Sung-Tak Jou and Kyo-Beum Lee, "Sensing of Three Phase PWM Voltages Using Analog Circuits," The Transactions of the Korean Institute of Electrical Engineers, vol. 64, no. 11, pp. 1564–1570, Nov. 2015. > Paper

This paper intends to suggest a sensing circuit of PWM voltage for a motor emulator operated in the inverter. In the emulation of

the motor using a power converter, it is necessary to measure instantaneous voltage at the PWM voltage loaded from the inverter.

Using a filter can generate instantaneous voltage, while it is difficult to follow the rapidly changing inverter voltage caused by the

propagation delay and signal attenuation. The method of measuring the duty of PWM using FPGA can generate output voltage from

the one-cycle delay of PWM, while the cost of hardware is increasing in order to acquire high precision. This paper suggests a PWM

voltage sensing circuit using the analogue system that shows high precision, one-cycle delay of PWM and low-cost hardware. The

PWM voltage sensing circuit works in the process of integrating input voltage for valid time by comparing levels of three-phase

PWM input voltage, and produce the output value integrated at zero vector. As a result of PSIM simulation and the experiment with

the produced hardware, it was verified that the suggested circuit in this paper is valid.