Speed Control of Five-Phase Induction Motor Drives with an Open Phase Fault Condition and Predictive Current Control Methods H. Guzman Universidad de Sevilla, Spain hguzman@esi.us.es M.J. Duran Universidad de Malaga, Spain, mjduran@uma.es F. Barrero Universidad de Sevilla, Spain, barrero@esi.us.es Abstract-Multiphase drives offer interesting advantages against their conventional three-phase counterparts, particularly during the post-fault operation where the higher number of phases allows drive operation under fault conditions. Post-fault performance in multiphase drives can be obtained maintaining a maximum current level and preserving ripple-free operation. Predictive current control techniques have also shown their interest in high performance control application of multiphase drives. However, fault tolerance of conventional and predictive current control methods of multiphase drives have been briely analyzed although the fault tolerance capability is a demanded feature in industrial applications. This paper analyzes the speed operation of a ive-phase drive with an open phase fault condition. The conventional model based predictive current controller is modiied to cope with the fault condition, and experimental results are provided to validate the proposed method. Keywords-Predictive current control methods, Speed control, Post-fault operation, Multiphase drives. I. [NTRODUCTION Fault-tolerance capability is an interesting feature in high performance industrial applications like wind farms or electric vehicles. Redundancies in the power converter and complex control strategies have been normally proposed to achieve an adequate post-fault operation using conventional three-phase drives. However fault tolerant solutions are expected to be simple and cost-effective in order to ensure their interest. Multiphase drives have gained recent attention of the research community due to their ability to produce better distribution of current among the higher number of phases and lower torque pulsations or harmonic currents [[]. Another interesting capability of a multiphase drive is the ability of producing torque under fault conditions [2]. Torque generation in electrical drives can be obtained with only 3 healthy phases in the multiphase drive, being even possible the generation of a smoothly rotating MMF with ripple-ree operation [3-6]. This means that post-fault operation in multiphase drives is viable, but some considerations must be provided in order to guarantee the controllability of the system. Post-fault operation in multiphase drives have been recently analyzed [5-11]. Conventional control techniques have been used with P[ or hysteresis controllers, proving that post-fault operation can be achieved with low torque ripples. The conventional controllers were modiied to satisy different post-fault operation, and different post-fault control objectives were established. For instance, healthy phases are regulated to achieve equal peak currents in [6], and the so called post-fault minimum derating method is presented. [n [[0] current references are modiied in order to reduce torque ripple or copper looses are minimized in [[[]. Notice that any of these post-fault criteria, minimum derating, reduced torque ripple or minimized copper losses, were deined using conventional control techniques. Model-based predictive curent control (MPC) technique has recently appeared as an interesting alternative to conventional control technique of three-phase [12] and multiphase [13, [4] drives. This recent interest lies on the discrete nature of the power converter, the lexibility of the control method, and the development of moden microelectronic devices [14]. However, post-fault analysis of MPC-based on conventional or multiphase drives is still in its earliest state, where the open phase post-fault case has been only analyzed in the multiphase case using simulation results [3-5]. Obtained results showed that the machine model becomes asymmetrical in the post-fault operation using the conventional Clarke transformation. Then, certain modiications of the conventional Clarke transformation were proposed to preserve the symmetry of the machine model and simpliy the post-fault control operation [4]. The proposed transformation is now experimentally veriied, previous to its implementation in the management of a fault condition in a real system, using a real ive-phase induction machine under an open phase fault condition. Post-fault minimum derating and copper losses operation modes are experimentally tested to conirm the viability of MPC in post-fault operation. The paper is organized as follows. Section II reviews the model of the ive-phase induction motor drive under an open phase fault condition. Next, the MPC technique in post-fault operation is shown. The proposed modiications in the conventional Clarke transformation are analyzed, and stator current references are discussed considering minimum derating and minimum copper losses criteria. Experimental results are presented in section [V, while conclusions are summarized in the last section. 978-1-4673-2421-2/12/$31.00 ©2012 IEEE 3647