Fault-tolerant control method of dual three-level inverter topology based on vector clamping modulation strategy

Abstract

The invention discloses a fault-tolerant control method of a dual three-level inverter topology based on a vector clamping modulation strategy. The fault-tolerant control method is suitable for being used by a motor driving system. A fault-tolerant circuit comprises six bidirectional thyristors TR1-TR6 which are respectively connected with a midpoint of a dual three-level inverter system. When the dual three-level inverter system has no fault, the TR1-TR6 are all in an off state, and when the dual three-level inverter system has a switch tube fault, the bidirectional thyristor of the phase where a faulty switch tube is located is turned on to realize fault-tolerant control. Meanwhile, in a PWM period, one inverter is in a clamping state, the other inverter performs vector synthesis, and the two inverters alternately operate in the clamping state and the vector synthesis state, so that the fault-tolerant control is realized, and the switching loss of the system is reduced. Particularly, the neutral-point potential balance problem needs to be considered in the three-level inverter topology, and the method can achieve neutral-point potential balance. The fault-tolerant control method is simple in structure, convenient to use and wide in practicability.

Description

technical field [0001] The invention relates to a fault-tolerant control method, and is especially suitable for a fault-tolerant control method of a double-three-level inverter topology based on a vector clamp modulation strategy used in a motor drive system. Background technique [0002] The motor drive system is mainly composed of a controller, a driver, an inverter and a motor, among which the inverter and the drive system are most prone to failure. Failure to detect such faults in time will lead to fault expansion. The reliable operation of the motor drive is directly related to the safety of personal property, so it is of great significance to study the fault-tolerant control of the inverter system to improve the reliability of the motor drive system. [0003] The open-winding structure itself has fault-tolerant performance, and a set of inverters are used for power supply at both ends of the open-winding structure, forming a double-inverter open-winding motor structur...

AI Technical Summary

Problems solved by technology

However, the lack of phase operation will lead to poor output voltage and current waveforms, which cannot be practically applied

[0005] On the other hand, most of the current literature focuses on the fault-tolerant control of dual two-level inverter systems, and few people have studied the fault-tolerant control technology of dual three-level inverter systems. It should be noted that the midpoint potential balance problem existing in the three-level inverter system

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