Switching Techniques for Minimizing Current Measurement Noise in Integrated Single Shunt Power Conversion System With Common DC Link

Abstract

This paper suggests a technique to reduce noise in DC current measurements within an integrated power conversion system, which includes a three-phase inverter and a full-bridge converter both utilizing single shunt resistors as current sensors. Typically, current measurement is conducted after the stabilization of current ringing to minimize the impact of switching noise. However, in the integrated power conversion system with common DC-link, switching ripples of the inverter may cause errors in the current measurement of converter, and vice versa. Therefore, switching transitions are not allowed during the current sensing periods of both the inverter and the converter in the integrated power conversion system. This paper proposes a method to adjust the switching timing of a three-phase inverter by regulating the offset voltage. While the method is explained using space vector pulse width modulation, it reconfigures the pole voltage references through offset voltage and is not dependent on the modulation technique. The paper details the process for determining the offset voltage and verifies the noise reduction effect of the technique through experimental results.

Keywords

• Circuit noise
• current measurement
• integrated circuit noise
• motor drives
• parallel machines
• pulse width modulation