Harald Klode

Four-Quadrant Pulse Injection and Sliding-Mode-Observer-Based Sensorless Operation of a Switched Reluctance Machine Over Entire Speed Range Including Zero Speed

The objective of this paper is to present a sensorless position estimation technique for switched reluctance machines (SRM) operating in constant dynamic mode over a wide speed range including zero speed. The technique combines two different methods to deliver high resolution position information over the wide speed range. At zero and low speeds, a voltage pulse injection method is used to estimate the rotor position in all four quadrants. For higher speeds, a sliding mode observer (SMO) based algorithm is used and combined to work with the low speed algorithm. Experimental results demonstrate the effectiveness of this new combined technique that has four-quadrant operation capability.

Four-quadrant and zero-speed sensorless control of a switched reluctance motor

A four-quadrant sensorless controller for switched reluctance motor (SRM) drives is presented in this paper. The drive system with appropriate turn-on and turn-off angles for each operating quadrant delivers excellent dynamic performance over a wide speed range including zero speed. The problems associated with practical implementation especially at low and zero speeds have been addressed and overcome with engineering solutions. Experimental results for a 1-kW SRM obtained on a dSPACE-based system are presented along with useful guidelines for practical implementation.

Four-quadrant control of a switched reluctance motor for a highly dynamic actuator load

A four-quadrant controller for switched reluctance motor (SRM) drives with optimal turn-on and turn-off angles for each operating quadrant is presented in this paper. The firing angles are chosen to maximize the average torque produced by the motor, which requires the optimization of the area of the energy conversion loop. The four-quadrant SR controller developed with the chosen optimization criterion gives fast motoring response as well as fast braking response. The underlying contribution of this paper is the development and solution of an optimal control problem to provide the best control strategies. The paper also provides the specific guideline to switch the firing angle position when the motor operation changes from one quadrant to another. The developed four-quadrant controller has been applied to control the linear displacement of a highly dynamic actuator load.

A hybrid sensorless SRM drive with eight- and six-switch converter topologies

This paper presents a hybrid sensorless controller used with both the classical eight-switch converter and a reduced six-switch converter topology for switched reluctance motor (SRM) drives. The hybrid sensorless scheme consists of a sliding mode observer (SMO)-based position sensorless approach for high speeds along with a low-resolution discrete sensor for low speeds and standstill. The hybrid position estimation switches between the SMO and the low-resolution sensor according to the speed sign and the position error difference between the SMO and the low-resolution sensor. The experimental results show the robustness of this hybrid low-cost control approach with the two converter topologies.

Four-quadrant pulse injection and sliding mode observer based sensorless operation of a switched reluctance machine over entire speed range including zero speed

The objective of this paper is to present a sensorless position estimation technique for switched reluctance machines (SRM) operating in constant dynamic mode over a wide speed range including zero speed. The technique combines two different methods to deliver high resolution position information over the wide speed range. At zero and low speeds, a voltage pulse injection method is used to estimate the rotor position in all four quadrants. For higher speeds, a sliding mode observer (SMO) based algorithm is used and combined to work with the low speed algorithm. Experimental results demonstrate the effectiveness of this new combined technique that has four-quadrant operation capability.

Acoustic Noise of Switched Reluctance and Permanent Magnet Motors: A Comparison in the Context of Electric Brakes

It is held as fact that Permanent Magnet (PM) brushless motors are less noisy than Switched Reluctance (SR) motors, and many methods have been published to reduce the noise of SR drives. This paper provides a systematic experimental comparison of both drives, and of proposed noise- mitigation strategies, in the context of a specific mass-market application: Automotive Electro Mechanical Brakes (EMB). The two motors were designed to fit into the same envelope and to produce similar dynamic performance for the brake system. Sound pressure levels produced by the two motors at key torque-speed points were measured through dynamometer tests under identical conditions. The influence of the hysteresis current and PWM control methods on the acoustic noise was also studied. The acoustic noise was then measured with the EMB systems assembled with the PM and SR motors. Though the measured acoustic noise of the SR motor with dynamometer tests was higher compared to that of the PM motor, the acoustic noise levels of the two EMB systems were found to be similar with only a slight advantage to the PM based system.

Switched reluctance and permanent magnet brushless motors in highly dynamic situations: A comparison in the context of electric brakes

Vehicular brake systems with electro-mechanical brakes (EMBs) are emerging as a way to enhance system features and performance. Of particular interest in this context is the EMB actuator motor, which needs to be designed to meet the dynamic brake system performance requirements. Two motors with fundamentally different operating principles, a switched reluctance (SR) motor and a permanent magnet (PM) brushless motor, were designed, built, and evaluated in an identical EMB actuator environment. This paper compares their design and performance. Experimental as well as simulation results demonstrate that the upper motor speed limit has a significant effect on the overall dynamic performance of the EMB system. The high-speed capability of the switched reluctance motor, which may be considered an advantage, can actually be a detriment when highly dynamic response patterns are required. In order to improve the dynamic performance of the SR system, a solution with a software-based speed limit for the motor is suggested. The resulting design trade-offs to choose the motor speed limit can be addressed with a graphical approach developed in the paper