Vector compensation control method of winding open permanent magnet generator system

Abstract

The invention relates to a control method of a winding open permanent magnet generator system and belongs to the field of vector modulation of an alternating current power generation system. The method is characterized in that one side of the end part of a winding of a winding open permanent magnet generator is connected with a rectifier bridge and combined with a filter capacitor to form a rectification side to supply power to a load; the other side of the end part of the winding is connected with a storage battery by an inverter to form an inversion control side; a controller forms an external voltage loop by detecting the direct current side load voltage and the given voltage, controls an inversion side output and controls the rectification side output voltage; and the direct current voltage output by the rectification side is stable with the variations of the rotating speed and the load. The method can effectively inhibit current harmonics brought by the rectifier bridge in the winding open permanent magnet generator system, and improve the operating efficiency of the system.

Description

technical field [0001] The invention relates to a vector compensation control method for an open-winding permanent magnet generator system, belonging to the field of generator control. Background technique [0002] Since the 21st century, with the global energy depletion and environmental protection issues becoming more and more serious, seeking a new type of high-efficiency and energy-saving generator system has become a research hotspot. The permanent magnet generator uses permanent magnets for excitation, without brushes and slip rings, and has the advantages of high power density, simple structure, and high efficiency. Moreover, my country is rich in rare earth resources, which has the natural advantages of developing and researching high-performance rare earth permanent magnet generators. With the rapid development of permanent magnet materials, power electronic devices, and digital control technology, the performance of permanent magnet generator systems is getting bet...

AI Technical Summary

Problems solved by technology

Taking the on-board power supply system as an example, the idle speed of the gasoline engine is around 1000r / min, and the maximum speed can reach 7000r / min. It is required that the on-board generator can effectively control the output within such a wide speed range to obtain efficient energy utilization. Harsh conditions are proposed for the permanent magnet generator system. Although this problem can be solved by adding a DC / DC converter, this will undoubtedly increase the cost of the system and increase the complexity of the control

[0004] Aiming at the problems of difficult power generation and voltage regulation and narrow speed range in the above-mentioned permanent magnet generator system, related research has proposed solutions from different perspectives: (1) The field weakening control method is aimed at the permanent magnet starter / generator system, A specially designed low-voltage embedded permanent magnet motor is adopted, and it adopts field-weakening power generation control during high-speed operation. In the voltage limit ellipse and current limit circle of the system, the air-gap magnetic field is weakened by increasing the direct-axis current component of the motor, which can avoid high-speed power generation The lower DC bus voltage rises, but the active component of the stator current decreases during field weakening, resulting in a decrease in the output power of the system

(2) The permanent magnet excitation method and the electric excitation method are combined to form a hybrid excitation motor structure. In 1985, American scholar Mc-Carty first proposed the idea of ​​hybrid excitation. The air gap magnetic field is mainly generated by permanent magnets. On this basis, the The excitation winding can realize the function of increasing or weakening the field, which not only retains the inherent advantages of the permanent magnet excitation method, but also realizes the adjustment of the magnetic field to a certain extent, improves its power generation and voltage regulation performance, and has a good development prospect, but additional The increased field winding will affect the power generation efficiency and power density. At the same time, the related motor design and control research is still in its infancy, and there are many problems to be solved urgently.

(3) Structural design scheme of double-rotor permanent magnet generator. Permanent magnets are installed on the inner rotor of the motor, and the windings on the outer rotor are drawn out through slip rings. The inner and outer rotors are respectively connected to a wind turbine, and the rotation direction of the two wind turbines On the contrary, when the wind speed is low, there is still a high relative speed between the two rotors, thereby widening the minimum operating speed of the wind turbine, but the outer rotor winding is drawn out through the slip ring, which increases the failure rate of the system, and has its own The double-rotor structure and complex control technology also hinder its further development.

(4) Generator system design with variable topology structure. This scheme can adapt to the external characteristics of high-speed and low-speed motors by switching the series-parallel connection of rectifier topology, and realize voltage regulation control in a wide speed range. However, the stability of the generator system and Reliability will be affected by the switching process, which limits its application to a certain extent

However, since the generated power is rectified by the rectifier bridge and then supplied to the load, the rectifier bridge, as a nonlinear link in the system structure, will cause more harmonics in the generator winding current, resulting in distortion of the current waveform, which affects to a certain extent power generation efficiency

[0006] In order to improve the power quality of power generation systems with rectifier bridges, the commonly used current harmonic suppression methods mainly include: (1) Active power filter method, which calculates the current harmonic components at the input side of the rectifier bridge in real time, and uses the power electronic converter to inject corresponding The active power filtering effect is good, but the cost is high and the implementation is complicated; (2) Passive filtering method, using multi-pulse rectifier topology, current harmonic injection, new rectifier topology and other schemes to change the work of the rectifier bridge state, so that the input current sinusoidal

Although the above method can effectively improve the power quality at the input side of the rectifier bridge, it needs to add corresponding power electronic conversion devices, which increases the complexity of the system

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