Integration of FOC With DFVC for Interior Permanent Magnet Synchronous Machine Drives

Abstract

In this paper, the drawbacks of the conventional f-t frame based maximum torque per ampere (MTPA) control schemes are analyzed and mathematically proved. In order to inherit the merits of both the direct flux vector control (DFVC) in field weakening region and field orientated control (FOC) in constant torque region while avoiding their disadvantages, an integrated control scheme is proposed. The proposed control scheme integrates the FOC into f-t reference frame at low speeds to achieve a relatively accurate and robust MTPA control, while at high speeds, the DFVC is adopted to utilize the advantages of f-t frame based control scheme in field weakening region. A shape function is utilized by the proposed control scheme to achieve a smooth transition between the two control schemes. The proposed control scheme is verified by experiments under various operation conditions on a prototype IPMSM drive. The simulation and experimental results illustrate that the proposed control scheme could achieve a better MTPA control accuracy in constant torque region and a better field weakening performance in the constant power region. Meanwhile the complex look-up tables for FOC in field weakening region and the difficulties in observing flux vector at low speed are avoided. INDEX TERMS Maximum torque per ampere (MTPA) control, Direct flux vector control (DFVC), Field orientated control (FOC), Interior permanent magnet synchronous machine (IPMSM), Torque control.

Direct Voltage MTPA Speed Control of IPMSM-Based Electric Vehicles

“…Henceforth, the simplified motor's voltage amplitude and angle variation are defined in (31) and (36), with the control coefficients K v1 , K v2 and K θ calculated as in (32) and (37). Unlike other methods where control gains are set using an extensive trial-and-error procedure, formulation (32) and ( 37) provide an analytical solution to calculate these gains.…”

“…Furthermore, Fig. 7(e) depicts the IPMSM voltage angle for the FOC method and the simplified proposed technique (36) (voltage angle as a function of speed and load torque). A nonlinear relationship exists between the voltage angle and the speed and torque of the motor.…”

“…A nonlinear-PI (NPI) controller is utilized instead of the more common PI controller in order to improve the controller's convergence property [35]. Alternatively, a novel integrated control scheme, which combines the field-oriented control (FOC) scheme with the direct flux vector control (DFVC), is presented in [36]. This control method combines the advantages of both FOC and DFVC while avoiding the disadvantages of the two control methods.…”

Compensating Thermal Derated Torque of IPMSM Centric Electric Vehicles

“…Robust LPV observer is designed for flux estimation and hence torque which guarantees exact convergence. LPV observer is designed in stationary reference frame in equations (20)(21)(22)(23) to cater thermal effects due to variation of stator resistance given in equation (14).…”

“…For efficient performance of IPMSM drive, being the most significant part of EV, many distinguished control strategies have been demonstrated including sliding mode controls catering the chattering effects [8], [9], intelligent control methods [10], [11], and modern control strategies [12], [13]. However, FOC and Direct Torque Control (DTC) are the most common and effective methods adopted for speed and torque control [14], [15]. Even though DTC is considered due to less dependency of parameters but does not perform well at low motor speeds because of high torque ripples.…”