Permanent magnetic brushless constant voltage generator and voltage stabilizing method thereof

Abstract

The invention relates to a permanent magnetic brushless constant voltage generator and a voltage stabilizing method thereof. The generator is driven by a speed change wind wheel, the sent constant voltage direct current is output to the electric network after the frequency conversion through an inverter, the leakage reactance per-unit value X<*> of an armature winding at the maximum work rotating speed of the generator equals to the ratio of the difference of the maximum work rotating speed and the minimum work rotating speed of the generator to the minimum work rotating speed, and the range of the leakage reactance per-unit value X<*> is from 1 to 1.8. The method increases the leakage inductance value of the armature winding of the generator through the optimized electromagnetic design on the generator per se, so the leakage inductance resistance of the armature winding of the generator in work is increased, the potential E of the generator is in isometric and synchronous change with the leakage resistance voltage reduction X.I of the armature winding when the rotating speed of the generator is changed in the work rotating speed range, and thus, the constant voltage output is realized. The generator can realize the voltage stabilization without increasing any detection and control links, executing mechanisms and the like, the structure is greatly simplified, the cost is greatly reduced, and the invention has the advantages of simplicity, economy, effectiveness and reliability.

Description

technical field [0001] The invention relates to a generator, in particular to a permanent magnet brushless constant voltage generator. In addition, the invention also relates to a voltage stabilizing method of the generator. Background technique [0002] The grid-connected wind turbine converts the mechanical energy captured by the wind wheel into electrical energy and transmits it to the constant voltage and constant frequency grid. When high-power power electronics technology is not mature enough, it is very difficult to change the frequency and voltage of wind power generated by generators. In order to directly transmit wind power to the grid, only AC asynchronous generators or AC synchronous generators with the same frequency as the grid are selected. The asynchronous generator can only run within the speed difference range of 1% to 4% above the synchronous speed, and the synchronous generator can only run at the synchronous speed. In order to make the frequency of th...

AI Technical Summary

Problems solved by technology

The advantage of these two motors is that they can be directly connected to the grid without inverter, but there are many shortcomings: 1. The power-speed characteristics of the motor are relatively hard, and it is difficult to match the output characteristic curve of the wind wheel well, and it is also difficult to improve the capture rate. Wind energy efficiency to absorb wind energy to the maximum; 2. It is easy to cause impact on the unit and the grid when connected to the grid; 3. Due to the instability of wind speed, it is easy to impact on the gearbox and damage the gearbox, resulting in high maintenance costs; 4. Generators are often in the state of shutdown, low-speed power generation, and high-speed power generation. The control is complex and prone to failure; Not large and can only be driven by constant speed rotors which are less efficient at capturing wind energy on average

The disadvantages of this method are: 1. Due to the need to add sampling control circuits, voltage regulating actuators, executive motors and other equipment, the control system and mechanical structure are relatively complicated, which greatly increases the production cost; 2. Due to its complex regulation It is difficult to apply on large-scale generators (such as MW-level wind turbines) (because if large-scale generators use this method to regulate voltage, the pressure-regulating actuator will be very large, the structure is extremely heavy, and it is difficult to realize)

This traditional technical solution has many disadvantages, such as high production cost, complicated manufacturing process, and heavy weight of the overall magnetic yoke. Excessive weight will further lead to the enlargement of the entire wind power generation system, which brings inconvenience to installation and use and cannot realize the miniaturization of the equipment. development

In addition, there is a technical solution that cannot be realized due to its own structure, that is, the magnetic poles cannot be axially arranged on the yoke, and the circumferential offset and staggering between the axially arranged magnetic poles cannot be further realized.

[0005] In addition, in the existing permanent magnet DC generator, the square wave generated by the magnetic pole will generate a large number of harmonics, resulting in large iron loss of the motor and low power generation efficiency

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