Maximum Torque Per Ampere Control Scheme Considering NI HTS Field Coil Behavior for Synchronous Motor With Salient Rotor Core
Jong‐Hoon Yoon, Uijong Bong, JuKyung Cha, Jeonghwan Park, Seungyong Hahn
Abstract
This paper presents characteristics analysis results of no-insulation (NI) high-temperature superconducting (HTS) motor with saliency according to motor control schemes. In case of a salient motor, for efficient operation, the commonly-known maximum torque per ampere (MTPA) control method is applied to generate the maximum torque at the given absolute value of stator current by using optimal dq-axes current pair ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$i^{r}_{ds}$</tex-math></inline-formula> , <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$i^{r}_{qs}$</tex-math></inline-formula> ). To figure out whether MTPA control is applicable for NI HTS motor, we applied three control schemes referred from conventional motor control method: 1) MTPA with constant parameters; 2) MTPA with variable parameters; and 3) <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$i^{r}_{ds}=0$</tex-math></inline-formula> control. In addition, we proposed MTPA control with exponential function for suppressing radial leak current. The following key transient profiles of 500 kW NI HTS motor according to motor control schemes are presented: 1) dq-axes current; 2) field coil radial leak current; and 3) torque per ampere value.