Motor system and method for switching series connection and parallel connection

Abstract

The invention discloses a series-parallel switching motor system and method. The system comprises 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 scenes, the single-phase windings of the synchronous motor and the asynchronous motor are connected in series, so that the terminal voltage of the synchronous motor is adjusted, the loss of an electric control switch is reduced, and the motor efficiency in a low-speed area is improved. Moreover, when the synchronous motor is short-circuited or is out of control at high voltage, the target switch tube of the asynchronous motor can be quickly controlled to be turned off, so that safety isolation is realized, and the safety of the motor system is further improved.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a series-parallel switching motor system and method. Background Art

[0002] Electric vehicles have the characteristics of low noise, no pollution, zero emissions and high energy conversion efficiency. They are an important way to solve the prominent problems of urban automobiles.

[0003] For dual-motor electric vehicles, the efficiency of the motor system directly affects the energy consumption of the entire vehicle, and thus affects the vehicle's range. For example, in some common driving conditions (e.g., urban conditions, high-speed cruising conditions, etc.), the motor system's high-efficiency area 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 adjusts the motor voltage by connecting the single-phase windings of the synchronous motor and the asynchronous motor in series, thereby improving the operating efficiency.

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

[0006] 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;

[0007] Wherein, the input end of the first inverter circuit is connected to the output end of the first switch and the output end of the second switch respectively, and the first output end of the first inverter circuit is connected to the input end of the synchronous motor; the input end of the second inverter circuit is connected to the output end of the third switch, and the first output end of the second inverter circuit is connected to the input end of the asynchronous motor; the positive electrode of the power battery is connected to the input end of the third switch, and the negative electrode of the power battery is connected to the second output end of the first inverter circuit and the second output end of the second inverter circuit respectively; the output end of the asynchronous motor is connected to the input end of the second switch; the output end of the third switch is connected to the input end of the first switch; the input end of the first capacitor is connected to the input end of the first inverter circuit, and the output end of the first capacitor is connected to the second output end of the first inverter circuit; the input end of the second capacitor is connected to the input end of the second inverter circuit, and the output end of the second capacitor is connected to the second output end of the second inverter circuit;

[0008] The controller is used to control a group of switch tubes in the second inverter circuit as target switch tubes when the second switch and the third switch are closed and the first switch is opened, so that the current of the power battery passes through a switch tube in the group of target switch tubes, flows through a target winding of the asynchronous motor, and flows into the input end of the first inverter circuit.

[0009] Optionally, the system further comprises a fourth switch, wherein an input end of the fourth switch is connected to the positive electrode of the power battery, and an output end of the fourth switch is connected to an output end of the asynchronous motor;

[0010] The controller is used to use a group of switch tubes in the second inverter circuit as target switch tubes when the first switch and the fourth switch are closed and the second switch and the third switch are opened, so that the current of the power battery flows through a target winding of the asynchronous motor and flows into the input end of the first inverter circuit after passing through a switch tube in the group of target switch tubes.

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

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

[0013] The controller is used to raise the pile end voltage of the charging pile to charge the power battery when the fifth switch and the third switch are closed and the first switch and the second switch are opened.

[0014] Optionally, after the second switch and the third switch are closed and the first switch is opened, another phase winding of the asynchronous motor is replaced with the target winding every preset interval.

[0015] Optionally, the system further includes providing a current sensor in front of each phase winding of the asynchronous motor.

[0016] According to a second aspect of the present invention, a series-parallel switching motor control method is provided, which is used in the aforementioned series-parallel switching motor system, and the method comprises:

[0017] Get the current vehicle's operating conditions;

[0018] If the vehicle operation condition is a parallel vehicle operation condition, the first switch and the third switch are controlled to be closed, and the second switch is controlled to be opened, 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, the third switch and the second switch are controlled to be closed, the first switch is controlled to be opened, and a group of target switch tubes in the second inverter circuit are controlled to be opened and closed, so that the synchronous motor is connected in series with a target winding of the asynchronous motor to reduce the terminal voltage of the synchronous motor.

[0020] Optionally, the method further includes:

[0021] If the vehicle operating condition is a series boost condition, the second switch and the fourth switch are controlled to be closed, the first switch and the third switch are controlled to be opened, and a group of target switch tubes in the second inverter circuit are controlled to be opened and closed, so that the synchronous motor is connected in series with a target winding of the asynchronous motor to increase the terminal voltage of the synchronous motor.

[0022] Optionally, the method further includes:

[0023] If the bus current monitored by the current sensor is greater than the current threshold, a group of target switch tubes in the second inverter circuit are controlled to be disconnected.

[0024] According to the 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, and the processor implements the aforementioned series-parallel switching motor control method when executing the computer program.

[0025] According to a fourth aspect of the present invention, a vehicle is provided, 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 one or more technical solutions in the embodiments of this specification have at least the following technical effects:

[0027] The embodiments of the present 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; wherein the input end of the first inverter circuit is respectively connected to the output end of the first switch and the output end of the second switch, and the first output end of the first inverter circuit is connected to the input end of the synchronous motor; the input end of the second inverter circuit is connected to the output end of the third switch, and the first output end of the second inverter circuit is connected to the input end of the asynchronous motor; the positive electrode of the power battery is connected to the input end of the third switch, and the negative electrode of the power battery is respectively connected to the second output end of the first inverter circuit and the second output end of the second inverter circuit; The output end of the asynchronous motor is connected to the input end of the second switch; the output end of the third switch is connected to the input end of the first switch; the input end of the first capacitor is connected to the input end of the first inverter circuit, and the output end of the first capacitor is connected to the second output end of the first inverter circuit; the input end of the second capacitor is connected to the input end of the second inverter circuit, and the output end of the second capacitor is connected to the second output end of the second inverter circuit; the controller is used to control a group of switch tubes in the second inverter circuit as the target switch tube when the second switch and the third switch are closed and the first switch is disconnected, so that the current of the power battery passes through a switch tube in the group of target switch tubes, flows through a target winding of the asynchronous motor, and flows into the input end of the first inverter circuit. By connecting the synchronous motor in series with the single-phase winding of the asynchronous motor, the voltage at the terminal of the synchronous motor is regulated, the loss of the electronically controlled switch is reduced, and the motor efficiency in the low-speed zone is improved. In addition, when the synchronous motor is short-circuited or loses control at high voltage, the target switch tube of the asynchronous motor can be quickly controlled to shut down to achieve safe isolation, further improving the safety of the motor system.

[0028] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention, it can be implemented according to the contents of the specification. In order to make the above and other purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Also, throughout the accompanying drawings, the same reference figures are used to represent the same components. In the drawings:

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

[0031] Figure 2 A flow chart of a series-parallel switching motor control method in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0033] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0035] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

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

[0037] Power battery, synchronous motor, asynchronous motor, first switch K1, second switch K2, third switch K3, first capacitor C1, second capacitor C2, first inverter circuit (consisting of switch tube Q1, switch tube Q2, switch tube 3, switch tube Q4, switch tube 5, switch tube 6), second inverter circuit (consisting of switch tube Q7, switch tube Q8, switch tube 9, switch tube QA, switch tube QB, switch tube QC) and controller.

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

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

[0040] The controller is used to control a group of switch tubes in the second inverter circuit as target switch tubes when the second switch K2 and the third switch K3 are closed and the first switch K1 is open, so that the current of the power battery flows through a target winding of the asynchronous motor after passing through a switch tube in the group of target switch tubes, and flows into the input end of the first inverter circuit. At this time, the synchronous motor is connected in series with a winding of the asynchronous motor.

[0041] In this embodiment, there are three windings in the synchronous motor, namely Figure 1 There are three windings in the asynchronous motor, namely Figure 1 The winding L4, winding L5 and winding L6 in the second inverter circuit are divided into three groups, namely, switch tube Q7 and switch tube Q8, switch tube Q9 and switch tube QA, switch tube QB and switch tube QC. The switch tube is also called a power tube.

[0042] In this embodiment, the switch tube is described by taking an insulated gate bipolar transistor (IGBT) as an example.

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

[0044] In one embodiment, the switch tube QB and the switch tube QC are used as the target switch tubes, and the winding L4 is used as the target winding. When the switch tube QB and the switch tube QC are connected in series, the DC power of the power battery passes through the target switch tube QB of the second inverter circuit, and then passes through the connected target winding L4, and then enters the first inverter circuit, becomes AC power, and then enters the three-phase winding of the synchronous motor.

[0045] In one embodiment, the switch tube Q9 and the switch tube QA are used as the target switch tubes, and the winding L5 is used as the target winding. When the switch tube Q9 and the switch tube QA are connected in series, the DC power of the power battery passes through the target switch tube Q9 of the second inverter circuit, and then passes through the connected target winding L5, and then enters the first inverter circuit, becomes AC power, and then enters the three-phase winding of the synchronous motor.

[0046] In one embodiment, the switch tube Q7 and the switch tube Q8 are used as the target switch tubes, and the winding L6 is used as the target winding. When the switch tube Q7 and the switch tube Q8 are connected in series, the DC power of the power battery passes through the target switch tube Q7 of the second inverter circuit, and then passes through the connected target winding L6, and then enters the first inverter circuit, becomes AC power, and then enters the three-phase winding of the synchronous motor.

[0047] This embodiment is described by taking the switch tube QB and the switch tube QC as target switch tubes.

[0048] When the single-phase windings of the synchronous motor and the asynchronous motor are connected in series, the terminal voltage of the synchronous motor can be reduced by controlling the target switch tube 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 area. Because in the low-speed area, the high-efficiency area of ​​the motor tends to be low voltage. At the same time, the voltage reduction can also reduce the loss of the electronically controlled switch.

[0049] In addition, a current sensor, such as a Hall current sensor, is provided between the second inverter circuit and each phase winding of the asynchronous motor. When the synchronous motor and the asynchronous motor are operated 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. Improve safety redundancy without increasing costs. When the synchronous motor is short-circuited, the current sensor will detect a large current, at which time the target switch tube QB can be quickly turned off, thereby playing a protective role. Moreover, the response of the switch tube is in nanoseconds, which is faster than the fuse on the power battery (millisecond response).

[0050] In addition, considering some other driving conditions (driving at low temperatures and high-speed cruising, etc.), the motor voltage needs to be increased. Because at low temperatures and when the power battery is low in power, although the power battery can be discharged, its discharge capacity is very weak. An 800V power battery may only output a voltage of about 300V, which is lower than the motor's minimum operating voltage of 450V. At this time, the power battery can be boosted so that the motor can operate and move the vehicle at extremely low temperatures, or at least limp, to prevent the vehicle from breaking down on the road. In the case of high-speed cruising, the center point of the motor efficiency map will shift toward high voltage. If the voltage is increased, the efficiency can be significantly improved.

[0051] Based on this, the series-parallel switching motor system of this embodiment is provided with a fourth switch K4 for series voltage boosting to increase the voltage at the synchronous motor terminal. On the one hand, it effectively alleviates the reduction in motor efficiency at high speed and high load of the whole vehicle. On the other hand, it enables the vehicle to boost voltage to keep running when the vehicle is started with low power and low voltage, thus improving the vehicle's ability to escape from low voltage.

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

[0053] When series boost is required, the first switch K1 and the fourth switch K4 are closed, and the second switch K2 and the third switch K3 are opened. The controller uses a group of switch tubes in the second inverter circuit as target switch tubes, so that the current of the power battery flows through a target winding of the asynchronous motor, and after passing through a switch tube in the group of target switch tubes, flows into the input end of the first inverter circuit. The second output end of the first inverter circuit is connected to the negative electrode of the power battery.

[0054] This embodiment uses switch tube QB and switch tube QC as target switch tubes for explanation. When series voltage boost is required, the switch tube QC is controlled to open and close at a certain frequency. When switch tube QC is closed, switch tube QB is disconnected; when switch tube QC is disconnected, switch tube QB is closed. Thus, the voltage at the terminal of the synchronous motor is boosted.

[0055] It is worth mentioning that, whether it is series bucking or series boosting, in this embodiment, a phase winding of the asynchronous motor needs to be connected to the circuit as the target winding. In order to prevent the thermal management in the asynchronous motor from getting out of control, this embodiment will replace another phase winding of the asynchronous motor with the target winding after a preset interval after series bucking or series boosting. In other words, the three-phase windings in the asynchronous motor are used as the target winding in turn.

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

[0057] Among them, the input end of the fifth switch K5 is used to be connected to the negative electrode of the charging pile, and the output end of the fifth switch K5 is connected to the negative electrode of the power battery; the input end of the inductor L7 is used to be connected to the positive electrode of the charging pile, and the output end of the inductor L7 is connected to the output end of the asynchronous motor; the input end of the third capacitor C3 is connected to the input end of the inductor L7, and the output end of the third capacitor C3 is connected to the output end of the fifth switch K5;

[0058] During series boost charging, the fifth switch K5 and the third switch K3 are closed, and the first switch K1, the second switch K2 and the fourth switch K4 are opened, and the controller raises the voltage at the charging pile end to charge the power battery, thereby being compatible with a wide range of charging piles.

[0059] In summary, the embodiments of the present 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; wherein the input end of the first inverter circuit is respectively connected to the output end of the first switch and the output end of the second switch, and the first output end of the first inverter circuit is connected to the input end of the synchronous motor; the input end of the second inverter circuit is connected to the output end of the third switch, and the first output end of the second inverter circuit is connected to the input end of the asynchronous motor; the positive electrode of the power battery is connected to the input end of the third switch, and the negative electrode of the power battery is respectively connected to the second output end of the first inverter circuit and the output end of the second inverter circuit. The output end of the asynchronous motor is connected to the input end of the second switch; the output end of the third switch is connected to the input end of the first switch; the input end of the first capacitor is connected to the input end of the first inverter circuit, and the output end of the first capacitor is connected to the second output end of the first inverter circuit; the input end of the second capacitor is connected to the input end of the second inverter circuit, and the output end of the second capacitor is connected to the second output end of the second inverter circuit; when the second switch and the third switch are closed and the first switch is disconnected, a group of switch tubes in the second inverter circuit is used as the target switch tube, so that the current of the power battery passes through one of the switch tubes in the group of target switch tubes, flows through a target winding of the asynchronous motor, and flows into the input end of the first inverter circuit. This embodiment takes into account the low overall efficiency of the existing asynchronous motor, which is in a follow-up state in most driving conditions of the vehicle. This embodiment adjusts the voltage of the synchronous motor terminal by connecting the synchronous motor in series with the single-phase winding of the asynchronous motor, and always runs the motor in the optimal voltage range to reduce the loss of the electronic control switch and achieve the optimal endurance. At the same time, the motor efficiency in the low-speed zone is improved. In addition, when the synchronous motor is short-circuited or loses control due to high voltage, the target switch tube of the asynchronous motor can be quickly controlled to shut down to achieve safe isolation, further improving the safety of the motor system.

[0060] Based on the same inventive concept, an embodiment of the present invention further provides a series-parallel switching motor control method, which is used in the aforementioned series-parallel switching motor system. Figure 2 As shown in the flowchart, the series-parallel switching motor control method includes steps 101 to 103:

[0061] Step 101: Obtain the current vehicle operation condition;

[0062] In this embodiment, the contents of the series-parallel switching motor system are referred to above and will not be repeated here. The vehicle operating condition refers to the operating condition that the vehicle is currently driving in. From the perspective of motor cascading, the vehicle operating condition can be divided into two types, namely, the vehicle operating condition of synchronous motors and asynchronous motors in parallel, and the vehicle operating condition of synchronous motors and asynchronous motors in series.

[0063] Step 102: If the vehicle operation condition is a parallel vehicle operation condition, the first switch and the third switch are controlled to be closed, and the second switch is controlled to be opened, so that the synchronous motor and the asynchronous motor are connected in parallel;

[0064] In the parallel vehicle operation condition, the first switch and the third switch are closed, and the other switches are all opened, that is, the second switch is opened, the fourth switch is opened, and the fifth switch is opened. At this time, the synchronous motor and the asynchronous motor output torque according to the specific torque distribution.

[0065] Step 103: If the vehicle operating condition is a series step-down condition, the third switch and the second switch are controlled to be closed, the first switch is controlled to be opened, and a group of target switch tubes in the second inverter circuit are controlled to be opened and closed, so that the synchronous motor is connected in series with a target winding of the asynchronous motor to reduce the terminal voltage of the synchronous motor.

[0066] Under the series step-down condition, the third switch and the second switch are controlled to be closed, and the first switch, the fourth switch and the fifth switch are controlled to be opened. Any set of switch tubes in the second inverter circuit is used as the target switch tube, and the terminal voltage of the synchronous motor is reduced by controlling the opening and closing of this set of target switch tubes. It should be noted that the target winding of the asynchronous motor only passes direct current, and the target winding is equivalent to an energy storage inductor.

[0067] Among them, the specific driving scenario that matches the series voltage reduction working condition can be a low-speed urban driving scenario. In the low-speed urban driving scenario, reducing the voltage can improve the motor efficiency and reduce the loss of the electronic control switch.

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

[0069] Specifically, if the vehicle operation condition is a series boost operation condition, the second switch and the fourth switch are controlled to be closed, and the first switch, the third switch and the fifth switch are controlled to be opened. Any group of switch tubes in the second inverter circuit is used as the target switch tube, and a group of target switch tubes in the second inverter circuit are controlled to be opened and closed, so that 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 line circuit. When the synchronous motor is connected in series with the asynchronous motor, the current sensor monitors the bus current on one side of the power battery. When the synchronous motor is connected in parallel with the asynchronous motor, the current sensor monitors the AC current on the asynchronous motor winding.

[0071] If the bus current on the power battery side detected by the current sensor is greater than the current threshold, a group of target switch tubes in the second inverter circuit are controlled to be disconnected. The response speed of the switch tube is much faster than the response speed of the fuse in the power battery, and it can be turned off quickly, thereby improving the safety of the motor system and the power battery.

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

[0073] Specifically, if the vehicle operation condition is a boost charging condition, the third switch and the fifth switch are controlled to be closed, and the first switch, the second switch and the fourth switch are controlled to be opened. Any set of switch tubes in the second inverter circuit is used as the target switch tube, and a set of target switch tubes in the second inverter circuit is controlled to be opened and closed, so that 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 the series step-down condition, the series boost condition or the boost charging condition, in this embodiment, a certain phase winding of the asynchronous motor is required to be used as the target winding. In order to prevent the thermal management in the asynchronous motor from getting out of control, this embodiment will replace another phase winding of the asynchronous motor with the target winding after the above-mentioned condition starts, every time a preset interval has passed. In other words, the three-phase windings in the asynchronous motor are used as the target winding in turn.

[0075] In summary, the embodiments of the present 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; wherein the input end of the first inverter circuit is respectively connected to the output end of the first switch and the output end of the second switch, and the first output end of the first inverter circuit is connected to the input end of the synchronous motor; the input end of the second inverter circuit is connected to the output end of the third switch, and the first output end of the second inverter circuit is connected to the input end of the asynchronous motor; the positive electrode of the power battery is connected to the input end of the third switch, and the negative electrode of the power battery is respectively connected to the second output end of the first inverter circuit and the second output end of the second inverter circuit; the output end of the asynchronous motor is connected to the second switch. The input end of the first capacitor is connected to the input end of the first inverter circuit, and the output end of the first capacitor is connected to the second output end of the first inverter circuit; the input end of the second capacitor is connected to the input end of the second inverter circuit, and the output end of the second capacitor is connected to the second output end of the second inverter circuit; when the first switch and the third switch are closed and the second switch is disconnected, the synchronous motor is connected in parallel with the asynchronous motor; when the second switch and the third switch are closed and the first switch is disconnected, a group of switch tubes in the second inverter circuit is used as the target switch tube, so that the current of the power battery passes through one of the switch tubes in the group of target switch tubes, flows through a target winding of the asynchronous motor, and flows into the input end of the first inverter circuit. By connecting the synchronous motor in series with the single-phase winding of the asynchronous motor, the voltage at the terminal of the synchronous motor is regulated, thereby improving the motor efficiency. In addition, the current sensor on the asynchronous motor can be reused. When the synchronous motor is detected to be out of control due to short circuit or high voltage, the target switch tube of the asynchronous motor can be quickly controlled to be turned off to achieve voltage isolation, further improving the safety of the motor system.

[0076] Based on the same inventive concept, an embodiment of the present invention also provides a controller, which includes a motor control device for series-parallel switching, a memory, a processor and a communication unit. The memory stores machine-readable instructions executable by the processor. When the controller is running, the processor and the memory communicate through a bus, the processor executes the machine-readable instructions, and executes the motor control method for series-parallel switching.

[0077] The memory, the processor, and the communication unit are electrically connected to each other directly or indirectly to achieve signal transmission or interaction. For example, these elements can be electrically connected to each other through one or more communication buses or signal lines. The motor control device for series-parallel switching 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 (for example, the software function module or computer program included in the motor control device for series-parallel switching).

[0078] Among them, the memory can be, but is not limited to, random access memory (Random Access Memory, RAM), read-only memory (Read On ly Memory, ROM), programmable read-only memory (Programmable Read-Only Memory, PROM), erasable read-only memory (Erasab le Programmable Read-Only Memory, EPROM), electrically erasable read-only memory (Electrical 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 (eg, 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 a communication connection between the controller and other devices through the network, and to send and receive data through the network.

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

[0083] Based on the same inventive concept, an embodiment of the present invention further provides a 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 is used to implement the above-mentioned series-parallel switching motor control method. The vehicle is a new energy electric vehicle.

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

[0085] The above are only various embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A series-parallel switching motor system, characterized in that: include: 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; Wherein, the input end of the first inverter circuit is connected to the output end of the first switch and the output end of the second switch respectively, and the first output end of the first inverter circuit is connected to the input end of the synchronous motor; the input end of the second inverter circuit is connected to the output end of the third switch, and the first output end of the second inverter circuit is connected to the input end of the asynchronous motor; the positive electrode of the power battery is connected to the input end of the third switch, and the negative electrode of the power battery is connected to the second output end of the first inverter circuit and the second output end of the second inverter circuit respectively; the output end of the asynchronous motor is connected to the input end of the second switch; the output end of the third switch is connected to the input end of the first switch; the input end of the first capacitor is connected to the input end of the first inverter circuit, and the output end of the first capacitor is connected to the second output end of the first inverter circuit; the input end of the second capacitor is connected to the input end of the second inverter circuit, and the output end of the second capacitor is connected to the second output end of the second inverter circuit; The controller is used to control a group of switch tubes in the second inverter circuit as target switch tubes when the second switch and the third switch are closed and the first switch is opened, so that the current of the power battery passes through a switch tube in the group of target switch tubes, flows through a target winding of the asynchronous motor, and flows into the input end of the first inverter circuit.

2. The system according to claim 1, characterized in that The system further includes a fourth switch, wherein an input end of the fourth switch is connected to the positive electrode of the power battery, and an output end of the fourth switch is connected to an output end of the asynchronous motor; The controller is used to control a group of switch tubes in the second inverter circuit as target switch tubes when the first switch and the fourth switch are closed and the second switch and the third switch are opened, so that the current of the power battery flows through a target winding of the asynchronous motor and flows into the input end of the first inverter circuit after passing through a switch tube in the group of target switch tubes.

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 end of the fifth switch is used to be connected to the negative electrode of the charging pile, and the output end of the fifth switch is connected to the negative electrode of the power battery; the input end of the inductor is used to be connected to the positive electrode of the charging pile, and the output end of the inductor is connected to the output end of the asynchronous motor; the input end of the third capacitor is connected to the input end of the inductor, and the output end of the third capacitor is connected to the output end of the fifth switch; The controller is used to raise the pile end voltage of the charging pile to charge the power battery when the fifth switch and the third switch are closed and the first switch and the second switch are opened.

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

5. The system according to claim 1, characterized in that The system further comprises a current sensor arranged before each phase winding of the asynchronous motor.

6. A motor control method for series-parallel switching, characterized in that: A series-parallel switching motor system according to any one of claims 1 to 5, the method comprising: Get the current vehicle's operating conditions; If the vehicle operation condition is a parallel vehicle operation condition, the first switch and the third switch are controlled to be closed, and the second switch is controlled to be opened, so that the synchronous motor and the asynchronous motor are connected in parallel; If the vehicle operating condition is a series step-down condition, the third switch and the second switch are controlled to be closed, the first switch is controlled to be opened, and a group of target switch tubes in the second inverter circuit are controlled to be opened and closed, so that the synchronous motor is connected in series with a target winding of the asynchronous motor to reduce the terminal voltage of the synchronous motor.

7. The method according to claim 6, characterized in that The method further comprises: If the vehicle operating condition is a series boost condition, the second switch and the fourth switch are controlled to be closed, the first switch and the third switch are controlled to be opened, and a group of target switch tubes in the second inverter circuit are controlled to be opened and closed, so that the synchronous motor is connected in series with a target winding of the asynchronous motor to increase the terminal voltage of the synchronous motor.

8. The method according to claim 6 or 7, characterized in that: The method further comprises: If the bus current monitored by the current sensor is greater than the current threshold, a group of target switch tubes in the second inverter circuit are controlled to be disconnected.

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, the motor control method for series-parallel switching described in any one of claims 6-8 is implemented.

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 described in any one of claims 6-8.

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