Self-enhanced excitation demagnetization isolation decoupling simple switched reluctance generator power converter

Abstract

The invention discloses a self-reinforcing excitation, demagnetization, isolation and decoupling power converter of a simple switched reluctance generator. The power converter comprises two major parts, namely a main circuit and an excitation circuit; decoupling of excitation voltage and generating voltage is achieved through the excitation circuit and the excitation voltage is independently adjustable; the main circuit is simple in structure and self-reinforcing excitation and rapid demagnetization can be achieved through the main circuit without a separate circuit; and the excitation circuitalso has an isolation link, and the volume and the weight are reduced during high-frequency working. The self-reinforcing excitation, demagnetization, isolation and decoupling power converter can adapt to the field of a constant-speed and variable-speed switched reluctance generator system with a relatively high power level.

Description

technical field [0001] The invention relates to the field of switched reluctance motor systems, in particular to a power converter system of a switched reluctance generator and a control method thereof. Background technique [0002] Compared with the main traditional motors such as DC motors, asynchronous motors, and synchronous motors, switched reluctance motors have a simple and firm structure, low manufacturing cost, no windings on the rotor, no permanent magnets, high reliability, and broad application prospects. It is the ability to have high performance in a wide speed range. [0003] Switched reluctance generators generally have 2-5 phase windings placed on the stator, and the specific phase windings that need to be energized are determined according to the relative position of the salient poles between the stator and rotor. The operation of each phase winding is generally divided into two stages: excitation and power generation. In the excitation stage, the phase wi...

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Problems solved by technology

[0005] The main circuit of the mature power converter of the switched reluctance generator is an asymmetrical half-bridge structure, which is widely used, but its structure is relatively complicated

[0006] Switched reluctance generators are divided into separate excitation type and self-excitation type according to the source of the excitation power source. The separate excitation type generally requires a separate battery, which increases the daily maintenance workload; the traditional self-excitation type is generated by the switched reluctance generator. The electric energy is directly used as the excitation power supply, resulting in large fluctuations in electrical parameters, which in turn result in increased torque ripple and poor practicability; Converter structure, that is, the excitation voltage is decoupled from the generating voltage, and the excitation voltage is adjusted through the chopper circuit in the middle, even if the input generating voltage remains unchanged; and the adjustment of the excitation voltage greatly enhances the performance of the switched reluctance generator. Control flexibility, sought after by the industry

[0007] In order to enhance the power output capability of the switched reluctance generator, it is a particularly effective way to increase the special circuit for strengthening the excitation. For example, the industry has proved that the very effective power converter based on the Z source network strengthens the excitation. However, these methods are not Special circuits need to be added, and some even need one set for each phase winding, and the structure becomes extremely complicated

[0008] According to the operating mechanism of the switched reluctance generator, when each phase winding generates power, it is hoped that the winding current can be reduced to zero as soon as possible, that is, rapid demagnetization, so as to avoid entering the next stage of positive torque zone and reducing the power generation efficiency. The method is to add a separate switch circuit, such as introducing a new capacitor in series to increase the reverse voltage, which makes the structure and control complicated

[0009] As mentioned above, the excitation power supply, especially the decoupling excitation power supply, is mostly implemented by a chopper circuit that can be boosted or buckled, and most of them cannot adapt to large power levels; some excitation power supply structures use magnetic isolation to enhance In order to improve the adaptability, but its power frequency working condition makes the transformer occupy a large area

[0010] The aforementioned excitation power supply based on the chopper circuit, based on the characteristics of the chopper circuit, is difficult to achieve a large-scale adjustment of the output voltage (ie: excitation voltage) in practice, so that the switched reluctance generator cannot adapt to a wider operating range

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