NVH control method for series motor systems

Abstract

This invention discloses an NVH control method for a series motor system, which improves the NVH performance of a series motor by mounting the rotors of two motors with a phase shift, and calculates and searches for the optimal phase shift angle between the two rotors by an optimization method, thereby maximizing the reduction of the amplitude of the combined cogging torque of the series motor, the rotors employ a step-skew structure, and further improves the performance of the series motor by multi-motor vector control technology and PWM phase shift control technology.

Description

Technical Field

[0006] ,

[0007] ,

[0001] The present invention relates to the technical field of motors and their control, and more specifically, to a method for controlling NVH of a series motor system.

Background Art

[0002] In recent years, the sales of new energy vehicles in China have been growing rapidly. Due to the rapid development of new energy vehicles, a complete industrial chain has been formed in China, such as in the field of manufacturing power motors.

[0003] However, according to the requirements of different vehicle models, the requirements for the output of the drive motor are different. Although it is possible to increase the types of motors by adjusting the stacking thickness of the stator and rotor, it is still impossible to meet the needs of different vehicle models. In high-power applications, in order to meet the requirements, it is still necessary to invest different production lines.

[0004] On the other hand, in the fields of new energy commercial vehicles and non-road applications, the need for high-power motors is relatively high. Currently, there are few motor models that can meet these needs. If a new production line is established, the manufacturing cost will undoubtedly increase.

[0005] The multi-motor series connection technology provides a solution to solve the above problems. By connecting existing motors in series coaxially, this technology can achieve an improvement in output. Utilizing existing motor production equipment and production lines, it is possible to manufacture motor products with a wider output range. Therefore, it has currently become one of the directions that the industry is working on.

[0006] In addition, new energy vehicles have high requirements for the NVH performance of the entire vehicle. Especially in the non-road application field, due to the poor road surface conditions, in order to ensure the NVH performance of the entire vehicle, not only high mechanical rigidity is required for motor products, but various harmonic torques generated by the motor system itself are also strictly restricted.

[0007] Current NVH control technologies are basically proposed for single motors, and there are very few NVH control technologies for series motors. Therefore, the present invention proposes a cooperative design technology and a cooperative control technology for series motors, and aims to optimize the NVH performance of a series motor system by reducing or eliminating normal harmonic torque. [Overview of the project] [Problems that the invention aims to solve]

[0008] In response to the shortcomings of conventional technology, the present invention provides an NVH control method for a series motor system that can improve the NVH performance of the series motor. [Means for solving the problem]

[0009] To achieve the above objective, the present invention provides the following technical solution: A method for controlling NVH of a series motor system, comprising motor 1 and motor 2, wherein their rotor shafts are connected to each other to form a series motor, and the rotor of motor 1 and the rotor of motor 2 are angled relative to each other. JPEG2026521791000002.jpg54 is mounted with a phase shift, and the combined cogging torque of the series motors is It changes according to JPEG2026521791000003.jpg54, Maximum value of JPEG2026521791000004.jpg54 JPEG2026521791000005.jpg58 shows the motor status lot number Z and rotor pole pair number. Determined by JPEG2026521791000006.jpg54, JPEG2026521791000007.jpg512 The amplitude of the composite cogging torque is When it changes according to JPEG2026521791000008.jpg54, JPEG2026521791000009.jpg is best suited within the 514 range. JPEG2026521791000010.jpg58 exists, and at this time, the amplitude of the combined cogging torque of the series motor is minimized, and as shown in the figure, the angle JPEG2026521791000011.jpg58 shows the optimal phase shift mounting angle of the rotors of motor 1 and motor 2, controlled by the controller. How to optimize JPEG2026521791000012.jpg54 Step S1 involves mounting the series motor to the test stand, Divide JPEG2026521791000013.jpg511 into equal parts, It is written as JPEG2026521791000014.jpg527 (however, JPEG2026521791000015.jpg521, JPEG2026521791000016.jpg510) Step S2, First, let's assume i=1, and then determine the phase difference angle between the rotors of motor 1 and motor 2 when i=1. Step S3 calculates JPEG2026521791000017.jpg516, Step S4 involves starting the series motor and waiting until the rotation speed stabilizes, Step S5 involves measuring and recording the combined cogging torque of a series motor when the rotational speed is stable, Step S6 involves stopping the motor and setting i = i + 1, Determine whether i is equal to N+1. If so, proceed to the next step S8; otherwise, return to step S3 and determine the phase shift angle based on the new i value. Step S7 recalculates JPEG2026521791000018.jpg55, We will perform a final analysis of the measurement results to determine the optimal Step S8 includes obtaining JPEG2026521791000019.jpg58.

[0010] Furthermore, both motor 1 and motor 2 are three-phase motors, and the electromagnetic torque of motor 1 and motor 2 are coordinately controlled using multi-motor vector control technology.

[0011] Furthermore, the series motor uses PWM phase shift control technology.

[0012] Furthermore, the rotor structures in the motors 1 and 2 use a stepped skew structure.

Advantages of the Invention

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows. By shifting the poles between the two single motor rotors in the series motor and calculating the optimal phase shift angle, the minimization of the cooperative cogging torque of the series motor can be achieved, and the cooperative NVH performance of the series motor can be improved. By using the multi-phase motor unified cooperative vector control technology, the harmonic torque of a specific order can be removed, and the cooperative NVH performance of the series motor can be improved. By using the PWM phase shift control technology, the high-frequency harmonic current of the DC bus can be weakened, the loss of the DC bus capacitor can be reduced, the requirement for the capacitance value of the capacitor can be lowered, and the controller cost can be reduced. When a single motor fails, the series motor system still has the power output ability, establishing the redundancy of the electric drive system and improving the reliability of the system.

Brief Description of the Drawings

[0014] [Figure 1] It is a schematic diagram of motors 1 and 2 rotors mounted with a phase shift in the series motor system according to the present invention. [Figure 2] It is a flowchart of the optimization method of the angle of the control method of the series motor system according to the present invention. [Figure 3] It is a schematic diagram of the synthetic cogging torque in the series motor system according to the present invention. [Figure 4] It is a schematic diagram of harmonic torque cancellation in the series motor system according to the present invention. [Figure 5] It is a schematic diagram of bus harmonic current reduction in the series motor system according to the present invention.

Best Mode for Carrying Out the Invention

[0015] In the description of the present invention, terms indicating orientation and positional relationships such as "center", "horizontal direction (X)", "vertical direction (Y)", "vertical direction (Z)", "length", "width", "thickness", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or positional relationship shown in the drawings, and are merely for facilitating the explanation of the present invention and simplifying the description, and do not indicate or imply that the shown device or element necessarily has a specific orientation and is configured and operated in a specific orientation, and should not be understood as limiting the specific protection scope of the present invention.

[0016] Also, the terms "first" and "second" are used only for the purpose of description and should not be understood as indicating or implying relative importance or implicitly specifying the number of technical features. Thus, the features limited by "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise specified, "plural" and "several" mean two or more.

[0017] The present invention will be further described with reference to FIGS. 1 to 5.

[0018] An NVH control method for a series motor system, including a motor 1 and a motor 2, whose rotor shafts are connected to each other to form a series motor, and the rotor of the motor 1 and the rotor of the motor 2 are attached with a phase shift of only an angle JPEG2026521791000020.jpg54, and the combined cogging torque of the series motor varies according to JPEG2026521791000021.jpg54, The maximum value of JPEG2026521791000022.jpg54 JPEG2026521791000023.jpg58 is the number of stator slots Z of the motor and the rotor pole pairs Determined by JPEG2026521791000024.jpg54, JPEG2026521791000025.jpg512 The amplitude of the composite cogging torque is When it changes according to JPEG2026521791000026.jpg54, JPEG2026521791000027.jpg is best suited within the 514 range. JPEG2026521791000028.jpg58 exists, and at this time, the amplitude of the combined cogging torque of the series motor is minimized, and as shown in the figure, the angle JPEG2026521791000029.jpg58 shows the optimal phase shift mounting angle for the rotors of motor 1 and motor 2, controlled by the controller. How to optimize JPEG2026521791000030.jpg54 Step S1 involves mounting the series motor to the test stand, Divide JPEG2026521791000031.jpg511 into equal parts, It is written as JPEG2026521791000032.jpg527 (however, JPEG2026521791000033.jpg521, JPEG2026521791000034.jpg510) Step S2, First, let's assume i=1, and then determine the phase difference angle between the rotors of motor 1 and motor 2 when i=1. Step S3 calculates JPEG2026521791000035.jpg516, Step S4 involves starting the series motor and waiting until the rotation speed stabilizes, Step S5 involves measuring and recording the combined cogging torque of a series motor when the rotational speed is stable, Step S6 involves stopping the motor and setting i = i + 1, Determine whether i is equal to N+1. If so, proceed to the next step S8; otherwise, return to step S3 and determine the phase shift angle based on the new i value. Step S7 recalculates JPEG2026521791000036.jpg55, We will perform a final analysis of the measurement results to determine the optimal Step S8 includes obtaining JPEG2026521791000037.jpg58.

[0019] As shown in Figure 4, in this embodiment, preferably, both motor 1 and motor 2 are three-phase motors, and the electromagnetic torque of motor 1 and motor 2 are coordinately controlled using multi-motor vector control technology.

[0020] As shown in Figure 5, in this embodiment, the series motor preferably uses PWM phase shift control technology.

[0021] In this embodiment, preferably, the rotor structure within motor 1 and motor 2 uses a step skew structure.

[0022] By mounting the magnetic poles between the two single motor rotors in a series motor with a phase shift and calculating the optimal phase shift angle, the coordinated cogging torque of the series motor can be minimized, improving the coordinated NVH performance of the series motor. By using multiphase motor unified coordinated vector control technology, specific harmonic torques can be eliminated, improving the coordinated NVH performance of the series motor. By using PWM phase shift control technology, high-frequency harmonic currents in the DC bus can be weakened, reducing losses in the DC bus capacitor, lowering the capacitor capacitance value requirements, and reducing controller costs. In the event of a single motor failure, the series motor system still maintains its power output capability, establishing redundancy in the electric drive system and improving system reliability.

[0023] The above description represents only preferred embodiments of the present invention, and the scope of protection of the present invention is not limited to the above embodiments. All technical solutions based on the concept of the present invention fall within the scope of protection of the present invention. Furthermore, those skilled in the art should consider various improvements and modifications made without departing from the principles of the present invention to be within the scope of protection of the present invention.

Claims

1. An NVH control method for a series motor system, comprising a motor 1 and a motor 2, wherein their rotor shafts are connected to each other to form a series motor, wherein the rotor of motor 1 and the rotor of motor 2 are angled relative to each other. They are mounted with a phase shift of only that much, and the combined cogging torque of the series motors is It changes accordingly, Maximum value This refers to the motor's status lot number Z and rotor pole pair number. Determined by, The amplitude of the combined cogging torque is When it changes in accordance with, Best within the range When such a condition exists, the amplitude of the combined cogging torque of the series motors is minimized, and as shown in the figure, the angle This is the optimal phase-shift mounting angle for the rotors of motor 1 and motor 2, and is controlled by the controller. The optimization method is, Step S1 involves mounting the series motor to the test stand, Divide it into equal parts, It is written as (however, 、 ) Step S2 and, First, let i = 1, and then the phase difference angle between the rotors of motor 1 and motor 2 when i = 1. Step S3 for calculating, Step S4 involves starting the series motor and waiting until the rotation speed stabilizes, Step S5 involves measuring and recording the combined cogging torque of a series motor when the rotational speed is stable, Step S6 involves stopping the motor and setting i = i + 1, Determine whether i is equal to N+1. If so, proceed to the next step S8; otherwise, return to step S3 and determine the phase shift angle based on the new i value. Step S7 involves recalculating, We will perform a final analysis of the measurement results to determine the optimal A method for controlling the NVH of a series motor system, characterized by including step S8 to obtain a result.

2. The NVH control method for a series motor system according to claim 1, characterized in that both motor 1 and motor 2 are three-phase motors, and the electromagnetic torque of motor 1 and motor 2 are controlled in a coordinated manner using multi-motor vector control technology.

3. The NVH control method for a series motor system according to claim 1, characterized in that the series motor uses PWM phase shift control technology.

4. The NVH control method for a series motor system according to claim 1, characterized in that the rotor structure in the motor 1 and motor 2 uses a step skew structure.

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