Jiongkang Lin

Optimal Control Method of Motoring Operation for SRM Drives in Electric Vehicles

This paper presents three criteria for evaluating the motoring operations of switched reluctance motor (SRM) drives for electric vehicles (EVs). They imply motoring torque, copper loss, and torque ripple, respectively. The effects of the turn-off and turn-on angles on these criteria are investigated under hysteresis current control. To fulfill the best motoring operation, consequently, the multiobjective optimization function is developed by using three weight factors and three groups of base values: the correct balance between the maximum average torque, the maximum average torque per root mean square current, and the maximum torque smoothness factor. The study in this paper shows that the turn-off and the turn-on angles can be optimized to maximize the developed multiobjective function. In addition, the control method for the best motoring operation of SRM drives in EVs is proposed. In this method, two angular controllers are proposed to automatically tune the turn-off and turn-on angles to obtain high motoring torque, low copper loss, and low torque ripple. Simulations and experimental results have demonstrated the proposed optimal control method. Therefore, this paper offers a valuable and feasible approach for implementing the best motoring operation of SRM drives for EVs.

Active Suspension System Based on Linear Switched Reluctance Actuator and Control Schemes

In this paper, an active suspension system utilizing a low-cost high-performance linear switched reluctance actuator with proportional-derivative (PD) control is presented. With the tracking differentiator (TD) calculating the displacement and its derivatives directly under the presence of noise, velocity and acceleration can be evaluated, and accurate position control can be achieved. Comparison is made between linear and nonlinear PD control methods in terms of various system parameters and road profiles. A nonlinear PD controller with better dynamic responses is evaluated and developed for real-time suspension application. The proposed PD control schemes are simulated, tested, and analyzed to prove its robustness and reliability. Finally, a quarter-car active suspension system prototype is built to demonstrate the effectiveness of the proposed control schemes with experiment results.

Topology, Modeling, and Design of Switched-Capacitor-Based Cell Balancing Systems and Their Balancing Exploration

A series of switched-capacitor (SC) cell balancing circuits is proposed for rechargeable energy storage devices like battery and supercapacitor strings in this paper. Taking a basic SC-based cell balancing unit as an equivalent resistor, the behavioral models of the proposed cell balancing circuits are developed to evaluate their balancing performance. Comparing with existing SC-based cell balancing circuits, the main advantage of the proposed circuits is that their balancing speed is independent of both of the number of battery cells and initial mismatch distribution of cell voltages. In order to improve the operation performance of SC-based cell balancing circuits in the respect of minimizing the equivalent resistance, optimizing methodologies of circuit parameters are introduced by referring the concepts of slow switching limit and fast switching limit as well as inductive switching limit of SC power converters. Simulation and experimental results are provided to verify the feasibility of the proposed cell balancing circuits.

A Novel Method to Minimize Force Ripple of Multimodular Linear Switched Reluctance Actuators/Motors

Force ripple is the main disadvantage of conventional linear switched reluctance actuators/motors (LSRAs/LSRMs). Based on finite element analysis (FEA), a new method to minimize force ripple is proposed for multimodular LSRAs/LSRMs in this paper. First, the force distribution of an LSRA/LSRM module is computed by using FEA. Then, the scheme of the spatial distribution of modules is developed. Finally, the modular spatial displacement is optimized to minimize force ripple. The computed results based on the FEA demonstrate the proposed method. The proposed method does not require any change in both module design and motor control. Thus, it is simple, cost-low, feasible, and effective.

Direct Instantaneous Force Control With Improved Efficiency for Four-Quadrant Operation of Linear Switched Reluctance Actuator in Active Suspension System

A direct instantaneous force control with improved efficiency for the linear switched reluctance actuator (LSRA) is proposed in this paper. Four-quadrant operation is investigated for application in the active suspension system. Force ripple minimization is considered as the primary objective due to the direct impact on passenger ride comfort. An adaptive force distribution function based on the instantaneous force feedback is proposed to achieve a ripple-free system. The choice of switching parameters for improved operation efficiency is examined. The optimal switching positions are online adjusted with respect to the force demand. Simulation and experimental results are presented to verify the effectiveness of the proposed control strategy.

Estimation of Inductance Derivative for Force Control of Linear Switched Reluctance Actuator

This paper presents an inductance derivative estimation method of linear switched reluctance actuator (LSRA) employing tracking-differentiating technology. The inductance of LSRA is highly nonlinear and varies with phase current and translator position. To achieve direct force control, the derivative of inductance must be estimated to generate required phase currents. The inductance profile of LSRA is obtained from finite element analysis calculation. Tracking differentiator is introduced to track the inductance and its derivative for further control purpose. A simple Proportional-Integral control with compensation unit using the estimated inductance derivative is used to examine the effectiveness of the estimation of inductance derivative.