Multiple freedom degree dynamic control method for inverse transform bridge phase shifting advance angle of stationary frequency conversion starter

Abstract

Disclosed is a multi-degree-of-freedom dynamic control method of an inverter bridge advance commutation angle of a static frequency converter starter, comprising the steps of: the detection of motor operating frequency, main circuit direct current of a static frequency converter, terminal voltage, and the calculation of the inverter bridge advance commutation angle, Beta=cos<-1>(cos(360f(t(off)+t0))-(square root 2X(C)I(d) / U))+Xi. The control method enables the inverter bridge advance commutation angle to carry on the dynamic control with the change of motor operating frequency, of main circuit direct current of the static frequency converter and of terminal voltage in the process of frequency conversion start, and causes a considerable reduction in the inverter bridge advance commutation angle while ensuring the constant of the arc extinguishing time of the inverter bridge commutation, so as to reduce the main circuit output direct current of the frequency converter and increase the power factor of the inverter bridge and the start efficiency of the static frequency converter starter.

Description

technical field [0001] The invention relates to a multi-degree-of-freedom dynamic control method for a stationary frequency-variable starter of a pumped-storage unit at a natural commutation stage at an inverter bridge commutation lead angle, and belongs to the static-frequency conversion start-up technology of a pumped-storage unit. Background technique [0002] At present, in countries all over the world, static variable frequency start-up is generally used as the preferred starting method for pumped storage power stations. In the automatic control system and complete sets of equipment of pumped storage power stations, static frequency converters are the key starting equipment. It is of great significance for the fast and reliable start-up of energy generating units and the stable operation of pumped storage power plants. However, in the field of static frequency conversion start-up technology for pumped storage power stations, its core technology has been monopolized by f...

AI Technical Summary

Problems solved by technology

According to the inverter bridge power factor cosψ≈cos(β-μ / 2): the inverter bridge power factor will be too low in the high-speed stage of frequency conversion startup

In addition, because γ=β-μ is too large in the high-speed stage, the starting torque of the motor is too small. To increase the starting torque of the motor and ensure that the unit starts from static frequency conversion to rated speed within the specified time, the main circuit of the frequency converter must be increased. DC current, which increases the output power of the inverter, but also makes the starting efficiency of the inverter too low

Images