Inductive energy storage commutation cutoff thyristor method and power converter

Abstract

The utility model relates to a method and a power converter for inductance energy conservation current converting shut off thyristor, belonging to the technical filed of power converting. The utility model comprises an inductance energy storing current converting cell HL which consists of an energy storing inductance L, a high-end electric switch Gp, a low-end electric switch Gn and an after-low electric switch Mx; and a main power converting cell ZG which consists of a main thyristor T, an after-flow power diode D and an assistant thyristor T1. when in current converting, the flow path of the energy storing inductance L current IL is controlled through the electric switch of the inductance energy storing current converting cell HL and the assistant thyristor T1 of the main power converting cell ZG, so that the main thyristor T which needs to be shut off by the main power converting cell ZG is arranged reversely to be shut off. As the utility model converts current through a plurality of main power converter cells of a current converter with a multiple structure, the utility model reduces the cost of the inductance energy conservation current converting cell. The utility model is suitable to be used in various large capacity and low cost power converters which are mainly made of thyristors.

Description

technical field [0001] The invention belongs to the technical field of power conversion, and in particular relates to a method for turning off a thyristor and a power converter thereof. [0002] Power inverters are the basic components of modern industry. Various power converters can be formed on the basis of inverters, which are widely used in AC and DC transmission, wind power generation, ship propulsion and electric locomotive traction, reactive power compensation in power systems, etc. In all fields of national economic construction, it is of great significance to develop high-performance and low-cost power inverters. Background technique [0003] There are two main types of technologies that can constitute the main circuit of the inverter: one is the thyristor power converter with capacitive energy storage LC oscillation forced commutation, and the other is the use of gate self-turn-off devices GTO, GTR, IGBT, A power converter composed of gate fully controlled devices...

AI Technical Summary

Problems solved by technology

The disadvantages of this type of power inverter are: 1. The LC discharge pulse current is large, the oscillation voltage is high, and the discharge pulse will generate a large electrical stress on the SCR, which deteriorates the working conditions of the device, especially for large-capacity devices. 2. The commutation process is limited by the LC charge-discharge time constant and the off-time of the SCR device. The operating frequency of the device should not be high, which limits the The performance of the device is improved. 3. The converter energy storage capacitor needs to use a non-inductive pulse capacitor with a high discharge rate and a low loss angle, which is expensive, and the capacitor is large in size, occupying a considerable position in the device, making the device bulky. 4. The commutation capacity mainly depends on the commutation capacity. In the parameter selection, the value is often small, and the commutation capacity is not enough when the load is started and overloaded, and reliable operation cannot be guaranteed. When the value is large, the light-load commutation is too strong. , the commutation loss increases, reducing the efficiency of the device

[0004] Although the power converter composed of fully-gate-controlled devices does not have the disadvantages of capacitive energy storage forced commutation thyristor power converters, it has other disadvantages: 1. The voltage is very sensitive, and a little carelessness will cause permanent damage to the device. Therefore, the protection requirements are strict and the maintenance cost is high. 2. Most gate fully controlled devices have a high on-state voltage drop (IGBT), or The large buffer loss (GTO) increases the heat load of the whole machine, makes it difficult to dissipate heat, and affects the efficiency of the whole machine. 3. The price of the gate full control device is high, and it cannot be produced in my country. It is inappropriate to rely entirely on imports to meet the large demand of our country

As a result, such a situation has been formed: the low-cost thyristors produced in large quantities in my country have limited uses because they have no self-shutoff capability, and there is a large demand for self-shutoff devices, but they cannot be produced domestically.

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