Electromagnetic transient analysis method for large-capacity power-electron conversion system

Abstract

The invention discloses an electromagnetic transient analysis method for a large-capacity power-electron conversion system and belongs to the technical field of power-electron conversion and control. The method comprises the following steps: the large-capacity power-electron conversion system carries out one protection action; system parameters before and after protection action of the conversion system are collected to determine a safe working area of the conversion system; stray parameters of the conversion system are extracted to further determine a transient bus structure of the conversion system; a feedback control set value of a gate drive signal of a semiconductor switching device is determined according to the bus structure and the stray parameters; delay time of the conversion system is determined according to the feedback control set value of the gate drive signal of the semiconductor switching device; and at last the delay time of the safe working area of the system is determined. By the method, the existing device safe working area is extended to the system safe working area, the existing lumped parameter topological structure is expanded to a main circuit structure which considers stray parameters, and the existing signal pulse modulation algorithm is extended to main circuit pulse control strategies.

Description

technical field [0001] The invention belongs to the technical field of power electronic conversion and control, and in particular relates to an electromagnetic transient analysis method for a large-capacity power electronic conversion system. Background technique [0002] Large-capacity power electronic conversion systems generally refer to power electronic conversion systems with a power level of hundreds, hundreds of kilowatts or even megawatts, a voltage level of hundreds of volts, kilovolts or even 10,000 volts, and a current capacity of hundreds or thousands of amperes. system. With the urgent demand for large-capacity power electronic devices worldwide, such as high-voltage frequency conversion speed regulation, power quality control, electric traction, wind power / photovoltaic grid-connected power generation, distributed independent power systems, large-scale smelting, material processing, plasma The application of large-capacity power electronic systems has become on...

AI Technical Summary

Problems solved by technology

However, there are two obvious defects in the application of large-capacity conversion systems: (1) only focus on the device itself, and do not establish the interactive relationship between the device and the system

In practice, devices in the system are affected by many factors such as line spurious parameters, control and protection parameters, and exhibit different operating characteristics. Only using the safe working area of ​​devices cannot analyze and control these complex characteristics.

(2) The device safe working area describes the relationship between the steady-state current and its terminal voltage in the switching device, and cannot describe the switching transient process of the device, and cannot be used in the optimization design and transient modeling of the conversion system

The laminated busbar structure with low stray inductance is widely used in the DC busbar design of the conversion system, but there are the following problems in the conventional main circuit design and laminated busbar design: (1) The conventional main circuit is an ideal circuit topology, There are only concentrated parameters and no distributed parameters, so the problem of distributed stray parameters cannot be analyzed; (2) The laminated busbar is only a connection in the ideal circuit topology, and it is regarded as a whole, which is equivalent to a concentrated stray inductance parameter, which is difficult to carry out Distribution parametric analysis to optimize busbars

But in fact, due to the continuity and non-linearity of the switching device action, the ideal pulse generated by the control system is very different from the main circuit pulse output after passing through the drive circuit and the switching device.

Especially in the transition process of large-capacity power electronic conversion systems, the impact of this difference is more obvious, resulting in a lot of abnormal pulses, the light ones cause distortion, and the severe ones damage devices and devices

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