Direct Voltage MTPA Speed Control of IPMSM-Based Electric Vehicles

Abstract

A simple maximum torque per ampere (MTPA) method is designed for interior permanent magnet synchronous motors (IPMSMs) with no current control. The proposed method tracks the rotor speed by finding the best pair of voltage angle and amplitude for each motor's speed and torque condition. This is achieved without stand for any current control loop and using a single controller, which makes the technology simple to a great extent, contrary to the majority of methodologies in the literature. Moreover, a thorough insight analysis is provided to determine analytically the control gains, which simplifies control and tuning and makes it a suitable contender for the development of low-cost PMSM drives. To illustrate the capability of the suggested control method, a comparative study is conducted using the popular MTPA vector control strategy. Experimental results for various situations reveal the ability of the suggested MTPA controller in steady-state, standstill, and transient conditions. Additionally, to quantitatively assess the MTPA trajectory tracking accuracy, both control methods are compared using an efficiency metric. Besides, the US06 standard driving cycle is implemented experimentally to validate the proposed method for electric vehicle applications.INDEX TERMS speed trajectory control, maximum torque per ampere (MTPA), interior PM synchronous motors (IPMSMs).

Multiparameter Estimation-Based Sensorless Adaptive Direct Voltage MTPA Control for IPMSM Using Fuzzy Logic MRAS

“…A direct voltage maximum torque per ampere speed control (DVC) of IPMSM was developed and confirmed against the well-known field-oriented control (FOC) in [21], where the effect of motor parameter variation was not considered. A schematic diagram of DVC is shown in Figure 1.…”

“…Since infinite combinations of v and ∆θ can generate a given torque and speed, DVC aims to extract the optimum pairs to develop the maximum torque with the minimum current consumption. Considering the motor is under steady-state working conditions, and its parameters are constant, the voltage amplitude (v) and angle (∆θ) control laws are derived directly from the motor's electrical model, as follows [21]:…”

“…In an attempt to reduce the complexity and the tuning efforts associated with conventional current regulation-based MTPA control structures, direct voltage MTPA control for IPMSM has been studied in [16][17][18][19][20][21]. The main feature of this strategy is that it acts directly on the voltage vector through its magnitude and angle [17].…”

Online MTPA Control of IPM Motor Using NN-Based Perturb and Observe Algorithm

“…where L d and L q are the d-and q-axis stator inductances, R s is the resistance of the stator winding, u d and u q are the d-and q-axis stator voltage, i d and i q are the d-and q-axis stator current, ψ f is the permanent magnet flux linkage, p n is the polar pairs, J is the moment of inertia, T e and T L are the electromagnetic and the load torques, B is the viscous friction coefficient, ω m and ω e are the mechanical and the electrical angular speeds. The copper loss power p c evaluating the efficiency of MTPA control can be expressed as (5). At constant torque, lower copper loss power indicates the higher efficiency of the copper-loss-minimization control.…”

“…Therefore, in IPM motor control technologies, maximum torque per ampere (MTPA) control methods are often used to improve the efficiency of IPM motors and provide maximum torque or minimum stator current to minimize copper losses. Based on the field oriented control (FOC) technology and the equivalent model of IPM motor in the direct-quadrature (dq) frame, the conventional offline method for implementing MTPA control is to calculate MTPA equations, under the assumption of stable and known motor parameters [5], [6]. However, due to steel saturation, crosssaturation and flux linkage affected by temperature, motor parameters vary depending on different operating conditions.…”