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Stator resistance compensation method and system for V/F control of permanent magnet synchronous motor

A permanent magnet synchronous motor and stator resistance technology, which is applied in the control system, vector control system, motor generator control and other directions, can solve the problems of irrespective of the voltage drop of the stator resistance, low starting torque of the motor, and high cost. Starting performance and low speed performance, simple and practical control algorithm, the effect of increasing starting torque

Inactive Publication Date: 2020-01-31
WENLI GUANGDONG TECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Vector control and direct torque control have high control precision and fast dynamic response, but the algorithm is complex and expensive, and highly dependent on motor parameters; scalar control algorithm is simple, reliable control, no need to depend on motor parameters, very suitable for fan and water pump loads
The traditional scalar control does not consider the voltage drop of the stator resistance, resulting in low starting torque of the motor and even difficulty in starting
The stator resistance vector compensation based on the motor model can fully compensate the voltage drop of the stator resistance, but the algorithm is too complicated to realize
For example, in the prior art with the application number CN201710532982.2, by adding a V / F curve controller to the system, the compensated speed is obtained according to the given speed and the compensated speed, and the V / F curve controller is based on the compensated speed and The V / F control curve obtains a given voltage, and after modulation, the input current of the permanent magnet synchronous motor is controlled by means of voltage compensation. The control circuit and algorithm are complex, and the system control cost is high, which cannot well meet the current requirements. Market demand

Method used

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  • Stator resistance compensation method and system for V/F control of permanent magnet synchronous motor
  • Stator resistance compensation method and system for V/F control of permanent magnet synchronous motor
  • Stator resistance compensation method and system for V/F control of permanent magnet synchronous motor

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Effect test

Embodiment 1

[0038] The traditional scalar control does not consider the voltage drop of the stator resistance, resulting in low starting torque of the motor and even difficulty in starting. However, when the permanent magnet synchronous motor works in the low speed area, the voltage drop caused by the stator resistance cannot be ignored.

[0039] In a specific embodiment, the technical solution of the present invention is realized by a permanent magnet synchronous motor V / F control stator resistance compensation method:

[0040] This includes the following steps:

[0041] Step 1. Deduce the motor stator resistance voltage drop compensation formula according to the motor voltage vector diagram.

[0042] When the permanent magnet synchronous motor works in the low speed area, the voltage drop caused by the stator resistance cannot be ignored.

[0043] Depend on figure 1 It can be known that the stator voltage is

[0044]

[0045] where U s is the stator voltage, I s is the phase cur...

Embodiment 2

[0061] In yet another specific embodiment, the present invention also provides a permanent magnet synchronous motor V / F control stator resistance compensation system, such as figure 2 As shown, the system can fully realize the compensation method as described in Embodiment 1, and the system includes:

[0062] A voltage-frequency conversion module, used to obtain the back electromotive force E of the motor based on a given frequency;

[0063] An integral module, used to obtain the motor voltage angle θ based on the given frequency;

[0064] The compensation module is used to obtain the modulus value of the stator voltage U based on the motor back EMF E and the voltage drop of the stator resistance; the compensation module is connected to the voltage-frequency conversion module and the stator resistance to receive the motor back EMF E and the stator resistance voltage drop;

[0065] The PWM module is connected to the compensation module, the integral module, and the motor, an...

Embodiment 3

[0076] In yet another specific embodiment, a specific motor compensation control method is taken as an example to illustrate the implementation of the technical solution of the present invention. Taking a permanent magnet synchronous motor with a rated power of 6Kw, a rated frequency of 50Hz, and a rated voltage of 380V as an example, the traditional V / F control method and the V / F control method of the present invention were used respectively at a low speed of 120r / min to obtain two The steady-state current-voltage waveform diagram of the control method, such as image 3 and Figure 4 shown.

[0077] Compared image 3 and Figure 4 It can be clearly seen that the V / F control of the present invention is very stable at low speeds, the noise is very small, and the current fluctuation is weaker than that of the traditional V / F control, indicating that the V / F control method of the present invention can obtain good starting performance and low-speed performance.

[0078] Take a...

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Abstract

The invention provides a stator resistance compensation method and system for the V / F control of a permanent magnet synchronous motor. According to the compensation algorithm, a positive feedback linkis added before the stator voltage of a traditional V / F control algorithm and is used for voltage compensation to realize closed-loop control. According to the method, the three-phase current of thepermanent magnet synchronous motor is collected; the three-phase current is converted to a synchronous rotating coordinate system which takes a stator voltage vector as a d axis by utilizing Park transformation and Clark transformation, so that decomposition current Id under the synchronous rotation coordinate system is obtained; the Id is multiplied by stator resistance Rs, so that stator resistance voltage drop U is obtained and is used for voltage compensation; and therefore, a stator voltage is increased, the starting torque of the motor is increased, it is guaranteed that the motor can besmoothly started, and the starting performance and low-speed performance of the motor are improved. The stator resistance compensation method and system provided by the technical schemes of the invention are simple and practical, and have a wide application prospect.

Description

technical field [0001] The invention belongs to the technical field of permanent magnet synchronous motor V / F control, and in particular relates to a novel permanent magnet synchronous motor V / F control stator resistance compensation method and system. Background technique [0002] Due to the advantages of high power density, small torque ripple, low loss and high efficiency, permanent magnet synchronous motors have been widely used in various fields. The control methods of permanent magnet synchronous motors are roughly divided into: vector control, direct torque control, and scalar control (V / F control). Vector control and direct torque control have high control precision and fast dynamic response, but the algorithm is complex and expensive, and highly dependent on motor parameters; scalar control algorithm is simple, reliable, and does not need to depend on motor parameters, which is very suitable for fan and water pump loads. The traditional scalar control does not take...

Claims

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Application Information

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IPC IPC(8): H02P21/04H02P21/28H02P6/20
CPCH02P6/20H02P21/04H02P21/28
Inventor 华青松徐晓通何袁生丁茂起李力
Owner WENLI GUANGDONG TECH CO LTD