New energy automobile electric driving method and structure of electric driving device

Abstract

The invention discloses a new energy automobile electric driving method and an electric driving device structure. A multi-phase alternating current output end of an MCU motor control unit is connected to a circuit structure formed by connecting stator windings of EM driving motors in series in a split-phase mode, and a common-mode rotating magnetic field is generated; all the rotors generate electromagnetic torque output and mutual coupling effects through the split-phase series circuit structure and the common-mode rotating magnetic field, and native self-coupling and driving are achieved. The problems of poor adaptive capacity, complex software and hardware structure, poor reliability, high cost and the like of a scheme for forcibly controlling the rotating speed of each EM driving motor in the distributed electric driving system by depending on an external software algorithm in the prior art are solved.

Description

Technical Field

[0001] This invention relates to a method and structure of an electric drive device for new energy vehicles, belonging to the field of electric drive technology for new energy vehicles. Background Technology

[0002] The adoption of distributed electric drive systems in new energy vehicles has become a trend. The characteristics of existing distributed electric drive technology are: the Vehicle Control Unit (VCU) uses a CAN communication network to control two or more Microcontroller Units (MCUs) (MCUs include controllers and inverters, etc.), each MCU independently drives one electric motor (EM), and each EM independently drives one drive wheel or one drive axle. The problem with existing distributed electric drive technology is that the speeds of all EMs must be precisely matched to ensure stable and safe vehicle operation. For example, when the vehicle turns, the VCU must transmit the required precise speed data of the left and right drive wheels to the corresponding MCUs. The MCUs must then precisely coordinate the speeds of the left and right drive wheels in real time to ensure a smooth turn. Clearly, in existing distributed electric drive technologies, there is no direct physical connection between the EMs; coupling is only achieved through digital connections in software algorithms. This means that the algorithmic coupling scheme, which relies entirely on external software to forcibly control and coordinate the speeds of each EM, is a typical non-native drive coupling technology. This necessitates that the vehicle's electronic and electrical systems, including the VCU, MCUs, and CAN communication network, possess extremely high functional safety and stability. After all, any functional abnormality in the software calculations could lead to safety risks for the entire vehicle. Therefore, the international standard ISO... The ASIL-C to ASIL-D level upgrade for 26262 vehicles leads to higher redundancy and more complex structures in the electronic and electrical systems of new energy vehicles. Secondly, software algorithms forcibly control and coordinate the speeds of each electric drive motor, making it difficult to achieve the adaptive capabilities of drive coupling via the native self-coupling mechanism of a gear differential. For example, when a single drive wheel runs over a small stone or road bump, the software struggles to accurately calculate or even detect this, potentially leading to uneven tire wear, unnatural driving feel, and loss of control at high speeds. Therefore, it is necessary to develop a new generation of distributed electric drive methods and structures that directly establish a self-coupling mechanism between each electric drive motor, achieving native self-coupling drive and eliminating the need for software algorithms to forcibly control and coordinate the speeds of each electric drive motor. Summary of the Invention

[0003] To address the aforementioned issues, this invention provides a structure for an electric drive method and device for new energy vehicles, enabling distributed electric drive systems to possess the aforementioned native self-coupling drive capability, while also simplifying the structure.

[0004] A method for electric drive of new energy vehicles, characterized by: Step S1: The MCU motor control unit outputs a set of multiphase AC power; Step S2: The multiphase AC power is connected to a circuit with phase-series connection characteristics, which is composed of the phase windings of the stator windings of each EM drive motor, and a common-mode rotating magnetic field is generated on each stator of each EM drive motor. Step S3: The common-mode rotating magnetic field of each EM drive motor and the corresponding rotor generate electromagnetic torque through electromagnetic induction, and the electromagnetic torque of each rotor drives its corresponding drive wheel. Step S4: The rotors of each EM drive motor are self-coupled and driven by electromagnetic induction with the common-mode rotating magnetic field and a phase-separated series circuit structure.

[0005] As a further improvement to the above method, the method is characterized in that: the self-coupling drive in step S4 includes differential coupling drive when the EM drive motor is an asynchronous motor. The rotor of at least one of the EM drive motors changes speed due to load changes, which changes the current flowing through its stator winding. The common-mode rotating magnetic field of each EM drive motor also changes with the change of current. The rotor speed of the other EM drive motors changes accordingly due to the change of the common-mode rotating magnetic field, thereby realizing differential coupling drive between the rotors.

[0006] As a further improvement to the above method, the method is characterized in that: the self-coupling drive in step S4 includes constant speed coupling drive when the EM drive motor is a synchronous motor, and the rotor speed of each EM drive motor is synchronized with the rotation speed of the common mode rotating magnetic field, thereby realizing constant speed coupling drive between each rotor.

[0007] A structure of an electric drive device for a new energy vehicle is disclosed, comprising an MCU motor control unit electrically connected to an EM drive motor, a power battery, and a VCU vehicle control unit. The device is characterized in that: each phase of the stator winding of each EM drive motor is connected in series and then electrically connected to a set of multiphase AC power at the output of the MCU motor control unit; the common-mode rotating magnetic field generated on the stator of each EM drive motor is electromagnetically induced to its respective rotor; and each rotor is mechanically driven to its respective drive wheel.

[0008] As a further improvement to the above structure for achieving the limited slip function, the feature is that: each phase winding of the stator winding of each EM drive motor is electrically connected in parallel with the limited slip switch to form a bypass of the phase winding controlled by the limited slip switch, and the control terminal of the limited slip switch is electrically connected to the MCU motor control unit.

[0009] As a further improvement to the above structure to achieve the reversal function, the feature is that at the input end of the phase winding of the stator winding of the EM drive motor that needs to be reversed, at least two phase windings are electrically connected to the phase reversal switch, which swaps the phases of the corresponding phase windings.

[0010] The beneficial effects of this invention are as follows: This patent proposes a phase-series series drive electrical configuration for the EM drive motors in a distributed electric drive system for new energy vehicles, along with a common-mode rotating magnetic field self-coupling drive technology. Since the stator windings of each EM drive motor are connected in phases and series to the same multiphase AC port, the AC current, phase, and frequency passing through the stator windings of each EM drive motor are identical, exhibiting common-mode characteristics. The resulting magnetic field is the common-mode rotating magnetic field. Each rotor generates electromagnetic torque through electromagnetic induction with the common-mode rotating magnetic field, and simultaneously reacts to the common-mode rotating magnetic field, achieving coupling with other rotors. Clearly, this coupling mechanism is an autonomous coupling behavior achieved directly by each EM drive motor through the most primitive, purely physical layer of electromagnetic interaction—a native self-coupling behavior—rather than an algorithmic coupling behavior that forcibly controls and coordinates the speeds of each EM drive motor through software. Therefore, this patent achieves its invention objective. Furthermore, since this patent eliminates the need for software to forcibly control and coordinate the speeds of each EM drive motor, the hardware and software of the control end are simplified. At the same time, the MCU motor control unit of this patent only needs one multi-phase AC output terminal. Therefore, the number of controllers and inverters in the MCU motor control unit is reduced and the structure is simplified. Thus, this patent simplifies the distributed electric drive system of new energy vehicles, reduces costs, and increases reliability. Attached Figure Description

[0011] Figure 1 This is a flowchart of the electric drive method of this patent; Figure 2 This is a schematic diagram of the system structure of this patent when two EM drive motors are used and connected in a delta configuration; Figure 3 This is a schematic diagram of the system structure of this patent when two EM drive motors are used and a star connection is adopted; Figure 4 This is a schematic diagram of the electric drive device structure when two EM drive motors are used and connected in a delta configuration, as per this patent. Figure 5 This is a schematic diagram of the circuit principle of the stator windings connected in phases when using four EM drive motors in a delta connection. Figure 6 This is a schematic diagram of the circuit principle of the stator windings connected in phases when using six EM drive motors in a star connection. Figure 7 This is a schematic diagram of the circuit principle of the limited-slip switch when using two EM drive motors in a delta connection. Figure 8 This is a schematic diagram of the reverse-phase switch circuit principle of a four-wheel drive vehicle using four EM drive motors connected in a star configuration, as per this patent. Figure 9 yes Figure 4 The circuit diagram of the electric drive device shown is shown. Figure 10 This patented EM drive motor is a schematic diagram of the differential drive energy recovery circuit when two permanent magnet synchronous motors are connected in a delta configuration.

[0012] The attached figures are labeled as follows: Power battery 1; MCU motor control unit 2; EM drive motor 3, stator 31, stator winding 311, rotor 32; Drive wheel 4; Limited-slip switch 5; Phase inverter 6; VCU (Vehicle Control Unit) 7; Gear reducer 8. Detailed Implementation

[0013] A method for electric drive of new energy vehicles, such as Figure 1 As shown, its characteristics are: Step S1: The MCU motor control unit 2 outputs a set of multi-phase AC power; Step S2: The multiphase AC power is connected to a circuit with phase-separated series characteristics, which is composed of the phase windings of the stator windings 311 of each EM drive motor 3, and a common-mode rotating magnetic field is generated on each stator 31 of each EM drive motor 3. Step S3: The common-mode rotating magnetic field of each EM drive motor 3 and the corresponding rotor 32 generate electromagnetic torque through electromagnetic induction, and the electromagnetic torque of each rotor 32 drives its corresponding drive wheel 4. Step S4: The rotors 32 of each EM drive motor 3 are self-coupled and driven by electromagnetic induction with the common mode rotating magnetic field and a phase-separated series circuit structure.

[0014] The MCU motor control unit 2 of this patent only requires one multi-phase AC output port. This multi-phase AC output port outputs only one set of multi-phase AC power. This multi-phase AC power can be the three-phase AC power commonly used in the current EM drive motor 3, or the four-phase AC power, six-phase AC power, etc., which will be used in the next generation of electric drive vehicles. In short, it only needs to match the multi-phase AC power of the EM drive motor 3. Since the MCU motor control unit 2 of this patent only needs to output one set of multi-phase AC power, the number of controllers and inverters used to generate multi-phase AC power can be reduced to only one set. This significantly simplifies the structure of the MCU motor control unit 2, improves its reliability, and reduces manufacturing costs. This advantage can significantly enhance the competitiveness of new energy vehicles.

[0015] like Figure 2As shown, the multiphase AC power output from the MCU motor control unit 2 can simultaneously drive at least two EM drive motors 3 connected in series with separate phases. Of course, more EM drive motors 3 can also be connected in series with separate phases, such as... Figure 5 , Figure 6 As shown, details are described below. Each EM drive motor 3 can be adopted... Figure 2 The triangle connection shown can also be used... Figure 3 The star connection shown is illustrated. The phase windings of each stator winding 311 of each EM drive motor 3 are connected in series and electrically connected to a multiphase AC power output from the MCU motor control unit 2. This generates a common-mode rotating magnetic field on the stator 31 of each EM drive motor 3. Each stator winding 311 of the EM drive motor 3 forms an electromagnetic induction connection with its respective rotor 32 through the common-mode rotating magnetic field. The rotor 32 obtains electromagnetic torque through electromagnetic induction and also acts in response to the stator winding 311. Each rotor 32 is mechanically connected to its respective drive wheel 4 through a gear reducer 8. Figure 4 As shown.

[0016] Since each phase winding of the stator winding 311 of each EM drive motor 3 in this patent has the technical feature of phase-separated series electrical connection, and since each EM drive motor 3 after phase-separated series connection is connected to the same set of multi-phase AC output ports of MCU motor control unit 2, the frequency, current and phase of the rotating magnetic field generated by the stator winding 311 of each EM drive motor 3 are the same, that is, it has common mode characteristics, hence it is called common mode rotating magnetic field. Each stator winding 311 of the EM drive motor 3 generates an electromagnetic induction-based interaction with its rotor 32 through its own common-mode rotating magnetic field. This interaction includes the generation of electromagnetic torque and speed on the rotor 32, as well as the reaction of the rotor 32 on the stator winding 311, such as changes in back electromotive force and inductive reactance. This reaction causes the current of all stator windings 311 in the phase-series circuit structure to change together, which in turn causes the common-mode characteristics of the common-mode rotating magnetic field to change together. This enables mutual coupling between the rotors 32 of each EM drive motor 3. This is the original self-coupling drive principle of this patent, which specifically includes: differential speed coupling drive, constant speed coupling drive, energy coupling drive, etc., as described below:

[0017] When each EM drive motor 3 is an asynchronous motor, the rotor 32 corresponding to each stator 31 rotates in its own common-mode rotating magnetic field. If the load on one of the rotors 32 suddenly changes, the speed of that rotor 32 will change, which in turn will cause changes in the back electromotive force and inductive reactance acting on the corresponding stator winding 311, and consequently, changes in the current of that stator winding 311. The current in the stator windings 311 of the other EM drive motors 3 in the entire split-phase series electric drive system will also change synchronously, causing changes in their respective common-mode rotating magnetic field characteristics and corresponding rotor 32 speeds, thus achieving differential coupling drive; for example, when the vehicle makes a left turn. Figure 4 The left drive wheel 4 shown is located inside the curve. The load on the rotor 32 of its corresponding left EM drive motor 3 increases, and its speed decreases. This leads to a decrease in the back electromotive force and inductive reactance generated by the rotor 32 on the corresponding stator winding 311, resulting in an increase in the current of the stator winding 311. Figure 4 , Figure 9 It is known that each phase of the stator winding 311 of the two EM drive motors 3 is connected in series in separate phases. Therefore, the current in the stator winding 311 of the right EM drive motor 3 also increases synchronously, the magnetic flux of the common-mode rotating magnetic field increases, and the rotor speed 32 of the right EM drive motor 3 increases. This achieves a self-coupling change in the speed of the two EM drive motors 3 when the vehicle turns left, with the left side being lower and the right side being higher, realizing native self-coupling differential drive. This native self-coupling differential drive technology enables the distributed electric drive system of this patent to have the same adaptive capability as a centralized electric drive system using a gear differential.

[0018] When each EM drive motor 3 is a synchronous motor, such as a permanent magnet synchronous motor, since the speed of a synchronous motor is usually synchronized with the speed of the rotating magnetic field, in this embodiment, the rotor 32 of each EM drive motor 3 is synchronized with the speed of its own common-mode rotating magnetic field. Furthermore, since the common-mode rotating magnetic fields of this patent have common-mode characteristics and equal speeds, therefore... Figure 4As shown in this embodiment, the two rotors 32 can always maintain synchronized speeds. Each rotor 32 drives its respective drive wheel 4 through the gear reducer 8, which also always maintains the same speed. That is, each EM drive motor 3 has a native self-coupled constant speed drive capability, without the need for any software coordination and control. This native self-coupled constant speed drive capability solves the high cost and low reliability problems of traditional off-road vehicles that must rely on differential locks to achieve constant speed drive, and also solves the high cost and low reliability problems of existing distributed electric drive technology that relies on software algorithms to forcibly control each EM drive motor 3 to achieve constant speed drive. The native self-coupling constant velocity drive technology of this patent is also particularly applicable to the electric drive driving system of various non-road mobile platforms, such as military multi-axle all-terrain vehicles, tracked vehicles, loaders and other engineering machinery, combine harvesters and other agricultural machinery, mining trucks and other mining machinery, etc. Therefore, the name "drive wheel 4" used in this patent is only for ease of description and understanding, and is only used as an abbreviation or alias for a walking device in the electric drive driving system of the mobile platform. It is not intended to limit the specific structure. In fact, the drive wheel 4 can be a drive wheel of a vehicle, a track of a tank, or a drive axle of a military multi-axle all-terrain vehicle, etc. The application of this patent technology in these fields is still within the protection scope of this patent, and implementers still need to obtain authorization from the patentee.

[0019] Further improvements to this patent can provide a limited-slip solution for the distributed electric drive system. As is well known to those skilled in the art, in existing mechanical gear differential drive technology, without a differential lock, if one wheel slips and spins due to low road traction, the other wheel will lose driving force. Therefore, mechanical differentials must be equipped with differential locks or brakes on the slipping wheel to limit slip. This limited-slip function is an advanced feature found in high-end vehicles. Further improvements to this patent can also provide advanced limited-slip functionality, such as: Figure 7As shown, each phase winding of the stator winding 311 of each EM drive motor 3 is electrically connected in parallel to the limited-slip switch 5, thus forming a bypass circuit for that phase winding controlled by the limited-slip switch 5. The limited-slip control method is as follows: by triggering the limited-slip switch 5, each phase winding of the stator winding 311 of the EM drive motor 3 that needs to be limited-slip is bypassed and short-circuited, the EM drive motor 3 is deconstructed from the phase-series circuit structure, causing its stator winding 311 to lose drive current, the common-mode rotating magnetic field to disappear, and the rotor 32 to stop electromagnetic torque output, thereby achieving limited slip. At this time, other EM drive motors 3 that have not triggered the corresponding limited-slip switch 5 still have a phase-series circuit structure and can still self-couple drive output, so that the whole vehicle still has Driving capability; simultaneously, when the EM drive motor 3 corresponding to the slipping drive wheel 4 is deconstructed, the ineffective power loss stops, and the rotor speed 32 drops significantly, reducing the back electromotive force and inductive reactance in the entire split-phase series circuit, increasing the current, and increasing the common-mode rotating magnetic flux of the other non-slipping EM drive motors 3. This enhances the electromagnetic torque of the rotors 32 of these EM drive motors 3 and increases the traction of the corresponding drive wheel 4. In other words, the energy saved by the limited-slip mechanism is autonomously coupled to the other non-slipping drive wheels 4, allowing each non-slipping drive wheel 4 to obtain more energy and stronger traction. This is the energy coupling drive in the self-coupling drive described in this patent. Obviously, this limited-slip technology achieves the effect of increasing traction through efficient energy self-coupling, and is applicable to distributed electric drive systems composed of asynchronous motors or synchronous motors. The aforementioned limited-slip switch 5 can be controlled by the MCU motor control unit 2, or by the VCU vehicle control unit 7 or other control units; the limited-slip switch 5 can be a combination switch or a single switch. Figure 7 The multiple independent switches for linkage control shown; the limited slip switch 5 can be either a relay or a solid-state electronic switch. The limited slip switch 5 can be installed on the EM drive motor 3 body, or on the circuit board of the MCU motor control unit 2 or the VCU vehicle control unit 7. Such local modifications and changes obviously fall within the protection scope of this patent and still require the authorization of the patentee.

[0020] Further improvements to this patent can provide two solutions for turning around on the spot for the distributed electric drive system of this patent. The first solution is: as is well known to those skilled in the art, turning around on the spot requires the drive wheels 4 on the left and right sides of the vehicle to rotate in opposite directions. The further improvements to this patent can also make the drive wheels 4 on the left and right sides of the vehicle rotate in opposite directions: for example, Figure 8The diagram shows the circuit of a four-wheel drive off-road vehicle using the distributed four-motor electric drive system of this patent. By simultaneously triggering two sets of phase-reversing switches 6 on the left and right sides, two phases of the three-phase windings 311 of the stator windings of the two left-side EM drive motors 3 are reversed after the wiring phases are swapped by the first set of phase-reversing switches 6. However, the two right-side EM drive motors 3 are restored to their original phases after the two sets of phase-reversing switches 6 are swapped, maintaining forward rotation. This causes the drive wheels 4 on both sides to rotate in opposite directions, resulting in torque steering of the vehicle body and achieving a turnaround. Obviously, the turnaround technology of this patent is also applicable to multi-phase AC motors such as four-phase motors and six-phase motors. For four-phase motors, simply swapping the wiring phases of the second and fourth phases achieves reversal. For six-phase motors, simply swapping the wiring phases of the second and sixth phases, and the third and fifth phases achieves reversal. Obviously, those skilled in the art, after understanding the three-phase, four-phase, and six-phase AC motor reversal technology disclosed in this patent, can also implement reversal control for other specifications of motors without further creative effort. Therefore, due to space limitations, these will not be elaborated upon further. The aforementioned phase-reversing switch 6 can be controlled by the MCU motor control unit 2, the VCU vehicle control unit 7, or other control units; the phase-reversing switch 6 can be a combination switch or a single switch. Figure 8 The multiple independent switches for linkage control shown; the inverting switch 6 can be either a relay or a solid-state electronic switch. The inverting switch 6 can be installed on the EM drive motor 3 body, or on the circuit board of the MCU motor control unit 2 or the VCU vehicle control unit 7. Such local modifications and changes obviously fall within the protection scope of this patent and still require the authorization of the patentee.

[0021] The second solution for turning around on the spot is to utilize the aforementioned limited-slip technology for unilateral drive, which also enables a turn-around. Specifically, for each EM drive motor 3 corresponding to the drive wheel 4 on one side of the vehicle, the corresponding limited-slip switch 5 is triggered to stop its power output, while the EM drive motor 3 corresponding to the drive wheel 4 on the other side of the vehicle continues to output power, causing the vehicle to generate torque steering and achieve a turn-around. Obviously, those skilled in the art, after understanding the limited-slip technology disclosed in this patent and being inspired by this embodiment, can implement this embodiment without any other creative effort; therefore, due to space limitations, it will not be described in detail.

[0022] In this patent's distributed electric drive system, when the EM drive motor 3 is a synchronous motor, in order to meet the needs of differential drive scenarios such as vehicle turning, this patent further improves the system to provide two solutions, which can be used individually or in combination, as described below:

[0023] The first scheme of differential drive using synchronous motors in this patent is as follows: the current intensity of the multiphase AC power output by the MCU motor control unit 2 in the phase-series series circuit is less than the step-out current threshold, that is, the current intensity is lower than the minimum value required to maintain synchronous rotation of each rotor 32. In this way, the rotor 32 with the highest relative running resistance among the rotors 32 of each EM drive motor 3 will be the first to lose synchronization. After the speed of the step-out rotor 32 decreases, the back electromotive force and inductive reactance on its corresponding stator winding 311 will decrease, leading to an increase in the current intensity in the phase-series series circuit, an increase in the common-mode rotating magnetic field flux, and allowing other rotors 32 to obtain greater electromagnetic torque, thus relatively mitigating the degree of step-out or even avoiding step-out, thereby achieving the purpose of differential drive. For example, using... Figure 4 When the vehicle with the electric drive device shown turns, the two drive wheels 4, one inside and one outside the curve, will inevitably rotate at different speeds due to the different turning radii and the road friction. At this time, the rotor 32 of the EM drive motor 3 corresponding to the inner drive wheel 4 experiences greater rotational resistance from the road friction and will lose synchronization first. This loss of synchronization will inevitably cause its speed to be lower than that of the EM drive motor 3 corresponding to the outer drive wheel 4, thus achieving the differential drive objective of this patent when using a synchronous motor. This solution has the advantage of smooth and seamless differential drive, making it most suitable for high-speed vehicle operation.

[0024] The second approach to differential drive using a synchronous motor in this patent is a differential drive approach further improved from the aforementioned drive limited-slip technology, specifically as follows: Figure 7 As shown, when differential drive is required, the limited-slip switch 5 of the EM drive motor 3 corresponding to the drive wheel 4 to be decelerated only needs to be triggered at least once or multiple times. This bypasses and short-circuits the phase winding of its stator winding 311, causing the common-mode rotating magnetic field to disappear, the rotor 32 to become out of sync, and the speed to decrease. At this time, the speed of the other EM drive motors 3 remains synchronized with the common-mode rotating magnetic field, thus achieving differential drive. For example, when the vehicle turns right, if... Figure 7 The limited-slip switch 5 of the right-side EM drive motor 3 corresponding to the right-side drive wheel 4 is repeatedly triggered by the duty cycle signal output by the MCU motor control unit 2, repeatedly performing a bypass short-circuit action of being on and off, on and off... causing the right-side drive wheel 4 to intermittently lose driving force, and its speed will inevitably be lower than that of the left side, thus realizing differential drive when the vehicle turns right. The characteristics of this solution are higher current intensity and stronger driving force during differential drive, making it more suitable for low-speed driving conditions, off-road conditions, and tracked vehicle conditions. This solution, combined with the first solution, can perfectly meet all vehicle driving conditions, including high and low speeds and off-road conditions.

[0025] The second synchronous motor differential drive scheme also has the following shortcomings: when using Figure 7When the limited-slip switch 5 is bypassed, the EM drive motor 3 will be driven by its own drive wheel 4 to rotate, generating an electromotive force and becoming a generator. The electricity generated by this generator is transmitted through... Figure 7 The limited-slip switch 5 shown forms a current loop, generating Joule heat and affecting the energy efficiency of this distributed electric drive system. Therefore, it can be further improved, as follows: Figure 10 As shown, the limited-slip switch 5 includes a normally open bypass short-circuit channel A, a normally closed winding drive channel B, and a normally open battery charging channel C. When differential drive is required, Figure 10 When the limited-slip switch 5 shown is triggered, the corresponding phase winding is switched from the winding drive channel B to the battery charging channel C. At the same time, the bypass short-circuit channel A of the limited-slip switch 5 is turned on. This allows the electricity generated by the EM drive motor 3 in generator mode to be stored in the power battery 1, thereby improving energy efficiency. At the same time, the bypass short-circuit channel A of the limited-slip switch 5 can also allow the stator windings 311 of other EM drive motors 3 to maintain their original self-coupling drive capability in a phase-series series state.

[0026] Figure 5 This is a schematic diagram of the circuit principle when the MCU motor control unit 2 of this patent simultaneously drives four EM drive motors 3 and adopts a delta connection, and the phase windings of each stator winding 311 are connected in series. At this time, the four EM drive motors 3 drive their respective corresponding drive wheels 4 to form a distributed electric four-wheel drive structure. This scheme is suitable for civilian 4×4 off-road vehicles.

[0027] Figure 6 This is a schematic diagram illustrating the circuit principle of the phase windings of each stator winding 311 connected in series when the MCU motor control unit 2 of this patent simultaneously drives six EM drive motors 3 in a star configuration. In this configuration, each EM drive motor 3 drives one drive wheel 4, forming a distributed electric six-wheel drive structure. This scheme is suitable for 6×6 off-road trucks, 6×6 military multi-axle all-terrain vehicles, etc. Because the MCU motor control unit 2 drives a large number of EM drive motors 3, cable routing can be difficult. Therefore, a method is adopted... Figure 6 The star connection shown requires fewer cables and is easier to wire than the delta connection. Obviously, this patent can also add more EM drive motors 3 to this phase-series series circuit structure; details will not be elaborated further. In short, regardless of the number of EM drive motors 3 used in a new energy vehicle employing this patented technology, as long as it follows the... Figure 2 , Figure 3 , Figure 5 , Figure 6The disclosure and examples demonstrate that after each phase winding of the stator winding 311 of each EM drive motor 3 is connected in series and connected to the multi-phase AC port of the MCU motor control unit 2, it can have self-coupling drive capability, without the need for specially written software to forcibly control and coordinate the speed of each EM drive motor 3 to implement algorithmic coupling. In particular, when there are more drive wheels 4 and more EM drive motors 3 in the distributed electric drive system, this patent can significantly reduce the complexity of the distributed electric drive system and the research and development and production costs.

[0028] Obviously, the EM drive motor 3 of this patent can be arranged on the vehicle body, installed on the drive axle, or installed in the wheel hub. Furthermore, the EM drive motor 3 can be either an axial flux motor or a radial flux motor. These are modifications and variations that can be implemented by those skilled in the art without creative effort based on the disclosure of this patent. Due to space limitations, this specification will not elaborate further. However, these modifications and variations still fall within the protection scope of this patent, and implementers still need to obtain authorization from the patentee.

[0029] Although certain terms and vocabulary are used in this specification, they are merely for ease of explanation and understanding and do not constitute any limitation on this patent. Based on the disclosure and description in this specification, those skilled in the art can obviously make changes and modifications to the above embodiments. Therefore, this patent is not limited to the specific embodiments disclosed and described above, and other modifications and changes to this patent still fall within the protection scope of this invention. Implementers still need to obtain authorization from the patentee.

Claims

1. A method for electric drive of a new energy vehicle, characterized by: Step S1: The MCU motor control unit (2) outputs a set of multiphase AC power; Step S2: The multiphase AC power is connected to a circuit with phase-series connection characteristics, which is composed of the phase windings of the stator windings (311) of each EM drive motor (3), and a common-mode rotating magnetic field is generated on each stator (31) of each EM drive motor (3). Step S3: The common-mode rotating magnetic field of each EM drive motor (3) and the corresponding rotor (32) generate electromagnetic torque through electromagnetic induction, and the electromagnetic torque of each rotor (32) drives its corresponding drive wheel (4). Step S4: The rotors (32) of each EM drive motor (3) are self-coupled and driven by electromagnetic induction with the common mode rotating magnetic field and the phase-separated series circuit structure.

2. The electric drive method for a new energy vehicle according to claim 1, characterized in that: The self-coupling drive in step S4 includes differential coupling drive when the EM drive motor (3) is an asynchronous motor. The rotor (32) of at least one of the EM drive motors (3) changes speed due to load change, which changes the current flowing through its stator winding (311). The common mode rotating magnetic field of each EM drive motor (3) also changes with the change of the current. The rotor (32) of other EM drive motors (3) changes speed due to the change of the common mode rotating magnetic field, thereby realizing differential coupling drive between each rotor (32).

3. The electric drive method for a new energy vehicle according to claim 1, characterized in that: The self-coupling drive in step S4 includes constant speed coupling drive when the EM drive motor (3) is a synchronous motor. The rotational speed of each rotor (32) of each EM drive motor (3) is synchronized with the rotational speed of the common mode rotating magnetic field, thereby realizing constant speed coupling drive between each rotor (32).

4. The electric drive method for a new energy vehicle according to claim 1, characterized in that: Bypass short-circuit each phase winding of the stator winding (311) of the EM drive motor (3) that requires limited slip in each of the EM drive motors (3), so that the common mode rotating magnetic field of the stator winding (311) disappears and the rotor (32) stops electromagnetic torque output, thereby playing a limited slip role.

5. The electric drive method for a new energy vehicle according to claim 1, characterized in that: The phase windings of at least two phases of the stator windings (311) of the EM drive motors (3) that need to rotate in the opposite direction are swapped, so that the common mode rotating magnetic field of the EM drive motor (3) rotates in the opposite direction, thereby realizing the reverse rotation of the drive wheel (4) connected to the EM drive motor (3).

6. The electric drive method for a new energy vehicle according to claim 3, characterized in that: The EM drive motor (3) is a synchronous motor. When differential drive is required, the current intensity of the multiphase AC power output by the MCU motor control unit (2) in step S1 is less than the minimum value for maintaining the synchronous rotation of each rotor (32), thereby utilizing the out-of-step phenomenon of the synchronous motor to achieve differential drive.

7. The electric drive method for a new energy vehicle according to claim 3, characterized in that: The EM drive motor (3) is a synchronous motor. When differential drive is required, at least one bypass short circuit is simultaneously implemented on each phase winding of the stator winding (311) of the EM drive motor (3) that requires differential drive. After the rotor (32) loses the electromagnetic torque of the common mode rotating magnetic field, the speed decreases. At the same time, other EM drive motors (3) that do not require differential drive still maintain the multi-phase AC drive described in step S1, and their speed is still synchronized with the common mode rotating magnetic field, thereby realizing the differential drive of the synchronous motor.

8. A structure of an electric drive device for a new energy vehicle, comprising an MCU motor control unit (2) electrically connected to an EM drive motor (3), a power battery (1), and a VCU vehicle control unit (7), characterized in that: After each phase of the stator winding (311) of each EM drive motor (3) is connected in series, it is connected to a set of multiphase AC power at the output of the MCU motor control unit (2). The common mode rotating magnetic field generated on the stator (31) of each EM drive motor (3) forms an electromagnetic induction connection with its respective rotor (32). Each rotor (32) forms a mechanical transmission connection with its respective drive wheel (4).

9. The structure of an electric drive device for a new energy vehicle according to claim 8, characterized in that: Each phase winding of the stator winding (311) of each EM drive motor (3) is electrically connected in parallel with the limited slide switch (5) to form a bypass of the phase winding controlled by the limited slide switch (5). The control terminal of the limited slide switch (5) is electrically connected to the MCU motor control unit (2).

10. The structure of a new energy vehicle electric drive device according to claim 8, characterized in that: in At least two phase windings of the stator winding (311) of the EM drive motor (3) that requires reverse control are electrically connected to the phase inversion switch (6), which swaps the phases of the corresponding phase windings.

11. The structure of an electric drive device for a new energy vehicle according to claim 9, characterized in that: The limited-slip switch (5) includes a normally open bypass short-circuit channel A, a normally closed coil drive channel B, and a normally open battery charging channel C.

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