Motor driving system, power system and vehicle

Abstract

The utility model discloses a motor driving system, a power system and a vehicle, the motor driving system comprises a first bus capacitor and a first driving unit, and the first driving unit is configured to drive a first motor according to direct current provided by the first bus capacitor; a second bus capacitor and a second driving unit, wherein the second driving unit is configured to drive the second motor according to the direct current provided by the second bus capacitor; a first protection unit configured to suppress a circulating current between the first bus capacitor and the second bus capacitor; and the second protection unit is configured to suppress the circulating current between the first bus capacitor and the second bus capacitor. According to the system, the circulating current between the first bus capacitor and the second bus capacitor is suppressed through the first protection unit and the second protection unit, so that the risk of damage to the bus capacitors is reduced, and the safety of the motor driving system is improved.

Description

Technical Field

[0001] The present application relates to the field of vehicle technology, and in particular to a motor drive system, a power system and a vehicle. Background Art

[0002] The related art dual-motor drive system includes two motor drive systems and a bus capacitor. The two motor drive systems are connected in parallel and share a bus capacitor. If the bus capacitor is damaged, both motor drive systems will not work. To address this issue, a bus capacitor is provided for each motor drive system. The dual bus capacitors can support the operation of both motor drive systems simultaneously. Therefore, even if one bus capacitor is damaged, the dual-motor drive system can still operate normally. However, circulating current will form between the two bus capacitors, increasing the risk of device damage. Utility Model Content

[0003] The present invention aims to at least partially address one of the technical problems in the related art. To this end, a first object of the present invention is to provide a motor drive system that, through a first protection unit and a second protection unit, suppresses circulating current between a first bus capacitor and a second bus capacitor, respectively, thereby reducing the risk of damage to the bus capacitors and improving the safety of the motor drive system.

[0004] The second purpose of the present invention is to provide a power system.

[0005] The third object of the present invention is to provide a vehicle.

[0006] To achieve the above-mentioned purpose, according to an embodiment of the first aspect of the present utility model, a motor drive system is proposed, including: a first bus capacitor and a first drive unit, the first drive unit is configured to drive the first motor according to the DC power provided by the first bus capacitor; a second bus capacitor and a second drive unit, the second drive unit is configured to drive the second motor according to the DC power provided by the second bus capacitor; a first protection unit, one end of the first protection unit is suitable for connecting to the DC positive pole, and the other end of the first protection unit is connected to the first bus capacitor, and the first protection unit is configured to suppress the circulating current between the first bus capacitor and the second bus capacitor; a second protection unit, one end of the second protection unit is suitable for connecting to the DC positive pole, and the other end of the second protection unit is connected to the second bus capacitor, and the second protection unit is configured to suppress the circulating current between the first bus capacitor and the second bus capacitor.

[0007] According to an embodiment of the present invention, the motor drive system includes a first bus capacitor, a first drive unit, a second bus capacitor, a second drive unit, a first protection unit, and a second protection unit, wherein the first drive unit is configured to drive the first motor according to the DC power provided by the first bus capacitor, and the second drive unit is configured to drive the second motor according to the DC power provided by the second bus capacitor. One end of the first protection unit is suitable for connecting to the DC positive pole, and the other end of the first protection unit is connected to the first bus capacitor. The first protection unit is configured to suppress the circulating current between the first bus capacitor and the second bus capacitor. One end of the second protection unit is suitable for connecting to the DC positive pole, and the other end of the second protection unit is connected to the second bus capacitor. The second protection unit is configured to suppress the circulating current between the first bus capacitor and the second bus capacitor. Thus, the circulating current between the first bus capacitor and the second bus capacitor is suppressed by the first protection unit and the second protection unit, respectively, reducing the risk of damage to the bus capacitors, thereby improving the safety of the motor drive system.

[0008] According to an embodiment of the present invention, the first protection unit and the second protection unit respectively include a circulating inductor, one end of the circulating inductor is suitable for connecting to the DC positive pole, and the other end of the circulating inductor is the other end of the corresponding protection unit.

[0009] According to one embodiment of the present utility model, the first protection unit and the second protection unit respectively further include a DC protection device, one end of the DC protection device is connected to the other end of the circulating inductor, the other end of the DC protection device is the other end of the corresponding protection unit, and the DC protection device is configured to disconnect the power supply of the corresponding drive unit when the bus current of the corresponding drive unit is greater than the first preset current threshold within a preset time.

[0010] According to one embodiment of the present utility model, the motor drive system also includes: a control unit, which is respectively connected to the DC protection device in the first protection unit and the DC protection device in the second protection unit, and the control unit is configured to control the DC protection device in the first protection unit to disconnect when the bus current of the first drive unit is greater than the first preset current threshold within a preset time, and to control the DC protection device in the second protection unit to disconnect when the bus current of the second drive unit is greater than the first preset current threshold within a preset time.

[0011] According to one embodiment of the present invention, the motor drive system also includes: a third protection unit, which is arranged between the first drive unit and the first motor, and the third protection unit is configured to disconnect the connection between the first drive unit and the first motor when at least one phase output current of the first drive unit is greater than a second preset current threshold within a preset time; a fourth protection unit, which is arranged between the second drive unit and the second motor, and the fourth protection unit is configured to disconnect the connection between the second drive unit and the second motor when at least one phase output current of the second drive unit is greater than the second preset current threshold within a preset time.

[0012] According to one embodiment of the present invention, the control unit is also connected to the third protection unit and the fourth protection unit, and the control unit is further configured to control the third protection unit to disconnect when the output current of at least one phase of the first drive unit is greater than the second preset current threshold within a preset time, and to control the fourth protection unit to disconnect when the output current of at least one phase of the second drive unit is greater than the second preset current threshold within a preset time.

[0013] According to an embodiment of the present invention, the third protection unit and the fourth protection unit respectively include a first fuse device.

[0014] According to an embodiment of the present invention, the DC protection device is a second fuse device.

[0015] According to one embodiment of the present utility model, the motor drive system also includes: a first filtering unit, the input end of the first filtering unit is suitable for connecting to the battery module, the output end of the first filtering unit is respectively connected to one end of the first protection unit and one end of the second protection unit, and the first filtering unit is configured to filter the direct current output by the battery module; a second filtering unit, the second filtering unit is arranged between the first drive unit and the first motor, and the second filtering unit is configured to filter the alternating current output by the first drive unit; a third filtering unit, the third filtering unit is arranged between the second drive unit and the second motor, and the third filtering unit is configured to filter the alternating current output by the second drive unit.

[0016] According to one embodiment of the present utility model, the first filtering unit includes: a first capacitor, one end of the first capacitor is suitable for connecting to the positive pole of the battery module, and the other end of the first capacitor is suitable for connecting to the negative pole of the battery module; a second capacitor, one end of the second capacitor is respectively connected to one end of the first capacitor, one end of the first protection unit and one end of the second protection unit, the other end of the second capacitor is grounded, and has a first node; a third capacitor, one end of the third capacitor is connected to the first node, and the other end of the third capacitor is respectively connected to the other end of the first capacitor, the first bus capacitor and the second bus capacitor; a first common mode magnetic ring, the first common mode magnetic ring is sleeved on one end of the second capacitor and the other end of the third capacitor.

[0017] According to an embodiment of the present invention, the second filtering unit includes a second common-mode magnetic ring, and the third filtering unit includes a third common-mode magnetic ring.

[0018] To achieve the above-mentioned purpose, according to a second aspect of the present invention, a power system is proposed, comprising the motor drive system of any of the aforementioned embodiments.

[0019] According to the power system of an embodiment of the present invention, by adopting the above-mentioned motor drive system, the circulating current between the first bus capacitor and the second bus capacitor is suppressed by the first protection unit and the second protection unit respectively, thereby reducing the risk of damage to the bus capacitor and improving the safety of the motor drive system.

[0020] To achieve the above-mentioned purpose, according to a third aspect of the present invention, a vehicle is proposed, comprising the motor drive system of any one of the aforementioned embodiments, or the aforementioned power system.

[0021] According to the vehicle of the embodiment of the present invention, by adopting the above-mentioned motor drive system or power system, the circulating current between the first bus capacitor and the second bus capacitor is suppressed by the first protection unit and the second protection unit respectively, thereby reducing the risk of damage to the bus capacitor and improving the safety of the motor drive system.

[0022] Additional aspects and advantages of the present invention will be given in part in the following description and in part will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the structure of a dual-motor drive system with a single bus capacitor in the related art;

[0024] Figure 2 It is a structural diagram of a dual-motor drive system with dual bus capacitors in the related art;

[0025] Figure 3Schematic diagram of circulating current in a dual-motor drive system with dual bus capacitors in related art;

[0026] Figure 4 1 is a schematic structural diagram of a motor drive system according to an embodiment of the present invention;

[0027] Figure 5 is a schematic diagram of circulating current according to an embodiment of the present utility model;

[0028] Figure 6 This is a schematic diagram of a motor drive system when a bus capacitor fails according to an embodiment of the present utility model;

[0029] Figure 7 This is a schematic structural diagram of a first protection unit and a second protection unit according to an embodiment of the present utility model;

[0030] Figure 8 1 is a structural diagram of a motor drive system including a DC protection device, a third protection unit, and a fourth protection unit according to an embodiment of the present utility model;

[0031] Figure 9 1 is a schematic structural diagram of a motor drive system including a filter unit according to an embodiment of the present invention;

[0032] Figure 10 It is a structural schematic diagram of a power system according to one embodiment of the utility model;

[0033] Figure 11 is a schematic structural diagram of a vehicle according to an embodiment of the present utility model;

[0034] Figure 12 It is a structural schematic diagram of a vehicle according to another embodiment of the present utility model. DETAILED DESCRIPTION

[0035] The following describes in detail embodiments of the present invention, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to explain the present invention, and should not be construed as limiting the present invention.

[0036] It should be noted that this application is based on the inventor's understanding and research of the following issues:

[0037] Figure 1 The dual motor drive system in the related art is shown as Figure 1As shown, the dual-motor drive system includes a bus capacitor C, a first drive unit 10, a first motor M1, a second drive unit 20, and a second motor M2. One end of the bus capacitor C is suitable for connecting to the positive pole of the battery module 200 and is connected to the first end of the first drive unit 10 and one end of the second drive unit 20. The other end of the bus capacitor C is suitable for connecting to the negative pole of the battery module 200 and is connected to the first end of the first drive unit 10 and the second end of the second drive unit 20. The output end of the first drive unit 10 is connected to the first motor M1, and the output end of the second drive unit 20 is connected to the second motor M2. The first drive unit 10 and the first motor M1 constitute one motor drive system, and the second drive unit 20 and the second motor M2 constitute another motor drive system. The two motor drive systems are connected in parallel, and the bus capacitor C simultaneously supplies power to the two motor drive systems. Because the two motor drive systems each have independent drive units and motors, the two motor drive systems can be controlled to operate under different working conditions. However, this dual-motor drive system has the problem of poor reliability because it shares a bus capacitor C. Specifically, because the DC sides of the two motor drive systems are not completely decoupled, when one motor drive system fails, the entire power supply circuit needs to be cut off. In addition, the two motor drive systems share a bus capacitor C. If the bus capacitor C is damaged, both motor drive systems will not work.

[0038] In order to solve the above problems, Figure 2 As shown, the dual motor drive includes two bus capacitors (C1 and C2), namely the first bus capacitor C1 and the second bus capacitor C2, and each motor drive system is configured with a bus capacitor. The dual bus capacitors can support the operation of two motor drive systems at the same time. Therefore, when one bus capacitor is damaged, the dual motor drive system can also work normally, thereby improving the reliability of the motor drive system. However, because the two motor drive systems operate under different working conditions, the first bus capacitor C1 and the second bus capacitor C2 will charge and discharge each other, thereby generating a circulating current. Figure 3 As shown in the example, when the first drive unit 10 is in operation and the second drive unit 20 is not in operation, the first bus capacitor C1 discharges. The first bus capacitor C1 not only supplies power to the first drive unit 10 but also charges the second bus capacitor C2. This forms a current loop between the first bus capacitor C1 and the second bus capacitor C2, generating a circulating current. This circulating current can reach up to 200A at certain carrier frequencies, increasing the risk of device damage.

[0039] Based on this, an embodiment of the present invention provides a motor drive system, a power system and a vehicle, which suppress the circulating current between the first bus capacitor and the second bus capacitor through the first protection unit and the second protection unit respectively, thereby reducing the risk of damage to the bus capacitor and improving the safety of the motor drive system.

[0040] The motor drive system, power system and vehicle according to embodiments of the present invention will be described below with reference to the accompanying drawings.

[0041] Figure 4 FIG is a schematic diagram of the structure of a motor drive system according to an embodiment of the present invention. Figure 4 As shown, the motor drive system 100 includes: a first bus capacitor C1 , a first drive unit 10 , a second bus capacitor C2 , a second drive unit 20 , a first protection unit 30 and a second protection unit 40 .

[0042] Among them, the first drive unit 10 is configured to drive the first motor M1 according to the DC power provided by the first bus capacitor C1; the second drive unit 20 is configured to drive the second motor M2 according to the DC power provided by the second bus capacitor C2; one end of the first protection unit 30 is suitable for connecting to the DC positive pole B+, and the other end of the first protection unit 30 is connected to the first bus capacitor C1, and the first protection unit 30 is configured to suppress the circulating current between the first bus capacitor C1 and the second bus capacitor C2; one end of the second protection unit 40 is suitable for connecting to the DC positive pole B+, and the other end of the second protection unit 40 is connected to the second bus capacitor C2, and the second protection unit 40 is configured to suppress the circulating current between the first bus capacitor C1 and the second bus capacitor C2.

[0043] Specifically, one end of the first bus capacitor C1 is connected to the other end of the first protection unit 30, and the other end of the first bus capacitor C1 is suitable for connecting to the DC negative electrode B-. One end of the second bus capacitor C2 is connected to the other end of the second protection unit 40, and the other end of the second bus capacitor C2 is suitable for connecting to the DC negative electrode B-. The first bus capacitor C1 and the second bus capacitor C2 can suppress the DC voltage fluctuation caused by motor control, thereby providing more stable DC power. When the first bus capacitor C1 is discharged, the direction of the circulating current is as follows: Figure 5 As shown, it should be noted that Figure 5 The direction of the circulating current shown is only exemplary. In actual applications, the direction of the circulating current is not limited to Figure 5 The second protection unit 40 and the first protection unit 30 respectively suppress the circulating current, reducing the circulating current flowing into the first bus capacitor C1. Figure 6As shown, when the first bus capacitor C1 fails, no current loop is formed between the first bus capacitor C1 and the second bus capacitor C2, and no circulating current exists between the first bus capacitor C1 and the second bus capacitor C2. Therefore, the first protection unit 30 and the second protection unit 40 suppress the DC power provided by the second bus capacitor C2 to the first drive unit 10. Therefore, the first drive unit 10 can drive the first motor M1 according to the DC power provided by the second bus capacitor C2, thereby improving the reliability of the motor drive system 100.

[0044] In an optional embodiment, as Figure 4 As shown, when the first motor M1 and the second motor M2 are respectively three-phase motors, the first drive unit 10 and the second drive unit 20 are respectively three-phase full-bridge inverters, and the midpoint of each phase bridge arm of the first drive unit 10 is connected to one phase of the first motor M1, and the midpoint of each phase bridge arm of the second drive unit 20 is connected to one phase of the second motor M2.

[0045] It should be noted that the first motor M1 and the second motor M2 are not limited to three-phase motors, and the first drive unit 10 and the second drive unit 20 are not limited to three-phase full-bridge inverters, and can be set according to the types of the first motor M1 and the second motor M2.

[0046] In the above embodiment, because no circulating current will be formed between the two bus capacitors when one of the two bus capacitors is damaged, the two electric drive systems can share one bus capacitor for motor drive, and therefore will not affect the normal operation of the system. In addition, the first protection unit and the second protection unit reduce the circulating current in the line, thereby reducing the risk of damage to the bus capacitor, thereby improving the safety of the motor drive system while ensuring the reliability of the motor drive system.

[0047] In some embodiments, as Figure 7 As shown, the first protection unit 30 and the second protection unit 40 respectively include a circulating inductor, one end of the circulating inductor is suitable for connecting to the DC positive electrode B+, and the other end of the circulating inductor is the other end of the corresponding protection unit.

[0048] Specifically, one end of the circulating inductor L1 of the first protection unit 30 is connected to the DC positive electrode B+, and the other end of the circulating inductor L1 of the first protection unit 30 is connected to one end of the first bus capacitor C1. One end of the circulating inductor L2 of the second protection unit 40 is connected to the DC positive electrode B+, and the other end of the circulating inductor L2 of the second protection unit 40 is connected to one end of the second bus capacitor C2. The values ​​of the circulating inductors (L1 and L2) are set according to the resonant frequency and magnitude of the circulating current.

[0049] In the above embodiment, the circulating inductor increases the impedance of the circulating path between the first bus capacitor and the second bus capacitor, thereby changing the resonant frequency point and limiting the magnitude of the circulating current.

[0050] In some embodiments, as Figure 8 As shown, the first protection unit 30 and the second protection unit 40 respectively further include a DC protection device, one end of the DC protection device is connected to the other end of the circulating inductor, and the other end of the DC protection device is the other end of the corresponding protection unit. The DC protection device is configured to disconnect the power supply of the corresponding drive unit when the bus current of the corresponding drive unit is greater than the first preset current threshold within a preset time.

[0051] Specifically, when using Figure 1 and Figure 2 In the dual-motor drive system shown, the DC side of the dual-motor drive system is not designed with fuses. Therefore, when a fault occurs on the DC side of one motor drive system, it will affect the operation of the other motor drive system, thereby reducing the reliability of the dual-motor drive system. Therefore, a DC protection device is added to each of the first protection unit 30 and the second protection unit 40. When the bus current of the corresponding drive unit exceeds the first preset current threshold within a preset time, the power supply to the corresponding drive unit is disconnected. Because the power supply to the other drive unit is not disconnected, the normal operation of the other drive unit is not affected. For example, when the bus current of the first drive unit 10 exceeds the first preset current threshold within a preset time, the DC protection device 31 of the first protection unit 30 disconnects the power supply to the first drive unit 10. At this time, the DC protection device 41 of the second protection unit 40 does not disconnect the power supply to the second drive unit 20, so the second drive unit 20 can operate normally. Similarly, when the DC protection device 41 of the second protection unit 40 disconnects the power supply to the second drive unit 20, if the DC protection device 31 of the first protection unit 30 does not disconnect the power supply to the first drive unit 10, the first drive unit 10 can operate normally.

[0052] In the above embodiment, a DC protection device is further added to the first protection unit and the second protection unit respectively. When a fault occurs on the DC side of the corresponding drive unit, the DC protection device can disconnect the power supply of the corresponding drive unit, thereby improving the safety of the motor drive system.

[0053] In some embodiments, the motor drive system 100 also includes: a control unit (not shown), which is respectively connected to the DC protection device 31 in the first protection unit 30 and the DC protection device 41 in the second protection unit 40, and the control unit is configured to control the DC protection device 31 in the first protection unit 30 to disconnect when the bus current of the first drive unit 10 is greater than the first preset current threshold within a preset time, and to control the DC protection device 41 in the second protection unit 40 to disconnect when the bus current of the second drive unit 20 is greater than the first preset current threshold within a preset time.

[0054] Specifically, during the operation of the motor drive system 100, the control unit is respectively connected to the control ends of the first drive unit 10, the second drive unit 20, the DC protection device 31 in the first protection unit 30, and the control end of the DC protection device 41 in the second protection unit 40. The control unit can be directly connected to the DC protection device 31 and the DC protection device 41, or can be connected to the DC protection device 31 and the DC protection device 41 indirectly. Therefore, the control unit can detect the bus currents of the first drive unit 10 and the second drive unit 20 respectively, and then determine whether a fault occurs on the DC side of the corresponding drive unit based on the bus currents of the first drive unit 10 and the second drive unit 20. If the bus current of the first drive unit 10 is greater than the first preset current threshold within the preset time, a fault occurs on the DC side of the first drive unit 10, and the control unit controls the DC protection device 31 of the first protection unit 30 to disconnect to stop supplying power to the first drive unit 10; if the bus current of the second drive unit 20 is greater than the first preset current threshold within the preset time, a fault occurs on the DC side of the second drive unit 20, and the control unit controls the DC protection device 41 of the second protection unit 40 to disconnect to stop supplying power to the second drive unit 20.

[0055] In the above embodiment, the control unit can control the switching of the DC protection device of the first protection unit and the DC protection device of the second protection unit according to the bus current of the first drive unit and the bus current of the second drive unit, thereby protecting the DC side of the motor drive system.

[0056] In some embodiments, the DC protection device is a second fuse device.

[0057] by Figure 8As an example, if the bus current of the corresponding drive unit exceeds the rated current of the second fuse (FU1 and FU2) within a preset time, the second fuse (FU1 and FU2) will fuse, disconnecting the power supply to the corresponding drive unit. Furthermore, when the second fuse (FU1 and FU2) is an electronic fuse, the control unit is connected to the control terminal of the second fuse (FU1 and FU2) to control the switching of the second fuse (FU1 and FU2).

[0058] It should be noted that, provided the voltage withstand capability is met, the second fuse device may also be a semiconductor switch device, and specific limitations are not set forth herein. The control unit is connected to the control terminal of the controllable switch device, and by switching the controllable switch device, protection of the DC side of the motor drive system 100 can also be achieved.

[0059] In some embodiments, as Figure 8 As shown, the motor drive system 100 also includes: a third protection unit 50 and a fourth protection unit 60, wherein the third protection unit 50 is arranged between the first drive unit 10 and the first motor M1, and the third protection unit 50 is configured to disconnect the connection between the first drive unit 10 and the first motor M1 when at least one phase output current of the first drive unit 10 is greater than a second preset current threshold within a preset time; the fourth protection unit 60 is arranged between the second drive unit 20 and the second motor M2, and the fourth protection unit 60 is configured to disconnect the connection between the second drive unit 20 and the second motor M2 when at least one phase output current of the second drive unit 20 is greater than the second preset current threshold within a preset time.

[0060] Specifically, when using Figure 1 and Figure 2 In the dual-motor drive system shown, the AC side of the dual-motor drive system is not designed with insurance. When the bridge arm of a drive unit is short-circuited and the motor is running in reverse at high speed, the first drive unit 10 and the second drive unit 20 may explode and catch fire. Therefore, the safety of the dual-motor drive system in the related art is poor. In order to solve the above problem, a third protection unit 50 and a fourth protection unit 60 are added to the motor drive system 100. When the output current of at least one phase of the first drive unit 10 and / or the output current of at least one phase of the second drive unit 20 is greater than the second preset current threshold within a preset time, it indicates that a short circuit fault occurs in the bridge arm of the corresponding drive unit. The protection unit corresponding to the corresponding drive unit disconnects the connection between the corresponding drive unit and the corresponding motor, thereby disconnecting the output circuit of the corresponding drive unit to prevent risks such as fire. In addition, if the connection between only one drive unit and the corresponding motor is disconnected, the connection of the other drive unit is normal, so the other drive unit can operate normally.

[0061] For example, when the current of at least one phase of the first drive unit 10 is greater than the second preset current threshold within a preset time, the third protection unit 50 disconnects the connection between the first drive unit 10 and the first motor M1 to disconnect the output circuit of the first drive unit 10. At this time, the fourth protection unit 60 does not disconnect the connection between the second drive unit 20 and the second motor M2. Therefore, the second drive unit 20 can operate normally.

[0062] In the above embodiment, a third protection unit and a fourth protection unit are respectively added to the output ends of the first drive unit and the second drive unit. When a short circuit fault occurs in the corresponding drive unit, the third protection unit and the fourth protection unit can disconnect the output circuit of the corresponding drive unit, thereby further improving the safety of the motor drive system.

[0063] In some embodiments, the control unit is also connected to the third protection unit 50 and the fourth protection unit 60, and the control unit is also configured to control the third protection unit 50 to disconnect when the output current of at least one phase of the first drive unit 10 is greater than the second preset current threshold within a preset time, and to control the fourth protection unit 60 to disconnect when the output current of at least one phase of the second drive unit 20 is greater than the second preset current threshold within a preset time.

[0064] Specifically, when a short circuit fault occurs in the bridge arm of the first drive unit 10 or the second drive unit 20, if the corresponding motor is still rotating at high speed, the energy in the motor will be fed back to the DC side of the motor drive system 100 through the corresponding drive unit. Therefore, the output current of the corresponding drive unit will be very large. If the motor continues to operate, the corresponding drive unit will explode or even catch fire due to excessive temperature. Therefore, it is necessary to set a protection device on the AC side (in this embodiment, the third protection unit 50 and the fourth protection unit 60), and disconnect the output circuit of the corresponding drive unit through the protection device on the AC side, thereby avoiding the explosion or even fire of the electric drive system. In addition, when the wafer of the upper bridge arm or lower bridge arm of a phase bridge arm in the first drive unit 10 and the second drive unit 20 is damaged and the silicone gel is destroyed, a safe electrical gap cannot be guaranteed. If the lower bridge arm or upper bridge arm of the phase bridge arm enters a three-phase short circuit state at this time, an arc is easily generated at the damaged silicone gel, and the motor drive system 100 has a safety risk. At this time, the connection between the corresponding drive unit and the corresponding motor must also be disconnected by the protection device on the AC side, thereby avoiding the explosion or even fire of the electric drive system. Therefore, when the control unit detects that the output current of at least one phase of the first drive unit 10 is greater than the second preset current threshold within the preset time, it indicates that the first drive unit 10 has failed, and the control unit controls the third protection unit 50 to disconnect the connection between the first drive unit 10 and the first motor M1; when the output current of at least one phase of the second drive unit 20 is greater than the second preset current threshold within the preset time, it indicates that the second drive unit 20 has failed, and the control unit controls the fourth protection unit 60 to disconnect the connection between the second drive unit 20 and the second motor M2.

[0065] It should be noted that the control unit may be directly connected to the third protection unit 50 and the fourth protection unit 60 , or may be connected to the third protection unit 50 and the fourth protection unit 60 through an indirect connection.

[0066] In the above embodiment, the control unit can control the switching of the third protection unit and the fourth protection unit according to the detection of at least one phase output current of the first drive unit and at least one phase output current of the second drive unit, thereby protecting the AC side of the motor drive system.

[0067] In some embodiments, as Figure 8 As shown, the third protection unit 50 and the fourth protection unit 60 each include a first fuse device.

[0068] It is understood that if the output current of at least one phase of the corresponding drive unit exceeds the rated current of the first fuse device (FU3 and FU4) within a preset time, the first fuse device (FU3 and FU4) will fuse, thereby disconnecting the output circuit of the corresponding drive unit. Furthermore, when the first fuse device (FU3 and FU4) is an electronic fuse device, the control unit is connected to the control terminal of the first fuse device (FU3 and FU4) and can control the switching of the first fuse device (FU3 and FU4).

[0069] Similarly, the third protection unit 50 and the fourth protection unit 60 may also use controllable switch devices, which is not specifically limited here.

[0070] In an optional embodiment, as Figure 8 As shown, when the first drive unit 10 and the second drive unit 20 are respectively three-phase inverters, the third protection unit 50 and the fourth protection unit 60 respectively include three first fuse devices, each of which is arranged between the midpoint of a phase bridge arm of the corresponding drive unit and a phase of the corresponding motor.

[0071] In some embodiments, as Figure 9 As shown, the motor drive system 100 also includes: a first filter unit 70, a second filter unit 80 and a third filter unit 90, wherein the input end of the first filter unit 70 is suitable for connecting to the battery module 200, and the output end of the first filter unit 70 is respectively connected to one end of the first protection unit 30 and one end of the second protection unit 40, and the first filter unit 70 is configured to filter the direct current output by the battery module 200; the second filter unit 80 is arranged between the first drive unit 10 and the first motor M1, and the second filter unit 80 is configured to filter the alternating current output by the first drive unit 10; the third filter unit 90 is arranged between the second drive unit 20 and the second motor M2, and the third filter unit 90 is configured to filter the alternating current output by the second drive unit 20.

[0072] Specifically, the first filter unit 70 is a DC side filter unit of the motor drive system 100. The first end of the first filter unit 70 is suitable for connecting to the positive pole of the battery module 200, the second end of the first filter unit 70 is suitable for connecting to the negative pole of the battery module 200, the third end of the first filter unit 70 is the DC positive pole B+, and the fourth end of the first filter unit 70 is the DC negative pole B-. The first filter unit 70 filters the DC power output by the battery module 200 and provides the filtered DC power to the first protection unit 30 and the second protection unit 40 respectively. The high switching frequency of the first drive unit 10 and the second drive unit 20 will cause shaft current to be generated at the motor shaft, and the shaft current will burn the bearings, thereby reducing the service life of the motor. Therefore, a second filter unit 80 and a third filter unit 90 are respectively set at the output end of the first drive unit 10 and the output end of the second drive unit 20. The second filter unit 80 and the third filter unit 90 can reduce the shaft current of the motor, thereby improving the problem of motor bearing burning.

[0073] Furthermore, when the motor drive system 100 further includes a third protection unit 50 and a fourth protection unit 60 , the second filter unit 80 may be disposed between the third protection unit 50 and the first motor M1 , and the third filter unit 90 may be disposed between the fourth protection unit 60 and the first motor M1 .

[0074] In the above embodiment, the first filtering unit filters the DC power output by the battery module, thereby providing more stable DC power to the first protection unit and the second protection unit. The second filtering unit and the third filtering unit are filtering units for the AC measurement of the motor drive system, which can reduce the shaft current of the motor, thereby further improving the reliability of the motor drive system.

[0075] In some embodiments, as Figure 9 As shown, the first filtering unit 70 includes: a first capacitor CX, a second capacitor CY1, a third capacitor CY2 and a first common-mode magnetic ring FR1, wherein one end of the first capacitor CX is suitable for connecting to the positive electrode of the battery module 200, and the other end of the first capacitor CX is suitable for connecting to the negative electrode of the battery module 200; one end of the second capacitor CY1 is respectively connected to one end of the first capacitor CX, one end of the first protection unit 30 and one end of the second protection unit 40, the other end of the second capacitor CY1 is grounded and has a first node J1; one end of the third capacitor CY2 is connected to the first node J1, and the other end of the third capacitor CY2 is respectively connected to the other end of the first capacitor CX, the first bus capacitor C1 and the second bus capacitor C2; the first common-mode magnetic ring FR1 is sleeved on one end of the second capacitor CY1 and the other end of the third capacitor CY2.

[0076] It is understood that the first capacitor CX is connected between the positive and negative electrodes of the battery module 200 to filter out differential-mode noise in the circuit. The second capacitor CY1 is connected between the positive electrode of the battery module 200 and the ground, and the third capacitor CY2 is connected between the negative electrode of the battery module 200 and the ground. The second capacitor CY1 and the third capacitor CY2 are used to suppress common-mode noise, that is, the noise between the power line and the ground. The first common-mode magnetic ring FR1 is set on the two power lines to suppress common-mode noise, thereby suppressing electromagnetic interference and improving the electromagnetic compatibility of the motor drive system 100.

[0077] In some embodiments, as Figure 9 As shown, the second filtering unit 80 includes a second common mode magnetic ring FR2, and the third filtering unit 90 includes a third common mode magnetic ring FR3.

[0078] Specifically, the output of the first drive unit 10 passes through the second common-mode magnetic ring FR2 and is connected to the first motor M1. The output of the second drive unit 20 passes through the third common-mode magnetic ring FR3 and is connected to the second motor M2. The common-mode magnetic ring can suppress the shaft current of the motor, improve the ablation problem of the motor shaft, and enhance the reliability of the motor.

[0079] Furthermore, when the first drive unit 10 and the second drive unit 20 are respectively three-phase inverters, the second common-mode magnetic ring FR2 and the third common-mode magnetic ring FR3 are three-phase common-mode magnetic rings.

[0080] In summary, according to an embodiment of the present invention, the motor drive system includes a first bus capacitor, a first drive unit, a second bus capacitor, a second drive unit, a first protection unit, and a second protection unit, wherein the first drive unit is configured to drive the first motor according to the DC power provided by the first bus capacitor, and the second drive unit is configured to drive the second motor according to the DC power provided by the second bus capacitor. One end of the first protection unit is suitable for connecting to the DC positive pole, and the other end of the first protection unit is connected to the first bus capacitor. The first protection unit is configured to suppress the circulating current between the first bus capacitor and the second bus capacitor. One end of the second protection unit is suitable for connecting to the DC positive pole, and the other end of the second protection unit is connected to the second bus capacitor. The second protection unit is configured to suppress the circulating current between the first bus capacitor and the second bus capacitor. Thus, the circulating current between the first bus capacitor and the second bus capacitor is suppressed by the first protection unit and the second protection unit respectively, reducing the risk of damage to the bus capacitor, thereby improving the safety of the motor drive system.

[0081] Corresponding to the above embodiment, the embodiment of the present utility model further provides a power system. Figure 10 As shown, the power system 200 includes the motor drive system 100 of any of the aforementioned embodiments.

[0082] According to the power system of an embodiment of the present invention, by adopting the above-mentioned motor drive system, the circulating current between the first bus capacitor and the second bus capacitor is suppressed by the first protection unit and the second protection unit respectively, thereby reducing the risk of damage to the bus capacitor and improving the safety of the motor drive system.

[0083] Corresponding to the above embodiment, the embodiment of the present utility model further provides a vehicle. Figure 11 and Figure 12 As shown, the vehicle 1000 includes the motor drive system 100 of any of the aforementioned embodiments, or the aforementioned power system 200 .

[0084] According to the vehicle of the embodiment of the present invention, by adopting the above-mentioned motor drive system or power system, the circulating current between the first bus capacitor and the second bus capacitor is suppressed by the first protection unit and the second protection unit respectively, thereby reducing the risk of damage to the bus capacitor and improving the safety of the motor drive system.

[0085] Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with that embodiment or example are included in at least one embodiment or example of the present invention. In this specification, schematic representations 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 any one or more embodiments or examples.

[0086] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation to the present invention.

[0087] In addition, the terms "first" and "second" used in the embodiments of the present invention are for descriptive purposes only and should not be understood as indicating or implying relative importance, or implicitly indicating the number of technical features indicated in the embodiments. Therefore, the features defined in the embodiments of the present invention with terms such as "first" and "second" can explicitly or implicitly indicate that the embodiment includes at least one of such features. In the description of the present invention, the word "plurality" means at least two or two or more, such as two, three, four, etc., unless otherwise clearly and specifically defined in the embodiments.

[0088] In this utility model, unless otherwise clearly specified or limited in the embodiments, the terms "installed", "connected", "connected", and "fixed" appearing in the embodiments should be understood in a broad sense. For example, the connection can be a fixed connection, a detachable connection, or an integral connection. It can also be a mechanical connection, an electrical connection, etc.; of course, it can also be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication between two elements, or the interaction between two elements. For those skilled in the art, the specific meanings of the above terms in this utility model can be understood based on the specific implementation.

[0089] In the present invention, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediary. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0090] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are illustrative and cannot be understood as limitations on the present invention. Ordinary technicians in this field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A motor drive system, characterized in that: include: a first bus capacitor and a first driving unit, wherein the first driving unit is configured to drive a first motor according to direct current provided by the first bus capacitor; a second bus capacitor and a second drive unit, wherein the second drive unit is configured to drive a second motor according to direct current provided by the second bus capacitor; a first protection unit, wherein one end of the first protection unit is adapted to be connected to a DC positive electrode, the other end of the first protection unit is connected to the first bus capacitor, and the first protection unit is configured to suppress a circulating current between the first bus capacitor and the second bus capacitor; A second protection unit, one end of the second protection unit is suitable for connecting to the DC positive pole, the other end of the second protection unit is connected to the second bus capacitor, and the second protection unit is configured to suppress the circulating current between the first bus capacitor and the second bus capacitor.

2. The motor drive system according to claim 1, characterized in that: The first protection unit and the second protection unit respectively include a circulating inductor, one end of the circulating inductor is suitable for connecting to the DC positive electrode, and the other end of the circulating inductor is the other end of the corresponding protection unit.

3. The motor drive system according to claim 2, characterized in that: The first protection unit and the second protection unit respectively further include a DC protection device, one end of the DC protection device is connected to the other end of the circulating inductor, the other end of the DC protection device is the other end of the corresponding protection unit, and the DC protection device is configured to disconnect the power supply of the corresponding drive unit when the bus current of the corresponding drive unit is greater than a first preset current threshold within a preset time.

4. The motor drive system according to claim 3, characterized in that: Also includes: A control unit, the control unit being connected to the DC protection device in the first protection unit and the DC protection device in the second protection unit, respectively. The control unit is configured to control the DC protection device in the first protection unit to disconnect when the bus current of the first drive unit is greater than the first preset current threshold within a preset time, and to control the DC protection device in the second protection unit to disconnect when the bus current of the second drive unit is greater than the first preset current threshold within a preset time.

5. The motor drive system according to claim 4, characterized in that: Also includes: a third protection unit, disposed between the first drive unit and the first motor, configured to disconnect the first drive unit from the first motor when an output current of at least one phase of the first drive unit is greater than a second preset current threshold within a preset time; A fourth protection unit is arranged between the second drive unit and the second motor, and the fourth protection unit is configured to disconnect the connection between the second drive unit and the second motor when the output current of at least one phase of the second drive unit is greater than the second preset current threshold within a preset time.

6. The motor drive system according to claim 5, characterized in that: The control unit is also connected to the third protection unit and the fourth protection unit, and the control unit is further configured to control the third protection unit to disconnect when the output current of at least one phase of the first drive unit is greater than the second preset current threshold within a preset time, and to control the fourth protection unit to disconnect when the output current of at least one phase of the second drive unit is greater than the second preset current threshold within a preset time.

7. The motor drive system according to claim 5, characterized in that: The third protection unit and the fourth protection unit each include a first fuse device.

8. The motor drive system according to claim 3, characterized in that: The DC protection device is a second fuse device.

9. The motor drive system according to any one of claims 1 to 8, characterized in that: Also includes: a first filtering unit, wherein an input end of the first filtering unit is adapted to be connected to a battery module, an output end of the first filtering unit is respectively connected to one end of the first protection unit and one end of the second protection unit, and the first filtering unit is configured to filter the direct current output by the battery module; a second filtering unit, the second filtering unit being disposed between the first driving unit and the first motor, and configured to filter the alternating current output by the first driving unit; A third filtering unit is provided between the second driving unit and the second motor, and is configured to filter the alternating current output by the second driving unit.

10. The motor drive system according to claim 9, characterized in that: The first filtering unit includes: a first capacitor, one end of the first capacitor being adapted to be connected to the positive electrode of the battery module, and the other end of the first capacitor being adapted to be connected to the negative electrode of the battery module; a second capacitor, one end of the second capacitor being respectively connected to one end of the first capacitor, one end of the first protection unit, and one end of the second protection unit, the other end of the second capacitor being grounded, and having a first node; a third capacitor, one end of the third capacitor being connected to the first node, and the other end of the third capacitor being connected to the other end of the first capacitor, the first bus capacitor, and the second bus capacitor, respectively; A first common-mode magnetic ring is sleeved on one end of the second capacitor and the other end of the third capacitor.

11. The motor drive system according to claim 9, characterized in that: The second filtering unit includes a second common mode magnetic ring, and the third filtering unit includes a third common mode magnetic ring.

12. A power system, characterized in that: The invention comprises a motor drive system according to any one of claims 1 to 11.

13. A vehicle, characterized in that: The method comprises the motor drive system according to any one of claims 1 to 11, or the power system according to claim 12.

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