초록 ▼

Index signals which represent the degree of instability in a three-phase induction motor system is derived by using phase current signals which are usually already available in V/Hz PWM inverters for other purposes. Proportional integration compensators, which may be implemented in software, process

Index signals which represent the degree of instability in a three-phase induction motor system is derived by using phase current signals which are usually already available in V/Hz PWM inverters for other purposes. Proportional integration compensators, which may be implemented in software, process these index signals and generate frequency and/or voltage adjustments to the V/Hz controller in order to compensate for speed instability in the system. The compensation algorithm is robust to system changes and is also effective to improve acceleration and deceleration performance.

대표청구항 ▼

[ What is claimed is:] [1.] A method of identifying instability in a three-phase induction motor drive system, comprising:(a) detecting, in an instability detector circuit coupled to at least two of three phases of said motor drive system, a change ]EQU27 ] in the magnitude of stator current in the

[ What is claimed is:] [1.] A method of identifying instability in a three-phase induction motor drive system, comprising:(a) detecting, in an instability detector circuit coupled to at least two of three phases of said motor drive system, a change ]EQU27 ] in the magnitude of stator current in the system; and (b) detecting, in an instability detector circuit coupled to at least two of three phases of said motor drive system, a change .DELTA..omega. in angular speed change in the system; and(c) identifying instability in said motor drive system based upon values of ]EQU28 ] and .DELTA..omega..