阅读说明：本技术 一种高效直流驱动永磁转子电机的设计方法 (Design method of efficient direct-current driving permanent magnet rotor motor ) 是由 杨猛 于 2021-07-22 设计创作，主要内容包括：本发明公开了一种高效直流驱动永磁转子电机的设计方法,包括以下步骤：确定额定转矩T,最大转矩Tmax,调速区间最高转速Smax、最低转速Smin,确定三相额定供电电压VAC和整流后的电压VDCmax；计算最低转速时电机直流电压；按照最低转速时电机直流电压VDCmin,最低转速Smin,额定转矩T,最大转矩TMax设计电动机,达到额定效率；按VDCmax设计电机的绝缘等级及电机控制器的耐压等级；按Smax,Tmax设计电机的机械强度,本发明涉及电机设计技术领域,采用直流调压方式对永磁转子电机进行调速,转速与频率控制无关,消除了永磁同步电机超同步运行时弱磁调速问题,电机始终在高效范围运行,转速越高效率越高,采用小功率电机拖动大功率负载,降低成本。(The invention discloses a design method of a high-efficiency direct-current driving permanent magnet rotor motor, which comprises the following steps: determining rated torque T, maximum torque Tmax, highest rotating speed Smax and lowest rotating speed Smin of a speed regulation interval, and determining three-phase rated power supply voltage VAC and rectified voltage VDCmax; calculating the direct current voltage of the motor at the lowest rotating speed; designing a motor according to the direct-current voltage VDCmin, the lowest rotating speed Smin, the rated torque T and the maximum torque TMax of the motor at the lowest rotating speed to achieve the rated efficiency; designing the insulation grade of the motor and the voltage-resistant grade of a motor controller according to the VDCmax; the invention designs the mechanical strength of a motor according to Smax and Tmax, relates to the technical field of motor design, adopts a direct-current voltage regulation mode to regulate the speed of a permanent magnet rotor motor, has irrelevant speed control to frequency, solves the problem of weak magnetic speed regulation when the permanent magnet synchronous motor is in super-synchronous operation, always operates in a high-efficiency range, has higher efficiency when the rotating speed is higher, adopts a low-power motor to drag a high-power load, and reduces the cost.)

1. A design method of a high-efficiency direct-current drive permanent magnet rotor motor is characterized by comprising the following steps:

step 1, determining a rated torque T, a maximum torque Tmax, a highest rotating speed Smax and a lowest rotating speed Smin of a speed regulation interval, and determining a three-phase rated power supply voltage VAC and a rectified voltage VDCmax;

calculating the direct-current voltage VDCmin of the motor at the lowest rotating speed approximately equal to VDCmax Smin/Smax;

step 2, designing the motor according to the direct-current voltage VDCmin, the lowest rotating speed Smin, the rated torque T and the maximum torque TMax of the motor at the lowest rotating speed to achieve the rated efficiency;

step 3, designing the insulation grade of the motor and the voltage-resistant grade of the motor controller according to the VDCmax; the mechanical strength of the motor is designed according to Smax and Tmax.

2. The design method of the high-efficiency direct-current drive permanent magnet rotor motor according to claim 1, characterized in that: the design voltage of the motor is lower than the power supply voltage of the power grid.

Technical Field

The invention relates to the technical field of motor design, in particular to a design method of a high-efficiency direct-current drive permanent magnet rotor motor.

Background

The phenomenon that a trolley is pulled by a big horse exists in the field of motors. The power of the motor is selected according to the power required by the production machine, trying to operate the motor at rated load. If the power of the motor is selected to be too small, the phenomenon of 'small horse pulling cart' can occur, the motor is overloaded for a long time, the insulation of the motor is damaged due to heating, and even the motor is burnt. If the power of the motor is selected to be too large, the phenomenon of 'big horse pulls a trolley' can occur, the output mechanical power of the motor cannot be fully utilized, the power factor and the efficiency are not high, and the motor is not only unfavorable for users and power grids. But also causes a waste of electric energy.

The main factors determining the motor power are 3:

1. the heating and temperature rise of the motor are the most main factors for determining the power of the motor;

2. allowing for short-time overload capability;

3. starting capability is also considered for ac cage asynchronous motors.

In the application of a motor, the speed regulation operation is the common working condition requirement of equipment such as a fan, a water pump, a compressor and the like, the speed regulation of the motor by using a frequency converter is a common method, and once the rotating speed of the motor exceeds the synchronous rotating speed, the speed regulation can be carried out only at constant power but not at constant torque in the current motor design field.

The permanent magnet synchronous motor has excellent performance and is widely applied to various industries.

The permanent magnet synchronous motor adopts a star-shaped or triangular winding connection method of a three-phase alternating current winding, and special three-phase alternating current is adopted for frequency conversion control to realize the speed regulation of the motor.

Because the permanent magnet synchronous motor adopts permanent magnet excitation, the excitation magnetic field cannot be adjusted, and under the current technical condition, when the rotating speed of the motor exceeds the rated rotating speed, the field weakening control is required to be carried out so as to improve the rotating speed range of the motor. The disadvantages of this approach are reduced efficiency of the machine and the more irreversible demagnetization of the permanent magnets.

Disclosure of Invention

Aiming at the defects of the prior art, the inventor submits a patent of 'a permanent magnet rotor motor structure and a control method thereof', on the basis, the invention provides a design method of a high-efficiency direct-current driving permanent magnet rotor motor, and the problem of high-efficiency large-range speed regulation of the permanent magnet rotor motor is solved.

In order to achieve the purpose, the invention is realized by the following technical scheme: a design method of a high-efficiency direct-current drive permanent magnet rotor motor comprises the following steps:

step 1, determining a rated torque T, a maximum torque Tmax, a highest rotating speed Smax and a lowest rotating speed Smin of a speed regulation interval, and determining a three-phase rated power supply voltage VAC and a rectified voltage VDCmax;

calculating the direct-current voltage VDCmin of the motor at the lowest rotating speed approximately equal to VDCmax Smin/Smax;

step 2, designing the motor according to the direct-current voltage VDCmin, the lowest rotating speed Smin, the rated torque T and the maximum torque TMax of the motor at the lowest rotating speed to achieve the rated efficiency;

step 3, designing the insulation grade of the motor and the voltage-resistant grade of the motor controller according to the VDCmax; designing the mechanical strength of the motor according to Smax and Tmax;

a voltage regulator is arranged on a direct current bus inside the motor controller for controlling the rotating speed;

when the voltage regulator stabilizes the voltage at VDCmin, the motor works according to the rotating speed Smin and the torque T;

when the voltage regulator stabilizes the voltage at VDCmax, the motor works according to the rotating speed Smax and the torque T;

and adjusting the voltage of the direct-current bus, so that the motor operates in a speed-adjusting mode in a Smin-Smax interval, and the higher the rotating speed is, the higher the motor efficiency is.

Advantageous effects

The invention discloses a design method of a high-efficiency direct-current driving permanent magnet rotor motor, which has the following beneficial effects:

1. the permanent magnet rotor motor is regulated by adopting a direct current voltage regulation mode, the rotating speed is irrelevant to frequency control, and the problem of flux weakening speed regulation during the super-synchronous operation of the permanent magnet synchronous motor is solved.

2. The motor speed regulation range can be unlimited, and the motor has no synchronous rotating speed and constant power speed regulation working condition and is always constant torque speed regulation.

3. The motor always runs in a high-efficiency range, and the higher the rotating speed, the higher the efficiency.

4. And a low-power motor is adopted to drive a high-power load, so that the cost is reduced.

Detailed Description

The present invention will be further described with reference to the following examples.

The high-power permanent magnet rotor adopts a motor driven by high-voltage direct current to work, the rated torque T and the maximum torque Tmax are determined, the highest rotating speed Smax of a speed regulation interval is 1800rpm, the lowest rotating speed Smin is 500rpm, the three-phase rated power supply voltage is determined to be VAC 380VAC, and the rectified direct current voltage VDCmax is 1.35 380VAC 510 VDC;

calculating the direct-current voltage of the motor at the lowest rotating speed:

VDCmin≈VDCmax*Smin/Smax＝510*500/1800＝142VDC；

designing a motor according to the motor direct-current voltage VDCmin which is 142VDC at the lowest rotating speed, the lowest rotating speed Smin which is 500rpm, the rated torque T and the maximum torque TMax to achieve the ideal efficiency;

designing the insulation grade of the motor and the voltage-resistant grade of a motor controller according to the VDCmax; designing the mechanical strength of the motor according to Smax and Tmax;

a voltage regulator is arranged on a direct current bus inside the motor controller for controlling the rotating speed;

permanent magnet rotor motor designed according to method and controller thereof

When the voltage regulator stabilizes the voltage at VDCmin 170VDC, the motor works according to the rotating speed of Smin 500rpm, and the torque T;

when the voltage regulator stabilizes the voltage at VDCmax which is 510VDC, the motor works according to the rotating speed of Smax which is 1800rpm and the torque T;

and adjusting the voltage of the direct-current bus, so that the motor operates in a speed-adjusting mode in a Smin-Smax interval, and the higher the rotating speed is, the higher the motor efficiency is.

If the DC bus voltage is increased to be higher, the rotating speed of the motor is increased along with the increase, and the constant-torque operation is kept.

The above embodiments are merely illustrative of the technical ideas and features of the present invention, and the purpose thereof is to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and not to limit the protection scope of the present invention. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.