Motor driving system and device integrated with battery charging function

Abstract

The invention provides a motor driving system and device integrated with a battery charging function, and relates to the technical field of motor driving and battery charging. The device for integrating the battery charging function of the motor driving system comprises a motor driving module, a control system, a driving motor coupled to an engine, a low-voltage battery pack, a high-voltage battery pack and a first charging loop module. When the driving motor charges the power battery pack through the motor driving module, the compensation module associated with the motor speed is added to dynamically adjust the motor driving signal generated by the motor driving module, so that the charging current and voltage are accurately controlled, and the damage of unstable charging current to the battery is prevented; meanwhile, when the power battery loses power or breaks power, the low-voltage battery pack is controlled to provide excitation energy for the driving motor, and the driving motor works in a power generation mode, so that the power battery loses power or breaks power is activated and charged, and the problem of activation of the vehicle-mounted power battery is solved.

Description

Technical Field

[0001] This invention relates to the fields of motor drive and battery charging technology, and in particular to an apparatus and method for charging a power battery pack in an on-board hybrid motor drive system. Background Technology

[0002] The statements in this section are provided only as background information in connection with this disclosure and may not constitute prior art.

[0003] Typically, many applications combine a power battery and a motor drive system, with the engine providing the primary power. For example, in hybrid and new energy vehicles, the power battery powers the drive motor via a motor controller and is charged via internal or external charging equipment. When the motor enters regenerative braking mode, the motor controller also uses the motor's energy to charge the battery. However, the regenerative braking control of the motor controller is often coarse, lacking precise control over the charging current, which negatively impacts battery life and performance. If the power battery has a significant electrical load beyond the electric drive system, the charging function becomes even more crucial, requiring precise charging control. Furthermore, when the motor is a non-permanent magnet motor such as an induction motor, if the power battery has very low or no energy (depleted or discharged), the low voltage may prevent the motor controller from establishing a magnetic field within the motor, thus hindering battery charging. Therefore, it is necessary to utilize the motor controller to activate the power battery or start the motor into a generator state, using the energy generated by the engine to charge the power battery. When the battery's energy is very low, sometimes an external battery is used to activate the degraded battery. For example, an external battery is connected to the vehicle's power module (DC / DC converter) via a dedicated interface circuit. The power module converts the voltage of the external battery to the voltage required by the degraded battery, thus activating it. This method requires a technician to connect an external battery to activate the degraded battery and also requires a bidirectional DC / DC converter, which is costly and difficult to meet the needs of users, reducing the convenience of vehicle use and increasing costs.

[0004] Therefore, accurately charging and activating the power battery through the drive motor and electronic control system without increasing the cost of the vehicle battery system, thereby improving the user experience and the overall cost-effectiveness of the vehicle, is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] This application provides a motor drive system with integrated battery charging function, including: a control system, a drive motor coupled to an engine, a low-voltage battery pack, a motor drive module having a DC bus and a high-voltage battery pack coupled to the DC bus, and a first charging circuit module coupled to the low-voltage battery pack and the DC bus, wherein the control system includes a compensation module, the gain of which is adjusted according to the speed of the drive motor so that the voltage and current on the DC bus can be stably controlled when the drive motor operates over a wide speed range, so as to utilize the engine's capability to accurately charge the high-voltage battery pack.

[0006] Furthermore, the drive motor is a non-permanent magnet motor, and the first charging circuit module is configured to charge the capacitor of the DC bus when the voltage of the high-voltage battery pack is lower than a threshold, so as to provide excitation energy for the drive motor, and the drive motor is configured to use the excitation energy to enter generator mode and activate the high-voltage battery pack.

[0007] Furthermore, the first charging circuit module includes a diode configured to turn off when the DC bus voltage is higher than the voltage of the low-voltage battery pack, thereby isolating the low-voltage battery pack from the DC bus.

[0008] Furthermore, the first charging circuit module includes a power switch configured to disconnect when the low-voltage battery pack is not required to charge the DC bus.

[0009] Furthermore, the compensation module includes a compensation factor. Where ω is the real-time speed of the drive motor, and k is the damping coefficient.

[0010] Furthermore, the first charging circuit module is physically integrated into the motor drive module.

[0011] This application also provides a motor drive device with integrated battery charging function, including: a control system, a drive motor coupled to an engine, and a converter coupled to a low-voltage battery pack and having a DC bus, wherein: the DC bus is coupled to a high-voltage battery pack and is coupled to the low-voltage battery pack and the DC bus through a first charging circuit module; and the control system includes a compensation module whose gain is adjusted according to the speed of the drive motor so that the voltage and current on the DC bus can be stably controlled when the drive motor operates over a wide speed range, so as to utilize the engine's capability to accurately charge the high-voltage battery pack.

[0012] Furthermore, the drive motor is a non-permanent magnet motor, and the first charging circuit module is configured to charge the capacitor of the DC bus when the voltage of the high-voltage battery pack is lower than a threshold, so as to provide excitation energy for the drive motor, and the drive motor is configured to use the excitation energy to enter generator mode and activate the high-voltage battery pack.

[0013] Furthermore, the first charging circuit module includes a diode configured to turn off when the DC bus voltage is higher than the voltage of the low-voltage battery pack, thereby isolating the low-voltage battery pack from the DC bus.

[0014] Furthermore, the first charging circuit module includes a power switch configured to disconnect when the low-voltage battery pack is not required to charge the DC bus.

[0015] Furthermore, the compensation module includes a compensation factor. Where ω is the real-time speed of the drive motor, and k is the damping coefficient.

[0016] Furthermore, the first charging circuit module is physically integrated into the converter.

[0017] A device for integrating battery charging function into a motor drive system, characterized in that the device comprises: a control system, a drive motor, a transmission shaft, an engine, a low-voltage battery pack, a high-voltage battery pack, a first charging circuit module, and a motor drive module; wherein:

[0018] The control system acquires the DC bus voltage U of the motor drive module. R or current I R In conjunction with the battery pack charging command voltage U* or command current I*, a compensation module determines the final torque command T of the motor drive module. r .

[0019] Furthermore, the compensation coefficient of the compensation module generally includes a supplementary factor related to the motor speed. Where ω is the rotational speed of the drive motor and k is the damping coefficient, its purpose is to correct the system gain at different speeds and prevent excessive oscillations in the system when the drive motor speed is very low or sudden, so as to maintain stable charging current and voltage. The compensation module can prevent damage to the battery caused by drastic changes in charging voltage and charging current during the charging process of the power battery by dynamically adjusting the compensation coefficient, thereby improving the service life of the power battery.

[0020] Furthermore, the engine can drive the drive motor to rotate via the transmission shaft. The drive motor has two operating modes: motor mode and generator mode. The motor drive module can activate and charge the high-voltage battery pack using the generator mode of the drive motor. The low-voltage battery pack can provide excitation energy to the drive motor using the first charging circuit and the motor drive module, thereby enabling the drive motor to operate in generator mode. In the case of a depleted high-voltage battery pack, the DC bus capacitor voltage of the motor drive module can be increased through the first charging circuit module, and excitation energy can be provided to the motor through appropriate control of the motor drive module. This allows the motor drive module to be controlled to enter generator mode, further increasing the DC bus capacitor voltage and achieving charging or activation of the high-voltage battery pack. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the circuit structure of a motor drive system with integrated battery charging function according to an embodiment of the present invention.

[0022] Figure 2 This is a flowchart of a motor drive system charging a power battery according to an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the control block diagram for charging the power battery in a motor drive system according to an embodiment of the present invention;

[0024] Figure 4 This is a schematic diagram of an example of a first charging circuit module according to an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of an example of a motor drive module according to an embodiment of the present invention;

[0026] Figure 6 This is a flowchart illustrating the activation of a de-energized or degraded power battery pack by a motor drive system according to an embodiment of the present invention.

[0027] Figure 7 This is a flowchart of a control method for activating a de-energized or depleted power battery pack according to an embodiment of the present invention. Detailed Implementation

[0028] The technical solutions of this invention will now be clearly and completely described with reference to the accompanying drawings. It should be understood that this invention provides inventive concepts applicable in various specific environments. The specific embodiments discussed are merely exemplary specific ways of manufacturing and using this invention and do not limit the scope of this invention. All other embodiments obtained based on the embodiments of this invention fall within the scope of protection of this invention.

[0029] Figure 1This is a schematic diagram of the circuit structure of a motor drive system with integrated battery charging function according to an embodiment of the present invention, including: a control system, a drive motor, a low-voltage battery pack, a high-voltage battery pack, a first charging circuit module, and a motor drive module.

[0030] In actual implementation, such as Figure 1 As shown, the motor drive system with integrated battery charging function also includes: a drive shaft and an engine.

[0031] The engine drives the drive motor to rotate via a transmission shaft. The drive motor, which can be any type of non-permanent magnet motor such as an induction motor, switched reluctance motor, or synchronous reluctance motor, has two operating modes: motor mode and generator mode. However, generator mode requires excitation energy to start. The motor drive module can activate and charge the high-voltage battery pack using the generator mode of the drive motor. The low-voltage battery pack, in addition to providing control power to the motor drive module, can also provide excitation energy to the drive motor when needed, utilizing the first charging circuit module and the motor drive module. The control system then controls the drive motor to generate excitation current, allowing the drive motor to operate in generator mode. When the high-voltage battery pack, i.e., the power battery, is in a depleted or lost-power state (i.e., the battery voltage is too low, below a threshold, and the battery cannot function normally), the motor drive module can control the drive motor to use the energy generated by the engine to produce a higher voltage, thereby increasing the voltage of the high-voltage battery pack and activating and charging it. The first charging circuit module can charge the bus capacitor of the motor drive module when the high-voltage battery pack fails or loses power, causing the bus voltage of the motor drive module to be too low, thereby providing excitation energy to the drive motor. The motor drive module is configured to use the energy of its bus capacitor to generate a magnetic field in the drive motor, and use the energy of the motor mechanically coupled to the drive motor to further increase the voltage of the bus capacitor, activating and charging the high-voltage battery pack. During the charging process of the high-voltage battery pack, even if the speed of the drive motor varies over a wide range (e.g., the maximum operating speed is more than 10 times the minimum operating speed), a compensation module is provided to adjust the gain according to the speed of the drive motor. The motor drive module can also stably adjust and control the charging current or charging voltage (e.g., the fluctuation range is less than 20% of the given value), thereby achieving precise charging control (e.g., the error of the charging voltage is less than 2% or the error of the charging current is less than 5%), ensuring the charging safety of the high-voltage battery pack. The first charging circuit module can be integrated with the motor drive module or implemented as part of the motor drive module.

[0032] Figure 2 This is a flowchart illustrating the charging process of a power battery in a motor drive system according to an embodiment of the present invention. The method for integrating battery charging functionality into the motor drive system includes the following steps: the motor drive control system acquires the DC bus voltage U of the motor drive module.R and / or current I R And based on the DC bus voltage U R and / or current I R In conjunction with the battery pack charging command voltage U* and / or command current I*, closed-loop regulation is performed. Then, based on the speed and other operating data, compensation calculations are performed to obtain the final torque command T of the motor drive module. r .

[0033] Figure 3 This is a schematic block diagram of a motor drive system for charging a high-voltage battery pack according to an embodiment of the present invention. When the drive motor and motor drive module precisely charge the high-voltage battery pack, the control system will adjust the charging voltage based on a given value U* and the detected actual value U. R Or the given value I* of the charging current and the detected actual value I. R To generate the corresponding error voltage signal U D or error current signal I D An adjustment module, typically in proportional-integral (PI) or proportional-integral-derivative (PI-DE) form or other suitable form, converts the error signal into a control signal. Since the motor drive system can usually operate efficiently in torque mode, this signal can serve as the torque setpoint signal for the motor drive module, allowing the drive motor and its coupled module to function as a charging system for the power battery coupled to the DC bus of the motor drive module. When the drive motor needs to operate over a wide range, the gain of this charging system from torque to battery voltage or current also changes significantly with the drive motor's speed, easily causing system instability and harming the power battery. To maintain system stability and allow for precise control of the charging current and / or voltage, and to largely offset the effects of speed variations and maintain stable operation of the charging system during startup or low-speed operation, the gain of the compensation module generally includes a compensation factor. in ω The real-time speed of the drive motor is given by k, which is the damping coefficient. Its purpose is to prevent excessive gain in the charging control system when the drive motor speed is too low or changes abruptly. The torque command T is given by... r A high degree of overshoot occurs. The gain compensation module can be placed before the adjustment module, after the adjustment module as shown in the figure, or integrated into the adjustment module. Its function is to dynamically adjust the compensation coefficient (i.e., gain) to prevent damage to the battery caused by drastic changes in charging voltage and charging current during the charging process of the high-voltage battery pack by the drive motor and motor drive module, thereby improving the safety and service life of the high-voltage battery pack (power battery).

[0034] Figure 4This is a schematic diagram of a first charging circuit module according to an embodiment of the present invention. The first charging circuit module mainly includes: a power control transistor Q1, a diode D1, and a charging resistor R1. D1 can withstand voltage when the first charging circuit module is not working, isolating the low-voltage battery pack from the high-voltage battery pack. One end of the low-voltage battery pack is coupled to one end of the power transistor Q1, the other end of Q1 is coupled to one end of D1, and the other end of the diode D1 is coupled to the DC bus of the motor drive module, and can be coupled together with the DC bus capacitor of the motor drive module. The charging resistor R1 can be connected in parallel with Q1 or in series with Q1 to limit the current flowing through Q1. R1 is an optional component, and Q1 is also an optional component. Its purpose is to provide a charging circuit for the low-voltage battery pack to the DC bus capacitor C when the voltage on the DC bus capacitor C is too low.

[0035] Figure 5 This is a schematic diagram of an example of a motor drive module according to an embodiment of the present invention. The motor drive module is essentially a converter, mainly composed of a DC bus capacitor C and a converter module consisting of power switches. The motor drive module can be configured to use the energy of the drive motor M to precisely charge the DC bus capacitor C and the battery coupled thereto. The motor can be a permanent magnet motor of different types, or an induction motor, switched reluctance motor, or synchronous reluctance motor without its own excitation capability. The energy in the DC bus capacitor C can be used to provide the energy required for the drive motor to enter generator mode operation, including excitation energy. The motor drive module can control the drive motor M to enter engine mode operation, thereby converting the energy of an engine mechanically coupled to the drive motor M into energy transmitted to the bus of the drive control module, increasing the voltage of the bus capacitor C, and / or charging or activating the high-voltage battery pack coupled to C.

[0036] Figure 6 This is a flowchart illustrating the activation of a de-energized or faulty high-voltage battery pack by a motor drive module according to an embodiment of the present invention. In this process, the control system coordinates the first charging circuit module and the motor drive module, transferring a portion of the energy from the low-voltage battery pack to the DC bus capacitor of the motor drive module as excitation energy for the drive motor, and controlling the drive motor to operate in generator mode, utilizing the energy of the coupled engine to activate the de-energized or faulty high-voltage battery pack (power battery pack). The specific method includes the following steps:

[0037] The control system detected that the voltage at the high-voltage battery pack terminal was lower than the preset threshold U. i1 Furthermore, the low-voltage battery pack terminal voltage is higher than the preset threshold U. i2 At that time, the control system initiates the activation procedure for the high-voltage degraded battery pack;

[0038] The control system controls the engine to drive the drive motor to rotate, and the low-voltage battery pack charges the DC bus capacitor C through the charging circuit, thereby providing excitation energy to the drive motor.

[0039] The control system detected that the DC bus capacitance C was higher than a preset threshold U. c1 The motor drive module generates excitation current in the motor and makes the drive motor work in the power generation mode. The drive motor uses the energy of the engine to activate the high-voltage battery pack through de-energization.

[0040] When the control system detects that the terminal voltage of the high-voltage battery pack is higher than a preset threshold U b1 The engine, drive motor, and motor drive module are deactivated, and the high-voltage battery pack activation ends.

[0041] Figure 7 A flowchart illustrating the process of a motor drive system according to an embodiment of the present invention, under the control of a control system, in coordination with a first charging circuit module, converts a portion of the energy from the low-voltage battery pack into excitation energy for the drive motor, and then transmits the energy of the engine to the DC bus through the drive motor to activate a power battery pack that has lost or collapsed power, includes the following steps:

[0042] Step S1: The control program starts, and the control system sets the activation voltage threshold of the high-voltage battery pack to U. i1 The constant voltage charging threshold of the high-voltage battery pack is U. e1 The rated voltage threshold of the high-voltage battery pack is U. b1 Discharge voltage threshold U of low-voltage battery pack i2 The initial operating voltage threshold of the DC bus capacitor C is U. c1 The control system detects the high-voltage battery pack terminal voltage U1 and the low-voltage battery pack terminal voltage U2.

[0043] Step S2: Compare and judge the high-voltage battery pack data and low-voltage battery pack data obtained from step S1. If U1≤U i1 And U2≥U i2 The control system controls the engine to rotate and drives the drive motor to rotate synchronously through the transmission shaft, and then executes the next step S3; otherwise, the control program ends.

[0044] Step S3: The control system sets the power transistor Q1 to the closed state, the low-voltage battery pack charges the DC bus capacitor, and the control system detects the voltage Uc across the DC bus capacitor C.

[0045] Step S4: Combine the DC bus voltage Uc acquired in step S3 with the initial operating voltage threshold of the DC bus capacitor C, which is Uc. c1 Compare, if U c ≥U c1The control system sets the power transistor Q1 to the off state and executes the next step S5; otherwise, it returns to step S3.

[0046] Step S5: The control system controls the converter module to generate excitation current for the drive motor and controls the drive motor to be in generator mode, which can output electrical energy to the outside.

[0047] Step S6: The control system controls the converter module to charge the high-voltage battery pack with constant current and detects the voltage U1 of the high-voltage battery pack.

[0048] Step S7: Combine the high-voltage battery pack voltage U1 detected in step S6 with the constant-voltage charging threshold U of the high-voltage battery pack. e1 Compare, if U1≥U e1 If the current state is not in order, proceed to the next step S8; otherwise, return to step S6.

[0049] Step S8: Control the converter module to perform constant voltage charging on the high-voltage battery pack, and at the same time detect the voltage U1 of the high-voltage battery pack;

[0050] Step S9: The high-voltage battery pack voltage U1 detected in step S8 and the rated voltage threshold of the high-voltage battery pack are set to U. b1 Compare, if U1≥U b1 If the current state is not in order, proceed to the next step S10; otherwise, return to step S8.

[0051] Step S10: Control the converter module, drive motor, and engine to stop running, activate the high-voltage battery pack after it fails to charge, and end the charging process.

[0052] Although embodiments of the present disclosure and their advantages have been described in detail, it should be understood that various changes, substitutions and alterations may be made herein without departing from the spirit and scope of the present disclosure as defined by the appended claims.

[0053] Furthermore, the scope of this application is not intended to be limited to the specific embodiments of the processes, machines, manufactures, compositions of matter, apparatuses, methods, and steps described in the specification. As will be readily understood by those skilled in the art from the disclosure of this publication, processes, machines, manufactures, compositions of matter, means, methods, or steps that perform substantially the same function, currently exist or will be developed or implemented thereafter, will yield substantially the same results as the corresponding embodiments described herein that are available according to this disclosure. Therefore, the appended claims are intended to include such processes, machines, manufactures, compositions of matter, apparatuses, methods, or steps within their scope.

Claims

1. A motor drive system integrating battery charging function, characterized in that, include: The control system includes a drive motor coupled to an engine, a low-voltage battery pack, a motor drive module having a DC bus and a high-voltage battery pack coupled to the DC bus, and a first charging circuit module coupled to the low-voltage battery pack and the DC bus, wherein... The control system includes a compensation module whose gain is adjusted according to the speed of the drive motor so that the voltage and current on the DC bus can be stably controlled when the drive motor operates over a wide speed range, so as to utilize the engine's capability to precisely charge the high-voltage battery pack.

2. The motor drive system with integrated battery charging function according to claim 1, wherein the drive motor is a non-permanent magnet motor, and the first charging circuit module is configured to charge the capacitor of the DC bus when the voltage of the high-voltage battery pack is lower than a threshold, so as to provide excitation energy for the drive motor, and the drive motor is configured to use the excitation energy to enter generator state and activate the high-voltage battery pack.

3. The motor drive system with integrated battery charging function according to claim 2, wherein the first charging circuit module includes a diode configured to cut off when the DC bus voltage is higher than the voltage of the low-voltage battery pack, so as to isolate the low-voltage battery pack and the DC bus.

4. The motor drive system with integrated battery charging function according to claim 2, wherein the first charging circuit module includes a power switch configured to disconnect when the low-voltage battery pack is not required to charge the DC bus.

5. The motor drive system with integrated battery charging function according to claim 1, wherein the compensation module includes a compensation factor. in ω is the real-time speed of the drive motor, and k is the damping coefficient.

6. The motor drive system with integrated battery charging function according to claim 1, wherein the first charging circuit module is physically integrated into the motor drive module.

7. A motor drive device integrating battery charging function, characterized in that, include: The control system includes a drive motor coupled to the engine and a converter coupled to a low-voltage battery pack and having a DC bus, wherein: The DC bus is coupled to a high-voltage battery pack, and is also coupled to the low-voltage battery pack and the DC bus via a first charging circuit module; and The control system includes a compensation module whose gain is adjusted according to the speed of the drive motor so that the voltage and current on the DC bus can be stably controlled when the drive motor operates over a wide speed range, so as to utilize the engine's capability to precisely charge the high-voltage battery pack.

8. The motor drive device with integrated battery charging function according to claim 7, wherein the drive motor is a non-permanent magnet motor, and the first charging circuit module is configured to charge the capacitor of the DC bus when the voltage of the high-voltage battery pack is lower than a threshold, so as to provide excitation energy for the drive motor, and the drive motor is configured to use the excitation energy to enter generator state and activate the high-voltage battery pack.

9. The motor drive device with integrated battery charging function according to claim 8, wherein the first charging circuit module includes a diode configured to cut off when the DC bus voltage is higher than the voltage of the low-voltage battery pack, so as to isolate the low-voltage battery pack and the DC bus.

10. The motor drive device with integrated battery charging function according to claim 8, wherein the first charging circuit module includes a power switch configured to disconnect when the low-voltage battery pack is not required to charge the DC bus.

11. The motor drive device with integrated battery charging function according to claim 7, wherein the compensation module includes a compensation factor. in ω is the real-time speed of the drive motor, and k is the damping coefficient.

12. The motor drive device with integrated battery charging function according to claim 7, wherein the first charging circuit module is physically integrated in the converter.

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