage phase-locked loop. ω and phase angle ωt ; Calculate the two-phase currents of the first three-phase winding module and the second three-phase winding module in a synchronous rotating coordinate system oriented by grid voltage. i d1 , i q1 , i d2 , i q2 ; Calculate the output voltage of the first rectifier unit. U dc1 Output voltage of the second rectifier unit U dc2 The sum Σ U dc With the given output voltage of the first rectifier unit U dc1 The given output voltage of the second rectifier unit U dc2 The sum Σ U dc Subtracting the two, the DC component of the given input active current is output by the voltage and outer loop proportional-integral controller. I g ; Calculate the output voltage of the first rectifier unit. U dc1 Output voltage of the second rectifier unit U dc2 The difference ∆U dc With the given output voltage of the first rectifier unit U dc1 The given output voltage of the second rectifier unit U dc2 The difference ∆U dc Subtracting the two, the AC component of the output current vector from the voltage difference outer loop proportional-integral controller is given an amplitude. I m ; Phase angle based on grid voltage ωt and motor rotor position angle θ Calculate the given value of the AC component in the current vector. im The expression is: ； Calculate the given value of the AC component in the current vector. im The given value of the d-axis component in the synchronous rotating coordinate system oriented by grid voltage. id_m q-axis component given value iq_m The expression is: ； Calculate the two-phase current setpoints of the first three-phase winding module and the second three-phase winding module in a synchronous rotating coordinate system oriented by grid voltage. id1 , iQ1 , id2 , iQ2 The expression is as follows: in, id1 The given value for the d-axis current of the first three-phase winding module in the synchronous rotating coordinate system. iQ1 The given value for the q-axis current of the first three-phase winding module in the synchronous rotating coordinate system. id2 The given value for the d-axis current of the second and third phase winding modules in the synchronous rotating coordinate system. iQ2 The given value for the q-axis current of the second and third phase winding modules in the synchronous rotating coordinate system; The two-phase currents of the first three-phase winding module and the second three-phase winding module in a synchronous rotating coordinate system oriented towards grid voltage are compared. i d1 , i q1 , i d2 , i q2 With two-phase current setpoint i d1 , i q1 , i d2 , i q2 The corresponding difference is input to the proportional resonant controller to realize closed-loop control of the two-phase current. The output of the proportional resonant controller is generated into a switching signal through space vector pulse width modulation to drive the switch in the integrated charging system.

2. The control method for an integrated charging system as described in claim 1, characterized in that, It also includes controlling the integrated charging system to achieve grid-side power factor correction during the charging process, specifically including controlling the sum of the active currents of the dual rectifier units to be twice the DC component of the input active current; and controlling the sum of the reactive currents of the dual rectifier units to be zero.

3. The control method for an integrated charging system as described in claim 1, characterized in that, It also includes suppressing motor torque ripple during the charging process, specifically including controlling the DC component in the active current of the dual rectifier unit to be equal; when the AC component in the current vector of the dual rectifier unit transmits unbalanced power through the motor armature winding, by distributing the AC component in the current vector in the three-phase winding, the q-axis current in the motor coordinate system cancels each other out, and the unbalanced power is transmitted through the d-axis current in the motor coordinate system.

4. The control method for an integrated charging system as described in claim 1, characterized in that, It also includes controlling the integrated charging system to achieve dual-port power distribution, specifically including controlling the DC components in the active current of the dual rectifier units to be equal, with the magnitude being the DC component of the given input active current; when the battery charging power of the two independent channels is not equal, by controlling the amplitude of the AC component in the current vector of the two rectifier units, the difference in output power of the two channels is transmitted through the three-phase winding from the side with lower battery power requirement to the side with higher battery power requirement.

5. The control method for an integrated charging system as described in claim 3, characterized in that, The current value in the motor winding is: in, i motor_d This is the current vector in the rotor direction, i.e., the d-axis current in the motor coordinate system; i motor_q This refers to the q-axis current in the motor coordinate system. i m This represents the AC component in the current vector.

6. An integrated charging system, characterized in that, The control method of an integrated charging system according to any one of claims 1-5 is applied. The integrated charging system includes an open-winding motor unit, a first rectifier unit, a second rectifier unit, a charging control unit, a first battery, and a second battery. A three-phase power grid is connected to the first end of the open-winding motor unit. The second end of the open-winding motor unit is connected to the first end of the first rectifier unit. The second end of the first rectifier unit is connected to the first battery. The third end of the open-winding motor unit is connected to the first end of the second rectifier unit. The second end of the second rectifier unit is connected to the second battery. The charging control unit outputs drive signals for the switches in the first rectifier unit and the second rectifier unit. The open-winding motor unit includes a first three-phase winding module and a second three-phase winding module. The first end of the first three-phase winding module and the first end of the second three-phase winding module are connected to form the first end of the open-winding motor unit. The second end of the first three-phase winding module is the second end of the open-winding motor unit, and the second end of the second three-phase winding module is the third end of the open-winding motor unit.

7. The integrated charging system as described in claim 6, characterized in that, The open-winding motor unit is an open-winding permanent magnet synchronous motor.

8. The integrated charging system as described in claim 6, characterized in that, The first rectifier unit and the second rectifier unit are three-phase rectifier units.

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