Real‐Time Reference Voltage Angle Error Compensation Method for Quasi‐Continuous Sampling Angles Under Low Carrier Ratios

ABSTRACT Rapid variations in motor speed can cause significant angular errors in traditional synchronous modulation voltage sampling methods, leading to increased current harmonics and exacerbated torque fluctuations. To address this challenge, this paper introduces a real‐time reference voltage angle error compensation technique employing quasi‐continuous sampling angles. In each control cycle, the angular discrepancy between the voltage sampling angle and the desired quasi‐continuous output angle is computed and transformed into a frequency error to determine the compensation frequency. This compensation frequency is then integrated, using the quasi‐continuous angle from the previous control cycle as the initial value to ascertain the current cycle's quasi‐continuous angle. Subsequently, this angle undergoes 2 N (carrier ratio) frequency multiplication to produce a sawtooth waveform. To minimise angular errors during transitions between different carrier ratios, switching occurs at the intersection points of the sawtooth waves, ensuring both are ascending, which ultimately generates a triangular carrier wave. This approach obviates the need for a phase‐locked loop, facilitating angle error compensation in each control cycle, reducing voltage sampling angle errors, and enabling smoother transitions. The method demonstrates robust real‐time performance and resilience, as validated by experimental results confirming its effectiveness and feasibility.