Battery dynamic balancing device, control method thereof and vehicle

Abstract

This invention discloses a battery dynamic balancing device, its control method, and a vehicle. The device includes: a power battery; at least one phase first arm; at least one phase first inductor; and a controller connected to the first arm. The controller is configured to: in a first preset state, control the first arm to cause a first battery pack and a second battery pack to alternately charge and discharge, thereby achieving self-heating of the first and second battery packs, and ensuring that the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack is lower than a preset threshold. The balancing device of this invention can achieve dynamic balancing of the charge between the first and second battery packs during the battery self-heating process, thereby improving battery performance and extending battery life.

Description

Technical Field

[0001] This invention relates to the field of battery protection technology, and in particular to a battery dynamic balancing device, a control method for the battery dynamic balancing device, and a vehicle. Background Technology

[0002] With the development and rapid popularization of electric vehicles, electric vehicle power batteries are becoming increasingly important. Currently, during the self-heating process of vehicle power batteries, the voltage difference between the individual cells can gradually increase, leading to imbalances between the cells and potentially shortening battery life. Summary of the Invention

[0003] This invention aims to at least partially solve one of the technical problems in related technologies. Therefore, the first objective of this invention is to provide a battery dynamic balancing device capable of dynamically balancing the charge levels between the first and second battery packs during the battery self-heating process, thereby improving battery performance and extending battery life.

[0004] The second objective of this invention is to provide a control method for a battery dynamic balancing device.

[0005] The third objective of this invention is to provide a vehicle.

[0006] To achieve the above objectives, a first aspect of the present invention provides a battery dynamic balancing device, comprising: a power battery, including a first battery pack and a second battery pack connected in series, with a first node between the first battery pack and the second battery pack; at least one phase first bridge arm, with a first end of each phase first bridge arm connected to the positive terminal of the first battery pack and a second end of each phase first bridge arm connected to the negative terminal of the second battery pack; at least one phase first inductor, with a first end of each phase first inductor connected to the corresponding first bridge arm and a second end of each phase first inductor connected to the first node; and a controller connected to the first bridge arm, configured to: in a first preset state, control the first bridge arm to cause the first battery pack and the second battery pack to alternately charge and discharge, thereby achieving self-heating of the first battery pack and the second battery pack, and causing the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold.

[0007] According to an embodiment of the present invention, a battery dynamic balancing device includes a first node between battery packs. A first end of each phase's first bridge arm is connected to the positive terminal of the first battery pack, and a second end of each phase's first bridge arm is connected to the negative terminal of the second battery pack. A first end of each phase's first inductor is connected to the corresponding first bridge arm, and a second end of each phase's first inductor is connected to the first node. A controller is connected to the first bridge arm and configured to: in a first preset state, control the first bridge arm to cause the first and second battery packs to alternately charge and discharge, thereby achieving self-heating of the first and second battery packs, and ensuring that the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack is lower than a preset threshold. Thus, the balancing device can achieve dynamic balancing of the charge between the first and second battery packs during the battery self-heating process, thereby improving battery performance and extending battery life.

[0008] In addition, the battery dynamic balancing device according to the above embodiments of the present invention may also have the following additional technical features:

[0009] According to one embodiment of the present invention, the bridge arm of the multiplexed motor controller is used as the first bridge arm, and the coil of the multiplexed motor is used as the first inductor; the motor leads out an N line, which is connected to the first node.

[0010] According to one embodiment of the present invention, the controller is configured to: acquire equalization battery parameters and temperature requirement parameters of the power battery; obtain a target equalization current based on the equalization battery parameters and a target self-heating current based on the temperature requirement parameters; and adjust a first control signal of the motor controller based on the target equalization current, the target self-heating current and the actual phase current of the motor to perform self-heating and equalization processing on the first battery pack and the second battery pack.

[0011] According to one embodiment of the present invention, the controller is configured to: perform integral calculation on the equalization battery parameters to obtain a target equalization current, wherein the equalization battery parameters include one of the following: discharge capacity difference, voltage difference, and instantaneous power difference, wherein the discharge capacity difference, voltage difference, and instantaneous power difference represent the difference in discharge capacity, voltage difference, and instantaneous power difference between the first battery pack and the second battery pack, respectively.

[0012] According to one embodiment of the present invention, the equalization battery parameter is the discharge capacity difference; the controller is configured to: collect the phase current of each phase of the motor; calculate the N-line current of the motor based on the phase current of each phase of the motor; and perform integration processing on the N-line current to obtain the discharge capacity difference.

[0013] According to one embodiment of the present invention, the equalization battery parameter is the discharge capacity difference; the controller is configured to: collect the bus positive current and bus negative current of the power battery; perform ampere-hour integration on the bus positive current of the power battery to obtain the discharge capacity of the first battery pack, and perform ampere-hour integration on the bus negative current of the power battery to obtain the discharge capacity of the second battery pack; and obtain the discharge capacity difference based on the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

[0014] According to one embodiment of the present invention, the equalization battery parameter is the discharge capacity difference; the controller is configured to: collect the positive bus current and the negative bus current of the motor controller; perform ampere-hour integration on the positive bus current of the motor controller to obtain the discharge capacity of the first battery pack, and perform ampere-hour integration on the negative bus current of the motor controller to obtain the discharge capacity of the second battery pack; and obtain the discharge capacity difference based on the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

[0015] According to one embodiment of the present invention, the equalization current parameter is the voltage difference; the controller is configured to: acquire the bus voltage of the motor controller and the voltage of the second battery pack; calculate the voltage of the first battery pack based on the bus voltage and the voltage of the second battery pack; and determine the voltage difference based on the voltage of the first battery pack and the voltage of the second battery pack.

[0016] According to one embodiment of the present invention, the equalization current parameter is the instantaneous power difference; the controller is configured to: collect the positive current of the power battery bus, the negative current of the battery bus, the voltage of the first battery pack, and the voltage of the second battery pack; determine the instantaneous power of the first battery pack based on the positive current of the battery bus and the voltage of the first battery pack, and determine the instantaneous power of the second battery pack based on the negative current of the battery bus and the voltage of the second battery pack; and determine the instantaneous power difference based on the instantaneous power of the first battery pack and the instantaneous power of the second battery pack.

[0017] According to one embodiment of the present invention, the controller is configured to: obtain the required heating power based on the temperature requirement parameters; determine the amplitude and frequency of the self-heating current of the N-line based on the required heating power; and determine the target heating current based on the amplitude and frequency.

[0018] According to one embodiment of the present invention, the controller is further configured to obtain the target heating equalization current by means of the following formula:

[0019] In*=indc+ipk·sin(2·π·f·t)

[0020] Where In* represents the target heating equalization current, indc represents the target equalization current, ipk represents the amplitude of the target self-heating current, f represents the frequency of the target self-heating current, and t represents the current time.

[0021] According to one embodiment of the present invention, the controller is further configured to: acquire the actual phase current of the motor; obtain a common-mode voltage based on the target heating equalization current and the actual phase current; and adjust a first control signal of the motor controller based on the common-mode voltage.

[0022] According to one embodiment of the present invention, the controller is further configured to: in a second preset state, control the bridge arm of the motor controller to drive the motor and cause the first battery pack and the second battery pack to charge and discharge alternately, so as to achieve self-heating of the first battery pack and the second battery pack, and cause the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold.

[0023] According to one embodiment of the present invention, the controller is configured to: collect the equalization battery parameters, temperature demand parameters, and drive demand parameters of the power battery; obtain a target drive current based on the drive demand parameters, obtain a target self-heating current based on the temperature demand parameters, and obtain a target equalization current based on the equalization battery parameters; adjust the second control signal of the motor controller according to the target drive current, the target self-heating current, the target equalization current, and the actual phase current to drive the motor, and perform self-heating and equalization processing on the first battery pack and the second battery pack.

[0024] According to one embodiment of the present invention, the controller is configured to: acquire the torque output of the motor, the speed of the motor, the voltage of the power battery, and the rotor electrical angle of the motor; upon receiving a drive command, obtain a target drive current based on the torque output of the motor, the speed of the motor, and the voltage of the power battery, and obtain the differential mode voltage of each phase arm based on the target drive current, the actual phase current, and the rotor electrical angle of the motor.

[0025] According to one embodiment of the present invention, the target drive current is the synthesis of the d-axis target current and the q-axis target current, and the actual phase current is the synthesis of the d-axis actual current and the q-axis actual current. The controller is configured to: perform closed-loop control on the d-axis target current and the d-axis actual current, as well as the q-axis target current and the q-axis actual current, to obtain the d-axis target voltage and the q-axis target voltage; and obtain the differential mode voltage of each phase arm based on the d-axis target voltage, the q-axis target voltage, and the rotor electrical angle of the motor.

[0026] According to one embodiment of the present invention, the controller is further configured to: obtain a target heating equalization current based on a target self-heating current and a target equalization current; acquire the actual phase current of the motor; obtain a common-mode voltage based on the target heating equalization current and the actual phase current; and adjust a second control signal of the motor controller based on the differential-mode voltage and the common-mode voltage of each phase arm.

[0027] According to one embodiment of the present invention, the controller is configured to: in a third preset state, if the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack is not lower than a preset threshold, control the bridge arm of the motor controller to perform equalization processing on the first battery pack and the second battery pack.

[0028] According to an embodiment of the present invention, the above-mentioned battery dynamic balancing device further includes: a DC charging and discharging port, the positive terminal of the DC charging and discharging port being connected to a first busbar of the motor controller, and the negative terminal of the DC charging and discharging port being connected to a second busbar of the motor controller; the controller is configured to: in a fourth preset state, charge the power battery through the DC charging and discharging port, and control the bridge arm of the motor controller to cause the first battery pack and the second battery pack to alternately charge and discharge, so as to realize the self-heating of the first battery pack and the second battery pack, and cause the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold.

[0029] According to an embodiment of the present invention, the above-mentioned battery dynamic balancing device further includes: a DC charging and discharging port, the positive terminal of the DC charging and discharging port being connected to the N line, and the negative terminal of the DC charging and discharging port being connected to the second bus terminal of the motor controller; the controller is configured to: in a fifth preset state, control the bridge arm of the motor controller to boost the charging of the power battery.

[0030] To achieve the above objectives, a second aspect of the present invention provides a control method for a battery dynamic balancing device. The battery dynamic balancing device includes: a power battery, at least one phase first bridge arm, at least one phase first inductor, and a controller. The power battery includes a first battery pack and a second battery pack connected in series, with a first node between the first battery pack and the second battery pack. The first end of each phase first bridge arm is connected to the positive terminal of the first battery pack, and the second end of each phase first bridge arm is connected to the negative terminal of the second battery pack. The first end of each phase first inductor is connected to the corresponding first bridge arm, and the second end of each phase first inductor is connected to the first node. The controller is connected to the first bridge arm. The method is applied to the controller and includes: in a first preset state, controlling the first bridge arm to cause the first battery pack and the second battery pack to alternately charge and discharge, thereby achieving self-heating of the first battery pack and the second battery pack, and causing the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold.

[0031] According to an embodiment of the present invention, a control method for a battery dynamic balancing device includes a power battery, at least one phase first bridge arm, at least one phase first inductor, and a controller. The power battery includes a first battery pack and a second battery pack connected in series, with a first node between the first and second battery packs. A first end of each phase first bridge arm is connected to the positive terminal of the first battery pack, and a second end of each phase first bridge arm is connected to the negative terminal of the second battery pack. A first end of each phase first inductor is connected to the corresponding first bridge arm, and a second end of each phase first inductor is connected to the first node. The controller is connected to the first bridge arm. The method is applied to the controller and includes: in a first preset state, controlling the first bridge arm to cause the first and second battery packs to alternately charge and discharge, thereby achieving self-heating of the first and second battery packs, and ensuring that the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack is lower than a preset threshold. Thus, this method can achieve dynamic balancing of the charge between the first and second battery packs during the battery self-heating process, thereby improving battery performance and extending battery life.

[0032] To achieve the above objectives, a vehicle is provided in a third aspect of the present invention, including the aforementioned battery dynamic balancing device.

[0033] According to the vehicle of the present invention, the above-described battery dynamic balancing device can achieve dynamic balancing of the charge between the first battery pack and the second battery pack during the battery self-heating process, thereby improving battery performance and extending battery life.

[0034] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0035] Figure 1 This is a block diagram of a battery dynamic balancing device according to an embodiment of the present invention;

[0036] Figure 2 This is a circuit diagram of a battery dynamic balancing device according to an embodiment of the present invention;

[0037] Figure 3 This is a schematic diagram illustrating the dynamic balancing of the battery under driving conditions and self-heating mode according to an embodiment of the present invention.

[0038] Figure 4 A flowchart of a control method for a battery dynamic balancing device according to an embodiment of the present invention;

[0039] Figure 5 A flowchart of a control method for a battery dynamic balancing device according to a specific example of the present invention;

[0040] Figure 6This is a block diagram of a vehicle according to an embodiment of the present invention. Detailed Implementation

[0041] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0042] During the self-heating operation of the vehicle battery, each battery pack is constantly charging and discharging at a high frequency. In reality, differences in the state, impedance, and temperature characteristics of each battery cell mean that once a voltage difference appears between battery packs, if not balanced, this imbalance will accelerate. As the self-heating time increases, the voltage difference between battery packs gradually increases, leading to increasingly uneven battery capacity (e.g., two battery packs, E1 and E2, one fully charged and the other depleted), resulting in a sharp decrease in driving range and potentially shortening battery life over time. Therefore, to address the voltage imbalance between battery packs during battery self-heating, this invention proposes a dynamic battery balancing device. Before the battery self-heating function is activated, it determines whether the initial charge level of each battery pack is balanced, and whether the charge level is balanced between battery packs during self-heating. This enables dynamic balancing of the charge level between battery packs even when there is an imbalance during self-heating, thereby improving battery performance and extending battery life.

[0043] The following description, with reference to the accompanying drawings, describes the battery dynamic balancing device, the control method of the battery dynamic balancing device, and the vehicle proposed in the embodiments of the present invention.

[0044] Figure 1 This is a block diagram of a battery dynamic balancing device according to an embodiment of the present invention.

[0045] like Figure 1 As shown, the battery dynamic balancing device may include: a power battery 110, at least one phase first bridge arm 120, at least one phase first inductor 130, and a controller 140.

[0046] The power battery 110 includes a first battery pack E1 and a second battery pack E2 connected in series, with a first node J1 between them. The first end of each phase first bridge arm 120 is connected to the positive terminal of the first battery pack E1, and the second end of each phase first bridge arm 120 is connected to the negative terminal of the second battery pack E2. The first end of each phase first inductor 130 is connected to the corresponding first bridge arm 120, and the second end of each phase first inductor 130 is connected to the first node J1. A controller 140 is connected to the first bridge arm 120 and is configured to: in a first preset state, control the first bridge arm 120 to cause the first battery pack E1 and the second battery pack E2 to alternately charge and discharge, thereby achieving self-heating of the first battery pack E1 and the second battery pack E2, and ensuring that the absolute value of the difference between the capacitance of the first battery pack E1 and the capacitance of the second battery pack E2 is lower than a preset threshold. The first preset state refers to a state where the vehicle is parked, the power battery is self-heating, and the power battery is balancing; the preset threshold can be determined according to actual conditions.

[0047] Furthermore, according to one embodiment of the present invention, such as Figure 2 As shown, the bridge arm of the multiplexed motor controller is used as the first bridge arm 120, and the coil of the multiplexed motor is used as the first inductor 130; the motor leads out an N line, which is connected to the first node.

[0048] Specifically, motor 130 may include permanent magnet synchronous motors, asynchronous motors, and other types of motors. Motor 130 may be three-phase, five-phase, six-phase, nine-phase, etc. Motor 130 may include multiple sets of windings: the motor coil includes x sets of windings, where x ≥ 1 and x is an integer. Each set of windings contains at least two phase windings, and each phase winding corresponds to a set of bridge arms for control. Figure 2The following example illustrates a set of windings, using a three-phase motor as an example. The two battery packs (first battery pack E1 and second battery pack E2) of the power battery 110 are connected in series. Each battery pack consists of multiple battery cells (or battery nodes) connected in series. The two battery packs contain the same battery cells, and the total number of battery cells in the power battery 110 is even. Positive busbar, negative busbar, and lead-out line from the midpoint of the series connection of the battery packs are drawn from the power battery 110. The positive and negative busbars of the power battery 110 are connected to the positive and negative busbars of the inverter via switches K2 and K1, respectively. The three-phase bridge arms (first bridge arm 120) A, B, and C of the multiplexed motor controller are connected to the three-phase coils (first inductor 130) of the motor. The neutral line (N line) of the motor is connected to switch K6, which is connected to the lead-out line of the series midpoint J1 of the power battery 110. The bus capacitor C1 is connected in parallel to the positive and negative busbars of the motor controller. The positive terminal of the DC charging / discharging port is connected in series with switch K5 to the positive terminal of the motor controller busbar. The positive terminal of the DC charging / discharging port is connected in series with switch K4 to the neutral line N of the motor lead-out line. The negative terminal of the DC charging / discharging port is connected in series with switch K3 to the negative terminal of the motor controller busbar. The positive terminal of capacitor C2 is connected to the positive terminal of the DC charging / discharging port, and the negative terminal of capacitor C2 is connected to the negative terminal of the motor controller busbar. In the shutdown state, i.e., when the vehicle is neither charging nor driving and the system is powered off, switches K1, K2, K3, K4, K5, and K6 are all in the open state. When the vehicle is in the first preset state, i.e., when the vehicle is parked, upon receiving a self-heating demand signal, control switch K6 closes, and the power battery 110 can self-heat. During the self-heating process, each battery pack is continuously charging and discharging. The controller 140 (not shown in the figure) can adjust the duty cycle of each phase arm to balance the first battery pack E1 and the second battery pack E2. For example, when the second battery pack E2 has a higher capacity and the first battery pack E1 has a lower capacity, the duty cycle of the upper bridge arm can be increased to allow the charge from the second battery pack E2 to be transferred to the first inductor 130 in the motor for storage, and then discharged to the first battery pack E1 via the neutral (N) line from the motor. This alternating charging and discharging of the first and second battery packs reduces the absolute value of the difference between their capacities, bringing it below a preset threshold. This achieves dynamic balance of charge between the first and second battery packs during battery self-heating, improving battery performance and extending battery life. The duty cycle refers to the duty cycle of the upper bridge arm. The duty cycles of the upper and lower bridge arms are complementary; for example, if the upper bridge arm is on for 70% of its total conduction time, the lower bridge arm will be on for 30%. This allows the higher-capacity battery pack to discharge more and the lower-capacity battery pack to discharge less, while also preserving a certain dead time based on the characteristics of the power devices.

[0049] The battery dynamic balancing device of the present invention will be described in detail below.

[0050] According to one embodiment of the present invention, the controller 140 is configured to: acquire the equalization battery parameters and temperature requirement parameters of the power battery 110; obtain a target equalization current based on the equalization battery parameters and a target self-heating current based on the temperature requirement parameters; and adjust the first control signal of the motor controller based on the target equalization current, the target self-heating current and the actual phase current of the motor to perform self-heating and equalization processing on the first battery pack E1 and the second battery pack E2.

[0051] Furthermore, according to an embodiment of the present invention, the controller 140 is configured to: perform integral calculation on the equalization battery parameters to obtain a target equalization current, wherein the equalization battery parameters include one of: discharge capacity difference, voltage difference, and instantaneous power difference, wherein the discharge capacity difference, voltage difference, and instantaneous power difference represent the difference in discharge capacity, voltage difference, and instantaneous power difference between the first battery pack E1 and the second battery pack E2, respectively.

[0052] Specifically, the controller 140 collects the balancing battery parameters and the required temperature parameters of the power battery 110. The balancing battery parameters of the power battery 110 may include the discharge capacity difference ΔQ. The target balancing current is calculated by integrating the discharge capacity difference ΔQ. After obtaining the target balancing current, the target self-heating current can be obtained based on the required temperature parameters of the power battery 110 during self-heating. For example, a higher required temperature parameter results in a larger target self-heating current, and a lower required temperature parameter results in a smaller target self-heating current. After obtaining the target balancing current and the target self-heating current, the first control signal of the motor controller can be adjusted based on the target balancing current, the target self-heating current, and the actual phase current of the motor. The first control signal can adjust the duty cycle of the first bridge arm 120, thereby enabling self-heating and balancing processing of the first battery pack E1 and the second battery pack E2, realizing the self-heating and active balancing function between the first battery pack E1 and the second battery pack E2.

[0053] The balancing current parameter of the power battery 110 may also include the voltage difference ΔU. The target balancing current is obtained by integrating the voltage difference ΔU between the first battery pack E1 and the second battery pack E2. The target self-heating current is obtained according to the temperature requirement parameter when the power battery 110 self-heats. For example, if the current temperature requirement parameter is higher, the target self-heating current is larger; if the current temperature requirement parameter is smaller, the target self-heating current is smaller. After obtaining the target balancing current and the target self-heating current, the first control signal of the motor controller can be adjusted according to the target balancing current, the target self-heating current, and the current actual phase current of the motor. The first control signal can adjust the duty cycle of the first bridge arm 120, thereby enabling self-heating and balancing processing of the first battery pack E1 and the second battery pack E2 to realize the self-heating and active balancing function between the first battery pack E1 and the second battery pack E2.

[0054] The balancing current parameters of the power battery 110 may also include the instantaneous power difference ΔP. The target balancing current is obtained by integrating the instantaneous power difference ΔP between the first battery pack E1 and the second battery pack E2. The target self-heating current is also obtained based on the temperature requirement parameters when the power battery 110 self-heats. For example, if the current temperature requirement parameter is higher, the target self-heating current is larger; if the current temperature requirement parameter is lower, the target self-heating current is smaller. After obtaining the target balancing current and the target self-heating current, the first control signal of the motor controller can be adjusted according to the target balancing current, the target self-heating current, and the current actual phase current of the motor. The first control signal can adjust the duty cycle of the first bridge arm 120, thereby enabling self-heating and balancing processing of the first battery pack E1 and the second battery pack E2 to achieve the self-heating and active balancing functions between the first battery pack E1 and the second battery pack E2.

[0055] According to one embodiment of the present invention, the equalization battery parameter is the discharge capacity difference; the controller 140 is configured to: collect the phase current of each phase of the motor; calculate the N-line current of the motor based on the phase current of each phase of the motor; and perform integration processing on the N-line current to obtain the discharge capacity difference.

[0056] Specifically, the motor is an M-phase N-wire motor. For example, in a six-phase seven-wire motor, the current of each phase is collected to obtain six phase currents (ia, ib, ic, iu, iv, and iw). Taking the direction of current flow into the motor as the positive direction, the following condition is met: ia + ib + ic + iu + iv + iw + in = 0, where in is the N-wire current of the motor. The controller 140 collects the phase current of each phase of the motor. For example, the current magnitudes of phase currents ia, ib, ic, iu, iv, and iw can be collected by current sensors. After obtaining the phase current of each phase of the motor, the N-wire current in can be calculated using in = -ia - ib - ic - iu - iv - iw. After obtaining the N-wire current in, the N-wire current in can be integrated to obtain the discharge capacity difference ΔQ between the first battery pack E1 and the second battery pack E2. The motor control employs phase-shift control technology (sampling the troughs and peaks of the PWM count value for each phase arm; phase-shift control can achieve sampling at multiples of the carrier cycle). The MCU simultaneously collects the phase current of each phase of the motor at the zero-crossing point or period point of the carrier cycle of each phase arm to calculate the neutral (N) line current of the motor. This increases the sampling frequency of the motor's N line current per unit cycle, allowing for a more accurate calculation of the discharge difference between the two battery packs. Phase-shift control technology can also reduce the current ripple of the motor's neutral line, thereby reducing EMC (Electromagnetic Compatibility) interference and NVH (noise, vibration, harshness) noise. The update cycle for the discharge capacity difference ΔQ is calculated by simultaneously sampling the phase current of each phase of the motor and the N current of the motor according to the carrier cycle of each arm, and updating the motor's N current integrally within one self-heating cycle.

[0057] According to another embodiment of the present invention, the equalization battery parameter is the discharge capacity difference; the controller 140 is configured to: collect the bus positive current and bus negative current of the power battery 110; perform ampere-hour integration on the bus positive current of the power battery 110 to obtain the discharge capacity of the second battery pack, and perform ampere-hour integration on the bus negative current of the power battery 110 to obtain the discharge capacity of the first battery pack; and obtain the discharge capacity difference based on the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

[0058] Specifically, during the self-heating process of the power battery 110, the controller 140 collects the positive and negative currents of the power battery 110 bus. It then calculates the cumulative discharge capacity Q1 by integrating the positive and negative currents of the power battery 110 bus, and calculates the cumulative discharge capacity Q2 by integrating the negative current of the power battery 110 bus. After obtaining the discharge capacities Q1 and Q2, the discharge capacity difference ΔQ can be obtained based on the discharge capacity Q1 of the first battery pack E1 and the discharge capacity Q2 of the second battery pack E2. The positive and negative currents of the power battery terminal bus can be collected through the BMS (Battery Management System). The BMS directly integrates the current Hall effect sensors for the positive and negative terminals of the power battery pack bus and the voltage sampling circuit for each battery cell, eliminating the need for additional components.

[0059] According to another embodiment of the present invention, the discharge capacity difference of the battery parameters is balanced; the controller 140 is configured to: collect the positive current of the motor controller bus and the negative current of the motor controller bus; perform ampere-hour integration on the positive current of the motor controller bus to obtain the discharge capacity of the first battery pack, and perform ampere-hour integration on the negative current of the motor controller bus to obtain the discharge capacity of the second battery pack; and obtain the discharge capacity difference based on the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

[0060] Specifically, during the self-heating process of the power battery 110, the controller 140 collects the positive and negative bus currents of the motor controller. By integrating the positive and negative bus currents of the motor controller (i.e., integrating the positive bus current at the motor controller terminal in ampere-hours), the cumulative discharge capacity Q1 is calculated; and by integrating the negative bus current at the motor controller terminal, the cumulative discharge capacity Q2 is calculated. After obtaining the discharge capacities Q1 and Q2, the discharge capacity difference ΔQ can be obtained based on the discharge capacity Q1 of the first battery pack E1 and the discharge capacity Q2 of the second battery pack E2. The use of an MCU to collect the positive and negative bus currents of the motor controller avoids the switching time of power devices, thus avoiding interference and making the current acquisition more accurate.

[0061] According to one embodiment of the present invention, the equalization current parameter is the voltage difference, and the controller 140 is configured to: acquire the bus voltage and the voltage of the second battery pack; calculate the voltage of the first battery pack based on the bus voltage and the voltage of the second battery pack; and determine the voltage difference based on the voltage of the first battery pack and the voltage of the second battery pack.

[0062] Specifically, the controller 140 can acquire the bus voltage of the motor controller and the N-line voltage of the motor (voltage of the second battery pack E2). The bus voltage of the motor controller is the sum of the voltages of the first battery pack E1 and the second battery pack E2. After acquiring the bus voltage of the motor controller and the voltage of the second battery pack E2, the voltage of the first battery pack E1 can be calculated by subtracting the voltage of the second battery pack E2 from the bus voltage of the motor controller. After acquiring the voltages of the first battery pack E1 and the second battery pack E2, the voltage difference ΔU can be determined based on these voltages.

[0063] According to one embodiment of the present invention, the equalization current parameter is the instantaneous power difference; the controller 140 is configured to: collect the positive current of the power battery bus, the negative current of the battery bus, the voltage of the first battery pack and the voltage of the second battery pack; determine the instantaneous power of the first battery pack based on the positive current of the battery bus and the voltage of the first battery pack, and determine the instantaneous power of the second battery pack based on the negative current of the battery bus and the voltage of the second battery pack; and determine the instantaneous power difference based on the instantaneous power of the first battery pack and the instantaneous power of the second battery pack.

[0064] Specifically, the controller 140 simultaneously collects the positive current of the bus of the power battery 110, the negative current of the bus of the power battery, the voltage of the first battery pack E1, and the voltage of the second battery pack E2. The instantaneous power p1 of the first battery pack E1 can be determined by multiplying the voltage of the first battery pack E1 and the positive current of the bus of the power battery 110. The instantaneous power p2 of the second battery pack E2 can be determined by multiplying the voltage of the second battery pack E2 and the negative current of the bus of the power battery. After calculating the instantaneous power of each battery pack, the instantaneous power difference Δp can be determined by using the instantaneous power p1 of the first battery pack E1 and the instantaneous power p2 of the second battery pack E2.

[0065] According to one embodiment of the present invention, the controller 140 is configured to: obtain the required heating power based on the temperature requirement parameters; determine the amplitude and frequency of the N-line self-heating current based on the required heating power; and determine the target heating current based on the amplitude and frequency.

[0066] Furthermore, according to one embodiment of the present invention, the controller 140 is further configured to obtain the target heating equalization current by means of the following formula:

[0067] In*=indc+ipk·sin(2·π·f·t)(1)

[0068] Where In* represents the target heating equalization current, indc represents the target equalization current, ipk represents the amplitude of the target self-heating current, f represents the frequency of the target self-heating current, and t represents the current time.

[0069] Specifically, upon receiving the self-heating demand signal of the power battery 110, the system can determine whether self-heating is required based on the current temperature of the power battery 110. When the current temperature of the power battery 110 is low, to ensure its power supply capacity, the system can initiate a self-heating program. The required heating power is determined based on the heating demand of the power battery, specifically the temperature requirement parameters of the power battery 110. For example, if the current temperature of the power battery 110 is low, the required heating power will be higher; if the current temperature of the power battery 110 is high, the required heating power will be lower. After obtaining the required heating power, the amplitude ipk and frequency f of the self-heating current of the N-line can be determined based on the magnitude of the required heating power. The target heating current In* can be determined using the formula (1) above, based on the target equalization current indc, the amplitude ipk and frequency f of the target self-heating current, and the current time.

[0070] It should be noted that the temperature requirements of the power battery 110, the amplitude of the target self-heating current ipk, and the required heating power corresponding to the frequency f of the target self-heating current can be pre-calibrated on the test bench and can generally be obtained by looking up a table or by linear fitting.

[0071] According to one embodiment of the present invention, the controller 140 is further configured to: acquire the actual phase current of the motor; obtain a common-mode voltage based on the target heating equalization current and the actual phase current; and adjust a first control signal of the motor controller based on the common-mode voltage.

[0072] Specifically, after receiving the power battery balancing command, the actual phase current of each phase of the motor is obtained, and the N-line current value of the motor is calculated through the phase current value of each phase of the motor. By integrating the N-line current value, the discharge tolerance ΔQ of the first battery pack E1 and the second battery pack E2 is calculated. By integrating the tolerance ΔQ, the given target balancing current indc is obtained. After obtaining the target balancing current indc, for example, the target heating balancing current in* is obtained through the above formula (1). Based on the neutral line target heating balancing current in* and the actual N-line current in (the actual N-line current in is calculated by the sum of the actual N-line current in and the actual phase current of each phase of the motor being zero), the common mode voltage Un of the bridge arm control is obtained through PI or PR closed-loop control. The first control signal of the motor controller is adjusted according to the common mode voltage Un. By adjusting the duty cycle of each phase bridge arm, the positive and negative currents of the bus are adjusted to achieve self-heating and balancing processing of the first battery pack E1 and the second battery pack E2 when the vehicle is parked.

[0073] According to one embodiment of the present invention, the controller 140 is further configured to: in a second preset state, control the bridge arm of the motor controller to drive the motor, and cause the first battery pack E1 and the second battery pack E2 to alternately charge and discharge, so as to achieve self-heating of the first battery pack E1 and the second battery pack E2, and cause the absolute value of the difference between the capacitance of the first battery pack E1 and the capacitance of the second battery pack E2 to be lower than a preset threshold. The preset threshold can be determined according to actual conditions.

[0074] Specifically, when the vehicle is in driving mode (i.e., while driving) and the battery self-heating function is activated, if the absolute value of the difference between the capacity of the first battery pack E1 and the capacity of the second battery pack E2 is large, indicating that the current power battery is not in an balanced state, the motor controller's bridge arm can be controlled to drive the motor, causing the first battery pack E1 and the second battery pack E2 to alternately charge and discharge. That is, when the capacity of the first battery pack E1 is large, it can discharge while the second battery pack E2 is charged; when the capacity of the first battery pack E1 is small, it can discharge while the second battery pack E2 is charged. This achieves self-heating of both the first and second battery packs while keeping the absolute value of the difference between their capacities small (less than a preset threshold), thus achieving battery balance between the battery packs during the self-heating process when the vehicle is in driving mode.

[0075] According to one embodiment of the present invention, the controller 140 is configured to: collect the equalization battery parameters, temperature demand parameters, and drive demand parameters of the power battery 110; obtain a target drive current based on the drive demand parameters, obtain a target self-heating current based on the temperature demand parameters, and obtain a target equalization current based on the equalization battery parameters; adjust the second control signal of the motor controller according to the target drive current, the target self-heating current, the target equalization current, and the actual phase current to drive the motor, and perform self-heating and equalization processing on the first battery pack E1 and the second battery pack E2.

[0076] According to one embodiment of the present invention, the controller 140 is configured to: acquire the torque output of the motor, the speed of the motor, the voltage of the power battery, and the rotor electrical angle of the motor; upon receiving a drive command, acquire a target drive current based on the torque output of the motor, the speed of the motor, and the voltage of the power battery, and acquire the differential mode voltage of each phase arm based on the target drive current, the actual phase current, and the rotor electrical angle of the motor.

[0077] Furthermore, according to one embodiment of the present invention, the target drive current is the synthesis of the d-axis target current and the q-axis target current, and the actual phase current is the synthesis of the d-axis actual current and the q-axis actual current. The controller 140 is configured to: perform closed-loop control on the d-axis target current and the d-axis actual current, as well as the q-axis target current and the q-axis actual current, to obtain the d-axis target voltage and the q-axis target voltage; and obtain the differential mode voltage of each phase bridge arm based on the d-axis target voltage, the q-axis target voltage, and the rotor electrical angle of the motor.

[0078] Specifically, in the control of permanent magnet synchronous motors, in order to obtain control characteristics similar to those of a DC motor, a coordinate system is established on the motor rotor. This coordinate system rotates synchronously with the rotor. The direction of the rotor's magnetic field is taken as the d-axis, and the direction perpendicular to the rotor's magnetic field is taken as the q-axis. By transforming the mathematical model of the motor into this coordinate system, the d-axis and q-axis can be decoupled, thereby obtaining good control characteristics. That is, by performing coordinate transformation on the phase current of each phase of the motor, the d-axis current and q-axis current of the motor can be obtained. The d-axis current and q-axis current are used to drive the vehicle. Figure 3 As shown, the motor has p-phase currents, i1, i2 to ip. After two coordinate transformations of each phase current, the d-axis current id and q-axis current iq of the motor are obtained. The actual phase current is the synthesis of the actual d-axis current id and the actual q-axis current iq. The motor's torque output Te*, motor speed W, power battery voltage Udc, and rotor electrical angle θ are obtained. When a drive command is received, the vehicle is in drive mode, and the target drive current can be obtained based on the motor's torque output Te*, motor speed W, and power battery voltage Udc. The target drive current is the synthesis of the d-axis target current and the q-axis target current. PID closed-loop control based on the d-axis target current id* and the actual d-axis current id yields the d-axis target voltage Ud, and PID closed-loop control based on the q-axis target current iq* and the actual q-axis current iq yields the q-axis target voltage Uq. After obtaining the target voltage Ud on the d-axis and the target voltage Uq on the q-axis, the differential mode voltages U1, U2 and Up of each phase bridge arm are obtained by inverse coordinate transformation based on the target voltages Ud, Uq and the rotor electrical angle θ of the motor.

[0079] According to one embodiment of the present invention, the controller is further configured to: obtain a target heating equalization current based on a target self-heating current and a target equalization current; acquire the actual phase current of the motor; obtain a common-mode voltage based on the target heating equalization current and the actual phase current; and adjust a second control signal of the motor controller based on the differential-mode voltage and the common-mode voltage of each phase arm.

[0080] Specifically, such as Figure 3As shown, after the vehicle receives the self-heating power command and the battery balancing command, the command calculation module 2 obtains the target heating balancing current in* based on the target self-heating current and the target balancing current indc. For example, in a p-phase p+1 line motor, the current of each phase of the motor is collected to obtain p phase currents (i1, i2, ..., ip). Taking the direction of current flow into the motor as the positive direction, i1 + i2 + ..., ip + in = 0 is satisfied, where in is the N-line current of the motor. The magnitude of the current of each phase can be collected by the current sensor. After obtaining the phase current of each phase of the motor, the N-line current in of the motor can be calculated by in = -i1 - i2 - ... - ip. The common-mode voltage is obtained based on the target heating equalization current in* and the actual phase current. That is, after obtaining the actual N-line current in, the common-mode voltage Un of the p-phase bridge arm is obtained through PR closed-loop control based on the target heating equalization current in* and the actual N-line current in. Based on the common-mode voltage Un and the differential-mode voltage (U1, U2...Up) of each phase bridge arm of the motor, the PWM duty cycle of each phase in the p-phase bridge arm is adjusted to adjust the second control signal of the motor controller, so that the vehicle can achieve self-heating of the power battery and equalization of the power battery pack under driving conditions.

[0081] According to one embodiment of the present invention, the controller 140 is configured to: in a third preset state, if the absolute value of the difference between the capacitance of the first battery pack E1 and the capacitance of the second battery pack E2 is not lower than a preset threshold, control the bridge arm of the motor controller to perform equalization processing on the first battery pack E1 and the second battery pack E2.

[0082] Specifically, when the absolute value of the difference between the capacity of the first battery pack E1 and the capacitance of the second battery pack E2 is detected to be not lower than a preset threshold, it indicates that the absolute value of the difference between the current capacity of the first battery pack E1 and the capacitance of the second battery pack E2 is large, and the power battery 110 is not in an balanced state. That is, in the third preset state (the state in which the power battery 100 only performs charge balancing), the bridge arm of the motor controller can be controlled to balance the first battery pack E1 and the second battery pack E2, so that the absolute value of the difference between the capacity of the first battery pack E1 and the capacitance of the second battery pack E2 is small. For example, when the capacity of the first battery pack E1 is large and the capacity of the second battery pack E2 is small, the discharge time of the first battery pack E1 can be longer and the charging time of the second battery pack E2 can be longer, thereby achieving the balance of capacitance between the first battery pack E1 and the second battery pack E2.

[0083] According to one embodiment of the present invention, such as Figure 2As shown, the above-mentioned battery dynamic balancing device further includes: a DC charging and discharging port, the positive terminal of which is connected to the first busbar of the motor controller, and the negative terminal of which is connected to the second busbar of the motor controller; the controller 140 is configured to: in a fourth preset state, charge the power battery 110 through the DC charging and discharging port, and control the bridge arm of the motor controller to cause the first battery pack E1 and the second battery pack E2 to charge and discharge alternately, so as to achieve self-heating of the first battery pack E1 and the second battery pack E2, and cause the absolute value of the difference between the capacitance of the first battery pack E1 and the capacitance of the second battery pack E2 to be lower than a preset threshold.

[0084] According to an embodiment of the present invention, the above-mentioned battery dynamic balancing device further includes: a DC charging and discharging port, the positive terminal of the DC charging and discharging port being connected to the N line, and the negative terminal of the DC charging and discharging port being connected to the second bus terminal of the motor controller; the controller is configured to: in a fifth preset state, control the bridge arm of the motor controller to boost the charging of the power battery.

[0085] Specifically, in the fourth preset state, when the power battery 110 has a low charge and needs charging, it can be charged through the DC charging / discharging port. While the power battery 110 is charging, the motor controller's arm can be controlled to alternately charge and discharge the first battery pack E1 and the second battery pack E2. This allows the self-heating of the first and second battery packs E1 and E2 to minimize the absolute value of the difference between their capacities, thus balancing the first and second battery packs E1 and E2. After capacity balancing is complete, when the power battery needs boost charging (in the fifth preset state), when the battery charge is low, the motor controller's arm can be controlled to boost the power battery's charge, thereby achieving capacity balancing between the battery packs during the power battery's self-heating process.

[0086] In summary, according to the battery dynamic balancing device of the present invention, the battery packs have a first node, the first end of each phase first bridge arm is connected to the positive terminal of the first battery pack, the second end of each phase first bridge arm is connected to the negative terminal of the second battery pack, the first end of each phase first inductor is connected to the corresponding first bridge arm, the second end of each phase first inductor is connected to the first node, and the controller is connected to the first bridge arm. The controller is configured to: in a first preset state, control the first bridge arm to cause the first battery pack and the second battery pack to alternately charge and discharge, thereby achieving self-heating of the first battery pack and the second battery pack, and causing the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold. Therefore, the balancing device can achieve dynamic balancing of the charge between the first battery pack and the second battery pack during the battery self-heating process, thereby improving battery performance and extending battery life.

[0087] Corresponding to the above embodiments, the present invention also proposes a control method for a battery dynamic balancing device.

[0088] like Figure 4 As shown, the control method of the battery dynamic balancing device in this embodiment of the invention includes the following steps:

[0089] S1, in the first preset state, control the first bridge arm to cause the first battery pack and the second battery pack to charge and discharge alternately, so as to achieve self-heating of the first battery pack and the second battery pack, and cause the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than the preset threshold.

[0090] The following is combined with Figure 5 The control method of the present invention will be described below.

[0091] As a specific example, the control method of the battery dynamic balancing device of the present invention may include the following steps:

[0092] S100: The MCU receives the battery self-heating demand signal and enters the battery self-heating program.

[0093] S101. Determine whether self-heating is needed based on the current battery temperature. If yes, proceed to step S102; otherwise, proceed to step S108.

[0094] S102 controls the closing of the switch module of the battery dynamic balancing device.

[0095] S103 determines the required heating power based on the battery temperature, and determines the amplitude and frequency of the self-heating current. It also determines the initial bias current based on the initial voltage or capacity of the battery pack.

[0096] S104. Determine whether a battery active balancing command has been received. If yes, proceed to step S105; otherwise, proceed to step S110.

[0097] S105: Collect the current of each phase of the motor and calculate the N-line current value based on the motor phase current value. Integrate the N-line current value over N1 self-heating cycles to obtain the discharge capacity difference. Perform PID calculation on the discharge capacity difference to obtain a new N-line self-heating balancing current. Perform battery dynamic balancing control based on the new N-line self-heating balancing current. After executing N2 self-heating cycles, the N-line self-heating balancing current is zero, and the PID integral value of the discharge capacity difference is cleared. Note that no PID calculation of the discharge capacity difference is performed during the N2 self-heating cycles. N1 and N2 are both positive integers, with N2 being much larger than N1 (e.g., N2 = 100N1).

[0098] S106: Obtain the target heating equalization current value and the actual phase current value, perform PI or PR closed-loop control, and calculate the duty cycle of the self-heating bridge arm.

[0099] S107, Exit the battery self-heating program.

[0100] S108, adjusts the battery self-heating target current value to zero according to the battery heating requirements.

[0101] S109, the switch module controlling the battery dynamic balancing device is disconnected, and the process proceeds to step S107.

[0102] S110, the self-heating dynamic balancing current is zero, and the PID integral value of the battery pack dynamic voltage or discharge capacity difference is cleared, and then proceed to step S106.

[0103] It should be noted that for details not disclosed in the control method of the battery dynamic balancing device in the embodiments of the present invention, please refer to the details disclosed in the battery dynamic balancing device in the embodiments of the present invention, which will not be repeated here.

[0104] According to an embodiment of the present invention, a control method for a battery dynamic balancing device includes a power battery, at least one phase first bridge arm, at least one phase first inductor, and a controller. The power battery includes a first battery pack and a second battery pack connected in series, with a first node between the first and second battery packs. A first end of each phase first bridge arm is connected to the positive terminal of the first battery pack, and a second end of each phase first bridge arm is connected to the negative terminal of the second battery pack. A first end of each phase first inductor is connected to the corresponding first bridge arm, and a second end of each phase first inductor is connected to the first node. The controller is connected to the first bridge arm. The method is applied to the controller and includes: in a first preset state, controlling the first bridge arm to cause the first and second battery packs to alternately charge and discharge, thereby achieving self-heating of the first and second battery packs, and ensuring that the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack is lower than a preset threshold. Thus, this method can achieve dynamic balancing of the charge between the first and second battery packs during the battery self-heating process, thereby improving battery performance and extending battery life.

[0105] Corresponding to the above embodiments, the present invention also proposes a vehicle.

[0106] like Figure 6 As shown, the vehicle 200 in this embodiment of the invention may include the battery dynamic balancing device 100 described above.

[0107] According to the vehicle of the present invention, by including the above-described battery dynamic balancing device, dynamic balancing of the charge between the first battery pack and the second battery pack during the battery self-heating process can be achieved, thereby improving battery performance and extending battery life.

[0108] It should be noted that the logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (such as a computer-based system, a processor-included system, or other system that can fetch and execute instructions from, an instruction execution system, apparatus, or device). For the purposes of this specification, "computer-readable medium" can be any means that can contain, store, communicate, propagate, or transmit programs for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include: an electrical connection having one or more wires (electronic device), a portable computer disk drive (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and editable read-only memory (EPROM or flash memory), fiber optic devices, and portable optical disc read-only memory (CDROM). Alternatively, the computer-readable medium may be paper or other suitable media on which the program can be printed, since the program can be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, interpreting, or otherwise processing as necessary, and then stored in a computer memory.

[0109] It should be understood that various parts of the present invention can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0110] In the description of this specification, references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0111] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0112] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0113] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A battery dynamic balancing device, characterized in that, include: A power battery, comprising a first battery pack and a second battery pack connected in series, and having a first node between the first battery pack and the second battery pack; At least one phase first bridge arm, the first end of each phase first bridge arm is connected to the positive terminal of the first battery pack, and the second end of each phase first bridge arm is connected to the negative terminal of the second battery pack. At least one phase first inductor, the first end of each phase first inductor is connected to the corresponding first bridge arm, and the second end of each phase first inductor is connected to the first node; A controller connected to the first bridge arm is configured to: in a first preset state, control the first bridge arm to cause the first battery pack and the second battery pack to charge and discharge alternately, so as to achieve self-heating of the first battery pack and the second battery pack, and cause the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold. The bridge arm of the multiplexed motor controller is used as the first bridge arm. The controller is configured to: Collect the equalization battery parameters and temperature requirement parameters of the power battery; The target equalization current is obtained based on the equalization battery parameters, and the target self-heating current is obtained based on the temperature requirement parameters. The first control signal of the motor controller is adjusted based on the target equalization current, the target self-heating current and the actual phase current of the motor to perform self-heating and equalization processing on the first battery pack and the second battery pack. Collect the equalization battery parameters, temperature requirement parameters, and drive requirement parameters of the power battery; The target drive current is obtained based on the drive requirement parameters, the target self-heating current is obtained based on the temperature requirement parameters, and the target equalization current is obtained based on the equalization battery parameters. The second control signal of the motor controller is adjusted and controlled according to the target drive current, the target self-heating current, the target equalization current and the actual phase current to drive the motor, and to perform self-heating and equalization processing on the first battery pack and the second battery pack.

2. The battery dynamic balancing device according to claim 1, characterized in that, The coil of the multiplexed motor is used as the first inductor; the motor leads out an N-line, which is connected to the first node.

3. The battery dynamic balancing device according to claim 2, characterized in that, The controller is configured to perform integral calculations on the equalization battery parameters to obtain the target equalization current, wherein the equalization battery parameters include one of the following: discharge capacity difference, voltage difference, and instantaneous power difference, wherein the discharge capacity difference, voltage difference, and instantaneous power difference represent the difference in discharge capacity, voltage, and instantaneous power between the first battery pack and the second battery pack, respectively.

4. The battery dynamic balancing device according to claim 3, characterized in that, The equalization battery parameter is the discharge capacity difference; The controller is configured to: acquire the phase current of each phase of the motor; calculate the N-line current of the motor based on the phase current of each phase of the motor; and perform integration processing on the N-line current to obtain the discharge capacity difference.

5. The battery dynamic balancing device according to claim 3, characterized in that, The equalization battery parameter is the discharge capacity difference; The controller is configured to: collect the positive current and negative current of the power battery bus; perform ampere-hour integration on the positive current of the power battery bus to obtain the discharge capacity of the first battery pack, and perform ampere-hour integration on the negative current of the power battery bus to obtain the discharge capacity of the second battery pack; and obtain the discharge capacity difference based on the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

6. The battery dynamic balancing device according to claim 3, characterized in that, The equalization battery parameter is the discharge capacity difference; The controller is configured to: collect the positive bus current and the negative bus current of the motor controller; perform ampere-hour integration on the positive bus current to obtain the discharge capacity of the first battery pack, and perform ampere-hour integration on the negative bus current to obtain the discharge capacity of the second battery pack; and obtain the discharge capacity difference based on the discharge capacity of the first battery pack and the discharge capacity of the second battery pack.

7. The battery dynamic balancing device according to claim 3, characterized in that, The equalization current parameter is the voltage difference value; The controller is configured to: acquire the bus voltage of the motor controller and the voltage of the second battery pack; calculate the voltage of the first battery pack based on the bus voltage and the voltage of the second battery pack; and determine the voltage difference based on the voltage of the first battery pack and the voltage of the second battery pack.

8. The battery dynamic balancing device according to claim 3, characterized in that, The equalization current parameter is the instantaneous power difference; The controller is configured to: collect the positive current of the bus, the negative current of the bus, the voltage of the first battery pack, and the voltage of the second battery pack of the power battery; determine the instantaneous power of the first battery pack based on the positive current of the bus and the voltage of the first battery pack, and determine the instantaneous power of the second battery pack based on the negative current of the bus and the voltage of the second battery pack; and determine the instantaneous power difference based on the instantaneous power of the first battery pack and the instantaneous power of the second battery pack.

9. The battery dynamic balancing device according to claim 2, characterized in that, The controller is configured to: obtain the required heating power based on the temperature requirement parameters; determine the amplitude and frequency of the self-heating current of the N-line based on the required heating power; and determine the target self-heating current based on the amplitude and frequency.

10. The battery dynamic balancing device according to claim 9, characterized in that, The controller is also configured to obtain the target heating equalization current using the following formula: in, This represents the target heating equalization current. This represents the target equalization current. This indicates the amplitude of the target self-heating current. The frequency of the target self-heating current. Indicates time.

11. The battery dynamic balancing device according to claim 10, characterized in that, The controller is also configured to: Obtain the actual phase current of the motor; obtain the common-mode voltage based on the target heating equalization current and the actual phase current; The first control signal of the motor controller is adjusted according to the common-mode voltage.

12. The battery dynamic balancing device according to claim 11, characterized in that, The controller is further configured to: in a second preset state, control the bridge arm of the motor controller to drive the motor and cause the first battery pack and the second battery pack to charge and discharge alternately to achieve self-heating of the first battery pack and the second battery pack, and cause the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than the preset threshold.

13. The battery dynamic balancing device according to claim 12, characterized in that, The controller is configured to: The torque output of the motor, the speed of the motor, the voltage of the power battery, and the rotor electrical angle of the motor are obtained. Upon receiving a drive command, the target drive current is obtained based on the motor's torque output, the motor's rotational speed, and the power battery's voltage. The differential mode voltage of each phase arm is then obtained based on the target drive current, the actual phase current, and the motor's rotor electrical angle.

14. The battery dynamic balancing device according to claim 13, characterized in that, The target drive current is the synthesis of the d-axis target current and the q-axis target current, the actual phase current is the synthesis of the d-axis actual current and the q-axis actual current, and the controller is configured to: Closed-loop control is performed on the d-axis target current and the d-axis actual current, as well as the q-axis target current and the q-axis actual current, to obtain the d-axis target voltage and the q-axis target voltage; The differential mode voltage of each phase bridge arm is obtained based on the target voltage of the d-axis, the target voltage of the q-axis, and the rotor electrical angle of the motor.

15. The battery dynamic balancing device according to claim 14, characterized in that, The controller is also configured to: The target heating equalization current is obtained based on the target self-heating current and the target equalization current; Obtain the actual phase current of the motor; obtain the common-mode voltage based on the target heating equalization current and the actual phase current; The second control signal of the motor controller is adjusted based on the differential mode voltage and the common mode voltage of each phase arm.

16. The battery dynamic balancing device according to claim 1, characterized in that, The controller is configured to: in a third preset state, if the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack is not lower than the preset threshold, control the bridge arm of the motor controller to perform equalization processing on the first battery pack and the second battery pack.

17. The battery dynamic balancing device according to claim 2, characterized in that, It also includes: A DC charging / discharging port, wherein the positive terminal of the DC charging / discharging port is connected to the first bus terminal of the motor controller, and the negative terminal of the DC charging / discharging port is connected to the second bus terminal of the motor controller; The controller is configured to: in a fourth preset state, charge the power battery through the DC charging and discharging port, and control the bridge arm of the motor controller to cause the first battery pack and the second battery pack to charge and discharge alternately, so as to achieve self-heating of the first battery pack and the second battery pack, and cause the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold.

18. The battery dynamic balancing device according to claim 2, characterized in that, It also includes: A DC charging / discharging port, the positive terminal of which is connected to the N line, and the negative terminal of which is connected to the second bus terminal of the motor controller; The controller is configured to, in a fifth preset state, control the bridge arm of the motor controller to boost the charging voltage of the power battery.

19. A control method for a battery dynamic balancing device, characterized in that, The battery dynamic balancing device includes: a power battery, at least one phase first bridge arm, at least one phase first inductor, and a controller. The power battery includes a first battery pack and a second battery pack connected in series, with a first node between them. A first end of each phase first bridge arm is connected to the positive terminal of the first battery pack, and a second end of each phase first bridge arm is connected to the negative terminal of the second battery pack. A first end of each phase first inductor is connected to the corresponding first bridge arm, and a second end of each phase first inductor is connected to the first node. The controller is connected to the first bridge arm. The method applied to the controller includes: In the first preset state, the first bridge arm is controlled to cause the first battery pack and the second battery pack to charge and discharge alternately, so as to achieve self-heating of the first battery pack and the second battery pack, and to cause the absolute value of the difference between the capacitance of the first battery pack and the capacitance of the second battery pack to be lower than a preset threshold. The bridge arm of the multiplexed motor controller is used as the first bridge arm. The controller is configured to: Collect the equalization battery parameters and temperature requirement parameters of the power battery; The target equalization current is obtained based on the equalization battery parameters, and the target self-heating current is obtained based on the temperature requirement parameters. The first control signal of the motor controller is adjusted based on the target equalization current, the target self-heating current and the actual phase current of the motor to perform self-heating and equalization processing on the first battery pack and the second battery pack. Collect the equalization battery parameters, temperature requirement parameters, and drive requirement parameters of the power battery; The target drive current is obtained based on the drive requirement parameters, the target self-heating current is obtained based on the temperature requirement parameters, and the target equalization current is obtained based on the equalization battery parameters. The second control signal of the motor controller is adjusted and controlled according to the target drive current, the target self-heating current, the target equalization current and the actual phase current to drive the motor, and to perform self-heating and equalization processing on the first battery pack and the second battery pack.

20. A vehicle, characterized in that, Includes the battery dynamic balancing device as described in any one of claims 1-18.

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