Active discharge circuit, method of active discharge, controller, and vehicle

Abstract

The application discloses an active discharge circuit, an active discharge method, a controller and a vehicle, and the method comprises the following steps: when a switch drive detects a discharge signal, a driving voltage is generated through the switch drive, the driving voltage is transmitted into a semiconductor switch tube, and energy in a bus capacitor is consumed based on the driving voltage so that the semiconductor switch tube works in a constant current area to perform a discharge operation. By using the constant current characteristic of the semiconductor switch tube, the situation that the instantaneous impact current is increased is avoided, and then the effect that the energy in the bus capacitor can be consumed without damaging the components based on the simple layout of the semiconductor switch tube is realized, and the discharge requirements of low cost, simple layout design and low application risk are met.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motor control, and in particular to an active discharge circuit, an active discharge method, a motor controller and a vehicle. BACKGROUND

[0002] In the case that the motor controller is in a shutdown state or a fault state, active discharge is a basic requirement for the motor controller, and the traditional discharge scheme is generally to perform active discharge through additional discharge resistors or through the shoot-through loss of three-phase drive switching tubes.

[0003] In the process of performing active discharge through additional discharge resistors, in order to ensure that the discharge resistors can withstand instantaneous discharge power, a large number of discharge resistors need to be incorporated, which has the problems of excessive PCB (Printed Circuit Board) area occupation and high cost. In the scheme of performing active discharge through the shoot-through loss of three-phase drive switching tubes, due to the large instantaneous energy impact, the scheme has the problems of complex layout design and high application difficulty, especially in the case of SIC power semiconductor devices, due to the fast switching speed of SIC devices and the weak energy impact resistance, which further increases the application risk. Therefore, the traditional discharge scheme lacks a discharge scheme with low cost, simple layout design and low application risk. SUMMARY

[0004] The main purpose of the present application is to provide an active discharge circuit, an active discharge method, a motor controller and a vehicle, which aims to solve the technical problem that the traditional discharge scheme cannot simultaneously meet the requirements of low cost, simple layout design and low application risk.

[0005] To achieve the above purpose, the present application provides an active discharge circuit, which is connected in parallel with a bus capacitor, and comprises a semiconductor switching tube and a switching drive.

[0006] The first end of the semiconductor switching tube is connected to the switching drive, and the switching drive is used to generate a drive voltage to control the semiconductor switching tube to work in a constant current region for discharge.

[0007] The second end of the semiconductor switching tube is connected to the positive electrode of the bus capacitor, and the third end of the semiconductor switching tube is connected to the negative electrode of the bus capacitor, and the semiconductor switching tube is used to work in the constant current region for discharge to consume the energy in the bus capacitor.

[0008] Optionally, the semiconductor switch tube comprises a field effect tube, a gate of the field effect tube is connected with the switch drive as a first end of the semiconductor switch tube, a drain of the field effect tube is connected with a positive pole of the bus capacitor as a second end of the semiconductor switch tube, and a source of the field effect tube is connected with a negative pole of the bus capacitor as a third end of the semiconductor switch tube.

[0009] Optionally, the semiconductor switch tube comprises an insulated gate bipolar transistor, a base of the insulated gate bipolar transistor is connected with the switch drive as a first end of the semiconductor switch tube, a collector of the insulated gate bipolar transistor is connected with a positive pole of the bus capacitor as a second end of the semiconductor switch tube, and an emitter of the insulated gate bipolar transistor is connected with a negative pole of the bus capacitor as a third end of the semiconductor switch tube.

[0010] Optionally, the active discharge circuit further comprises a discharge resistor.

[0011] The discharge resistor is connected between the positive pole of the bus capacitor and the second end of the semiconductor switch tube, the discharge resistor and the semiconductor switch tube are used for consuming energy in the bus capacitor, and the discharge resistor is further used for providing voltage data for controlling the semiconductor switch tube as a voltage detection target to control the semiconductor switch tube to work in the constant current area for discharging.

[0012] The application further provides an active discharge method, which comprises the following steps:

[0013] generating a drive voltage when a discharge signal is detected by the switch drive in the active discharge circuit, and transmitting the drive voltage into a semiconductor switch tube in the active discharge circuit;

[0014] discharging by the semiconductor switch tube based on the drive voltage to work in a constant current area to consume energy in a bus capacitor connected in parallel with the active discharge circuit.

[0015] Optionally, the discharging by the semiconductor switch tube based on the drive voltage to work in a constant current area comprises:

[0016] entering a normal on state by the semiconductor switch tube to work in a constant current area to discharge when the drive voltage is in a preset voltage range; or,

[0017] discharging by the semiconductor switch tube based on the drive voltage to work in a constant current area according to a set frequency and duty cycle, wherein the frequency and duty cycle comprise a fixed mode and a variable mode.

[0018] Optionally, after the step of discharging, by the semiconductor switch, based on the driving voltage, in the constant current region to consume the energy in the bus capacitor connected in parallel with the active discharge circuit, the method further comprises:

[0019] detecting the junction temperature of the semiconductor switch to obtain a first detection result, and adjusting the driving voltage based on the first detection result for the semiconductor switch to work in the constant current region; or,

[0020] detecting the current of the semiconductor switch to obtain a second detection result, and adjusting the driving voltage based on the second detection result for the semiconductor switch to work in the constant current region; or,

[0021] detecting the voltage across the bus capacitor to obtain a third detection result, and adjusting the driving voltage based on the third detection result for the semiconductor switch to work in the constant current region; or,

[0022] detecting the time-varying across the bus capacitor to obtain a fourth detection result, and adjusting the driving voltage based on the fourth detection result for the semiconductor switch to work in the constant current region.

[0023] Optionally, the switch drive includes an adjustable voltage source, an active filter, a passive filter, or an analog isolator, and the step of adjusting the driving voltage includes:

[0024] adjusting the driving voltage based on the adjustable voltage source; or,

[0025] adjusting the driving voltage based on the active filter; or,

[0026] adjusting the driving voltage based on the passive filter; or,

[0027] adjusting the driving voltage based on the analog isolator.

[0028] In addition, in order to achieve the above-mentioned purpose, the application further provides a motor controller, comprising the active discharge circuit, the bus capacitor and the three-phase inverter module as described above, wherein the bus capacitor is connected with the active discharge circuit, and the active discharge circuit is connected with the three-phase inverter module.

[0029] In addition, in order to achieve the above-mentioned purpose, the application further provides a vehicle, comprising a battery and a motor controller as described above, wherein the motor controller is connected with the battery.

[0030] The application can avoid the situation of large energy impact existing in straight-through loss, thus can reduce the design difficulty of layout and the risk degree of application, and because the semiconductor switch tube consumes the energy in the bus capacitor by working in the constant current area, the situation of needing to incorporate a large number of discharge resistors to bear the instantaneous discharge power is avoided, so the active discharge circuit based on the application can meet the discharge requirements of low cost, simple layout design and low application risk. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 is a terminal structure schematic diagram of a hardware running environment related to the embodiment scheme of the application;

[0032] Figure 2 is a structure schematic diagram of the active discharge circuit when the semiconductor switch tube in the semiconductor switch tube is a field effect tube;

[0033] Figure 3 is a structure schematic diagram of the active discharge circuit when the semiconductor switch tube in the semiconductor switch tube is an insulated gate bipolar transistor;

[0034] Figure 4 is a curve schematic diagram of the field effect tube output;

[0035] Figure 5 is a curve schematic diagram of the insulated gate bipolar transistor output;

[0036] Figure 6 is a structure schematic diagram of the active discharge circuit with a discharge resistor;

[0037] Figure 7 is a flow schematic diagram of the method for active discharge of the application.

[0038] BRIEF DESCRIPTION OF DRAWINGS

[0039] Reference Name Q1 Semiconductor switch 10 Switch drive C1 Bus capacitor R1 Discharge resistor 20 Inverter Q2-Q7 Power switching element

[0040] The application achieves the purpose, functional features and advantages by combining the embodiments with the drawings. DETAILED DESCRIPTION

[0041] It should be understood that the specific embodiments described herein are only used to explain the application, and are not used to limit the application.

[0042] The main solution of the embodiment of the present application is: through improvement on the traditional active discharge circuit, through the connection mode of the semiconductor switch tube and the switch drive, the conduction state of the semiconductor switch tube is controlled on the constant current area based on the switch drive, and the energy in the bus capacitor is consumed by the semiconductor switch tube working in the constant current area.

[0043] However, the traditional active scheme circuit generally actively discharges through additional discharge resistance or through the through loss of the three-phase driven switch tube, and the two active discharge schemes have the problems of high cost, complex layout design and high application risk, and lack a discharge scheme with low cost, simple layout design and low application risk.

[0044] The present application provides a solution, which improves the traditional active discharge circuit, that is, through the switch drive, the semiconductor switch tube for active discharge is controlled in the constant current area to actively discharge, which can avoid the case that the through loss exists and the instantaneous energy impact is large, so as to reduce the design difficulty of the layout and the risk degree of application, and because the semiconductor switch tube consumes the energy in the bus capacitor by working in the constant current area, the problem of high cost caused by the need to incorporate a large number of discharge resistors to withstand the instantaneous discharge power is avoided, the safety and stability of the active discharge circuit are improved, and the discharge resistance is reduced, and the discharge cost is reduced.

[0045] As shown in Figure 1 , the terminal structure schematic diagram of the hardware running environment involved in the embodiment scheme of the present application is shown in Figure 1

[0046] The application carrier of the active discharge method of the embodiment of the present application is a motor controller, as shown in Figure 1 , the motor controller can include: a processor 1001 such as CPU, a network interface 1004, a user interface 1003, a memory 1005, and a communication bus 1002. The communication bus 1002 is used to realize the connection communication between the components. The user interface 1003 can include a display area (Display) and an input unit such as a keyboard (Keyboard). The optional user interface 1003 can also include a standard wired interface and a wireless interface. The network interface 1004 can optionally include a standard wired interface and a wireless interface (such as a WI-FI interface). The memory 1005 can be a high-speed RAM memory or a stable memory (non-volatile memory) such as a magnetic disk memory. The memory 1005 can also be a storage device independent of the aforementioned processor 1001.

[0047] ​Optionally, the motor controller can further include sensors, audio circuit, WiFi module, etc. Among them, the sensors can be light sensor, motion sensor and other sensors. Specifically, the light sensor can include ambient light sensor and proximity sensor, wherein the ambient light sensor can adjust the brightness of the display according to the brightness of the ambient light, and the proximity sensor can turn off the display and / or backlight when the mobile terminal is moved to the ear. As one of the motion sensors, the gravity acceleration sensor can detect the size of acceleration in each direction (usually three axes), and can detect the size and direction of gravity when stationary, which can be used for identifying mobile terminal posture applications (such as landscape / portrait screen switching, related games, magnetometer posture calibration), vibration recognition related functions (such as pedometer, tapping), etc. Of course, the mobile terminal can also be configured with a gyroscope, barometer, hygrometer, thermometer, infrared sensor and other sensors, which will not be described here.

[0048] Those skilled in the art can understand that Figure 1 The motor controller structure shown in the above embodiments does not constitute a limitation on the motor controller, and can include more or fewer components than shown, or combine certain components, or different component arrangements.

[0049] As Figure 1 As shown, the memory 1005 as a computer storage medium can include an operating system, a network communication module, a user interface module and a computer processing program.

[0050] In Figure 1 As shown in the terminal, the network interface 1004 is mainly used for connecting the background server and communicating data with the background server; the user interface 1003 is mainly used for connecting the client (user end) and communicating data with the client; and the processor 1001 can be used to call the computer processing program stored in the memory 1005 and perform the following operations:

[0051] The drive voltage is generated when the discharge signal is detected by driving the switch in the active discharge circuit, and the drive voltage is transmitted into the semiconductor switch tube in the active discharge circuit;

[0052] The semiconductor switch tube discharges based on the drive voltage working in the constant current area to consume the energy in the bus capacitor connected in parallel with the active discharge circuit.

[0053] Further, the processor 1001 can call the computer processing program stored in the memory 1005 and further perform the following operations:

[0054] The discharging step by the semiconductor switch based on the driving voltage working in the constant current region includes: entering a normal on state by the semiconductor switch when the driving voltage is in a preset voltage range to discharge in the constant current region; or,

[0055] The discharging step by the semiconductor switch based on the driving voltage working in the constant current region includes: entering a normal on state by the semiconductor switch when the driving voltage is in a preset voltage range to discharge in the constant current region; or,

[0056] Further, the processor 1001 can call the computer processing program stored in the memory 1005, and further perform the following operations:

[0057] The method further includes: detecting the junction temperature of the semiconductor switch to obtain a first detection result, and adjusting the driving voltage based on the first detection result for the semiconductor switch to work in the constant current region; or,

[0058] Detecting the current of the semiconductor switch to obtain a second detection result, and adjusting the driving voltage based on the second detection result for the semiconductor switch to work in the constant current region; or,

[0059] Detecting the voltage across the bus capacitor to obtain a third detection result, and adjusting the driving voltage based on the third detection result for the semiconductor switch to work in the constant current region; or,

[0060] Detecting the time-varying across the bus capacitor to obtain a fourth detection result, and adjusting the driving voltage based on the fourth detection result for the semiconductor switch to work in the constant current region.

[0061] Further, the processor 1001 can call the computer processing program stored in the memory 1005, and further perform the following operations:

[0062] The step of adjusting the driving voltage includes:

[0063] Adjusting the driving voltage based on the adjustable voltage source; or,

[0064] Adjusting the driving voltage based on the active filter; or,

[0065] Adjusting the driving voltage based on the passive filter; or,

[0066] Adjusting the driving voltage based on the analog isolator.

[0067] Referring to Figure 2The application provides an active discharge circuit, which is connected with a bus capacitor C1 in parallel, and comprises a semiconductor switch Q1 and a switch drive 10.

[0068] A first end of the semiconductor switch Q1 is connected with the switch drive 10, and the switch drive 10 is used for generating a driving voltage to control the semiconductor switch Q1 to work in a constant current area for constant current discharge.

[0069] A second end of the semiconductor switch Q1 is connected with a positive end of the bus capacitor C1, and a third end of the semiconductor switch Q1 is connected with a negative end of the bus capacitor C1, and the semiconductor switch Q1 is used for working in the constant current area for constant current discharge to consume energy in the bus capacitor C1.

[0070] According to the application, Figure 2 It can be known that the active discharge circuit is connected between the bus capacitor C1 and an inverter bridge 20, the inverter bridge 20 receives direct current energy delivered by a battery, and converts the direct current energy into three-phase alternating current to provide power supply for a motor controller, and when the motor controller communicates with a whole vehicle to be in a shutdown state, or the controller of the whole vehicle sends an active discharge instruction to the motor controller through communication, or a collision signal of the whole vehicle is transmitted to the motor controller, or the motor controller detects an internal fault, in the above cases, the residual voltage in the motor controller needs to be discharged, otherwise the driving safety of a driver will be threatened.

[0071] Therefore, the embodiment discharges the residual voltage through the semiconductor switch Q1, the residual voltage is stored in the bus capacitor C1, the semiconductor switch Q1 consumes the energy in the bus capacitor C1, and the switch state of the semiconductor switch Q1 is controlled through the switch drive 10, when the switch drive 10 detects that the motor controller is in a shutdown state or a fault state, the switch drive 10 generates a driving voltage to drive the semiconductor switch Q1, so that the semiconductor switch Q1 is turned on.

[0072] It should be noted that the driving voltage generated by the switch drive 10 is controlled at a low gate voltage of the semiconductor switch Q1, the semiconductor switch Q1 is controlled to work in a constant current area based on the low gate voltage, so as to consume the energy in the bus capacitor C1, that is, the energy consumption of the bus capacitor C1 is realized on the semiconductor switch Q1 to discharge the residual voltage in the motor controller, so as to avoid the risk of electric shock of the driver.

[0073] In addition, the Figure 2 , Figure 3 or Figure 6As can be seen, the inverter 20 in this embodiment is equipped with 6 power switching transistors, namely the first power switching transistor Q2, the second power switching transistor Q3, the third power switching transistor Q4, the fourth power switching transistor Q5, the fifth power switching transistor Q6 and the sixth power switching transistor Q7.

[0074] Furthermore, referring to Figure 2 As shown, the semiconductor switch Q1 includes a field-effect transistor (FET). The gate of the FET serves as the first terminal of the semiconductor switch Q1 and is connected to the switch driver 10. The drain of the FET serves as the second terminal of the semiconductor switch Q1 and is connected to the positive terminal of the bus capacitor C1. The source of the FET serves as the third terminal of the semiconductor switch Q1 and is connected to the negative terminal of the bus capacitor C1.

[0075] Furthermore, referring to Figure 3 As shown, the semiconductor switch Q1 includes an insulated gate bipolar transistor (IGBT). The base of the IGBT serves as the first terminal of the semiconductor switch Q1 and is connected to the switch driver 10. The collector of the IGBT serves as the second terminal of the semiconductor switch Q1 and is connected to the positive terminal of the bus capacitor C1. The emitter of the IGBT serves as the third terminal of the semiconductor switch Q1 and is connected to the negative terminal of the bus capacitor C1.

[0076] In this embodiment, the semiconductor switch Q1 can be either a field-effect transistor or an insulated-gate bipolar transistor.

[0077] by Figure 2 For example, when the semiconductor switch Q1 is a field-effect transistor (FET), the gate of the FET is connected to the drive output terminal of the switch driver 10. This allows the FET to conduct when it receives a drive voltage input from the switch driver 10. At this time, the FET operates in the constant current region. (Refer to...) Figure 4 The output curve of the field-effect transistor is shown. The horizontal axis represents the drain-source voltage, the vertical axis represents the drain current, and the curve represents the gate-to-source voltage (i.e., the drive voltage). As can be seen from the figure, the transistor is divided into a variable resistance region based on the drain current value (i.e.,...). Figure 4 The region to the left of line a), the constant current region (i.e. Figure 4 The area between line a and line b) and the cutoff zone (i.e. Figure 4If a conducting MOSFET operates in the variable resistance region (i.e., when the drive voltage is from 0V to 10V, the drain current value fluctuates significantly between 0A and 3.75A when the drain-source voltage is between 0V and 25V), there is a risk of instantaneous surge current increasing and damaging the MOSFET. Therefore, the MOSFET needs to be controlled to operate in the constant current region, i.e., the drive voltage should be controlled at around 6V, so that the drain output current value remains constant at around 2A when the drain-source voltage is between 20V and 30V, achieving the effect of constant current output under low gate voltage, thereby avoiding the increase of instantaneous surge current.

[0078] by Figure 3 For example, when the semiconductor switch Q1 is an insulated-gate bipolar transistor (IGBT), the base of the IGBT is connected to the drive output terminal of the switch driver 10. This allows the IGBT to conduct when it receives a drive voltage input from the switch driver 10. At this time, the IGBT operates in the constant current region. (Refer to...) Figure 5 The output curve of the insulated-gate bipolar transistor (IGBT) is shown below. The horizontal axis represents the collector-emitter voltage, the vertical axis represents the collector current, and the curve represents the base-emitter voltage (i.e., the drive voltage). As can be seen from the figure, the transistor is divided into a variable resistance region based on the collector current value (i.e.,...). Figure 5 The region to the left of line a), the constant current region (i.e. Figure 5 The area between line a and line b) and the cutoff zone (i.e. Figure 5 (In the region to the right of line b), if there is a conducting insulated-gate bipolar transistor operating in the variable resistance region (for example, when the drive voltage is 0V-17V, the collector current value fluctuates significantly between 0A-20A when the collector-emitter voltage is 0V-3V; or when the drive voltage is 0V-15V, the collector current value fluctuates significantly between 0A-20A when the collector-emitter voltage is 0V-3V; or when the drive voltage is 0V-13V, the collector current value fluctuates significantly between 0A-20A when the collector-emitter voltage is 0V-3V), When the voltage is in the 4.2V range, there is a significant fluctuation between 0A and 20A. At this point, there is a risk of a sudden increase in inrush current that could damage the insulated gate bipolar transistor (IGBT). Therefore, the IGBT needs to be controlled to operate in the constant current region, i.e., the drive voltage should be controlled to around 11V or 9V. This ensures that the collector output current remains constant at around 14A or 6A when the collector-emitter voltage range is 4V-6V or 2.5V-6V, achieving a constant current output at a low gate voltage and thus avoiding an increase in the sudden inrush current.

[0079] It should be noted that the value of the output voltage of the control drive voltage mentioned above is based on... Figure 4 and Figure 5 This is just an example; in actual application, the specific voltage value should be used as the standard.

[0080] Further, the active discharging circuit further comprises a discharging resistor R1;

[0081] The discharging resistor R1 is connected between the positive terminal of the bus capacitor C1 and the second terminal of the semiconductor switch tube Q1, the discharging resistor R1 and the semiconductor switch tube Q1 are used for consuming the energy in the bus capacitor C1, and the discharging resistor R1 is also used as a voltage detection target to provide voltage data for controlling the semiconductor switch tube Q1, so as to control the semiconductor switch tube Q1 to work in the constant current area for constant current discharging.

[0082] Taking the semiconductor switch tube Q1 as a field effect tube as an example, Figure 6 As a derivative scheme of the active discharging circuit, according to Figure 6 It can be known that the discharging resistor R1 is connected between the positive terminal of the bus capacitor C1 and the drain of the field effect tube, because the field effect tube in the embodiment is still working in the constant current area when it is turned on, therefore, compared with the traditional discharging scheme which can only discharge through the discharging resistor R1, the energy in the bus capacitor C1 is consumed by the semiconductor switch tube Q1 and the discharging resistor R1 together in the embodiment, therefore, the number of the connected discharging resistors R1 does not need to consider the size of the instantaneous impact current, so that the number of the discharging resistors is greatly reduced, and the PCB area requirement and cost are reduced.

[0083] In addition, the connected discharging resistor R1 can not only consume the energy in the bus capacitor C1 together with the semiconductor capacitor, but also can indirectly detect, specifically, the voltage value on the discharging resistor R1 can be detected, and the voltage value, the switching state or the duty cycle of the semiconductor switch tube Q1 are dynamically controlled based on the detected voltage value, wherein the dynamic control mode can be directly controlled through a hardware circuit or controlled through software programming.

[0084] In addition, the application also provides a driving method. The driving method of the application is applied to the driving circuit in any one of the above embodiments.

[0085] Referring to Figure 7 , in the first embodiment of the active discharging method of the application, the active discharging method of the application comprises the following steps:

[0086] In step S10, a driving voltage is generated when a discharging signal is detected through the switch driving in the active discharging circuit, and the driving voltage is transmitted into the semiconductor switch tube in the active discharging circuit;

[0087] In step S20, the semiconductor switch tube works in the constant current area for constant current discharging based on the driving voltage, so as to consume the energy in the bus capacitor connected in parallel to the active discharging circuit.

[0088] When the motor controller enters the stop state or the fault state, in order to avoid damage to the vehicle caused by the residual voltage and the risk of electric shock to the human body, the active discharge circuit in the motor controller at this time will discharge the residual voltage, specifically: when the switch drive detects that the motor controller enters the stop state or the fault state, it is determined that the discharge signal is received, and based on the signal, it is determined that the active discharge operation exists at this time, and therefore a driving voltage is generated and sent to the semiconductor switch tube pair, based on the driving voltage, the semiconductor switch tube in the semiconductor switch tube is driven to enter the conduction state.

[0089] It should be noted that the driving voltage generated by the switch drive is controlled at the low gate voltage of the semiconductor switch tube, and the semiconductor switch tube is controlled to work in the constant current region based on the low gate voltage, so as to consume the energy in the bus capacitor, that is, the energy consumption of the bus capacitor is realized on the semiconductor switch tube to discharge the residual voltage in the motor controller, so as to avoid the risk of electric shock of the driver, and working in the constant current region can avoid the damage of the semiconductor switch tube caused by the increase of the instantaneous impact current.

[0090] In addition, when it is detected that the bus voltage is reduced below the set voltage, it is determined that the discharge operation is not needed at this time, and the switch drive stops inputting the driving voltage to the semiconductor switch tube, so that the semiconductor switch tube in the semiconductor switch tube enters the off state, wherein the reduction below the set voltage is that the residual voltage in the motor controller at this time is basically released.

[0091] Optionally, the step S20 of discharging the constant current by the semiconductor switch tube based on the driving voltage in the constant current region includes:

[0092] Step S201, by the semiconductor switch tube, entering a normal on state to work in the constant current region to discharge the constant current when the driving voltage is in a preset voltage range; or,

[0093] Step S202, by the semiconductor switch tube, based on the driving voltage entering the conduction state, discharging the constant current in the constant current region according to the set frequency and duty cycle, wherein the frequency and duty cycle include fixed mode and variable mode.

[0094] The normal on mode is, for example, when the driving voltage is from 0V to 5V, the semiconductor switch tube Q1 is normally on at this time, and when the driving voltage is from 5V to 0V, the semiconductor switch tube Q1 is normally off at this time, that is, the conduction and cutoff of the semiconductor switch tube Q1 are based on the fixed voltage value of the driving voltage.

[0095] The fixed frequency and duty cycle mode is that the semiconductor switching tube Q1 consumes the energy in the bus capacitor C1 at a fixed frequency and duty cycle, for example, the energy in the bus capacitor C1 can be consumed at a frequency of 100 Hz and a duty cycle of 1%, and the actual frequency and duty cycle are set based on the discharge requirement and the type of the semiconductor switching tube Q1.

[0096] The variable frequency mode is that the semiconductor switching tube Q1 varies within a certain frequency range, for example, within a frequency range of 10 Hz to 1000 Hz, to consume the energy in the bus capacitor C1.

[0097] The variable duty cycle mode is that the semiconductor switching tube Q1 varies within a certain duty cycle range, for example, within a duty cycle range of 20% to 50%, to consume the energy in the bus capacitor C1.

[0098] Optionally, after the step of consuming the energy in the bus capacitor connected in parallel with the active discharge circuit by the semiconductor switching tube working in the constant current region based on the driving voltage in step S20, the method further comprises:

[0099] Step S201: detecting the junction temperature of the semiconductor switching tube to obtain a first detection result, and adjusting the driving voltage based on the first detection result, so that the semiconductor switching tube works in the constant current region; or,

[0100] Step S202: detecting the current of the semiconductor switching tube to obtain a second detection result, and adjusting the driving voltage based on the second detection result, so that the semiconductor switching tube works in the constant current region; or,

[0101] Step S203: detecting the voltage across the bus capacitor to obtain a third detection result, and adjusting the driving voltage based on the third detection result, so that the semiconductor switching tube works in the constant current region; or,

[0102] Step S204: detecting the time-varying across the bus capacitor to obtain a fourth detection result, and adjusting the driving voltage based on the fourth detection result, so that the semiconductor switching tube works in the constant current region.

[0103] In the embodiment, the driving voltage output to the semiconductor switching tube in the switch driving can be fixed or dynamically varied during the output, so as to realize the power balance of the discharge power in the active discharge process.

[0104] When the driving voltage is dynamically changed during the output, the dynamic change of the driving voltage is realized based on a detection device. The detection device is connected between the second terminal of the semiconductor switch tube and the positive terminal of the bus capacitor or between the third terminal of the semiconductor switch tube and the negative terminal of the bus capacitor, and the semiconductor switch tube or the bus capacitor is detected. For example, the junction temperature of the semiconductor switch tube is detected by a temperature sensor, and the driving voltage is adjusted according to the detected junction temperature (i.e., a first detection result). When the junction temperature is detected to be increased, the driving voltage is lowered. When the junction temperature is detected to be decreased, the driving voltage is increased. For example, the current value of the semiconductor switch tube is detected by a current sensor, and the driving voltage is adjusted according to the detected current value (i.e., a second detection result). When the detected current value is increased, the driving voltage is increased. When the detected current value is decreased, the driving voltage is decreased. For example, the voltage between the bus capacitor is detected by a voltage sensor, and the driving voltage is adjusted according to the detected voltage value (i.e., a third detection result). When the detected voltage value is increased, the driving voltage is increased. When the detected voltage value is decreased, the driving voltage is decreased. For example, the time-varying of the bus voltage is detected by a time measurement chip, and the driving voltage is dynamically changed based on the change of the bus voltage with time, so as to realize the power balance of the discharge power in the active discharge process.

[0105] Optionally, the step of adjusting the driving voltage in step S20 comprises:

[0106] adjusting the driving voltage based on the adjustable voltage source; or,

[0107] adjusting the driving voltage based on the active filter; or,

[0108] adjusting the driving voltage based on the passive filter; or,

[0109] adjusting the driving voltage based on the analog isolator.

[0110] In the embodiment, the dynamic change of the driving voltage can be realized by adding an adjustable voltage source, an active filter, a passive filter or an analog isolator in the switch driving.

[0111] The adjustable voltage source is a power supply that realizes wide-range adjustable output voltage (generally 0V-continuous regulation of rated value) on the basis of the switch power supply of the switch driving. The active filter is a filter composed of RC elements and an operational amplifier, which changes the output driving voltage by using the principle that the reactance of the passive element changes with frequency. The passive filter is a filter composed of passive elements, which changes the output driving voltage by using the principle that the reactance of the passive element changes with frequency. The analog isolator is a hardware circuit matching that realizes the change of the driving voltage.

[0112] In the embodiment, the semiconductor switch tube is controlled in the constant current area by the driving voltage of the switch driving output, the situation of the instantaneous impact voltage increasing is avoided, and based on the effect, the semiconductor switch tube can consume the residual voltage, i.e., the energy in the bus capacitor, only by the semiconductor switch tube without the discharge resistor, the safety and stability of the active discharge circuit are improved, the discharge resistor is reduced, and the discharge cost is reduced.

[0113] In addition, the embodiment of the application further provides a motor controller, the motor controller comprising the active discharge circuit, the bus capacitor and the three-phase inverter module, wherein the bus capacitor is connected with the active discharge circuit, and the active discharge circuit is connected with the three-phase inverter module.

[0114] In addition, the application further provides a vehicle comprising a battery and the motor controller, wherein the motor controller is connected with the battery.

[0115] It should be noted that in this document, the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusions, so that a process, method, article or system including a series of elements not only includes those elements, but also includes other elements not explicitly listed, or further includes elements inherent to such a process, method, article or system. Without more limitations, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or system including the element.

[0116] The above-mentioned serial numbers of the embodiments of the application are only for description, and do not represent the advantages and disadvantages of the embodiments.

[0117] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be realized by means of software and necessary general hardware platform, of course, they can also be realized by hardware, but in many cases, the former is a better embodiment. Based on such understanding, the technical solutions of the application can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) and includes a plurality of instructions for making a terminal device (which can be a mobile phone, computer, server, air conditioner or network device) execute the method of each embodiment of the application.

[0118] The above merely describes the preferred embodiments of the present application, and is not intended to limit the patent scope of the present application, and any equivalent structure or equivalent process conversion, or direct or indirect application in other related technical fields, which are made by using the content of the present application specification and drawings, are also included in the patent protection scope of the present application.

Claims

1. An active discharge circuit, characterized by, The active discharge circuit is connected in parallel with a bus capacitor, and comprises a semiconductor switch tube and a switch driver; The first end of the semiconductor switch tube is connected with the switch driver, and the switch driver is configured to generate a driving voltage to control the semiconductor switch tube to work in a constant current region to discharge; The second end of the semiconductor switch tube is connected with the positive terminal of the bus capacitor, and the third end of the semiconductor switch tube is connected with the negative terminal of the bus capacitor, and the semiconductor switch tube is configured to work in the constant current region to discharge to consume the energy in the bus capacitor; wherein, when the driving voltage is in a preset voltage range, the semiconductor switch tube is controlled to enter a normal open state to work in the constant current region to discharge; or, the semiconductor switch tube is controlled to work in the constant current region to discharge according to a set frequency and duty cycle, wherein the frequency and duty cycle include a fixed mode and a variable mode; after the switch driver generates the driving voltage to control the semiconductor switch tube to work in the constant current region to discharge, a detection device integrated in the connection node of the semiconductor switch tube and the bus capacitor detects the junction temperature or current of the semiconductor switch tube, or detects the voltage or time-varying across the bus capacitor to obtain a detection result, and adjusts the driving voltage based on the detection result, so that the semiconductor switch tube works in the constant current region.

2. The active discharge circuit of claim 1, wherein, The semiconductor switch tube comprises a field effect tube, the gate of the field effect tube is connected with the switch driver as the first end of the semiconductor switch tube, the drain of the field effect tube is connected with the positive terminal of the bus capacitor as the second end of the semiconductor switch tube, and the source of the field effect tube is connected with the negative terminal of the bus capacitor as the third end of the semiconductor switch tube.

3. The active discharge circuit of claim 1, wherein, The semiconductor switch tube comprises an insulated gate bipolar transistor, the base of the insulated gate bipolar transistor is connected with the switch driver as the first end of the semiconductor switch tube, the collector of the insulated gate bipolar transistor is connected with the positive terminal of the bus capacitor as the second end of the semiconductor switch tube, and the emitter of the insulated gate bipolar transistor is connected with the negative terminal of the bus capacitor as the third end of the semiconductor switch tube.

4. The active discharge circuit of claim 1, wherein, The active discharge circuit further comprises a discharge resistor; The discharge resistor is connected between the positive terminal of the bus capacitor and the second end of the semiconductor switch tube, and the discharge resistor and the semiconductor switch tube are configured to consume the energy in the bus capacitor, and the discharge resistor is further configured to provide voltage data for controlling the semiconductor switch tube to work in the constant current region to discharge as a voltage detection target.

5. A method of active discharge, characterized by, The active discharge method is applied to the active discharge circuit according to any one of claims 1 to 4, and the active discharge method comprises the following steps: when the switch driver in the active discharge circuit detects a discharge signal, the switch driver generates a driving voltage and transmits the driving voltage to a semiconductor switch tube in the active discharge circuit; discharging by the semiconductor switch based on the driving voltage working in the constant current region to consume the energy in the bus capacitor connected in parallel with the active discharge circuit; detecting the junction temperature or current of the semiconductor switch, or detecting the voltage or time variation across the bus capacitor to obtain a detection result, and adjusting the driving voltage based on the detection result for the semiconductor switch working in the constant current region.

6. The method of actively discharging according to claim 5, wherein, The step of discharging by the semiconductor switch based on the driving voltage working in the constant current region includes: discharging by the semiconductor switch working in the constant current region in a normal on state when the driving voltage is in a preset voltage range; or, discharging by the semiconductor switch working in the constant current region in a conducting state based on the driving voltage at a set frequency and duty cycle, wherein the frequency and duty cycle include a fixed mode and a variable mode.

7. The method of actively discharging according to claim 5, wherein, The step of detecting the junction temperature or current of the semiconductor switch, or detecting the voltage or time variation across the bus capacitor to obtain a detection result, and adjusting the driving voltage based on the detection result for the semiconductor switch working in the constant current region includes: detecting the junction temperature of the semiconductor switch to obtain a first detection result, and adjusting the driving voltage based on the first detection result for the semiconductor switch working in the constant current region; or, detecting the current of the semiconductor switch to obtain a second detection result, and adjusting the driving voltage based on the second detection result for the semiconductor switch working in the constant current region; or, detecting the voltage across the bus capacitor to obtain a third detection result, and adjusting the driving voltage based on the third detection result for the semiconductor switch working in the constant current region; or, detecting the time variation across the bus capacitor to obtain a fourth detection result, and adjusting the driving voltage based on the fourth detection result for the semiconductor switch working in the constant current region.

8. The method of active discharge of claim 7, wherein, The switch drive includes an adjustable voltage source, an active filter, a passive filter, or an analog isolator, and the step of adjusting the driving voltage includes: adjusting the driving voltage based on the adjustable voltage source; or, adjusting the driving voltage based on the active filter; or, adjusting the driving voltage based on the passive filter; or, adjusting the driving voltage based on the analog isolator.

9. An electric machine controller characterized by The motor controller includes the active discharge circuit according to any one of claims 1 to 4, a bus capacitor, and a three-phase inverter module, wherein the bus capacitor is connected with the active discharge circuit, and the active discharge circuit is connected with the three-phase inverter module.

10. A vehicle characterized by comprising: The motor controller according to claim 9 and a battery are included, and the motor controller is connected with the battery. The motor controller according to claim 9 and a battery are included, and the motor controller is connected with the battery.

Images