Maximum Torque Per Ampere (MTPA) Control for IPMSM Drives Based on a Variable-Equivalent-Parameter MTPA Control Law

This paper presents a maximum torque per ampere (MTPA) control method for interior permanent-magnet synchronous motor drives. The proposed method employs a variable-equivalent-parameter MTPA control law to calculate the MTPA current references. Different from conventional MTPA control laws, this novel MTPA control law equivalently considers both the influence of the motor parameter values as well as the influence of the derivatives of motor parameters with respect to
d
- and
q
-axis currents on the MTPA control. Therefore, the proposed method can achieve the accurate MTPA control under different load conditions. In addition, this novel MTPA control law avoids the computation of derivatives of motor parameters and the complicated computations that exist in conventional MTPA control laws. Thus, the proposed method can provide the MTPA current references easily and in real time, allowing for fast MTPA control to be achieved. Both simulation and experimental results confirm the effectiveness of the proposed MTPA method.