Phase Current Measurement Method of Dual Inverter-Motor Drive System Using a Single DC Link Current Sensor

• Main Authors: Seon-Ik Hwang, Seong-Hyeon Cho, Jun-Hyung Jung, Jang-Mok Kim
• Format: Article
• Language: English
• Published: MDPI AG 2021-09-01
• Series: Energies
• Subjects: dual inverter-motor drive; single DC link current; current reconstruction; PWM shift; SVPWM
• Online Access: https://www.mdpi.com/1996-1073/14/18/5626

In recent years, electric propulsion systems have become widely, used and these systems have strict limits in volume and weight. Therefore, it is necessary to reduce the weight of the inverter-motor drive system. In a typical <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>n</mi></semantics></math></inline-formula> inverter-motor drive system, at least <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mi>n</mi></mrow></semantics></math></inline-formula> phase current sensors are required. In order to reduce the number of phase current sensors, this paper proposes a method for measuring phase current using <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo> </mo></mrow></semantics></math></inline-formula>DC link current sensors in a <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>2</mn><mi>n</mi></mrow></semantics></math></inline-formula> inverter-motor drive system. Two phase currents per inverter-motor system are measured during one period of the switching frequency using the pulse width modulation (PWM) shift method. However, since the measured phase current contains an error component in the average current, the error component was compensated for in order to obtain a current similar to the actual phase current by using the slope and dwell time of the phase current. The effectiveness of the proposed method is verified through experiments.