Digital Current Control Method of Induction Motor Using Synchronous Current Detection with PWM Signal.

Abstract

This paper proposes a fully digital current control method with DSP for the vector control of the induction motor.

Design of a Cascaded H-Bridge Multilevel Inverter Based on Power Electronics Building Blocks and Control for High Performance

“…It is shown that the expansion and modularization characteristics of the CHBM inverter are improved when using Phase-Shifted Pulse Width Modulation (PSPWM) since the individual inverter modules operate more independently. However, the PSPWM of a CHBM has a phase difference between the reference voltage and real voltage, which can cause instability in the current controller at high speeds where the ratio of the sampling frequency to the output frequency is insufficient [12]- [14]. This instability in the current controller is removed by adding the proposed method which compensates for the phase difference between reference voltage and real voltage.…”

Analysis and compensation of current sampling error in AC drive with discontinuous PWM

“…DPWM reduces the average switching frequency by 33% compared with CPWM and moreover if 60" intervals of no switching region is distributed to positive and negative peak of the phase current, the switching loss can be further minimized[ 111. If there is no time delay between the real current and the sampled one, it is well known that the sampled current represents the fundamental component of the motor current [5]. But if some delay is introduced, the above statement is invalid.…”

“…Assuming that the system delay is constant as (2) and is sufficiently small, the measurement error in DPWM is given by (5). where AI& = 1 :…”

“…But there have been a few studies about current measurement issue. To detect the fundamental component of the current and to maximize the bandwidth of the current controller the instantaneous sampling is widely used [5,6]. In this sampling method, the current measurement error comes from the A/D converter characteristics [7] and the analog filter [8,9] which suppresses the switching noise.…”