CN204361950U - The simple and easy power converter topologies of partly encouraging oneself of switching magnetic-resistance wind-driven generator - Google Patents

Abstract

The simple and easy power converter topologies of partly encouraging oneself of switching magnetic-resistance wind-driven generator, is made up of asymmetrical half-bridge formula power transforming main circuit, storage battery, capacitor, DC/DC converter, load; Described asymmetrical half-bridge formula power transforming main circuit is connected in parallel with the described storage battery of connecting and described capacitor, output and the storage battery of described DC/DC converter are connected in parallel, the series arm of the another two ends of DC/DC converter and storage battery and capacitor is connected in parallel, and is also connected in parallel with described load simultaneously; This topological structure is simple and practical, overcomes existing shortcoming, is suitable for the switching magnetic-resistance wind-driven generator power inverter field of middle low power grade.

Description

Simple semi-self-excited power converter topology for switched reluctance wind turbine

technical field

The invention relates to the field of switched reluctance motors and their control, in particular to a topology structure of a novel excitation mode of a power converter of a switched reluctance wind-driven generator.

Background technique

Clean, green and environmentally friendly wind power generation has been a form of renewable energy power generation that has been developed at home and abroad for many years; however, looking at Europe, North America and China, the reality of high cost has always been an important factor affecting the development of wind power. In addition to the grid-connected type, the micro-grid or independent wind power system is also the same. It has become an important development direction consensus in the industry to reduce costs, simplify structures, and reduce volume and weight.

The structure of the switched reluctance generator is simple, and there is no brush, no winding, and no permanent magnet on the rotor; when it operates, it is equivalent to a current source, so that within a certain speed range, the output terminal voltage will not change with the change of the speed. It is very suitable for the current mainstream wind turbines with variable speed operation, which can improve the utilization efficiency of wind energy; the switched reluctance generator has good low-speed controllability, so that it can save the gearbox under direct wind drive, and achieve higher power generation efficiency at the same time It makes the structure of the whole power generation system more concise and reliable, which is also the development trend of wind power generation systems; and in the process of operation, the switched reluctance generator has many controllable parameters, such as switching angle control, current chopping control, PWM control, etc., which can be It is convenient to implement more complex control strategies and flexibly control the output DC voltage and current; therefore, the introduction of switched reluctance generators into the field of wind power generation can realize the conversion of wind energy with high efficiency, and the simplicity of the structure means higher reliability With less maintenance, lower installation costs and equipment procurement costs, the power converters related to switched reluctance generators for wind power generation should also take this as the design and development direction, that is, the structure is as simple as possible while maintaining its flexible and controllable advantage.

Regarding the main circuit of the power converter of the switched reluctance generator, the asymmetrical half-bridge type is relatively mature. With a certain control mode, the excitation and power generation can be realized with the convenience of time-sharing and different circuits; as for the excitation method, there are generally other methods. There are two kinds of excitation and self-excitation. Unlike the self-excitation method, there will be larger voltage and current pulsations, and the stability is better, but the disadvantage is that a large inrush current will be generated at the initial start. This is because The capacitor connected in parallel at the output end does not have any energy storage in the initial stage, that is, it cannot play the role of voltage support, so a large current is generated in a short period of time after the sudden DC voltage is applied.

Although the separate excitation method generally requires a special battery, such as a battery as the excitation power supply, the self-excitation method generally also requires a special battery, but the difference between the two is that the battery power supply of the self-excitation method is used when the switched reluctance power generation system is initially started. Since then, it will no longer be used in operation, and the separate excitation method has been used all the time, and the structure is not obviously complicated. Therefore, the advantages of the separate excitation and self-excitation methods are fully utilized, and their shortcomings are overcome, and a power converter topology with a simple structure is designed. is very meaningful.

Contents of the invention

According to the above background technology, the utility model proposes a new topological structure of switched reluctance wind power generator power converter called semi-self-excitation mode, which is neither separate excitation mode nor self-excitation mode. It also overcomes the shortcomings of the large initial current impact of the separate excitation method and the large output current fluctuation of the self-excitation method, which affects the excitation performance, and can be used in the field of small and medium-sized switched reluctance wind power generator systems.

The technical scheme of the utility model is:

The simple semi-self-excited power converter topology of the switched reluctance wind turbine is composed of an asymmetrical half-bridge power conversion main circuit 1, a storage battery X, a capacitor Cd, a DC/DC converter 2, and a load R. It is characterized in that the The asymmetrical half-bridge power conversion main circuit 1 is connected in parallel with the battery X and the capacitor Cd that have been connected in series, the output terminal of the DC/DC converter 2 is connected in parallel with the battery X, and the DC/DC converter 2 is connected in parallel Both ends are connected in parallel to the series branch of the battery X and the capacitor Cd, and are also connected in parallel to the load R.

The rated voltage of the storage battery X is lower than the rated output voltage of the asymmetrical half-bridge power conversion main circuit 1, and the storage battery X is used as the excitation power supply for the stator winding A/B/C of the switched reluctance generator. The inverter 2 takes and charges the electric energy generated by the generator.

The main technical effects of the utility model are:

In the simple semi-self-excited power converter topology of the switched reluctance wind power generator of the utility model, the storage battery X plays the function of external excitation, and at the same time, because the electric energy comes from self-generated electric energy when there is a power shortage, it also has the characteristics of self-excitation, so It is called semi-self-excitation or semi-excitation excitation mode; only one set of battery X can complete the excitation power supply, compared with the separate excitation or self-excitation mode, there is no additional hardware; at the same time, the battery X is connected in series with the capacitor Cd and then connected in parallel to the generator At both ends of the output, the capacitor Cd plays the role of voltage stabilization and filtering during stable operation, but at the initial startup of the system, because there is no energy storage, it will not play the role of voltage stabilization. In the traditional separate excitation mode, if a simple capacitor Cd is connected in parallel to the output end of the power generation, and a large instantaneous current will be generated on the output busbar and the capacitor Cd branch, which increases the burden on the electrical components in the capacitor Cd and power converter related circuits. The structure connected in series with the capacitor Cd first, that is, at the moment of initial starting, there is already a certain voltage on the branch of the capacitor Cd, which can suppress the current impact; at the same time, because the battery power supply is stable, it also avoids the large excitation current pulsation in the self-excitation mode. Shortcomings.

Therefore, the above structural features make the topology of the present utility model greatly suppress the main shortcomings of the purely self-excited and self-excited modes.

Although the addition of the DC/DC converter 2 seems to complicate the structure, in fact, in the control system of the switched reluctance generator, a variety of DC power supplies with different DC voltage levels are necessary, so in practice, it can be completely based on The selection of the design value effectively utilizes the existing DC/DC converter in the system.

Description of drawings

Fig. 1 shows the topological circuit structure diagram of the simple semi-self-excited power converter of the switched reluctance wind power generator of the utility model.

Detailed ways

As shown in Figure 1, in the asymmetric half-bridge power conversion main circuit 1, A/B/C are the three-phase stator windings of the switched reluctance generator, and the three-phase windings have independent circuits and independent control; The rotor position information fed back by the motor, when a certain phase winding needs to be excited and energized, the power electronic switch tubes V1 and V2, or V3 and V4, or V5 and V6 that control the excitation circuit of this phase winding correspondingly receive the information from the switched reluctance generator control The driving signal of the device is turned on, and current excitation flows in under the action of the battery X; when the excitation ends, the corresponding power electronic switch tube is immediately turned off. It will flow through the circuit of power diodes D1 and D2, or D3 and D4, or D5 and D6, so as to output to the external load R and other energy storage components; the six power electronic switch tubes V1-V6, small and medium-sized switched reluctance power generation It is better to use IGBT in the system.

In the traditional excitation mode, regardless of self-excitation or separate excitation mode, the output terminal of the switched reluctance power generation system, that is, the output terminal of the asymmetrical half-bridge power conversion main circuit 1 in Figure 1, is often independently connected in parallel with a capacitor, and the utility model adopts The method of connecting the battery X for excitation in series with the capacitor Cd, and then connecting it in parallel with the output, when the power of the battery X is insufficient, it will be charged by the DC/DC converter 2; the battery X needs to be matched according to the voltage and power, in practice It should be a battery pack, however, its rated voltage should be significantly lower than the output rated voltage of the generator, that is, it should be significantly lower than the voltage value at both ends of the load R at rated time, and the rated ratio and ratio should be determined according to the load of the entire power generation system and the needs of maximum power tracking control. Corresponding specific ratings.

Although the three-phase winding switched reluctance generator used in this embodiment does not affect the protection of the utility model for other situations with different phase numbers.

Claims (2)

1. The topology of the simple semi-self-excited power converter of the switched reluctance wind power generator is composed of an asymmetrical half-bridge power conversion main circuit, a storage battery, a capacitor, a DC/DC converter, and a load. It is characterized in that the asymmetrical half-bridge The bridge power conversion main circuit is connected in parallel with the battery and the capacitor that have been connected in series, the output end of the DC/DC converter is connected in parallel with the battery, and the other two ends of the DC/DC converter are connected in series with the battery and the capacitor. The circuit is connected in parallel and is also connected in parallel with the load. 2. The simple semi-self-excited power converter topology of the switched reluctance wind turbine according to claim 1, wherein the rated voltage of the storage battery is less than the rated output voltage of the asymmetrical half-bridge power conversion main circuit, and the storage battery As the excitation power supply of the stator winding of the switched reluctance generator, the DC/DC converter takes the electric energy from the generator and charges it when there is a power shortage.