Motor driving circuit, control method and controller

Abstract

The invention relates to the technical field of motor control, and discloses a motor drive circuit, a control method and a controller, the circuit comprises a power output module, a three-phase drive axle and a control module, the three-phase drive axle comprises three drive arms with the same structure, each drive arm comprises a first power switch, a second power switch and a power switch group, three different potentials are provided for three-phase current of the motor through the power output module and the three-phase drive axle, and the control module selects a three-level drive mode or a two-level drive mode to drive the motor to operate by controlling on-off states of the first power switch, the second power switch and the power switch group. Therefore, the most suitable driving mode is selected under different working conditions, the efficient operation interval of the motor can be effectively expanded, and the working efficiency of the motor is improved.

Description

TECHNICAL FIELD

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

[0002] In the field of electric vehicle technology, the electric drive control system of the vehicle directly affects the efficiency and safety of the electric vehicle. At present, the mainstream electric drive system includes a three-level drive system and a two-level drive system. Compared with the two-level drive system, the three-level drive system can improve the efficiency, reduce the voltage output harmonic content and optimize the electromagnetic interference performance within a certain range. Therefore, the three-level drive and the two-level drive are usually selected according to the requirements and performance indicators of a specific system. If the system requires higher output waveform quality, better power transmission efficiency and more stable performance, the three-level drive mode is generally selected. For some relatively simple low-power applications, the two-level drive mode is usually selected.

[0003] However, the related technology ignores that in special working conditions such as low vehicle speed, high torque working condition or high speed, high torque heavy load working condition, the two-level drive mode has fewer switching devices, lower control delay and lower loss, and has higher efficiency than the three-level working mode. Therefore, a single three-level or two-level drive mode cannot maximize the high efficiency range interval. In order to expand the high efficiency interval of the inverter, it is necessary to flexibly switch between the three-level and two-level modes. SUMMARY

[0004] Therefore, the present application provides a motor drive circuit, a control method and a controller to solve or partially solve the technical problem that the existing motor drive uses a single three-level or two-level drive to cause low motor efficiency.

[0005] In a first aspect, the present application provides a motor drive circuit applied to a vehicle drive system, comprising: A power supply output module comprising a first potential output end, a second potential output end and a third potential output end for providing a first potential, a second potential and a third potential respectively, the voltages of the first potential, the second potential and the third potential decreasing in turn; A three-phase drive bridge comprising three drive arms, each drive arm comprising a first power switch, a second power switch and a power switch group, the first connection end of the first power switch being connected to the first potential output end, the first connection end of the power switch group being connected to the second potential output end, the first connection end of the second power switch being connected to the third potential output end, the second connection end of the first power switch being connected to the second connection end of the power switch group, the second connection end of the second power switch and the corresponding phase current input end of the motor respectively; The control module is connected with the control end of the first power switch, the control end of the second power switch and the control end of the power switch group respectively, and is used for switching to a three-level driving mode or a two-level driving mode according to the acquired real-time working condition of the motor to drive the motor to run, wherein in the three-level driving mode, the control module controls the on-off state of the first power switch, the second power switch and the power switch group to drive the motor to run, and in the two-level driving mode, the control module controls the power switch group to be in an off state, and controls the on-off state of the first power switch and the second power switch to drive the motor to run.

[0006] The motor driving circuit of the embodiment of the application provides three different potentials for three-phase current of the motor through the power supply output module and the three-phase driving bridge, the control module controls the on-off state of the first power switch, the second power switch and the power switch group, and selects the three-level driving mode or the two-level driving mode to drive the motor to run, so that the most suitable driving mode is selected under different working conditions, the high-efficiency running interval of the motor can be effectively expanded, and the working efficiency of the motor is improved.

[0007] Optionally, the power supply output module comprises a power supply, a first capacitor and a second capacitor, the first end of the first capacitor is connected with the positive pole of the power supply, the second end of the first capacitor is connected with the first end of the second capacitor, and the second end of the second capacitor is connected with the negative pole of the power supply, wherein the positive pole of the power supply is the first potential output end, the second end of the first capacitor is the second potential output end, and the negative pole of the power supply is the third potential output end.

[0008] In this mode, the connection mode of the power supply, the first capacitor and the second capacitor is used to determine the three potential output ends, and the energy storage and voltage stabilization characteristics of the capacitors can provide stable first potential, second potential and third potential for the three-phase driving bridge.

[0009] Optionally, the control module comprises a controller and a driving circuit, wherein the controller is used for switching to the three-level driving mode or the two-level driving mode according to the acquired real-time working condition of the motor, and outputs the corresponding control signal of the three-level driving mode or the two-level driving mode to the driving circuit according to the regulation and control parameters of the motor; and the driving circuit is used for controlling the on-off state of the first power switch, the second power switch and the power switch group to drive the motor to run according to the control signal.

[0010] In this mode, the hierarchical control structure of the controller and the driving circuit is adopted, so that the control logic is more clear, the complex control algorithm can be easily realized, the accuracy and timeliness of the control are improved, and the running requirements of the motor under different working conditions can be better adapted.

[0011] Optionally, the power switch group comprises a third power switch and a fourth power switch, a first connection end and a second potential output end of the third power switch are connected, a second connection end of the third power switch and a first connection end of the fourth power switch are connected, a second connection end of the fourth power switch is connected with the second connection end of the first power switch tube, the second connection end of the second power switch and the corresponding phase current input end of the motor respectively, and a control end of the third power switch and a control end of the fourth power switch are connected with the control module respectively.

[0012] In this mode, the power switch group adopts two power switches, the third power switch and the fourth power switch share the current, avoiding single switch overload, and reducing on-state loss and switching loss.

[0013] In a second aspect, the application provides a motor driving control method, applied to the motor driving circuit of any one of the first aspect of the application, comprising: Obtaining the real-time working condition of the motor; Comparing the efficiency of the real-time working condition of the motor in the three-level driving mode and the two-level driving mode according to the working condition efficiency table of the motor, and switching to the level driving mode with high efficiency to drive the motor to run.

[0014] The motor driving control method of the embodiment of the application can select the most suitable driving mode under different working conditions, effectively expand the high-efficiency running interval of the motor, and improve the working efficiency of the motor by comparing the efficiency of the real-time working condition of the motor in the three-level driving mode and the two-level driving mode according to the working condition efficiency table of the motor, and switching to the level driving mode with high efficiency to drive the motor to run.

[0015] Optionally, comparing the efficiency of the real-time working condition of the motor in the three-level driving mode and the two-level driving mode according to the working condition efficiency table of the motor, and switching to the level driving mode with high efficiency to drive the motor to run comprises: determining the first efficiency of the real-time working condition of the motor in the three-level driving mode and the second efficiency of the real-time working condition of the motor in the two-level driving mode according to the motor efficiency table of the motor in the three-level driving mode and the motor efficiency table of the motor in the two-level driving mode, wherein the working condition efficiency table comprises the motor efficiency table of the motor in the three-level driving mode and the motor efficiency table of the motor in the two-level driving mode; comparing the size of the first efficiency and the second efficiency, if the first efficiency is greater than the second efficiency, switching to the three-level driving mode to drive the motor to run, if the first efficiency is less than or equal to the second efficiency, switching to the two-level driving mode to drive the motor to run.

[0016] In this mode, the motor real-time working condition is determined in the efficiency map of the motor in two driving modes, the efficiency of the motor real-time working condition in each mode is determined, and the driving mode is switched after comparison, which can accurately determine which driving mode is more efficient in the current working condition, thereby making the optimal switching selection, further improving the efficiency optimization effect of the motor driving system, and ensuring that the motor can achieve the best operating performance in different working conditions.

[0017] Optionally, the efficiency of the motor real-time working condition in the three-level driving mode and the two-level driving mode is compared according to a motor working condition efficiency map, and the motor is switched to the level driving mode with high efficiency to drive the motor to operate, comprising: determining the high efficiency interval of the motor real-time working condition according to a working condition point high efficiency interval map, wherein the working condition efficiency map comprises the working condition point high efficiency interval map; if the motor real-time working condition is located in the three-level high efficiency interval, the motor is switched to the three-level driving mode to drive the motor to operate, and if the motor real-time working condition is located in the two-level high efficiency interval, the motor is switched to the two-level driving mode to drive the motor to operate.

[0018] In this mode, by pre-dividing the high efficiency interval, the high efficiency interval of the motor real-time working condition is determined according to the working condition point high efficiency interval map, and the driving mode is switched accordingly, which simplifies the efficiency comparison process and can quickly determine the most suitable driving mode, thereby improving the real-time performance and response speed of the control.

[0019] Optionally, before determining the high efficiency interval of the motor real-time working condition according to the working condition point high efficiency interval map, comprising: obtaining the motor efficiency map of the motor in the three-level driving mode and the motor efficiency map of the motor in the two-level driving mode; determining the third efficiency of any motor working condition point in the three-level driving mode and the fourth efficiency of the motor working condition point in the two-level driving mode according to the motor efficiency map of the motor in the three-level driving mode and the motor efficiency map of the motor in the two-level driving mode; the motor working condition points with the third efficiency greater than the fourth efficiency are divided into the three-level high efficiency interval, and the motor working condition points with the third efficiency less than or equal to the fourth efficiency are divided into the two-level high efficiency interval, to obtain the working condition point high efficiency interval map.

[0020] In this mode, before determining the working condition point high efficiency interval map, the efficiency of any motor working condition point in each mode is determined by obtaining the motor efficiency map of the motor in two driving modes, and the high efficiency interval is divided according to the efficiency, thereby providing a reliable reference for driving mode switching.

[0021] Optionally, the motor real-time working condition comprises the motor real-time torque and the motor real-time speed.

[0022] In this mode, the motor real-time torque and the motor real-time speed are used to feedback the motor working condition in real time.

[0023] Thirdly, the present invention provides a controller, including a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the motor drive control method as described in any of the second aspects of the present invention. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is a schematic diagram of the motor drive circuit according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the motor drive circuit in the three-level drive mode according to an embodiment of the present invention; Figure 3 This is a schematic diagram of the motor drive circuit in two-level drive mode according to an embodiment of the present invention; Figure 4 This is a flowchart illustrating the operation of the motor drive circuit according to an embodiment of the present invention; Figure 5 This is a flowchart illustrating the motor drive control method according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the hardware structure of the controller according to an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] Currently, motor drives generally employ three-level and two-level drives. This application discovers that during the operation of electric vehicle drive motors, two-level and three-level drives offer different efficiency advantages under different loads. Inverter losses are mainly divided into switching losses and conduction losses. Under heavy load conditions (high output current), the proportion of conduction losses in the total losses increases significantly. In two-level drive, at any given time, only one device in each bridge arm bears the conduction loss, resulting in a shorter conduction path and relatively lower losses. Under high modulation ratios, the fundamental amplitude of the output voltage is close to the maximum value of the DC bus voltage, leading to lower harmonic content and reduced motor losses. Therefore, under high loads, the two-level mode is more efficient. Under light and medium load conditions, the total losses are mainly due to switching losses. Three-level modulation can reduce harmonics and lower motor losses. Furthermore, since the power switch transistors are only affected by voltage clamping, switching losses are low, and the advantage of low conduction losses can be fully utilized without additionally increasing losses. Therefore, under medium and low loads, the three-level drive mode is more efficient.

[0028] Based on this, embodiments of the present invention provide a motor drive circuit, control method, and controller, which are suitable for controlling motor drives, and particularly suitable for controlling drive motors of electric vehicles.

[0029] This invention provides a motor drive circuit, such as... Figure 1 As shown, the motor drive circuit includes: The power output module includes a first potential output terminal, a second potential output terminal, and a third potential output terminal, which are used to provide a first potential, a second potential, and a third potential, respectively, with the voltages of the first potential, the second potential, and the third potential decreasing sequentially.

[0030] Specifically, the power output module is the power source for the motor, providing it with operating power. The power output module provides three different potentials, where the first, second, and third potentials are high, neutral, and low, respectively.

[0031] The three-phase drive bridge includes three drive arms. Each drive arm includes a first power switch T1, a second power switch T4, and a power switch group. The first connection terminal of the first power switch T1 is connected to the first potential output terminal. The first connection terminal of the power switch group is connected to the second potential output terminal. The first connection terminal of the second power switch T4 is connected to the third potential output terminal. The second connection terminal of the first power switch T1 is connected to the second connection terminal of the power switch group, the second connection terminal of the second power switch T4, and the corresponding phase current input terminal of the motor.

[0032] Specifically, the power switch group includes at least one power switch. The first power switch T1, the second power switch T4, and all power switches in the power switch group include two connection terminals, namely a first connection terminal and a second connection terminal, and a control terminal. By inputting different voltage levels to the control terminal of the power switch, the conduction of the first and second connection terminals can be controlled. For example, when a high-level signal is input to the control terminal of the power switch, the first and second connection terminals of the power switch are connected; when a low-level signal is input to the control terminal of the power switch, the first and second connection terminals of the power switch are disconnected.

[0033] The first power switch T1, the second power switch T4, and the power switches in the power switch group can be SiC power devices, silicon metal-oxide-semiconductor field-effect transistors (Si MOSFETs), insulated gate bipolar transistors (IGBTs), or GaN power devices, etc.

[0034] The control module is connected to the control terminals of the first power switch T1, the second power switch T4, and the power switch group, respectively. It is used to switch between a three-level drive mode and a two-level drive mode to drive the motor based on the acquired real-time operating conditions of the motor. In the three-level drive mode, the control module drives the motor by controlling the on / off states of the first power switch T1, the second power switch T4, and the power switch group. In the two-level drive mode, the control module controls the power switch group to be in the off state and drives the motor by controlling the on / off states of the first power switch T1 and the second power switch T4.

[0035] Specifically, the three drive arms correspond to the U-phase current input, V-phase current input, and W-phase current input of the motor, respectively. The control module controls the on / off state of the first power switch T1, the second power switch T4, and the power switch group, as follows: Figure 2 As shown, when the power switch group is in operation, it can provide three levels to the motor: the U phase, V phase, and W phase can be connected to a neutral level, a low level, or a high level, achieving three-level drive; for example... Figure 3 As shown, when the power switch group is off, the three-phase drive bridge is equivalent to a two-level full-bridge drive circuit, that is, the U phase, V phase and W phase can be connected to a low level or a high level to achieve two-level drive.

[0036] Furthermore, the real-time operating conditions of the motor include the real-time torque and real-time speed of the motor, which are collected by the corresponding sensors and sent to the control module. The control module selects the more efficient drive mode to drive the motor based on the real-time operating conditions of the motor.

[0037] like Figure 4 As shown, the working principle of the control module switching to three-level drive mode or two-level drive mode is as follows: A coordinate system is established using the real-time torque and real-time speed of the motor as the vertical and horizontal axes, respectively. The motor is divided into several intervals according to its external characteristics. Points in each interval are selected as input points for efficiency testing. The motor is driven to the above efficiency testing points using both three-level and two-level drive modes. The bus output power and motor power are calculated based on the bus current and three-phase current, respectively, to obtain the efficiency value at each operating point. Based on the efficiency values ​​at each operating point, motor efficiency diagrams under three-level drive mode and two-level drive mode are generated.

[0038] During motor operation, the motor efficiency graph is invoked, and the motor efficiency under both three-level and two-level drive modes is compared using real-time motor operating conditions. Based on the comparison result, the system switches to the drive mode with the higher efficiency. For example, if the current operating mode is three-level drive mode, and the comparison result shows that the motor efficiency in three-level drive mode is less than or equal to that in two-level drive mode, then the current operating mode is switched to two-level drive mode. If the comparison result shows that the motor efficiency in three-level drive mode is greater than that in two-level drive mode, then the current operating mode remains in three-level drive mode.

[0039] The motor drive circuit of this invention provides three different potentials for the three-phase current of the motor through the power output module and the three-phase drive bridge. The control module selects the three-level drive mode or the two-level drive mode to drive the motor by controlling the on and off states of the first power switch T1, the second power switch T4 and the power switch group. In this way, the most suitable drive mode can be selected under different working conditions, which can effectively expand the high-efficiency operating range of the motor and improve the working efficiency of the motor.

[0040] In some embodiments, the power output module includes a power supply, a first capacitor C1, and a second capacitor C2. The first terminal of the first capacitor C1 is connected to the positive terminal of the power supply, the second terminal of the first capacitor C1 is connected to the first terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is connected to the negative terminal of the power supply. The positive terminal of the power supply is a first potential output terminal, the second terminal of the first capacitor C1 is a second potential output terminal, and the negative terminal of the power supply is a third potential output terminal.

[0041] Specifically, the power source can be an energy storage element such as a single cell, a battery pack, or an energy storage capacitor. In one example, the power source uses a high-voltage battery pack.

[0042] The first capacitor C1 and the second capacitor C2 are of the same type, and provide a neutral level for the three-level topology through the first capacitor C1 and the second capacitor C2.

[0043] In this embodiment, the connection of the power supply, the first capacitor C1, and the second capacitor C2 is used to determine the three potential output terminals. By utilizing the energy storage and voltage regulation characteristics of the capacitors, stable first, second, and third potentials can be provided for the three-phase drive bridge.

[0044] In some embodiments, the control module includes: a controller, configured to switch to a three-level drive mode or a two-level drive mode according to the acquired real-time operating conditions of the motor, and output the corresponding control signal in the three-level drive mode or the two-level drive mode to the drive circuit according to the motor's control parameters; and a drive circuit, configured to control the on / off states of the first power switch T1, the second power switch T4, and the power switch group according to the control signal to drive the motor to run.

[0045] Specifically, the controller can be a microcontroller unit (MCU) or a field programmable gate array (FPGA) or other control chips.

[0046] It should be understood that the motor's control parameters can be current, speed, or torque, etc., and these parameters are collected by corresponding sensors. In one example, the control parameter is phase current. When generating a control signal, the controller needs to collect the motor's phase current through a current acquisition device and adjust the control signal based on the collected phase current.

[0047] The drive circuit is controlled by the controller, which controls the on / off state of the first power switch T1, the second power switch T4, and the power switch group according to the control signal.

[0048] In this embodiment, a hierarchical control structure of controller and drive circuit is adopted, which makes the control logic clearer, facilitates the implementation of complex control algorithms, improves the accuracy and timeliness of control, and can better adapt to the operating requirements of motor under different working conditions.

[0049] In some embodiments, the power switch group includes a third power switch T2 and a fourth power switch T3. The first connection terminal and the second potential output terminal of the third power switch T2 are connected. The second connection terminal of the third power switch T2 and the first connection terminal of the fourth power switch T3 are connected. The second connection terminal of the fourth power switch T3 is connected to the second connection terminal of the first power switch T1, the second connection terminal of the second power switch T4, and the corresponding phase current input terminal of the motor, respectively. The control terminals of the third power switch T2 and the fourth power switch T3 are connected to the control module, respectively.

[0050] The third power switch T2 and the fourth power switch T3 can be SiC power devices, silicon-based metal-oxide-semiconductor field-effect transistors, insulated-gate bipolar transistors, and GaN power devices, etc.

[0051] The power switch group uses two power switches, the third power switch T2 and the fourth power switch T3, to share the current, avoid overload of a single switch, and reduce conduction loss and switching loss.

[0052] According to an embodiment of the present invention, a motor drive control method embodiment is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0053] This embodiment provides a motor drive control method, applied to the motor drive circuit as described in the above embodiments of the present invention, such as... Figure 5 As shown, the method includes: Step S101: Obtain the real-time operating status of the motor.

[0054] Real-time motor operating conditions include real-time motor torque and real-time motor speed, which are collected by corresponding sensors.

[0055] Step S102: Compare the efficiency of the motor in the three-level drive mode and the two-level drive mode according to the motor's operating efficiency chart, and switch to the higher-efficiency level drive mode to drive the motor.

[0056] Specifically, the motor operating efficiency chart shows the efficiency at various motor operating points, including the operating efficiency charts for three-level drive mode and two-level drive mode.

[0057] The operating efficiency diagram is obtained by calibration in both three-level and two-level drive modes. Once the operating efficiency diagram is calibrated, it can be queried based on the real-time motor operating conditions to obtain the corresponding efficiency values ​​for each of the two modes, and then the drive mode with the higher efficiency can be selected for operation.

[0058] The motor drive control method of this invention compares the efficiency of the motor in real-time operation under three-level drive mode and two-level drive mode according to the motor's operating efficiency chart, and switches to the higher-efficiency level drive mode to drive the motor. This method can select the most suitable drive mode under different operating conditions, effectively expand the high-efficiency operating range of the motor, and improve the motor's working efficiency.

[0059] This invention establishes a precise mapping relationship between operating conditions and efficiency, and constructs an intelligent mode switching decision mechanism. This mechanism can fully leverage the efficiency advantages of three-level technology in the low-to-medium speed range and the performance strengths of two-level technology in the high-speed range, thereby achieving optimal matching and continuous optimization of system efficiency across the entire operating range.

[0060] In some embodiments, step S102, comparing the efficiency of the motor in real-time operating conditions under three-level drive mode and two-level drive mode according to the motor's operating efficiency chart, and switching to the higher-efficiency level drive mode to drive the motor, includes: Step a1: Determine the first efficiency of the motor in the three-level drive mode and the second efficiency in the two-level drive mode based on the motor efficiency diagram of the motor in the three-level drive mode and the motor efficiency diagram of the two-level drive mode. The efficiency diagram includes the motor efficiency diagram of the three-level drive mode and the motor efficiency diagram of the two-level drive mode. Step a2: Compare the first efficiency and the second efficiency. If the first efficiency is greater than the second efficiency, switch to the three-level drive mode to drive the motor. If the first efficiency is less than or equal to the second efficiency, switch to the two-level drive mode to drive the motor.

[0061] Specifically, the operating condition efficiency chart is the motor efficiency chart, i.e., the motor efficiency Map, and its calibration process is as follows: A coordinate system is established using the real-time torque and real-time speed of the motor as the vertical and horizontal axes, respectively. The motor is divided into several intervals according to its external characteristics. Points in each interval are selected as input points for efficiency testing. The motor is driven to the above efficiency testing points using both three-level and two-level drive modes. The bus output power and motor power are calculated based on the bus current and three-phase current, respectively, to obtain the efficiency value at each operating point. Based on the efficiency values ​​at each operating point, motor efficiency diagrams under three-level drive mode and two-level drive mode are generated.

[0062] During motor operation, the motor efficiency graph is invoked, and the motor efficiency under both three-level and two-level drive modes is compared using real-time motor operating conditions. Based on the comparison result, the system switches to the drive mode with the higher efficiency. For example, if the current operating mode is three-level drive mode, and the comparison result shows that the motor efficiency in three-level drive mode is less than or equal to that in two-level drive mode, then the current operating mode is switched to two-level drive mode. If the comparison result shows that the motor efficiency in three-level drive mode is greater than that in two-level drive mode, then the current operating mode remains in three-level drive mode.

[0063] This invention determines the efficiency of the motor under real-time operating conditions in each mode by comparing the motor efficiency graphs under two driving modes, and then switches the driving mode after comparison. This can accurately determine which driving mode is more efficient under the current operating conditions, thereby making the optimal switching choice, further improving the efficiency optimization effect of the motor drive system, and ensuring that the motor can achieve the best operating performance under different operating conditions.

[0064] In some embodiments, step S102, comparing the efficiency of the motor in real-time operating conditions under three-level drive mode and two-level drive mode according to the motor's operating efficiency chart, and switching to the higher-efficiency level drive mode to drive the motor, includes: Step b1: Determine the high-efficiency interval of the motor's real-time operating condition based on the high-efficiency interval diagram of the operating point. The operating efficiency chart includes the high-efficiency interval diagram of the operating point. Step b2: If the real-time operating condition of the motor is in the three-level high-efficiency range, switch to the three-level drive mode to drive the motor. If the real-time operating condition of the motor is in the two-level high-efficiency range, switch to the two-level drive mode to drive the motor.

[0065] Specifically, the real-time operating conditions of the motor include the real-time torque and the real-time speed of the motor. The high-efficiency interval diagram of the operating point uses the real-time torque and the real-time speed of the motor as the vertical axis and the horizontal axis, respectively, and marks the range of the three-level high-efficiency interval and the two-level high-efficiency interval.

[0066] Furthermore, the calibration steps for the high-efficiency interval diagram of the operating point include: Obtain the motor efficiency graphs in three-level drive mode and two-level drive mode; Based on the motor efficiency diagrams in the three-level drive mode and the two-level drive mode, determine the third efficiency of any motor operating point in the three-level drive mode and the fourth efficiency in the two-level drive mode. The operating points of motors with a third efficiency greater than the fourth efficiency are divided into the three-level high-efficiency interval, and the operating points of motors with a third efficiency less than or equal to the fourth efficiency are divided into the two-level high-efficiency interval, thus obtaining the high-efficiency interval diagram of the operating points.

[0067] This invention simplifies the efficiency comparison process by pre-dividing high-efficiency intervals and determining the high-efficiency interval of the motor's real-time operating condition based on the high-efficiency interval diagram of the operating point, and switches the drive mode accordingly. This enables the most suitable drive mode to be determined quickly, improving the real-time performance and response speed of the control.

[0068] This invention also provides a controller, such as... Figure 6As shown, the computer device includes one or more processors 10, memory 20, and interfaces for connecting the components, including high-speed interfaces and low-speed interfaces. The components communicate with each other via different buses and can be mounted on a common motherboard or otherwise installed as needed. The processors can process instructions executed within the controllers, including instructions stored in or on memory to display graphical information of a GUI on external input / output devices (such as display devices coupled to the interfaces). In some alternative implementations, multiple processors and / or multiple buses can be used with multiple memories and multiple memory modules, if desired. Similarly, multiple controllers can be connected, each providing some of the necessary operations (e.g., as a server array, a group of blade servers, or a multiprocessor system). Figure 6 Take a processor 10 as an example.

[0069] Processor 10 may be a central processing unit, a network processor, or a combination thereof. Processor 10 may further include a hardware chip. The hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The programmable logic device may be a complex programmable logic device (CAMP), a field-programmable gate array (FPGA), a general-purpose array logic (GPA), or any combination thereof.

[0070] The memory 20 stores instructions executable by at least one processor 10 to cause at least one processor 10 to perform the method shown in the above embodiments.

[0071] The memory 20 may include a program storage area and a data storage area. The program storage area may store the operating system and applications required for at least one function; the data storage area may store data created based on the use of the computer device. Furthermore, the memory 20 may include high-speed random access memory and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some alternative embodiments, the memory 20 may optionally include memory remotely located relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0072] The memory 20 may include volatile memory, such as random access memory; the memory may also include non-volatile memory, such as flash memory, hard disk or solid-state drive; the memory 20 may also include a combination of the above types of memory.

[0073] The controller also includes a communication interface 30 for the computer device to communicate with other devices or communication networks.

[0074] Although embodiments of the invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the invention, and all such modifications and variations fall within the scope of protection.

Claims

1. A motor drive circuit, applied to a vehicle drive system, characterized in that, include: The power output module includes a first potential output terminal, a second potential output terminal, and a third potential output terminal, respectively, for providing a first potential, a second potential, and a third potential, wherein the voltages of the first potential, the second potential, and the third potential decrease sequentially. The three-phase drive bridge includes three drive arms. Each drive arm includes a first power switch, a second power switch, and a power switch group. The first connection terminal of the first power switch is connected to the first potential output terminal. The first connection terminal of the power switch group is connected to the second potential output terminal. The first connection terminal of the second power switch is connected to the third potential output terminal. The second connection terminal of the first power switch is connected to the second connection terminal of the power switch group, the second connection terminal of the second power switch, and the corresponding phase current input terminal of the motor, respectively. The control module is connected to the control terminals of the first power switch, the second power switch, and the power switch group, respectively. It is used to switch between a three-level drive mode and a two-level drive mode to drive the motor based on the acquired real-time operating conditions of the motor. In the three-level drive mode, the control module drives the motor by controlling the on / off states of the first power switch, the second power switch, and the power switch group. In the two-level drive mode, the control module controls the power switch group to be in the off state and drives the motor by controlling the on / off states of the first power switch and the second power switch.

2. The motor drive circuit according to claim 1, characterized in that, The power output module includes a power supply, a first capacitor, and a second capacitor. The first terminal of the first capacitor is connected to the positive terminal of the power supply, the second terminal of the first capacitor is connected to the first terminal of the second capacitor, and the second terminal of the second capacitor is connected to the negative terminal of the power supply. The positive terminal of the power supply is the first potential output terminal, the second terminal of the first capacitor is the second potential output terminal, and the negative terminal of the power supply is the third potential output terminal.

3. The motor drive circuit according to claim 1, characterized in that, The control module includes: The controller is used to switch to a three-level drive mode or a two-level drive mode according to the acquired real-time operating conditions of the motor, and to output the corresponding control signal in the three-level drive mode or the two-level drive mode to the drive circuit according to the motor's control parameters. The drive circuit is used to control the on / off state of the first power switch, the second power switch, and the power switch group according to the control signal to drive the motor to run.

4. The motor drive circuit according to claim 1, characterized in that, The power switch group includes a third power switch and a fourth power switch. The first connection terminal of the third power switch is connected to the second potential output terminal. The second connection terminal of the third power switch is connected to the first connection terminal of the fourth power switch. The second connection terminal of the fourth power switch is connected to the second connection terminal of the first power switch, the second connection terminal of the second power switch, and the corresponding phase current input terminal of the motor. The control terminals of the third power switch and the fourth power switch are respectively connected to the control module.

5. A motor drive control method, characterized in that, Applied to the motor drive circuit as described in any one of claims 1 to 4, comprising: Obtain real-time motor operating status; Based on the motor's operating efficiency chart, compare the efficiency of the motor in real-time operating conditions under three-level drive mode and two-level drive mode, and switch to the higher-efficiency level drive mode to drive the motor.

6. The motor drive control method according to claim 5, characterized in that, Based on the motor's operating efficiency chart, compare the motor's real-time operating efficiency in three-level drive mode and two-level drive mode, and switch to the more efficient level drive mode to drive the motor, including: The first efficiency of the motor in the three-level drive mode and the second efficiency in the two-level drive mode are determined based on the motor efficiency diagram in the three-level drive mode and the motor efficiency diagram in the two-level drive mode. The efficiency diagram includes the motor efficiency diagram in the three-level drive mode and the motor efficiency diagram in the two-level drive mode. Compare the first efficiency and the second efficiency. If the first efficiency is greater than the second efficiency, switch to a three-level drive mode to drive the motor. If the first efficiency is less than or equal to the second efficiency, switch to a two-level drive mode to drive the motor.

7. The motor drive control method according to claim 5, characterized in that, Based on the motor's operating efficiency chart, compare the motor's real-time operating efficiency in three-level drive mode and two-level drive mode, and switch to the more efficient level drive mode to drive the motor, including: The high-efficiency interval of the motor's real-time operating condition is determined based on the high-efficiency interval diagram of the operating point, wherein the operating condition efficiency chart includes the high-efficiency interval diagram of the operating point. If the real-time operating condition of the motor is in the three-level high-efficiency range, then switch to the three-level drive mode to drive the motor. If the real-time operating condition of the motor is in the two-level high-efficiency range, then switch to the two-level drive mode to drive the motor.

8. The motor drive control method according to claim 7, characterized in that, Before determining the high-efficiency range of the motor's real-time operating condition based on the high-efficiency range diagram, the following steps are included: Obtain the motor efficiency graphs in three-level drive mode and two-level drive mode; Based on the motor efficiency diagrams in the three-level drive mode and the two-level drive mode, determine the third efficiency of any motor operating point in the three-level drive mode and the fourth efficiency in the two-level drive mode. The motor operating points where the third efficiency is greater than the fourth efficiency are divided into three-level high-efficiency intervals, and the motor operating points where the third efficiency is less than or equal to the fourth efficiency are divided into two-level high-efficiency intervals, thus obtaining an operating point high-efficiency interval diagram.

9. The motor drive control method according to claim 5, characterized in that, The real-time operating conditions of the motor include the real-time torque and the real-time speed of the motor.

10. A controller, characterized in that, include: A memory and a processor are communicatively connected, the memory stores computer instructions, and the processor executes the computer instructions to perform the motor drive control method of any one of claims 6 to 9.

Images