Optimal current reconstruction strategy utilizing various PWM switching generation schemes in DC-link single shunt resistor

Three-phase motor current information is essential for vector and torque control of motors. The use of dc-link single shunt has cost and size advantages and can reduce torque ripples caused by offset and scale differences. However, dc-link single shunt can measure the current only when an active voltage vector is applied, which will result in a large immeasurable region. Various current reconstruction schemes have been developed to eliminate immeasurable regions. Conventional solutions are effective only in specific immeasurable regions and limited in their ability to eliminate all the immeasurable regions and require complex calculations. This study proposes an optimal current reconstruction strategy that can be used in all immeasurable regions. The method divides the immeasurable region into three segments and selectively applies various pulsewidth modulation (PWM) techniques, including the proposed edge-aligned PWM method, which requires only simple calculations. The method can reduce the complexity and successfully eliminate all the immeasurable regions. The experiment results confirm the effectiveness and feasibility of the proposed method.