Model of Two-Phase Motor and Compressor for FIDVR Analysis

Abstract

The main focus of this research is dynamic load modeling for Fault Induced Delayed Voltage Recovery (FIDVR). FIDVR is the phenomenon whereby the system voltage remains at uncontrolled reduced levels for several seconds after fault in the system has been cleared. When FIDVR happens, the load loss due to motor protective device is significant, and subsequently leads to over voltage. The stalling of the motors in air-conditioners is believed to be one of the causes of FIDVR, so building a dynamic model for the motor and load to simulate the stall behavior during voltage fault is necessary. The air-conditioner unit consists of a two-phase induction motor and a compressor load. The first step is to model the two-phase induction motor with rotation field theory. Afterwards, a dynamic phasor model is developed and used to match the behavior observed during tests. The load torques of different compressor loads are studied. The load torque and moment of inertia variation due to gas pressure is modeled to better characterize the stall behavior of the motor. A regression parameter estimation model is constructed to estimate the machine parameters to match the simulation and measurement data. The model is built so that the simulation result can match the current and voltage waveforms for different operation conditions. Most importantly, the model is able to match the stall behavior for different voltage fault situations and predict the stall behavior for cases that are not tested in the lab for future use.