Drive motor for improving starting performance of electric vehicle and comprehensive control method thereof

Abstract

The application relates to a driving motor for improving the starting performance of an electric vehicle and a comprehensive control method thereof. The driving motor has a double magnetism adjusting function, the rotor structure is suitable for a high-speed large-torque operation state, has the advantages of high sine rate of induced electromotive force, low amplitude of tooth slot force fluctuation, low hysteresis loss and low eddy current loss, the driving motor is comprehensively controlled through driving motor current closed loop control parameter adjustment, driving motor rotating speed closed loop control parameter adjustment, inverter switching frequency adjustment and excitation magnetic flux adjustment, the rapidity and smoothness of the electric vehicle in the starting process are improved, and the starting process of the electric vehicle is suitable for various road conditions such as downhill road, horizontal road and uphill road. The driving motor structure design and comprehensive control method adopted by the application improve the performance of the electric vehicle in the starting process, increase the comfort and satisfaction of the electric vehicle driver and passenger, and thus increase the core competitiveness of the electric vehicle in the motor vehicle market.

Description

Technical Field

[0001] This invention relates to the field of electric vehicles, and more specifically to a drive motor and its integrated control method for improving the starting performance of electric vehicles. Background Technology

[0002] With the promotion and application of new energy sources, the sales volume of electric vehicles in China and even globally is increasing significantly.

[0003] However, while the overall technology of electric vehicles has improved significantly, some technical challenges still require further improvement and optimization. For example, compared to gasoline-powered vehicles, current electric vehicles suffer from lower starting torque, slower starting speed, and longer starting time. These weaknesses in the starting process of electric vehicles will lead to a negative driving experience for drivers and passengers, weaken the competitiveness of electric vehicles against gasoline-powered vehicles, and hinder the sustainable development of electric vehicles in the vehicle sales and usage market.

[0004] Regarding drive motors suitable for electric vehicles, Chinese patent application CN201911119823.5 discloses a hub motor with the stator mounted inside the rotor, fully considering vibration damping measures during electric vehicle operation. This type of drive motor is well-suited for installation in the wheel hub of an electric vehicle. However, to improve the operating performance of the drive motor (including starting, speed regulation, and braking), it is necessary to propose an optimal control method for the specific drive motor structure, thereby achieving the integration of drive motor hardware and software systems and ultimately improving the operating performance of the electric vehicle. Regarding control methods for electric vehicle drive motors, Chinese patent application CN202011325186.X discloses an electric vehicle starting control method. This method is mainly based on hardware such as a power module, a brushless DC motor, a control module, and a throttle, and achieves smooth starting of the electric vehicle drive motor through steps such as acquiring throttle signals, motor type determination, Hall initial deviation angle compensation, operating mode determination, and motor control. This method is mainly an electric vehicle start-up control technology implemented for non-motorized vehicles (small electric vehicles), and the type of drive motor controlled is a brushless DC motor. Since the drive motors of current new energy electric vehicles (motorized vehicles) are all AC motors, this method cannot be promoted and applied in new energy electric vehicles (motorized vehicles). Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this invention is to provide a drive motor for improving the starting performance of electric vehicles and a comprehensive control method based on the drive motor, which can improve the speed and smoothness of the electric vehicle during the starting process, thereby enhancing the driver's control performance of the electric vehicle and improving the comfort of the electric vehicle driver and passengers.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A drive motor for improving the starting performance of an electric vehicle includes a front cover, a shaft, a rotor core, bearings, a stator section, a housing, and a rear cover. The shaft and rotor core constitute the rotor section of the drive motor. The stator section comprises an armature winding, a field-adjusting winding, an excitation permanent magnet, a U-shaped stator inner core, and a ring-shaped stator inner core. The excitation permanent magnet is embedded within the armature winding, and the U-shaped and ring-shaped stator inner cores serve as the magnetic flux path for the excitation permanent magnet. The excitation direction of the excitation permanent magnet is perpendicular to the direction of the magnetic field generated after current is applied to the armature winding. The drive motor has a dual field-adjusting function, which is accomplished individually or jointly by the field-adjusting winding and the field-adjusting permanent magnet. When a pulse current of appropriate amplitude is applied, the field-adjusting winding can control the magnetization or demagnetization of the field-adjusting permanent magnet.

[0007] Preferably, the rotating shaft is provided with a dovetail keyway, and the rotating shaft is assembled with the rotor core as a whole through the dovetail keyway and wedge key.

[0008] Furthermore, the U-shaped stator inner core, the annular stator inner core, and the rotor core are made of stacked silicon steel sheets, with insulating rubber between the silicon steel sheets for electromagnetic isolation; the thickness of the silicon steel sheets is less than 0.5 mm.

[0009] Furthermore, the number of slots in the U-shaped stator core matches the number of slots in the rotor core, and the slots in the rotor core exhibit the optimal skew angle.

[0010] This invention also provides a comprehensive control method based on the aforementioned drive motor, including control parameter adjustment for the drive motor current closed loop, control parameter adjustment for the drive motor speed closed loop, inverter switching frequency adjustment, and excitation flux adjustment. The controller receives in real time the analog signal for rapid and smooth start applied by the driver to the electric vehicle, as well as the current and speed signals of the drive motor's operating status. After analysis and judgment by the controller's software program, a control signal is sent to the inverter to achieve smooth start-up and operation of the drive motor. The signals output by the controller mainly complete the switching frequency adjustment of the inverter and the adjustment of magnetization or demagnetization.

[0011] Furthermore, in the closed-loop control process of the drive motor current, the maximum torque / current control method is adopted, combined with the switching frequency adjustment of the inverter, to ensure that the drive motor outputs a large electromagnetic torque.

[0012] Specifically, based on the maximum torque / current control method, the inverter switching frequency is adjusted in segments, and the drive motor's torque is calculated in real time. shaft current and shaft current Then, the control parameters for the closed-loop current of the drive motor are adjusted. The specific process is as follows: Segment 1: From time 0 to point P1, the maximum torque / current control parameter 1 and the inverter regulation frequency are used. This allows the drive motor to output a large q-axis current in a short period of time. ; In obtaining real-time q-axis current In this case, the actual d-axis current It can be calculated; the calculation formula is... In the formula, It is the real-time current value of the armature winding obtained through the current measurement module; Segment Two: From point P1 to point P2, the maximum torque / current control parameter two and the inverter regulation frequency are used. This causes the q-axis current output by the drive motor to... The value initially tends to stabilize, and the relationship with the q-axis current is obtained through calculation. Corresponding real-time d-axis current ; Segment 3: From point P2 to point P3, adjust the maximum torque / current control parameter 3 and the inverter regulation frequency. This causes the q-axis current output by the drive motor to... Accelerate the approach to a stable value, and obtain the q-axis current through calculation. Corresponding real-time d-axis current .

[0013] Furthermore, the control parameters for the closed-loop speed control of the drive motor are adjusted using a saturation function. The sliding mode control method.

[0014] Furthermore, the adjusting permanent magnet alone can complete the primary stage of magnet adjustment of the drive motor, which is suitable for the starting process of electric vehicles on downhill roads; the adjusting winding and the adjusting permanent magnet working together can complete the intermediate and advanced stages of magnet adjustment of the drive motor, which is suitable for the starting process of electric vehicles on level roads and uphill roads.

[0015] Furthermore, the magnetization process of the magnetizing winding is continuous or intermittent; the magnetization process of the magnetizing permanent magnet is continuous.

[0016] The drive motor and the integrated control method for rapid and smooth start of an electric vehicle based on the drive motor provided by this invention have the following advantages compared with the prior art: First, the drive motor provided by the present invention has the advantages of dual magnetic adjustment function, preventing the excitation permanent magnet from being magnetized, the coercivity of the excitation permanent magnet being much greater than that of the adjustment permanent magnet, the rotor structure being suitable for high-speed and high-torque operation, and high induced electromotive force sinusoidal rate, low cogging force fluctuation amplitude, low hysteresis loss and eddy current loss.

[0017] Secondly, the integrated control method for the drive motor proposed in this invention includes the adjustment of control parameters for the drive motor current closed loop, the adjustment of control parameters for the drive motor speed closed loop, the adjustment of the inverter switching frequency, and the adjustment of the excitation flux. These control processes together complete the rapid and smooth start-up of the drive motor, thereby achieving the speed and smoothness of the electric vehicle's start-up process, and making the electric vehicle's start-up process suitable for various road conditions such as downhill roads, level roads, and uphill roads.

[0018] The drive motor structure design and integrated control technology adopted in this invention improve the performance of the electric vehicle's starting process on the one hand, and increase the comfort and satisfaction of the electric vehicle driver and passengers on the other hand, thereby increasing the core competitiveness of electric vehicles in the motor vehicle market. Attached Figure Description

[0019] Figure 1 It is a three-dimensional structure of a drive motor used in electric vehicles; Figure 2 It refers to the rotor part of the drive motor, including its composition and structure. Figure 3 It refers to the composition and structure of the stator part of the drive motor; Figure 4 This is a comprehensive control block diagram of the drive motor; Figure 5 This is a diagram showing the effect of closed-loop segmented control of drive motor current, which combines the maximum torque / current method and the inverter switching frequency method. Figure 6 It is a comparison of the differences between the two approach law functions of the closed-loop control of the drive motor speed; Figure 7 It is the theoretical simulation analysis result of the closed-loop control of the drive motor speed; Figure 8 These are simulation calculation results of the magnetization and demagnetization phenomena of the drive motor; Figure 9This is a specific application of the dual magnetic adjustment function of the drive motor in the rapid and smooth start of an electric vehicle. Reference numerals: Front cover 1, Shaft 2, Rotor core 3, Bearing 4, Stator section 5, Housing 6, Rear cover 7, Overall appearance 8, Current closed-loop control parameter adjustment 9, Drive motor speed closed-loop control parameter adjustment 10, Inverter switching frequency adjustment 11, Excitation flux adjustment 12; Dovetail keyway 2 / 21, Wedge key 2 / 22, View surface 3 / 31, Dashed line 3 / 32, Armature winding 5 / 51, Magnetic adjustment winding 5 / 52, Excitation permanent magnet 5 / 53, Magnetic adjustment permanent magnet 5 / 54, U-shaped stator inner core 5 / 55, Annular stator outer core 5 / 56. Detailed Implementation

[0020] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 The diagram shows a three-dimensional structure of a drive motor for electric vehicles that improves the starting performance of electric vehicles. It includes a front cover 1, a shaft 2, a rotor core 3, a bearing 4, a stator 5, a housing 6, and a rear cover 7. The diagram also shows the overall appearance of the drive motor after these components are assembled into one unit.

[0022] like Figure 2 The diagram shows the structure of the rotor portion of a drive motor, which consists of a rotating shaft 2 and a rotor core 3. The rotating shaft 2 is assembled with the rotor core 3 via a dovetail keyway 2 / 21 and a wedge key 2 / 22 to increase the structural robustness of the drive motor rotor portion under high-speed and high-torque operation. The rotor core 3 is made of stacked silicon steel sheets, and the rotor teeth exhibit an optimal skew angle. View plane 3 / 31 is the inclined surface generated by the skew teeth of the rotor core 3 in the radial sectional view. The dashed line 3 / 32 is the outline generated by the skew teeth of the rotor core 3 at the bottom of the radial sectional view.

[0023] like Figure 3 The diagram shows the composition and structure of the stator section of a drive motor. The stator section includes an armature winding 5 / 51, a field-adjusting winding 5 / 52, an excitation permanent magnet 5 / 53, a field-adjusting permanent magnet 5 / 54, a U-shaped stator inner core 5 / 55, and a ring-shaped stator outer core 5 / 56. The excitation permanent magnet 5 / 53 is embedded within the armature winding 5 / 51. The excitation direction of the excitation permanent magnet 5 / 53 is perpendicular to the direction of the magnetic field generated when current is applied to the armature winding 5 / 51, thus preventing the excitation permanent magnet 5 / 53 from being magnetized (enhanced or demagnetized). The U-shaped stator inner core 5 / 55 and the ring-shaped stator outer core 5 / 56 together serve as the magnetic flux path controlling the excitation permanent magnet 5 / 53 and the field-adjusting permanent magnet 5 / 54. This aims to increase the accumulation of magnetic flux and the amount of magnetic flux interaction with the rotor, ultimately improving the operating efficiency of the drive motor.

[0024] The drive motor has a dual magnet adjustment function, which can be completed by the magnet adjustment winding 5 / 52 and the magnet adjustment permanent magnet 5 / 54 individually, or by both of them together. When a pulse current of appropriate amplitude is applied, the magnet adjustment winding 5 / 52 can control the magnetization or demagnetization of the magnet adjustment permanent magnet 5 / 54. The magnitude of the pulse current applied to the magnet adjustment winding 5 / 52 determines the degree of magnetization control of the magnetization or demagnetization of the magnet adjustment permanent magnet 5 / 54.

[0025] Preferably, the coercivity of the excitation permanent magnet 5 / 53 is much greater than that of the tuning permanent magnet 5 / 54, in order to ensure that the excitation permanent magnet 5 / 53 is not affected by the current of the armature winding 5 / 51 or the current of the tuning winding 5 / 52 (magnetization or demagnetization occurs).

[0026] Preferably, the rotor core 3, the U-shaped stator inner core 5 / 55, and the annular stator outer core 5 / 56 are made of stacked silicon steel sheets (with insulating rubber between the silicon steel sheets to achieve electromagnetic insulation). Their shape and size can maximize the utilization rate of the motor's magnetic field. The thickness of the silicon steel sheets should be less than 0.5 mm, and the material should have the characteristics of high permeability, low coercivity, and high resistivity. The purpose is to reduce hysteresis loss and eddy current loss, thereby improving the working efficiency of the drive motor.

[0027] Preferably, the slots of the rotor core 3 exhibit an optimal skew angle, the purpose of which is to increase the sinusoidal rate of the armature induced electromotive force of the drive motor. This facilitates optimal operation control of the drive motor, thereby enhancing the speed of the drive motor during startup. Compared to the traditional straight slot structure of the rotor core, the principle by which the skewed slot structure of the rotor core can increase the sinusoidal rate of the armature induced electromotive force of the drive motor is as follows: First, assume that the drive motor rotor structure adopts a straight slot form, and straight slot a and straight slot b differ in phase. Mechanical angle; Secondly, when the rotor of the drive motor is rotating, induced electromotive forces will be generated in the armature winding. and ; Next, take the induced electromotive force. and average The average induced electromotive force The sinusoidal power will be greater than the induced electromotive force. and The sine law.

[0028] Finally, we can conclude that: compared to straight groove structures, inclined grooves are... The mechanically angled rotor tooth structure can improve the sinusoidal rate of the induced electromotive force in the armature winding of the drive motor.

[0029] In general, the mathematical relationship between the induced electromotive force of a skewed slot and the induced electromotive force of a straight slot can be expressed as follows: In the formula, It is the armature winding induced electromotive force generated by the rotor skew slots. It is the induced electromotive force generated by the straight slots of the rotor. It is the first The mechanical angle difference between the first rotor slot and the first rotor slot. It is the number of straight slots in the rotor.

[0030] Preferably, given that the number of slots in the stator section 5 and the number of slots in the rotor core 3 are determined, the formula for calculating the optimal skew angle of the rotor core 3 is as follows: In the formula, This refers to the number of tooth slots in stator section 5. It refers to the number of tooth slots in rotor core 3. It is the greatest common divisor.

[0031] Furthermore, the cogging width of the stator section 5 and the rotor core 3 can be optimally selected through electromagnetic field numerical calculation software. The purpose is to reduce the fluctuation amplitude of the cogging force of the drive motor, thereby enhancing the smoothness of the drive motor during the start-up process.

[0032] After all the components of the drive motor are assembled, there is an air gap between the inner diameter of the stator part 5 and the outer diameter of the rotor core 3. The width of this air gap should be less than 0.5mm. The purpose is to improve the magnetic field interaction rate between the stator part 5 and the rotor core 3 (reduce leakage flux), thereby improving the performance and efficiency of the drive motor in terms of its structure.

[0033] Based on the aforementioned drive motor structure types, this invention proposes a comprehensive control method for the rapid and smooth start-up of electric vehicles, such as... Figure 4 The diagram shown is a block diagram of the comprehensive control method for the drive motor. In general, the control method includes 9 adjustment of the control parameters of the drive motor current closed loop, 10 adjustment of the control parameters of the drive motor speed closed loop, 11 adjustment of the inverter switching frequency, and 12 adjustment of the excitation flux.

[0034] Generally, Figure 4 The implementation process of the control method shown is jointly completed by a controller with software program execution function, high frequency signal input and output function, and armature current measurement module and speed measurement module of drive motor; Figure 4 The inverter shown is designed to convert the DC power output from the DC power supply into AC power in real time under the control of the controller, and then supply the AC power to the drive motor.

[0035] The controller's function is to receive the amplitude of the analog signal for rapid and smooth start applied by the driver to the electric vehicle in real time, as well as the real-time data signals of the drive motor's operating status (armature current signal and speed signal). After analyzing and judging the data using software programs, the controller drives the inverter to operate, thereby achieving closed-loop control of the drive motor's current and speed. The controller's output signals are mainly used to adjust the inverter's switching frequency and to adjust the magnetization or demagnetization of the drive motor.

[0036] The analog signal for a quick and smooth start applied by the driver to the electric vehicle is a voltage signal. The larger the amplitude of this voltage signal, the shorter the time the driver intends to complete the start-up process of the electric vehicle. The armature current signal of the drive motor is collected by the current measurement module and uploaded to the controller. The speed signal of the drive motor is collected by the speed measurement module (incremental rotary encoder) and uploaded to the controller.

[0037] The higher the accuracy and frequency of the current measurement module in acquiring the current signal, the better it is for completing the precise and real-time control of the drive motor current closed loop; the higher the resolution of the speed measurement module (incremental rotary encoder), the better it is for completing the precise and real-time control of the drive motor speed closed loop.

[0038] For the drive motor proposed in this invention, a maximum torque / current control method is readily adopted during its current closed-loop control process. The purpose is to initially ensure that the drive motor outputs a large electromagnetic torque. The principle of this maximum torque / current control method is as follows: First, using coordinate transformation theory and methods, the acquired armature current of the drive motor is decomposed into... coordinate system shaft current and shaft current ; Secondly, the above-mentioned... shaft current and shaft current Substitute the electromagnetic torque formula of the drive motor And through differentiation and derivation, we obtain the minimum value that can currently enable the drive motor to output the maximum torque. shaft current and shaft current In the formula, It is the number of pole pairs of the drive motor. It is the excitation flux linkage of the drive motor. and These are the drive motors Shaft inductance and Shaft inductance; Finally, the minimum obtained by differentiation and derivation shaft current and shaft current The data is transmitted to the space vector pulse width modulation module, which controls the inverter's operating status in real time and ultimately provides high-sinusoidal AC power to the drive motor.

[0039] Based on the aforementioned maximum torque / current control method, this invention further refines the adjustment process of the inverter switching frequency and current closed-loop parameters, enabling segmented adjustment. This improves the amplitude characteristics, speed, and stability of the drive motor's output torque. Figure 5 As shown, based on the above maximum torque / current control method and considering the segmented adjustment of the inverter switching frequency, the real-time calculation of the drive motor's torque / current is performed. shaft current and shaft current Then, the control parameters for the drive motor current closed-loop are adjusted to ultimately ensure that the electromagnetic torque output by the drive motor has a reasonable amplitude characteristic and settling time. The specific segmented control process is as follows: Section 1: In Figure 5 The time interval from time 0 to point P1 is shown, using the maximum torque / current control parameters ① (kdp=0.5, kqp=0.6, kdi=kpi=14.6, kdp / kdq, kdi / kpi are the d / q axis proportional and integral coefficients of the current closed-loop control, respectively) and the inverter regulation frequency. This allows the drive motor to output a large q-axis current in a short period of time. ; In obtaining real-time q-axis current In this case, the actual d-axis current It can be calculated; the calculation formula is... In the formula, It is the real-time current value of the armature winding obtained through the current measurement module.

[0040] Section Two: In Figure 5 The time interval from P1 to P2 is shown, using the maximum torque / current control parameters ② (kdp=0.5, kqp=0.6, kdi=kpi=145.7) and the inverter regulation frequency. This causes the q-axis current output by the drive motor to... Initially approaching a stable value ( Figure 5 The q-axis stable value shown is 1.2A), and the q-axis current is obtained through calculation. Corresponding real-time d-axis current ; Section 3: To accelerate the stabilization of the drive motor's output electromagnetic torque, the maximum torque / current control parameters ③ (kdp=4.5, kqp=6.2, kdi=kpi=1457) and the inverter's regulating frequency are adjusted between points P2 and P3. This causes the q-axis current output by the drive motor to... Accelerate the approach to a stable value, and obtain the q-axis current through calculation. Corresponding real-time d-axis current .

[0041] The process of segmented adjustment of the maximum torque / current control parameters and inverter frequency described above has been verified by theoretical simulation experiments and physical experiments. Its advantages in achieving the output torque of the drive motor are: it has a large amplitude characteristic and can complete the stable operation of electromagnetic torque in a short time.

[0042] Furthermore, the drive motor speed closed-loop adopts a saturation function-based approach. The purpose of the sliding mode control method is to improve the smoothness of the drive motor's speed increase based on the above-mentioned current closed-loop control, thereby improving the smoothness of the electric vehicle's starting speed increase.

[0043] like Figure 6 As shown, the sign function is described. and saturation function The principle of sign function, and the difference between the two. Through comparison, we can see: The output signal is step-like and also has abrupt change characteristics; saturation function Within the boundary layer Δ, its output signal exhibits smooth characteristics. Therefore, compared to signals based on the sign function... Sliding mode control method based on saturation function The sliding mode control method can further improve the smoothness of the drive motor's speed increase, thereby improving the smoothness of the electric vehicle's starting speed increase.

[0044] Figure 7 It shows a symbolic function-based saturation function The effect of sliding mode control on the drive motor speed. Through comparison, it can be concluded that: based on the saturation function... The sliding mode control method can improve the smoothness of the drive motor's output speed; in particular, it can further modify the saturation function. In the case of boundary layer parameter Δ, for example, reducing the value of boundary layer Δ (from 0.02 to 0.005) can further improve the smoothness of the drive motor output speed.

[0045] Furthermore, the excitation flux adjustment process of the present invention is completed by the adjusting winding 5 / 52 and the adjusting permanent magnet 5 / 54 of the drive motor. The adjusting process of the adjusting winding 5 / 52 can be continuous or intermittent; the adjusting process of the adjusting permanent magnet 5 / 54 is continuous.

[0046] Generally, when the adjusting permanent magnet 5 / 54 acts alone (in demagnetized state), it can complete the primary stage of magnetization of the drive motor, which is suitable for starting and running electric vehicles on downhill roads. When the adjusting winding 5 / 52 and the adjusting permanent magnet 5 / 54 work together, they can complete the intermediate and advanced stages of magnetization of the drive motor, which is suitable for starting and running electric vehicles on level or uphill roads.

[0047] In particular, based on the working principle and characteristics of the motor, when the adjusting winding 5 / 52 and the adjusting permanent magnet 5 / 54 complete the dual magnetic adjustment function, the above-mentioned comprehensive control method can further improve the effect of the drive motor to start quickly and smoothly, thereby also improving the starting performance (speed and smoothness) of the electric vehicle.

[0048] like Figure 8 Figures (1) and (2) show the simulation results of the magnetic field distribution of the drive motor under demagnetizing and magnetizing conditions, respectively. By comparing... Figure 8 From (1) and (2), we can see that: under demagnetization and magnetization conditions, the excitation directions 12 / 1 and 12 / 2 of the excitation permanent magnet 5 / 53 remain unchanged, while the excitation direction of the magnetizing permanent magnet 5 / 54 changes (as shown in 13 / 1 and 13 / 2); under demagnetization conditions, the magnetic flux of the drive motor mainly forms a magnetic circuit through the U-shaped stator inner core 5 / 55 and the annular stator inner core 5 / 56, and the interaction magnetic flux between it and the rotor core 3 is relatively small; under magnetization conditions, the magnetic flux in the annular stator inner core 5 / 56 is relatively small, and most of the magnetic flux interacts between the U-shaped stator inner core 5 / 55 and the rotor core 3.

[0049] According to the electromagnetic torque formula of the drive motor mentioned above Therefore, when the drive motor is demagnetized, the magnetic flux in this torque formula is... This reduction leads to a decrease in the amplitude of the electromagnetic torque; when the drive motor is magnetized, the magnetic flux in this torque formula... This increases the amplitude of the electromagnetic torque.

[0050] like Figure 9 The figure shows the electromagnetic torque of the drive motor under different road conditions, based on the electromagnetic torque formula of the drive motor mentioned above. The role of the drive motor in the rapid and smooth start of an electric vehicle. Generally, the primary stage of magnet adjustment of the drive motor can be completed by the magnetizing permanent magnet 5 / 54 alone (in the demagnetized state), which is suitable for the starting process of electric vehicles on downhill roads; the intermediate and advanced stages of magnet adjustment of the drive motor can be completed by the magnetizing winding 5 / 52 and the magnetizing permanent magnet 5 / 54 together, which is suitable for the starting process of electric vehicles on level roads and uphill roads.

[0051] Preferably, the magnetizing process of the magnetizing winding 5 / 52 can be continuous or intermittent, depending on the need for a fast and smooth start-up of the electric vehicle; the magnetizing process of the permanent magnet 5 / 54 is continuous.

[0052] In summary, the drive motor and integrated control method based on the present invention firstly propose the application of a dual-tunable magnetic drive motor to the drive system of an electric vehicle; secondly, it employs an integrated control method that adjusts the inverter switching frequency, drive motor current closed-loop parameters, and speed closed-loop parameters to achieve rapid start-up and smooth acceleration of the drive motor; thirdly, it refines the adjustment process of the inverter switching frequency and current closed-loop parameters to achieve segmented adjustment, thereby improving the amplitude characteristics, speed, and stability of the drive motor's output torque; and finally, it adopts a control method based on a saturation function. The sliding mode control method improves the smoothness of the drive motor's output speed during startup. Furthermore, the demagnetizing and magnetizing functions of the drive motor further enhance the starting performance of electric vehicles under special road conditions such as climbing and descending slopes. This invention discloses a dual-adjustable magnetic drive motor and its integrated control method, aiming to improve the starting performance of electric vehicles through hardware structure and optimized control technology, thereby increasing the competitiveness of electric vehicles in the vehicle production and sales market, and ultimately promoting green travel and green transportation.

[0053] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A drive motor for improving the starting performance of an electric vehicle, characterized in that, The device includes a front cover (1), a shaft (2), a rotor core (3), a bearing (4), a stator section (5), a housing (6), and a rear cover (7). The shaft (2) and the rotor core (3) constitute the rotor section of the drive motor. The stator section (5) consists of an armature winding (5 / 51), a magnetic adjustment winding (5 / 52), an excitation permanent magnet (5 / 53), a magnetic adjustment permanent magnet (5 / 54), a U-shaped stator inner core (5 / 55), and an annular stator inner core (5 / 56). The excitation permanent magnet (5 / 53) is embedded in the armature winding (5 / 51), and the U-shaped stator inner core (5 / 55) and the annular stator inner core (5 / 56) serve as the magnetic flux path of the excitation permanent magnet (5 / 53). The excitation direction of the excitation permanent magnet (5 / 53) is perpendicular to the direction of the magnetic field generated by the armature winding (5 / 51) after current is applied. The coercivity of the excitation permanent magnet (5 / 53) is much greater than that of the tuning permanent magnet (5 / 54). The drive motor has a dual tuning function, which is completed by the tuning winding (5 / 52) and the tuning permanent magnet (5 / 54) ​​alone or together. When a pulse current of appropriate amplitude is applied, the tuning winding (5 / 52) can control the magnetization or demagnetization of the tuning permanent magnet (5 / 54). The magnitude of the pulse current applied to the tuning winding (5 / 52) determines the degree of magnetization control of the tuning permanent magnet (5 / 54). The comprehensive control method for the drive motor includes control parameter adjustment for the drive motor current closed loop, control parameter adjustment for the drive motor speed closed loop, inverter switching frequency adjustment, and excitation flux adjustment. The controller receives the analog signal for rapid and smooth start applied to the electric vehicle by the driver in real time, as well as the current and speed signals of the drive motor's operating status. After analysis and judgment by the controller's software program, a control signal is sent to the inverter to achieve smooth start-up of the drive motor. The signal output by the controller mainly completes the switching frequency adjustment of the inverter and the adjustment of magnetization or demagnetization. The magnetizing permanent magnet (5 / 54) ​​alone can complete the primary stage magnetization of the drive motor, which is suitable for the start-up process of the electric vehicle on downhill roads. The magnetizing winding (5 / 52) and the magnetizing permanent magnet (5 / 54) ​​together can complete the intermediate and advanced stage magnetization of the drive motor, which is suitable for the start-up process of the electric vehicle on level roads and uphill roads.

2. The drive motor for improving the starting performance of an electric vehicle as described in claim 1, characterized in that, The rotating shaft is provided with a dovetail keyway (2 / 21), and the rotating shaft (2) is assembled with the rotor core (3) through the dovetail keyway (2 / 21) and the wedge key (2 / 22).

3. The drive motor for improving the starting performance of an electric vehicle as described in claim 1, characterized in that, The U-shaped stator inner core (5 / 55), the annular stator inner core (5 / 56), and the rotor core (3) are made of stacked silicon steel sheets, with insulating rubber between the silicon steel sheets for electromagnetic isolation; the thickness of the silicon steel sheets is less than 0.5 mm.

4. A drive motor for improving the starting performance of an electric vehicle as described in claim 1, characterized in that, The number of slots in the U-shaped stator inner core (5 / 55) matches the number of slots in the rotor core (3), and the slots in the rotor core (3) exhibit the optimal skew angle.

5. A drive motor for improving the starting performance of an electric vehicle as described in claim 1, characterized in that: In the closed-loop control of the drive motor current, the maximum torque / current control method is adopted, combined with the switching frequency adjustment of the inverter, to ensure that the drive motor outputs a large electromagnetic torque.

6. The drive motor for improving the starting performance of an electric vehicle as described in claim 5, characterized in that: Based on the maximum torque / current control method, and by integrating segmented adjustment of the inverter switching frequency, the drive motor is calculated in real time. shaft current and shaft current Then, the control parameters for the closed-loop current of the drive motor are adjusted. The specific process is as follows: Segment 1: From time 0 to point P1, the maximum torque / current control parameter 1 and the inverter regulation frequency are used. This allows the drive motor to output a large q-axis current in a short period of time. ; Obtaining real-time q-axis current In this case, the actual d-axis current It can be obtained through calculation; the calculation formula is: In the formula, It is the real-time current value of the armature winding obtained through the current measurement module; Segment Two: From point P1 to point P2, the maximum torque / current control parameter 2 and the inverter regulation frequency are used. This causes the q-axis current output by the drive motor to... The value initially tends to stabilize, and the relationship with the q-axis current is obtained through calculation. Corresponding real-time d-axis current ; Segment 3: From point P2 to point P3, adjust the maximum torque / current control parameter 3 and the inverter regulation frequency. This causes the q-axis current output by the drive motor to... Accelerate the approach to a stable value, and obtain the q-axis current through calculation. Corresponding real-time d-axis current .

7. A drive motor for improving the starting performance of an electric vehicle as described in claim 6, characterized in that, The control parameters for the closed-loop speed control of the drive motor are adjusted based on a saturation function. The sliding mode control method.

8. A drive motor for improving the starting performance of an electric vehicle as described in claim 1, characterized in that, The magnetization process of the magnetizing winding (5 / 52) is continuous or intermittent; the magnetization process of the magnetizing permanent magnet (5 / 54) ​​is continuous.

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