A New Quick-Response and High-Efficiency Control Strategy of an Induction Motor

Abstract

New quick-response and high-efficiency control of an induction motor, which is quite different from that of the field-oriented control is proposed. The most obvious differences between the two are as follows. 1) The proposed scheme is based on limit cycle control of both flux and torque using optimum PWM output voltage; a switching table is employed for selecting the optimum inverter output voltage vectors so as to attain as fast a torque response, as low an inverter switching frequency, and as low harmonic losses as possible.2) The efficiency optimization in the steady-state operation is also considered; it can be achieved by controlling the amplitude of the flux in accordance with the torque command. To verify the feasibility of this scheme, experimentation, simulation, and comparison with field-oriented control are carried out. The results prove the excellent characteristics for torque response and efficiency, which confirm the validity of this control scheme.

Direct torque control using space vector modulation and dynamic performance of the drive, via a fuzzy logic controller for speed regulation

“…The stator flux controller imposes the time duration of the active voltage vectors, which move the stator flux along the reference trajectory, and the torque controller determinates the time duration of the zero voltage vectors, which keep the motor torque in the defined-by-hysteresis tolerance band. The corresponding output variables H Te , H Ψ and the stator flux position sector θ Ψs are used to select the appropriate voltage vector from a switching table scheme (Takahashi & Noguchi, 1986), which generates pulses to control the power switches in the inverter. At every sampling time the voltage vector selection block chooses the inverter switching state, which reduces the instantaneous flux and torque errors.…”

“…During the last decade, a lot of modifications in classic Direct Torque Control scheme (Takahashi & Noguchi, 1986) have been made (Casadei et al, 2000), (Reddy et al, 2006), (Chen et al, 2005), (Grabowski et al, 2005), (Romeral et al, 2003), (Ortega et al, 2005). The objective of these modifications was to improve the start up of the motor, the operation in overload conditions and low speed region.…”

An Improved DTC for In-wheel BLDC motors in Micro All-electric Vehicles

“…Those techniques are based on the assumption that there is a linear relationship between the phase current and torque. Direct torque control (DTC) has become a powerful and popular control scheme since it was firstly proposed in the 1980s by Takahashi and Noguchi [7] and Depenbrock [8]. Due to the merits of simple structure, quick dynamic response, and robust rotor parameters, DTC has now been extended to BLDC motor drives [9].…”

Improved Algorithms of Direct Torque Control Method

“…The method of direct flux and torque control with a switching table (DTC-ST) proposed by Takahashi and Noguchi [1] in 1985 has been used and developed up to now. In the literature on the subject the following problems have been discussed: -hexagonal flux vector trajectory and distorted stator current at low motor speed,…”

“…As a result, at low motor speed and large torque error values eT , dT signal take the values of 1 or −1 and a zero vector is not used for dT = 0 (Table I). The analysis of the DTC-ST method has been usually carried out basing on the motor torque equation as a product of stator ψ s and rotor ψ r fluxes and the angle between them as well as the dependence of the stator flux on the inverter output voltage vectors [1,4]. The analysis is usually carried out in the stationary coordinates αβ.…”