Series-parallel switched motor system and method

Abstract

This invention discloses a series-parallel switching motor system and method. The system includes a power battery, a synchronous motor, an asynchronous motor, a first switch, a second switch, a third switch, a first capacitor, a second capacitor, a first inverter circuit, a second inverter circuit, and a controller. In some driving scenarios, by connecting the single-phase windings of the synchronous motor and the asynchronous motor in series, the voltage at the terminal of the synchronous motor can be regulated, reducing the losses of the electronic control switch and improving the motor efficiency in the low-speed range. Furthermore, in the event of a short circuit or high-voltage runaway in the synchronous motor, the target switch of the asynchronous motor can be quickly shut off, achieving safe isolation and further enhancing the safety of the motor system.

Description

Technical Field

[0001] This invention relates to the field of new energy vehicle technology, and in particular to a series-parallel switching motor system and method. Background Technology

[0002] Electric vehicles are characterized by low noise, zero pollution, zero emissions, and high energy conversion efficiency, making them an important way to solve prominent problems related to automobiles in urbanization.

[0003] For dual-motor electric vehicles, the efficiency of the motor system directly affects the vehicle's energy consumption, and thus its range. For example, in some common driving conditions (such as urban driving conditions and highway cruising conditions), the high-efficiency range of the motor system deviates from the common driving conditions, resulting in reduced efficiency. Summary of the Invention

[0004] In view of the above problems, the present invention is proposed to provide a series-parallel switching motor system and method, which improves operating efficiency by adjusting the motor voltage through series connection of single-phase windings of synchronous motor and asynchronous motor.

[0005] According to a first aspect of the present invention, a series-parallel switching motor system is provided, comprising:

[0006] Power battery, synchronous motor, asynchronous motor, first switch, second switch, third switch, first capacitor, second capacitor, first inverter circuit, second inverter circuit, and controller;

[0007] In this configuration, the input terminal of the first inverter circuit is connected to the output terminals of the first switch and the second switch, respectively; the first output terminal of the first inverter circuit is connected to the input terminal of the synchronous motor; the input terminal of the second inverter circuit is connected to the output terminal of the third switch, and the first output terminal of the second inverter circuit is connected to the input terminal of the asynchronous motor; the positive terminal of the power battery is connected to the input terminal of the third switch, and the negative terminal of the power battery is connected to the second output terminals of the first inverter circuit and the second output terminal of the second inverter circuit, respectively; the output terminal of the asynchronous motor is connected to the input terminal of the second switch; the output terminal of the third switch is connected to the input terminal of the first switch; the input terminal of the first capacitor is connected to the input terminal of the first inverter circuit, and the output terminal of the first capacitor is connected to the second output terminal of the first inverter circuit; the input terminal of the second capacitor is connected to the input terminal of the second inverter circuit, and the output terminal of the second capacitor is connected to the second output terminal of the second inverter circuit.

[0008] The controller is used to control a set of switching transistors in the second inverter circuit as target switching transistors when the second switch and the third switch are closed and the first switch is open, so that the current of the power battery flows through one of the target switching transistors, then through a target winding of the asynchronous motor, and into the input terminal of the first inverter circuit.

[0009] Optionally, the system further includes a fourth switch, the input of which is connected to the positive terminal of the power battery, and the output of which is connected to the output of the asynchronous motor.

[0010] The controller is used to select a set of switches in the second inverter circuit as target switches when the first switch and the fourth switch are closed and the second switch and the third switch are open, so that the current of the power battery flows through a target winding of the asynchronous motor and then flows into the input terminal of the first inverter circuit after passing through one of the target switches.

[0011] Optionally, the system may further include a fifth switch, a third capacitor, and an inductor;

[0012] The input terminal of the fifth switch is connected to the negative terminal of the charging pile, and the output terminal of the fifth switch is connected to the negative terminal of the power battery; the input terminal of the inductor is connected to the positive terminal of the charging pile, and the output terminal of the inductor is connected to the output terminal of the asynchronous motor; the input terminal of the third capacitor is connected to the input terminal of the inductor, and the output terminal of the third capacitor is connected to the output terminal of the fifth switch.

[0013] The controller is used to charge the power battery by raising the terminal voltage of the charging pile when the fifth switch and the third switch are closed and the first switch and the second switch are open.

[0014] Optionally, after the second switch and the third switch are closed and the first switch is open, the other phase winding of the asynchronous motor is replaced with the target winding after a preset time interval.

[0015] Optionally, the system may also include a current sensor disposed before each phase winding of the asynchronous motor.

[0016] According to a second aspect of the present invention, a motor control method for series-parallel switching is provided for a aforementioned series-parallel switching motor system, the method comprising:

[0017] Obtain the current vehicle usage status;

[0018] If the vehicle usage condition is a parallel vehicle usage condition, then control the first switch and the third switch to close, and control the second switch to open, so that the synchronous motor and the asynchronous motor are connected in parallel;

[0019] If the vehicle operating condition is a series step-down condition, then the third switch and the second switch are closed, the first switch is opened, and a set of target switching transistors in the second inverter circuit are turned on and off, so that the synchronous motor and a target winding of the asynchronous motor are connected in series, thereby reducing the terminal voltage of the synchronous motor.

[0020] Optionally, the method further includes:

[0021] If the vehicle operating condition is a series boost operating condition, then the second switch and the fourth switch are closed, the first switch and the third switch are opened, and a set of target switching transistors in the second inverter circuit are turned on and off, so that the synchronous motor and a target winding of the asynchronous motor are connected in series, thereby increasing the terminal voltage of the synchronous motor.

[0022] Optionally, the method further includes:

[0023] If the bus current detected by the current sensor is greater than the current threshold, then a set of target switches in the second inverter circuit will be turned off.

[0024] According to a third aspect of the present invention, a controller is provided, characterized in that the controller includes: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the aforementioned series-parallel switching motor control method.

[0025] According to a fourth aspect of the present invention, a vehicle is provided, the vehicle comprising a vehicle body, a series-parallel switching motor system installed in the vehicle body, and a controller installed in the vehicle body, wherein the controller executes the aforementioned series-parallel switching motor control method.

[0026] The above-described one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0027] This specification provides an embodiment of a series-parallel switching motor system and method. The system includes a power battery, a synchronous motor, an asynchronous motor, a first switch, a second switch, a third switch, a first capacitor, a second capacitor, a first inverter circuit, a second inverter circuit, and a controller. The input terminal of the first inverter circuit is connected to the output terminals of the first switch and the second switch, respectively. The first output terminal of the first inverter circuit is connected to the input terminal of the synchronous motor. The input terminal of the second inverter circuit is connected to the output terminal of the third switch, and the first output terminal of the second inverter circuit is connected to the input terminal of the asynchronous motor. The positive terminal of the power battery is connected to the input terminal of the third switch, and the negative terminal of the power battery is connected to the second output terminals of the first inverter circuit and the second output terminal of the second inverter circuit, respectively. The output terminal of the asynchronous motor is connected to the input terminal of the second switch; the output terminal of the third switch is connected to the input terminal of the first switch; the input terminal of the first capacitor is connected to the input terminal of the first inverter circuit, and the output terminal of the first capacitor is connected to the second output terminal of the first inverter circuit; the input terminal of the second capacitor is connected to the input terminal of the second inverter circuit, and the output terminal of the second capacitor is connected to the second output terminal of the second inverter circuit; the controller is used to control a set of switching transistors in the second inverter circuit as target switching transistors when the second switch and the third switch are closed and the first switch is open, so that the current of the power battery flows through one of the target switching transistors, then through a target winding of the asynchronous motor, and into the input terminal of the first inverter circuit. By connecting the single-phase windings of the synchronous motor and the asynchronous motor in series, the voltage of the synchronous motor terminal is regulated, reducing the loss of the electronic control switch and improving the efficiency of the motor in the low-speed range. Furthermore, in the event of a short circuit or high-voltage runaway in the synchronous motor, the target switching transistor of the asynchronous motor can be quickly controlled to turn off, achieving safe isolation and further improving the safety of the motor system.

[0028] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0029] Various other advantages and benefits will become apparent to those skilled in the art upon reading the following detailed description of preferred embodiments. The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0030] Figure 1 A schematic diagram of a series-parallel switching motor control system according to an embodiment of the present invention is shown.

[0031] Figure 2 A flowchart of a motor control method for series-parallel switching according to an embodiment of the present invention is shown. Detailed Implementation

[0032] 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, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0034] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0035] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0036] Combination Figure 1 As shown, an embodiment of the present invention provides a series-parallel switching motor system, including:

[0037] The system includes a power battery, a synchronous motor, an asynchronous motor, a first switch K1, a second switch K2, a third switch K3, a first capacitor C1, a second capacitor C2, a first inverter circuit (composed of switching transistors Q1, Q2, Q3, Q4, Q5, and Q6), a second inverter circuit (composed of switching transistors Q7, Q8, Q9, QA, QB, and QC), and a controller.

[0038] In this configuration, the input terminal of the first inverter circuit is connected to the output terminal of the first switch K1 and the output terminal of the second switch K2, respectively; the first output terminal of the first inverter circuit is connected to the input terminal of the synchronous motor; the input terminal of the second inverter circuit is connected to the output terminal of the third switch K3, and the first output terminal of the second inverter circuit is connected to the input terminal of the asynchronous motor; the positive terminal of the power battery is connected to the input terminal of the third switch K3, and the negative terminal of the power battery is connected to the second output terminal of the first inverter circuit and the second output terminal of the second inverter circuit, respectively; the output terminal of the asynchronous motor is connected to the input terminal of the second switch K2; the output terminal of the third switch K3 is connected to the input terminal of the first switch K1; the input terminal of the first capacitor C1 is connected to the input terminal of the first inverter circuit, and the output terminal of the first capacitor C1 is connected to the second output terminal of the first inverter circuit; the input terminal of the second capacitor C2 is connected to the input terminal of the second inverter circuit, and the output terminal of the second capacitor C2 is connected to the second output terminal of the second inverter circuit.

[0039] The controller is used to control the synchronous motor and the asynchronous motor to be connected in parallel when the first switch K1 and the third switch K3 are closed and the second switch K2 is open.

[0040] The controller is used to control a set of switches in the second inverter circuit as target switches when the second switch K2 and the third switch K3 are closed and the first switch K1 is open. This allows the current from the power battery to flow through one of the target switches, then through a target winding of the asynchronous motor, and into the input terminal of the first inverter circuit. At this time, one winding of the synchronous motor and the asynchronous motor are connected in series.

[0041] In this embodiment, the synchronous motor has three windings, namely Figure 1 The asynchronous motor has three windings: L1, L2, and L3. Figure 1 The windings are L4, L5, and L6. The switching transistors in the second inverter circuit are divided into three groups: Q7 and Q8, Q9 and QA, and QB and QC. These switching transistors are also called power transistors.

[0042] In this embodiment, the switching transistor is described using an insulated-gate bipolar transistor (IGBT) as an example.

[0043] In series operation, a set of switches in the second inverter circuit is used as target switches. By controlling the opening and closing of these two target switches, the series connection of one target winding of the synchronous motor and the asynchronous motor is achieved. The target winding corresponds to the target switch. If switches QB and QC are used as target switches, then winding L4 is the target winding; if switches Q9 and QA are used as target switches, then winding L5 is the target winding; if switches Q7 and Q8 are used as target switches, then winding L6 is the target winding.

[0044] In one embodiment, switching transistors QB and QC are used as target switching transistors, and winding L4 is used as the target winding. During series operation, switching transistors QB and QC are turned on, and the DC power from the power battery passes through the target switching transistor QB of the second inverter circuit, then through the connected target winding L4, and then enters the first inverter circuit. After being converted into AC power, it enters the three-phase windings of the synchronous motor.

[0045] In one embodiment, switching transistors Q9 and QA are used as target switching transistors, and winding L5 is used as the target winding. During series operation, switching transistors Q9 and QA are turned on, and the DC power from the power battery passes through the target switching transistor Q9 of the second inverter circuit, then through the connected target winding L5, and then enters the first inverter circuit. After being converted into AC power, it enters the three-phase winding of the synchronous motor.

[0046] In one embodiment, switching transistors Q7 and Q8 are used as target switching transistors, and winding L6 is used as the target winding. During series operation, switching transistors Q7 and Q8 are turned on, and the DC power from the power battery passes through the target switching transistor Q7 of the second inverter circuit, then through the connected target winding L6, and then enters the first inverter circuit. After being converted into AC power, it enters the three-phase winding of the synchronous motor.

[0047] This embodiment uses switch QB and switch QC as target switch transistors for illustration.

[0048] When a synchronous motor and an asynchronous motor have their single-phase windings connected in series, the terminal voltage of the synchronous motor can be reduced by controlling the target switch QB to open and close at a certain frequency. For low-speed driving conditions on urban roads, reducing the terminal voltage of the synchronous motor can improve the motor efficiency in the low-speed range. This is because the high-efficiency range of the motor is biased towards lower voltages in the low-speed range. At the same time, reducing the voltage can also reduce the losses of the electronic control switch.

[0049] In addition, a current sensor, such as a Hall effect current sensor, is installed between the second inverter circuit and each phase winding of the asynchronous motor. When the synchronous motor and the asynchronous motor are running in parallel, the current sensor is used to monitor the AC current of each phase winding. When one phase winding of the asynchronous motor is connected in series with the synchronous motor, the current sensor on the asynchronous motor can be reused to monitor the bus current on the DC side of the power battery. This improves safety redundancy without increasing cost. When the synchronous motor is short-circuited, the current sensor will detect a large current, at which point the target switch QB can be quickly turned off, thus providing protection. Furthermore, the response of the switch is in the nanosecond range, which is much faster than the fuse on the power battery (millisecond response).

[0050] Additionally, considering other driving conditions (driving in low temperatures and high-speed cruising, etc.), it's necessary to increase the motor voltage. This is because, in low temperatures and when the battery is low on charge, although the battery can discharge, its discharge capacity is very weak. An 800V battery might only output around 300V, less than the motor's minimum operating voltage of 450V. In these situations, increasing the battery voltage allows the motor to operate and maneuver the vehicle even in extremely low temperatures, at least providing limp driving and preventing breakdowns. Furthermore, during high-speed cruising, the center point of the motor efficiency map shifts towards higher voltages; increasing the voltage can significantly improve efficiency.

[0051] Based on this, the series-parallel switching motor system in this embodiment adds a fourth switch K4 for series voltage boosting, thereby increasing the synchronous motor terminal voltage. On the one hand, this effectively alleviates the reduction in motor efficiency under high speed and high load conditions. On the other hand, it enables the vehicle to maintain operation even when facing low battery and low voltage starting conditions, improving the vehicle's ability to overcome low voltage obstacles.

[0052] Specifically, the input terminal of the fourth switch K4 is connected to the positive terminal of the power battery, and the output terminal of the fourth switch K4 is connected to the output terminal of the asynchronous motor, specifically, to the neutral point of the three-phase winding of the asynchronous motor.

[0053] When a series boost is required, the first switch K1 and the fourth switch K4 are closed, while the second switch K2 and the third switch K3 are open. The controller uses a set of switches in the second inverter circuit as target switches, so that the current from the power battery flows through a target winding of the asynchronous motor, passes through one of the target switches, and then flows into the input terminal of the first inverter circuit. The second output terminal of the first inverter circuit is connected to the negative terminal of the power battery.

[0054] This embodiment uses switching transistors QB and QC as examples for illustration. When a series boost voltage is required, the switching transistor QC is controlled to open and close at a certain frequency. When QC is closed, QB is open; when QC is open, QB is closed. This achieves the goal of boosting the voltage at the synchronous motor terminals.

[0055] It is worth mentioning that, regardless of whether it is a series buck or series boost converter, in this embodiment, one phase winding of the asynchronous motor needs to be connected to the circuit as the target winding. To prevent thermal management runaway in the asynchronous motor, this embodiment will replace another phase winding of the asynchronous motor with the target winding after a preset interval following the series buck or boost converter. In other words, the three phase windings in the asynchronous motor take turns serving as the target winding.

[0056] In one embodiment, considering that the voltage of current new energy vehicles has entered the 800V stage, but there are few ultra-high voltage or high voltage charging piles on the market, this embodiment adds a fifth switch K5, a third capacitor C3, and an inductor L7 for charging compatibility; wherein, the inductor L7 can be an adjustable inductor. The inductor L7 and the target winding in the asynchronous motor work together to increase the terminal voltage of the charging pile.

[0057] Specifically, the input terminal of the fifth switch K5 is connected to the negative terminal of the charging pile, and the output terminal of the fifth switch K5 is connected to the negative terminal of the power battery; the input terminal of the inductor L7 is connected to the positive terminal of the charging pile, and the output terminal of the inductor L7 is connected to the output terminal of the asynchronous motor; the input terminal of the third capacitor C3 is connected to the input terminal of the inductor L7, and the output terminal of the third capacitor C3 is connected to the output terminal of the fifth switch K5.

[0058] During series boost charging, the fifth switch K5 and the third switch K3 are closed, while the first switch K1, the second switch K2, and the fourth switch K4 are open. The controller then boosts the voltage at the charging pile terminals to charge the power battery. This ensures broad compatibility with various charging piles.

[0059] In summary, the embodiments of this specification provide a series-parallel switching motor system and method. The system includes a power battery, a synchronous motor, an asynchronous motor, a first switch, a second switch, a third switch, a first capacitor, a second capacitor, a first inverter circuit, a second inverter circuit, and a controller. The input terminal of the first inverter circuit is connected to the output terminals of the first switch and the second switch, respectively. The first output terminal of the first inverter circuit is connected to the input terminal of the synchronous motor. The input terminal of the second inverter circuit is connected to the output terminal of the third switch, and the first output terminal of the second inverter circuit is connected to the input terminal of the asynchronous motor. The positive terminal of the power battery is connected to the input terminal of the third switch, and the negative terminal of the power battery is connected to the second output terminal of the first inverter circuit and the second output terminal of the second inverter circuit. The second output terminal is connected; the output terminal of the asynchronous motor is connected to the input terminal of the second switch; the output terminal of the third switch is connected to the input terminal of the first switch; the input terminal of the first capacitor is connected to the input terminal of the first inverter circuit, and the output terminal of the first capacitor is connected to the second output terminal of the first inverter circuit; the input terminal of the second capacitor is connected to the input terminal of the second inverter circuit, and the output terminal of the second capacitor is connected to the second output terminal of the second inverter circuit; when the second switch and the third switch are closed, and the first switch is open, a set of switching transistors in the second inverter circuit is used as target switching transistors, so that the current of the power battery flows through one of the target switching transistors, then through a target winding of the asynchronous motor, and flows into the input terminal of the first inverter circuit. This embodiment considers that the overall efficiency of existing asynchronous motors is relatively low, and they are in a follow-up state in most driving conditions of the vehicle. This embodiment connects the synchronous motor and the single-phase winding of the asynchronous motor in series to adjust the voltage at the synchronous motor terminal, ensuring the motor always operates in the optimal voltage range, reducing electronic control switch losses, and achieving optimal range. It also improves motor efficiency in the low-speed range. Furthermore, in the event of a short circuit or loss of control under high voltage in a synchronous motor, the target switch of the asynchronous motor can be quickly shut off to achieve safe isolation and further enhance the safety of the motor system.

[0060] Based on the same inventive concept, embodiments of the present invention also provide a motor control method for series-parallel switching, used in the aforementioned series-parallel switching motor system. Combined with... Figure 2 The flowchart shown illustrates the motor control method for series-parallel switching, which includes steps 101 to 103:

[0061] Step 101: Obtain the current vehicle operating conditions;

[0062] In this embodiment, the details of the series-parallel switching motor system are as described above and will not be repeated here. Vehicle operating conditions refer to the current operating conditions of the vehicle. From the perspective of motor cascading, vehicle operating conditions can be divided into two types: parallel operation of synchronous and asynchronous motors, and series operation of synchronous and asynchronous motors.

[0063] Step 102: If the vehicle usage condition is a parallel vehicle usage condition, then control the first switch and the third switch to close, and control the second switch to open, so that the synchronous motor and the asynchronous motor are connected in parallel;

[0064] In parallel operation, the first and third switches are closed, while all other switches are open, namely the second, fourth, and fifth switches. At this time, the synchronous and asynchronous motors output torque according to the specific torque distribution.

[0065] Step 103: If the vehicle operating condition is a series step-down operating condition, then control the third switch and the second switch to close, control the first switch to open, and control a set of target switching transistors in the second inverter circuit to open and close, so that the synchronous motor and a target winding of the asynchronous motor are connected in series, thereby reducing the terminal voltage of the synchronous motor.

[0066] In series step-down operation, the third and second switches are closed, and the first, fourth, and fifth switches are opened. Any set of switches in the second inverter circuit is used as the target switches; by controlling the opening and closing of these target switches, the terminal voltage of the synchronous motor is reduced. It should be noted that the target winding of the asynchronous motor only receives DC current; the target winding is equivalent to an energy storage inductor.

[0067] The specific driving scenario for series step-down operation matching can be urban low-speed driving. In urban low-speed driving scenarios, reducing the voltage can improve motor efficiency and reduce the losses of electronic control switches.

[0068] In this embodiment, the vehicle operating conditions also include a series boost voltage condition, which involves increasing the terminal voltage of the synchronous motor. The vehicle operating scenarios matched by the series boost voltage condition include low-temperature driving scenarios and high-speed cruising scenarios.

[0069] Specifically, if the vehicle operating condition is a series boost voltage condition, then the second and fourth switches are closed, and the first, third, and fifth switches are opened. Any set of switches in the second inverter circuit is used as the target switches. By controlling the opening and closing of a target set of switches in the second inverter circuit, the synchronous motor is connected in series with a target winding of the asynchronous motor, thereby increasing the terminal voltage of the synchronous motor.

[0070] In one embodiment, the current sensor is used to monitor the circuit. When a synchronous motor and an asynchronous motor are connected in series, the current sensor monitors the bus current on the battery side. When a synchronous motor and an asynchronous motor are connected in parallel, the current sensor monitors the AC current on the asynchronous motor windings.

[0071] If the current sensor detects that the bus current on the power battery side exceeds the current threshold, it controls a set of target switches in the second inverter circuit to disconnect. The response speed of the switches is much faster than that of the fuses in the power battery, allowing for rapid shutdown and thus improving the safety of the motor system and the power battery.

[0072] In this embodiment, the vehicle usage scenario also includes a boost charging scenario. By increasing the terminal voltage of the charging pile, the low-voltage charging pile is adapted to high-voltage vehicles. The vehicle usage scenario matched by the boost charging scenario is using a low-voltage charging pile to charge the vehicle.

[0073] Specifically, if the vehicle operating condition is a boost charging condition, then the third and fifth switches are closed, and the first, second, and fourth switches are opened. Any set of switches in the second inverter circuit is used as the target switches. By controlling the opening and closing of this target set of switches in the second inverter circuit, the inductor is connected in series with a target winding of the asynchronous motor to increase the terminal voltage of the synchronous motor. The inductor is an adjustable inductor.

[0074] It should be noted that, regardless of whether it is the series buck, series boost, or boost charging operation, in this embodiment, one phase winding of the asynchronous motor is required as the target winding. To prevent thermal management runaway in the asynchronous motor, this embodiment will replace another phase winding of the asynchronous motor with the target winding after a preset interval following the start of the above operation. In other words, the three phase windings of the asynchronous motor take turns serving as the target winding.

[0075] In summary, the embodiments of this specification provide a series-parallel switching motor system and method. The system includes a power battery, a synchronous motor, an asynchronous motor, a first switch, a second switch, a third switch, a first capacitor, a second capacitor, a first inverter circuit, a second inverter circuit, and a controller. The input terminal of the first inverter circuit is connected to the output terminals of the first switch and the second switch, respectively. The first output terminal of the first inverter circuit is connected to the input terminal of the synchronous motor. The input terminal of the second inverter circuit is connected to the output terminal of the third switch, and the first output terminal of the second inverter circuit is connected to the input terminal of the asynchronous motor. The positive terminal of the power battery is connected to the input terminal of the third switch, and the negative terminal of the power battery is connected to the second output terminals of the first inverter circuit and the second output terminals of the second inverter circuit, respectively. The output terminal of the asynchronous motor is connected to the second switch. The input terminals of the first and second switches are connected; the output terminal of the third switch is connected to the input terminal of the first switch; the input terminal of the first capacitor is connected to the input terminal of the first inverter circuit, and the output terminal of the first capacitor is connected to the second output terminal of the first inverter circuit; the input terminal of the second capacitor is connected to the input terminal of the second inverter circuit, and the output terminal of the second capacitor is connected to the second output terminal of the second inverter circuit; when the first and third switches are closed and the second switch is open, the synchronous motor and the asynchronous motor are connected in parallel; when the second and third switches are closed and the first switch is open, a set of switches in the second inverter circuit is used as target switches, so that the current of the power battery flows through one of the target switches, then through a target winding of the asynchronous motor, and into the input terminal of the first inverter circuit. By connecting the single-phase windings of the synchronous motor and the asynchronous motor in series, the voltage at the terminal of the synchronous motor is regulated, thereby improving the motor efficiency. Furthermore, the current sensor on the asynchronous motor can be reused; when a short circuit or high voltage loss of control is detected in the synchronous motor, the target switch of the asynchronous motor can be quickly controlled to turn off, achieving voltage isolation and further improving the safety of the motor system.

[0076] Based on the same inventive concept, embodiments of the present invention also provide a controller, which includes a series-parallel switching motor control device, a memory, a processor, and a communication unit. The memory stores machine-readable instructions that can be executed by the processor. When the controller is running, the processor and the memory communicate with each other via a bus. The processor executes the machine-readable instructions and performs the series-parallel switching motor control method.

[0077] The memory, processor, and communication unit are electrically connected directly or indirectly to achieve signal transmission or interaction. For example, these components can be electrically connected to each other through one or more communication buses or signal lines. The series-parallel switching motor control device includes at least one software function module that can be stored in the memory in the form of software or firmware. The processor is used to execute the executable module stored in the memory (e.g., the software function module or computer program included in the series-parallel switching motor control device).

[0078] The memory can be, but is not limited to, Random Access Memory (RAM), Read Only Memory (ROM), Programmable Read-Only Memory (PROM), Erasable Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM), etc.

[0079] In some embodiments, the processor is used to perform one or more functions described in this embodiment. In some embodiments, the processor may include one or more processing cores (e.g., a single-core processor (S) or a multi-core processor (S)).

[0080] In this embodiment, the memory is used to store the program, and the processor is used to execute the program after receiving the execution instruction. The process definition method disclosed in any implementation of this embodiment can be applied to the processor, or implemented by the processor.

[0081] The communication unit is used to establish communication connections between the controller and other devices via the network, and to send and receive data via the network.

[0082] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the controller described above can be referred to the corresponding process in the aforementioned method, and will not be elaborated further here.

[0083] Based on the same inventive concept, this invention also provides a vehicle, including a vehicle body, a series-parallel switching motor system installed in the vehicle body, and a controller installed in the vehicle body. The controller is used to implement the aforementioned series-parallel switching motor control method. The vehicle is a new energy electric vehicle.

[0084] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working process of the vehicle controller described above can be referred to the corresponding process in the aforementioned method, and will not be elaborated further here.

[0085] The above are merely various embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A series-parallel switching motor system, characterized in that, include: Power battery, synchronous motor, asynchronous motor, first switch, second switch, third switch, first capacitor, second capacitor, first inverter circuit, second inverter circuit, and controller; In this configuration, the input terminal of the first inverter circuit is connected to the output terminals of the first switch and the second switch, respectively; the first output terminal of the first inverter circuit is connected to the input terminal of the synchronous motor; the input terminal of the second inverter circuit is connected to the output terminal of the third switch, and the first output terminal of the second inverter circuit is connected to the input terminal of the asynchronous motor; the positive terminal of the power battery is connected to the input terminal of the third switch, and the negative terminal of the power battery is connected to the second output terminals of the first inverter circuit and the second output terminal of the second inverter circuit, respectively; the output terminal of the asynchronous motor is connected to the input terminal of the second switch; the output terminal of the third switch is connected to the input terminal of the first switch; the input terminal of the first capacitor is connected to the input terminal of the first inverter circuit, and the output terminal of the first capacitor is connected to the second output terminal of the first inverter circuit; the input terminal of the second capacitor is connected to the input terminal of the second inverter circuit, and the output terminal of the second capacitor is connected to the second output terminal of the second inverter circuit. The controller is used to control a set of switching transistors in the second inverter circuit as target switching transistors when the second switch and the third switch are closed and the first switch is open, so that the current of the power battery flows through one of the target switching transistors, then through a target winding of the asynchronous motor, and into the input terminal of the first inverter circuit.

2. The system according to claim 1, characterized in that, The system also includes a fourth switch, the input of which is connected to the positive terminal of the power battery, and the output of which is connected to the output of the asynchronous motor. The controller is used to control a set of switches in the second inverter circuit as target switches when the first switch and the fourth switch are closed and the second switch and the third switch are open, so that the current of the power battery flows through a target winding of the asynchronous motor and then flows into the input terminal of the first inverter circuit after passing through one of the switches in the set of target switches.

3. The system according to claim 1, characterized in that, The system also includes a fifth switch, a third capacitor, and an inductor; The input terminal of the fifth switch is connected to the negative terminal of the charging pile, and the output terminal of the fifth switch is connected to the negative terminal of the power battery; the input terminal of the inductor is connected to the positive terminal of the charging pile, and the output terminal of the inductor is connected to the output terminal of the asynchronous motor; the input terminal of the third capacitor is connected to the input terminal of the inductor, and the output terminal of the third capacitor is connected to the output terminal of the fifth switch. The controller is used to charge the power battery by raising the terminal voltage of the charging pile when the fifth switch and the third switch are closed and the first switch and the second switch are open.

4. The system according to claim 1, characterized in that, After a preset time interval, the other phase winding of the asynchronous motor is replaced with the target winding.

5. The system according to claim 1, characterized in that, The system also includes a current sensor installed in front of each phase winding of the asynchronous motor.

6. A motor control method for series-parallel switching, characterized in that, For a series-parallel switching motor system according to any one of claims 1-5, the method includes: Obtain the current vehicle usage status; If the vehicle usage condition is a parallel vehicle usage condition, then control the first switch and the third switch to close, and control the second switch to open, so that the synchronous motor and the asynchronous motor are connected in parallel; If the vehicle operating condition is a series step-down condition, then the third switch and the second switch are closed, the first switch is opened, and a set of target switching transistors in the second inverter circuit are turned on and off, so that the synchronous motor and a target winding of the asynchronous motor are connected in series, thereby reducing the terminal voltage of the synchronous motor.

7. The method according to claim 6, characterized in that, The system also includes a fourth switch, the input of which is connected to the positive terminal of the power battery, and the output of which is connected to the output of the asynchronous motor. The method further includes: If the vehicle operating condition is a series boost operating condition, then the second switch and the fourth switch are closed, the first switch and the third switch are opened, and a set of target switching transistors in the second inverter circuit are turned on and off, so that the synchronous motor and a target winding of the asynchronous motor are connected in series, thereby increasing the terminal voltage of the synchronous motor.

8. The method according to claim 6 or 7, characterized in that, The method further includes: If the bus current detected by the current sensor is greater than the current threshold, then a set of target switches in the second inverter circuit will be turned off.

9. A controller, characterized in that, The controller includes: a memory, a processor, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, it implements the series-parallel switching motor control method according to any one of claims 6-8.

10. A vehicle, characterized in that, The vehicle includes a vehicle body, a series-parallel switching motor system installed in the vehicle body, and a controller installed in the vehicle body, wherein the controller executes the series-parallel switching motor control method according to any one of claims 6-8.

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