A motor controller, a motor drive system and a new energy vehicle

Abstract

Embodiments of the present invention disclose a motor controller, a motor drive system and a new energy vehicle, which relate to the field of discharge technology and are invented to simplify the structure of the new energy vehicle. The motor controller includes a circuit board, on which a processor, a bus capacitor, an inverter and a discharge circuit module are provided. The discharge circuit module includes a discharge resistor group and a discharge control circuit. The first terminal of the discharge resistor group is connected to the positive electrode of the bus capacitor, and the second terminal of the discharge resistor group is respectively connected to the negative electrode of the bus capacitor and the output end of the discharge control circuit. The input end of the discharge control circuit is connected to the processor, and the positive and negative electrodes of the bus capacitor are respectively connected to the inverter. The present invention is applicable to the discharge of the bus capacitor by the motor controller.

Description

Technical Field

[0001] The present invention relates to the technical field of discharge, and particularly to a motor controller, a motor drive system, and a new energy vehicle. Background Art

[0002] Currently, the commonly used fuel engine vehicles have various drawbacks, such as low energy utilization rate, serious pollution, etc. With the enhancement of people's environmental awareness, new energy vehicles are becoming more and more popular. A new energy vehicle uses an on-vehicle high-voltage battery as power. The electrical energy of the high-voltage battery is driven by a motor through a motor controller, and the motor drives the wheels to run, which can reduce environmental pollution. To ensure the reliable operation of the motor controller, a bus capacitor for storing electrical energy is provided at the front end of the motor controller. When in specific working conditions, such as when the vehicle needs to be repaired, even if the high-voltage battery is completely disconnected from the motor controller through the vehicle controller, since the output voltage of the high-voltage battery is higher than 100V, the voltage of the bus capacitor is higher than 100V, then the voltage on the bus connecting the battery and the motor controller (bus voltage) is also higher than the safety voltage of the human body. To ensure the safety of maintenance personnel or vehicle drivers, it is necessary to discharge the bus capacitor to make the bus voltage drop within the range of the human body safety voltage. The existing method for discharging the bus voltage is to use a DC-DC converter to convert the DC high voltage in the bus capacitor into DC low voltage to charge the on-vehicle low-voltage battery. When using such a discharge method, additional discharge equipment needs to be added, making the structure of the new energy vehicle relatively complex. Summary of the Invention

[0003] In view of this, embodiments of the present invention provide a motor controller, a motor drive system, and a new energy vehicle, which can discharge the bus capacitor while simplifying the structure of the new energy vehicle.

[0004] In a first aspect, an embodiment of the present invention provides a motor controller, including a circuit board, on which a processor, a bus capacitor, an inverter, and a discharge circuit module are provided. The discharge circuit module includes a discharge resistor group and a discharge control circuit. The first terminal of the discharge resistor group is connected to the positive electrode of the bus capacitor, and the second terminal of the discharge resistor group is respectively connected to the negative electrode of the bus capacitor and the output end of the discharge control circuit. The input end of the discharge control circuit is connected to the processor, and the positive and negative electrodes of the bus capacitor are respectively connected to the inverter.

[0005] According to a specific implementation manner of an embodiment of the present invention, the discharge resistor group includes a first parallel resistor group, a second parallel resistor group, and a third parallel resistor group connected in series in sequence; the discharge control circuit includes a constant current electronic switch; a first terminal of the first parallel resistor group is connected to the positive electrode of the bus capacitor, a first terminal of the third parallel resistor group is connected to a first terminal of the constant current electronic switch, and a second terminal of the constant current electronic switch is connected to the negative electrode of the bus capacitor.

[0006] According to a specific implementation manner of an embodiment of the present invention, the constant current electronic switch is an enhanced N-channel metal-oxide-semiconductor field effect transistor, a first terminal of the third parallel resistor group is connected to the drain of the enhanced N-channel metal-oxide-semiconductor field effect transistor, and the source of the enhanced N-channel metal-oxide-semiconductor field effect transistor is connected to the negative electrode of the bus capacitor.

[0007] According to a specific implementation manner of an embodiment of the present invention, the constant current electronic switch is an enhanced N-channel metal-oxide-semiconductor field effect transistor; the discharge control circuit further includes: a constant voltage source circuit and an opto-switch isolation circuit, the constant voltage source circuit includes a first NPN transistor, a first resistor, and a zener diode, one end of the first resistor is connected in series with the zener diode and then grounded; the opto-switch isolation circuit includes an opto-coupler and a second NPN transistor; a first input terminal of the opto-coupler is grounded, a second input terminal is connected to the processor, a first output terminal of the opto-coupler is connected to the collector of the second NPN transistor, and a second output terminal of the opto-coupler is grounded; the collector of the first NPN transistor is connected to the positive electrode of the bus capacitor, the emitter of the first NPN transistor is respectively connected to the base of the second NPN transistor and the other end of the first resistor, the base of the first NPN transistor is connected to the collector of the second NPN transistor, a node between the first resistor and the zener diode and the emitter of the second NPN transistor are respectively connected to the gate of the enhanced N-channel metal-oxide-semiconductor field effect transistor, and the source of the enhanced N-channel metal-oxide-semiconductor field effect transistor is connected to the negative electrode of the bus capacitor.

[0008] According to a specific implementation manner of an embodiment of the present invention, the constant voltage source circuit further includes a first thermistor, and the first thermistor is connected between the emitter of the first NPN transistor and the first resistor.

[0009] According to a specific implementation manner of an embodiment of the present invention, the discharge control circuit further includes a resistor group for providing a forward bias voltage to the base of the first NPN transistor and a load voltage to the collector of the second NPN transistor. One end of the resistor group is connected to the positive electrode of the bus capacitor, and the other end of the resistor group is respectively connected to the base of the first NPN transistor and the collector of the second NPN transistor.

[0010] According to a specific implementation manner of an embodiment of the present invention, the negative electrode of the bus capacitor is grounded. A current stabilizing resistor is connected in series between the source electrode of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor and the negative electrode of the bus capacitor, and the gate electrode of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor is grounded through a current limiting protection resistor.

[0011] According to a specific implementation manner of an embodiment of the present invention, a second thermistor is further connected in series between the source electrode of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor and the negative electrode of the bus capacitor.

[0012] According to a specific implementation manner of an embodiment of the present invention, a grounded capacitor is connected to the gate electrode of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor.

[0013] According to a specific implementation manner of an embodiment of the present invention, a bus voltage sampling circuit is further connected to both ends of the resistor group.

[0014] According to a specific implementation manner of an embodiment of the present invention, the discharge circuit module is printed on the circuit board.

[0015] In a second aspect, an embodiment of the present invention provides a motor drive system, including: a high-voltage battery, the motor controller according to any one of the foregoing implementation manners, and a motor. The high-voltage battery is connected to the bus capacitor in the motor controller, and the output end of the inverter in the motor controller is connected to the motor.

[0016] In a third aspect, an embodiment of the present invention provides a new energy vehicle, including: a vehicle frame, a power management system, and the motor drive system according to claim 12. The power management system and the motor drive system are respectively arranged on the vehicle frame, and the power management system is respectively connected to the high-voltage battery and the motor controller of the motor drive system.

[0017] An electric machine controller, an electric machine drive system, and a new energy vehicle provided by an embodiment of the present invention include a processor, a bus capacitor, an inverter, and a discharge circuit module disposed on a circuit board. The discharge circuit module includes a discharge resistor group and a discharge control circuit. In this way, the discharge circuit module is integrated in the electric machine controller, and a first terminal of the discharge resistor group is connected to a positive electrode of the bus capacitor, a second terminal of the discharge resistor group is respectively connected to a negative electrode of the bus capacitor and an output end of the discharge control circuit, an input end of the discharge control circuit is connected to the processor, and the positive electrode and the negative electrode of the bus capacitor are respectively connected to the inverter, so as to discharge the bus capacitor, such that during the process of reducing the bus voltage to within the range of human body safety voltage. In this way, when discharging the bus capacitor, there is no need to additionally increase a discharge device, thereby facilitating the simplification of the structure of the new energy vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following-described drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0019] Figure 1 Schematic structural diagram of Embodiment 1 of an electric machine controller provided by the present invention;

[0020] Figure 2 Schematic structural diagram of the discharge circuit module in one embodiment of the present invention;

[0021] Figure 3 Schematic structural diagram of the discharge circuit module in another embodiment of the present invention;

[0022] Figure 4 Schematic structural diagram of the discharge circuit module in still another embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] The following will describe the embodiments of the present invention in detail with reference to the drawings.

[0024] It should be clear that the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the scope of protection of the present invention.

[0025] Figure 1 Schematic structural diagram of Embodiment 1 of an electric machine controller provided by the present invention, as Figure 1 shown Figure 2Schematic diagram of the structure of the discharge circuit module in an embodiment of the present invention, as Figure 2 shown, in combination with Figure 1 and Figure 2 this embodiment is described. The motor controller of this embodiment includes a circuit board, and a processor 1, a bus capacitor 2, an inverter 3, and a discharge circuit module 4 are provided on the circuit board. The discharge circuit module 4 includes a discharge resistor group 41 and a discharge control circuit 42. The first terminal of the discharge resistor group 41 is connected to the positive electrode of the bus capacitor 2, and the second terminal of the discharge resistor group 41 is respectively connected to the negative electrode of the bus capacitor 2 and the output terminal of the discharge control circuit 42. The input terminal of the discharge control circuit 42 is connected to the processor 1. The positive and negative electrodes of the bus capacitor 2 are respectively connected to the inverter 3.

[0026] In this embodiment, the processor 1, the bus capacitor 2, the inverter 3, and the discharge circuit module 4 can be connected to the circuit board through the interfaces with the circuit board, or can be partially printed on the circuit board; the processor 1 can be a single-chip microcomputer or a DSP. It is used to process the input data to obtain a processing result, and can issue control instructions to the components connected thereto according to the processing result to implement corresponding functions. In this embodiment, the processor 1 controls whether the discharge circuit module 4 works; the bus capacitor 2 is arranged at the front end of the inverter 3 and is used to store the voltage provided by the storage battery in the new energy vehicle; the inverter 3 can convert the direct current of the high-voltage battery into alternating current, input the alternating current into the motor to make the motor rotate, and further drive the mechanical transmission device to work, and further drive the drive wheels of the new energy vehicle to rotate.

[0027] In this embodiment, the discharge circuit module 4 includes a discharge resistor group 41 and a discharge control circuit 42. The first terminal of the discharge resistor group 41 is connected to the positive electrode of the bus capacitor 2, and the second terminal of the discharge resistor group 41 is respectively connected to the negative electrode of the bus capacitor 2 and the output terminal of the discharge control circuit 42. The input terminal of the discharge control circuit 42 is connected to the processor 1.

[0028] Among them, the discharge circuit module can be printed on a separate circuit board or on the original circuit board in the motor controller. In order to make the internal structure of the motor controller simpler, in an embodiment of the present invention, the discharge circuit is printed on the circuit board of the motor controller.

[0029] It can be understood that since the output voltage of the high-voltage battery in the motor drive system is higher than 100V, in some working conditions, such as when maintenance is required or the vehicle collides, etc., to protect personal safety, it is necessary to discharge it to reduce the high voltage of the bus capacitor C in this working condition. The specific discharge working process of the motor controller in the embodiment of the present invention is as follows: when it is necessary to discharge the bus capacitor, the processor 1 issues a control signal to control the discharge control circuit 42 to work, so that the bus capacitor discharges through the discharge resistor group 41, and the bus capacitor is discharged to a safe voltage, thereby ensuring the safety of relevant personnel such as maintenance personnel or vehicle drivers.

[0030] The discharge scheme provided by the embodiment of the present invention is implemented on the basis of the motor controller, without adding additional hardware structures such as a DC-DC converter. By adding the discharge circuit module to the circuit board of the motor controller hardware, the discharge of the bus high voltage can be realized, and compared with adding additional hardware devices such as a DC-DC converter, the cost is lower.

[0031] A motor controller provided by an embodiment of the present invention includes a processor, a bus capacitor, an inverter, and a discharge circuit module provided on a circuit board. The discharge circuit module includes a discharge resistor group and a discharge control circuit. In this way, the discharge circuit module is integrated in the motor controller, and the first terminal of the discharge resistor group is connected to the positive electrode of the bus capacitor, the second terminal of the discharge resistor group is respectively connected to the negative electrode of the bus capacitor and the output terminal of the discharge control circuit, the input terminal of the discharge control circuit is connected to the processor, and the positive and negative electrodes of the bus capacitor are respectively connected to the inverter, so as to discharge the bus capacitor, so that the bus voltage is reduced to within the range of the human body safe voltage. In this way, when discharging the bus capacitor, there is no need to add additional discharge equipment, thereby facilitating the simplification of the structure of new energy vehicles.

[0032] See Figure 2 , in the figure, High-Voltage is the positive electrode of the high-voltage bus capacitor, that is, the high-voltage end, HGND is the ground. In this embodiment, the negative electrode of the bus capacitor, that is, the low-voltage end, is grounded, DIS-CHARGE indicates receiving a discharge control instruction; the discharge resistor group 41 includes a first parallel resistor group 41a, a second parallel resistor group 41b, and a third parallel resistor group 41c connected in series in sequence; the discharge control circuit 42 includes a constant-current electronic switch 42a for realizing constant-current discharge control.

[0033] The first terminal of the first parallel resistor group 41a is connected to the positive electrode of the bus capacitor 2, the first terminal of the third parallel resistor group 41c is connected to the first terminal of the constant-current electronic switch 42a, and the second terminal of the constant-current electronic switch 42a is connected to the negative electrode of the bus capacitor 3.

[0034] In this embodiment, since a constant-current electronic switch is used to control the discharge, the discharge of the bus capacitor can be achieved. In this embodiment, the first parallel resistor group 41a, the second parallel resistor group 41b, or the third parallel resistor group 41c can be composed of one resistor, or can be composed of multiple resistors in series and / or in parallel; when the constant-current electronic switch 42a is turned on, the positive electrode of the bus capacitor 2, the first parallel resistor group 41a, the second parallel resistor group 41b, the third parallel resistor group 41c, and the negative electrode of the bus capacitor 2 form a conduction circuit to realize the discharge of the bus capacitor.

[0035] In this embodiment, compared with using only one resistor with the same resistance value, the resistance value after the first parallel resistor group, the second parallel resistor group, and the third parallel resistor group are connected in series is lower in cost, thus facilitating the reduction of the cost of the motor controller.

[0036] In an embodiment of the present invention, the constant-current electronic switch is an enhanced N-channel metal-oxide semiconductor field-effect transistor. The first terminal of the third parallel resistor group is connected to the drain of the enhanced N-channel metal-oxide semiconductor field-effect transistor, and the source of the enhanced N-channel metal-oxide semiconductor field-effect transistor is connected to the negative electrode of the bus capacitor.

[0037] Among them, metal-oxide semiconductor field-effect transistors (MOSFETs, metal-oxide-semiconduct orfield-effect transistors) can be divided into N-channel types with a majority of electrons and P-channel types with a majority of holes according to the different channel polarities, and are usually referred to as N-type metal-oxide semiconductor field-effect transistors (NMOSFETs) and P-type metal-oxide semiconductor field-effect transistors (PMOSFETs). In this embodiment, an enhanced NMOSFET is used. When a voltage is applied between the gate and the source, a drain current is generated, that is, the MOSFET is turned on.

[0038] Figure 3 It is a schematic structural diagram of the discharge circuit module in another embodiment of the present invention, as Figure 3 shown. In this embodiment, the constant-current electronic switch 42a is an enhanced N-channel metal-oxide semiconductor field-effect transistor;

[0039] On the basis of the foregoing embodiment, the discharge control circuit 42 further includes: a constant-voltage source circuit and an opto-switch isolation circuit 42d. The constant-voltage source circuit includes a first NPN-type triode 42c1, a first resistor 42c2, and a zener diode 42c3. One end of the first resistor 42c2 is connected in series with the zener diode 42c3 and then grounded, which plays a voltage-stabilizing role to protect the gate of the enhanced NMOSFET from being broken down.

[0040] The optoelectronic switch isolation circuit 42d includes an optocoupler 42d1 and a second NPN transistor 42d2; a first input terminal of the optocoupler 42d1 is grounded, a second input terminal is connected to the processor, a first output terminal of the optocoupler 42d1 is connected to a collector of the second NPN transistor 42d2, and a second output terminal of the optocoupler 42d1 is grounded;

[0041] The collector of the first NPN transistor 42c1 is connected to the positive electrode of the bus capacitor. The emitter of the first NPN transistor 42c1 is respectively connected to the base of the second NPN transistor 42d2 and the other end of a first resistor 42c2. The base of the first NPN transistor 42c1 is connected to the collector of the second NPN transistor 42d2. Nodes between the first resistor 42c2 and a voltage stabilizing diode 42c3 and the emitter of the second NPN transistor 42d2 are respectively connected to the gate of the enhancement-mode N-channel metal-oxide semiconductor field effect transistor. The source of the enhancement-mode N-channel metal-oxide semiconductor field effect transistor is connected to the negative electrode of the bus capacitor.

[0042] In this embodiment, the NPN transistor is composed of three semiconductors, including two N-type semiconductors and one P-type semiconductor. The P-type semiconductor is in the middle, and the two N-type semiconductors are on both sides. Its main functions are current amplification and switching.

[0043] In this embodiment, the voltage stabilizing diode 42c3 is a diode that uses the reverse breakdown state of the PN junction, where the current can vary within a large range while the voltage remains basically unchanged, to achieve voltage stabilization.

[0044] In this embodiment, the optocoupler 42d1 is an electro-optical-electrical conversion device that transmits electrical signals through light. It consists of a light source and a light receiver. The light source and the light receiver are assembled in the same sealed housing and isolated from each other by a transparent insulator. The second input terminal of the optocoupler 42d1 serves as the third terminal of the entire discharge circuit module.

[0045] In this embodiment, when the discharge circuit module is not working, the optocoupler 42d1 is always in the powered-on state. In this way, the collector of the second NPN transistor 42d2 is grounded. Since the base of the first NPN transistor 42c1 is connected to the collector of the second NPN transistor 42d2, the base of the first NPN transistor 42c1 is grounded. At this time, both the first NPN transistor 42c1 and the second NPN transistor 42d2 are in the cut-off state, making the entire discharge circuit module in a non-discharging state; when the processor sends a signal to control the optocoupler to make the discharge circuit module discharge, the collector of the second NPN transistor 42d2 is disconnected from the ground. Since the base of the first NPN transistor 42c1 is connected to the collector of the second NPN transistor 42d2, at this time, the positive voltage of the bus capacitor applies a voltage to the base of the first NPN transistor 42c1, making the first NPN transistor 42c1 conduct. The voltage on the first resistor 42c2 is applied to the base of the second NPN transistor 42d2, making the second NPN transistor 42d2 conduct. After passing through the zener diode, the voltage is applied to the gate of the NMOSFET tube, making the NMOSFET tube conduct. Thus, the positive voltage of the bus capacitor is discharged through the discharge resistor group and the NMOSFET tube.

[0046] In this embodiment, the collector of the first NPN transistor is connected to the positive pole of the bus capacitor, the emitter of the first NPN transistor is respectively connected to the base of the second NPN transistor and the other end of the first resistor. The base of the first NPN transistor is connected to the collector of the second NPN transistor. The node between the first resistor and the zener diode and the emitter of the second NPN transistor are respectively connected to the gate of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor. The source of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor is connected to the negative pole of the bus capacitor, and the bus voltage can be discharged.

[0047] Figure 4 It is a schematic structural diagram of the discharge circuit module in another embodiment of the present invention. As Figure 4 shown, on the basis of the foregoing embodiment, the discharge control circuit 42 further includes a resistor group 42e for providing a forward bias voltage to the base of the first NPN transistor and a load voltage to the collector of the second NPN transistor. One end of the resistor group 42e is connected to the positive pole of the bus capacitor, and the other end of the resistor group 42e is respectively connected to the base of the first NPN transistor 42c1 and the collector of the second NPN transistor 42d2.

[0048] Among them, the resistor group 42e can be a single resistor or multiple resistors connected in series and / or in parallel.

[0049] The voltage on the positive electrode of the bus capacitor 4 generates a certain amount of voltage drop across the resistor group on the resistor group 42e. In this way, the voltage provided to the base of the first NPN transistor 42c1 by the voltage on the bus capacitor 4 is smaller than the voltage on the bus capacitor 4. After reasonably determining the resistance value of the resistor group, a relatively small voltage that can maintain its conduction can be provided to the base of the first NPN transistor 42c1, and the load voltage is provided to the collector of the second NPN transistor 42d2, thereby increasing the service life of the first NPN transistor 42c1 and the second NPN transistor 42d2.

[0050] In this embodiment, by connecting one end of the resistor group to the positive electrode of the bus capacitor and the other end of the resistor group to the base of the first NPN transistor and the collector of the second NPN transistor respectively, it is convenient to increase the service life of the discharge circuit module and improve the reliability of the operation of the discharge circuit module at the same time.

[0051] See Figure 4 In an embodiment of the present invention, on the basis of the discharge control circuit in the Figure 3 discharge circuit module, the constant voltage source circuit 42c further includes a first thermistor 42c4, and the first thermistor 42c4 is connected between the emitter of the first NPN transistor 42c1 and the first resistor 42c2.

[0052] In this embodiment, the thermistor 42c4 is a sensitive element and exhibits different resistance values at different temperatures. The positive temperature coefficient thermistor has a larger resistance value when the temperature is higher.

[0053] In this embodiment, when the current flowing through the thermistor is too large, the resistance value of the thermistor becomes larger. The increase in the resistance value causes the current flowing through the thermistor to decrease, so that the voltage applied to the base of the second NPN transistor is maintained constant, which is convenient for the second NPN transistor to conduct stably and improves the stability of the discharge circuit module during discharge.

[0054] See Figure 4 In an embodiment of the present invention, the negative electrode of the bus capacitor is grounded, a current stabilizing resistor 43 is connected in series between the source electrode of the enhancement-mode N-channel metal-oxide-semiconductor field effect transistor and the negative electrode of the bus capacitor, and the gate of the enhancement-mode N-channel metal-oxide-semiconductor field effect transistor is grounded through a current limiting protection resistor 44.

[0055] In this embodiment, during the operation of the discharge circuit module, the enhancement-mode NMOSFET is in the linear operating state, and the voltage applied across the current stabilizing resistor 43 is constant, so that the discharge current is constant, that is, constant current discharge of the discharge circuit is achieved; different resistance values of the current stabilizing resistor 43 result in different discharge current magnitudes, and the magnitude of the discharge current can be adjusted by changing the resistance value of the current stabilizing resistor 43.

[0056] In this embodiment, when there is voltage on the gate of the enhanced NMOSFET tube, the current limiting protection resistor 44 is turned on; when the discharge circuit module is not working, under certain circumstances, there is voltage applied to the gate of the enhanced NMOSFET tube. Due to the existence of the current limiting protection resistor 44, the gate voltage applied to the enhanced NMOSFET tube is discharged through the current limiting protection resistor 44. In this way, the enhanced NMOSFET tube will not be mis-turned on due to other reasons.

[0057] In this embodiment, by connecting the stabilizing resistor between the source of the enhancement mode N-channel metal-oxide semiconductor field effect transistor and the negative electrode of the capacitor, the gate of the enhancement mode N-channel metal-oxide semiconductor field effect transistor is grounded through the current limiting protection resistor, so as to facilitate the constant current discharge of the discharge circuit and improve the reliability of the discharge circuit.

[0058] As an optional implementation, a second thermistor 45 is further connected in series between the source of the enhancement mode N-channel metal-oxide semiconductor field effect transistor and the negative electrode of the bus capacitor.

[0059] In this embodiment, when the discharge current is too large, the resistance value of the second thermistor 45 increases. The increase in resistance value can reduce the discharge current, thereby adjusting the discharge current to facilitate the discharge circuit to discharge at a constant current.

[0060] See also Figure 4 In one embodiment of the present invention, the gate of the enhancement mode N-channel metal-oxide semiconductor field effect transistor is connected to a grounded capacitor 46.

[0061] In this embodiment, the capacitor 46 filters the gate voltage applied to the enhancement mode NMOSFET tube, so that the enhancement mode NMOSFET tube works stably.

[0062] See also Figure 4 In one embodiment of the present invention, a bus voltage sampling circuit 47 is also connected to both ends of the resistor group.

[0063] In this embodiment, when the discharge circuit module discharges the bus capacitor, the bus voltage sampling circuit 47 collects the voltage value at both ends of the resistor group and returns the result to the processor. The processor returns the result based on the voltage value and obtains the voltage change on the bus capacitor. When the predetermined voltage value has been reached, the processor sends a control signal to control the discharge circuit to no longer discharge the bus voltage.

[0064] In this embodiment, the bus voltage sampling circuit is connected to both ends of the resistor group so that the processor can monitor the voltage change of the bus capacitor, thereby facilitating the control of the discharge circuit.

[0065] As an optional implementation manner, the discharge circuit further includes a first diode. The cathode of the voltage stabilizing diode, the other end of the second resistor, and the emitter of the second NPN-type triode are respectively connected to the anode of the first diode, and the cathode of the first diode is connected to the gate of the enhancement-mode N-channel metal-oxide-semiconductor field effect transistor.

[0066] The embodiment of the present invention further provides a motor drive system, including: a high-voltage battery, the motor controller in the above embodiment, and a motor. The high-voltage battery is connected to the bus capacitor in the motor controller, and the output end of the inverter in the motor controller is connected to the motor.

[0067] In this embodiment, by connecting the high-voltage battery to the bus capacitor in the motor controller and connecting the output end of the inverter in the motor controller to the motor, it is convenient to discharge the bus capacitor through the discharge circuit module in the motor controller.

[0068] The embodiment of the present invention further provides a new energy vehicle, including: a vehicle frame, a power management system, and the motor drive system in the above embodiment. The power management system and the motor drive system are respectively arranged on the vehicle frame, and the power management system is respectively connected to the high-voltage battery and the motor controller of the motor drive system.

[0069] In this embodiment, by arranging the power management system and the motor drive system on the vehicle frame respectively and connecting the power management system to the high-voltage battery and the motor controller of the motor drive system respectively, it is convenient to discharge the bus capacitor through the discharge circuit module in the motor drive system.

[0070] For the new energy vehicle provided by the embodiment of the present invention, since the motor controller provided by the foregoing embodiment is adopted, it is possible to discharge the bus capacitor without additionally adding a discharge device and reduce the bus voltage to within the human body safety voltage range; further, since no additional discharge device is required during the discharge process, the overall vehicle structure can be simplified.

[0071] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0072] Each embodiment in this specification is described in a related manner. For the same or similar parts among the embodiments, reference can be made to each other, and the differences between each embodiment and other embodiments are emphasized.

[0073] As described above, the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed by the present invention should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A motor controller, comprising a circuit board, characterized in that, A processor, a bus capacitor, an inverter, and a discharge circuit module are provided on the circuit board. The discharge circuit module includes a discharge resistor bank and a discharge control circuit. The first terminal of the discharge resistor bank is connected to the positive electrode of the bus capacitor. The second terminal of the discharge resistor bank is respectively connected to the negative electrode of the bus capacitor and the output terminal of the discharge control circuit. The input terminal of the discharge control circuit is connected to the processor. The positive and negative electrodes of the bus capacitor are respectively connected to the inverter. The discharge circuit module is printed on the circuit board. The discharge resistor bank includes a first parallel resistor bank, a second parallel resistor bank, and a third parallel resistor bank connected in series in sequence. The discharge control circuit includes a constant current electronic switch for implementing constant current control. The first terminal of the first parallel resistor bank is connected to the positive electrode of the bus capacitor. The first terminal of the third parallel resistor bank is connected to the first terminal of the constant current electronic switch. The second terminal of the constant current electronic switch is connected to the negative electrode of the bus capacitor. During the discharge operation, the processor issues a control signal to control the operation of the discharge control circuit. The constant current electronic switch is turned on, so that the positive electrode of the bus capacitor, the first parallel resistor bank, the second parallel resistor bank, the third parallel resistor bank, and the negative electrode of the bus capacitor form a conduction circuit, realizing the discharge of the bus capacitor. The constant current electronic switch is an enhancement-mode N-channel metal-oxide-semiconductor field effect transistor. The first terminal of the third parallel resistor bank is connected to the drain of the enhancement-mode N-channel metal-oxide-semiconductor field effect transistor. The source of the enhancement-mode N-channel metal-oxide-semiconductor field effect transistor is connected to the negative electrode of the bus capacitor. The constant current electronic switch is an enhancement-mode N-channel metal-oxide-semiconductor field effect transistor. The discharge control circuit further includes: a constant voltage source circuit and an opto-switch isolation circuit. The constant voltage source circuit includes a first NPN transistor, a first resistor, and a zener diode. One end of the first resistor is connected in series with the zener diode and then grounded. The opto-switch isolation circuit includes an opto-coupler and a second NPN transistor. The first input terminal of the opto-coupler is grounded. The second input terminal is connected to the processor. The first output terminal of the opto-coupler is connected to the collector of the second NPN transistor. The second output terminal of the opto-coupler is grounded. The collector of the first NPN transistor is connected to the positive electrode of the bus capacitor. The emitter of the first NPN transistor is respectively connected to the base of the second NPN transistor and the other end of the first resistor. The base of the first NPN transistor is connected to the collector of the second NPN transistor. The node between the first resistor and the zener diode and the emitter of the second NPN transistor are respectively connected to the gate of the enhancement-mode N-channel metal-oxide-semiconductor field effect transistor. The source of the enhancement-mode N-channel metal-oxide-semiconductor field effect transistor is connected to the negative electrode of the bus capacitor. When the discharge circuit module is not working, the optocoupler is kept powered on all the time, and the collector of the second NPN transistor is grounded. Since the base of the first NPN transistor is connected to the collector of the second NPN transistor, the base of the first NPN transistor is grounded. At this time, both the first NPN transistor and the second NPN transistor are in the cut-off state, making the entire discharge circuit module in a non-discharging state; when the processor sends a signal to control the optocoupler to make the discharge circuit module discharge, the collector of the second NPN transistor is disconnected from the ground. Since the base of the first NPN transistor is connected to the collector of the second NPN transistor, at this time, the positive voltage of the bus capacitor applies a voltage to the base of the first NPN transistor, making the first NPN transistor conduct. The voltage on the first resistor is applied to the base of the second NPN transistor, making the second NPN transistor conduct. After passing through the zener diode, the voltage is applied to the gate of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor, making the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor conduct. Thus, the positive voltage of the bus capacitor is discharged through the discharge resistor group and the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor.

2. The motor controller according to claim 1, wherein The constant voltage source circuit further includes a first thermistor, and the first thermistor is connected between the emitter of the first NPN transistor and the first resistor.

3. The motor controller according to claim 1, characterized in that, The discharge control circuit further includes a resistor group for providing a forward bias voltage to the base of the first NPN transistor and a load voltage to the collector of the second NPN transistor. One end of the resistor group is connected to the positive pole of the bus capacitor, and the other end of the resistor group is respectively connected to the base of the first NPN transistor and the collector of the second NPN transistor.

4. The motor controller according to any one of claims 1 to 3, characterized in that, The negative pole of the bus capacitor is grounded, a current stabilizing resistor is connected in series between the source of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor and the negative pole of the bus capacitor, and the gate of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor is grounded through a protection resistor.

5. The motor controller according to claim 4, wherein A second thermistor is further connected in series between the source of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor and the negative pole of the bus capacitor.

6. The motor controller according to any one of claims 1 to 3, characterized in that, A capacitor grounded is connected to the gate of the enhancement-mode N-channel metal-oxide-semiconductor field-effect transistor.

7. The motor controller according to claim 3, characterized in that, A bus voltage sampling circuit is also connected to both ends of the resistor group.

8. An electric motor drive system, characterized in that, Comprising: A high-voltage battery, a motor, and the motor controller according to any one of claims 1-7. The high-voltage battery is connected to the bus capacitor in the motor controller, and the output end of the inverter in the motor controller is connected to the motor.

9. A new energy vehicle, comprising: A vehicle frame, a power management system, and the motor drive system according to claim 8. The power management system and the motor drive system are respectively arranged on the vehicle frame, and the power management system is respectively connected to the high-voltage battery and the motor controller of the motor drive system.

Images