EPE Association: EPE 1989 - 25 - Lecture Session 3.8: ADJUSTABLE SPEED DRIVES

EPE 1989 - 25 - Lecture Session 3.8: ADJUSTABLE SPEED DRIVES
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   OPERATING ANALYSIS AND SIMULATION OF A BRUSHLESS DC MACHINE WITH A 120° HYSTERESIS CURRENT CONTROLLED VOLTAGE INVERTER
By R. Carlson; A. A. Tavares; M. Lajoie-Mazenc [View]
[Download]

Abstract: An operating analysis and simulation of a surface mounted permanent magnet synchronous machine fed by a 120° hysteresis current controlled power MOS-FET inverter is proposed. The Hysteresis-band current control technique is widely used because of its simplicity of implementation, fast current loop and inherent peak current limiting capability. In spite of this, a systematic analysis of the commutation phenomena in this kind of current control is not easily found in the literature when used in a 120° inverter with current measured in the DC section. Other schemes using hysteresis and PWM techniques on 180° inverters are found. The paper is mainly directed to the establishement of general equations that describe all possible configurations of the whole circuit. Special emphasis is given to the possibility of action of the hysteresis current comparator during the phase commutation an to the possibility of conduction of the open-circuited phase diodes. General equations are written that take into account the hysteresis comparator status. These equations demonstrate, among other things, that the decreasing current does not depends on this status. A simulation program was written that includes the mains rectifier, filtering RC, inverter, machine and command. This simulation is done by operating sequences taking, however, into account the hysteresis comparator and the rotor sensors signals.

   CHARACTERISTICS OF HALF-WAVE RECTIFIED BRUSHLESS SYNCHRONOUS MOTOR WITH PERMANENT MAGNETS
By Jun Oyama; Tsuyoshi Higuchi; Takashi Abe; Eiji Yamada [View]
[Download]

Abstract: The principle of a new type brushless synchronous motor is described and confirmation of the theory is demonstrated experimentally. In the rotor field winding the emf is induced by the mmf which rotates at synchronous speed and pulsates at bias frequency. The field excitation is produced by both the field current obtained by rectifying the emf with a diode inserted into the field winding and the permanent magnets installed in the rotor slots. This motor has not only simple and robust brushless structure but also high efficiency and power factor, and is anticipated for a new ac-servo drive motor.

   PROPULSION BY ELECTRONIC MOTOR
By J. Saint Michel; J. P. Riotte [View]
[Download]

Abstract: The electronic motor consists of a permanent-magnet polyphase motor each phase of which is supplied by a PWM converter. Intended for ship propulsion, this motor, associated with converters, offers prospects of major advances in the areas of acoustic discretion and maintainability. In addition to providing a substantial increase in power output per unit weight and per unit volume due to the permanent magnets, the motor design makes it possible to build the stator from easily separable elements. The converters, with reduced elementary power, allow the use of switches with operating-frequencies of several kHz, which provides fine matching to the machine waveforms, thereby reducing torque ripple. Owing to the multidrive structure, one or more faults can be eliminated without shutting down the system.

   EFFICIENCY CONSIDERATIONS ABOUT MOTORS FED BY BACK TO BACK THYRISTORS CONVERTERS SUPPLIED BY UNBALANCED VOLTAGE SUPPLY
By J. Oyama; F. Profumo [View]
[Download]

Abstract: The case of unbalanced supply is a uniquely problem in motor application since its causes are multivaried. In many situations a static starter utilizing back-to-back thyristors in series with the motor lines is already installed for the purpose of soft starting or for power factor improvement. An attractive low cost solution for phase unbalance is to modify the control strategy of the static starter by adjusting firing the angles of the three thyristor pairs independently. ln this manner the series connected thyristors serve the function of unsymmetrical, variable supply impedances which can be used to balance the voltage across the motorphases. A new digital controller utilizing a static starter with a 'losses calculator loop' for balancing the phase currents of an induction motor operating with unbalanced supply is the topic of this paper. Experimental results show a marked reduction in the current unbalance and in the related negative sequence of the currents. As a consequence, the motor efficiency is approximately constant around the motor rated efficiency, in the whole range of unbalanced supply operation ( -10% to + 10%).

   DYNAMIC BEHAVIOUR AND CURRENT CONTROL METHODS OF BRUSHLESS DC MOTORS WITH DIFFERENT ROTOR DESIGNS
By Gerhard Henneberger [View]
[Download]

Abstract: In the present paper different rotor configurations and a special current control method for brushless dc motors are described. lf a negative current component in the direct axis is applied and the permanent excited rotor has a reactance Xq > Xd, an additional torque is developed in such a way that the total armature current can be reduced and the power factor is improved. The steady-state operation curves are described and the influence of the rotor design is discussed. The dynamic equations of the two-axis theory are applied to the brushless dc motor. A special decoupled current control scheme is developed. The dynamic behaviour of the brushless dc motor including inverter and controller is investigated numerically integrating the state form of the dynamic equations using the Runge-Kutta algorithm. The theoretical results are verified by measurements and experimental investigations.

EPE 1989 - 25 - Lecture Session 3.8: ADJUSTABLE SPEED DRIVES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1989 - Conference > EPE 1989 - 25 - Lecture Session 3.8: ADJUSTABLE SPEED DRIVES
	[return to parent folder]

	OPERATING ANALYSIS AND SIMULATION OF A BRUSHLESS DC MACHINE WITH A 120° HYSTERESIS CURRENT CONTROLLED VOLTAGE INVERTER By R. Carlson; A. A. Tavares; M. Lajoie-Mazenc	[View] [Download]
Abstract: An operating analysis and simulation of a surface mounted permanent magnet synchronous machine fed by a 120° hysteresis current controlled power MOS-FET inverter is proposed. The Hysteresis-band current control technique is widely used because of its simplicity of implementation, fast current loop and inherent peak current limiting capability. In spite of this, a systematic analysis of the commutation phenomena in this kind of current control is not easily found in the literature when used in a 120° inverter with current measured in the DC section. Other schemes using hysteresis and PWM techniques on 180° inverters are found. The paper is mainly directed to the establishement of general equations that describe all possible configurations of the whole circuit. Special emphasis is given to the possibility of action of the hysteresis current comparator during the phase commutation an to the possibility of conduction of the open-circuited phase diodes. General equations are written that take into account the hysteresis comparator status. These equations demonstrate, among other things, that the decreasing current does not depends on this status. A simulation program was written that includes the mains rectifier, filtering RC, inverter, machine and command. This simulation is done by operating sequences taking, however, into account the hysteresis comparator and the rotor sensors signals.

	CHARACTERISTICS OF HALF-WAVE RECTIFIED BRUSHLESS SYNCHRONOUS MOTOR WITH PERMANENT MAGNETS By Jun Oyama; Tsuyoshi Higuchi; Takashi Abe; Eiji Yamada	[View] [Download]
Abstract: The principle of a new type brushless synchronous motor is described and confirmation of the theory is demonstrated experimentally. In the rotor field winding the emf is induced by the mmf which rotates at synchronous speed and pulsates at bias frequency. The field excitation is produced by both the field current obtained by rectifying the emf with a diode inserted into the field winding and the permanent magnets installed in the rotor slots. This motor has not only simple and robust brushless structure but also high efficiency and power factor, and is anticipated for a new ac-servo drive motor.

	PROPULSION BY ELECTRONIC MOTOR By J. Saint Michel; J. P. Riotte	[View] [Download]
Abstract: The electronic motor consists of a permanent-magnet polyphase motor each phase of which is supplied by a PWM converter. Intended for ship propulsion, this motor, associated with converters, offers prospects of major advances in the areas of acoustic discretion and maintainability. In addition to providing a substantial increase in power output per unit weight and per unit volume due to the permanent magnets, the motor design makes it possible to build the stator from easily separable elements. The converters, with reduced elementary power, allow the use of switches with operating-frequencies of several kHz, which provides fine matching to the machine waveforms, thereby reducing torque ripple. Owing to the multidrive structure, one or more faults can be eliminated without shutting down the system.

	EFFICIENCY CONSIDERATIONS ABOUT MOTORS FED BY BACK TO BACK THYRISTORS CONVERTERS SUPPLIED BY UNBALANCED VOLTAGE SUPPLY By J. Oyama; F. Profumo	[View] [Download]
Abstract: The case of unbalanced supply is a uniquely problem in motor application since its causes are multivaried. In many situations a static starter utilizing back-to-back thyristors in series with the motor lines is already installed for the purpose of soft starting or for power factor improvement. An attractive low cost solution for phase unbalance is to modify the control strategy of the static starter by adjusting firing the angles of the three thyristor pairs independently. ln this manner the series connected thyristors serve the function of unsymmetrical, variable supply impedances which can be used to balance the voltage across the motorphases. A new digital controller utilizing a static starter with a 'losses calculator loop' for balancing the phase currents of an induction motor operating with unbalanced supply is the topic of this paper. Experimental results show a marked reduction in the current unbalance and in the related negative sequence of the currents. As a consequence, the motor efficiency is approximately constant around the motor rated efficiency, in the whole range of unbalanced supply operation ( -10% to + 10%).

	DYNAMIC BEHAVIOUR AND CURRENT CONTROL METHODS OF BRUSHLESS DC MOTORS WITH DIFFERENT ROTOR DESIGNS By Gerhard Henneberger	[View] [Download]
Abstract: In the present paper different rotor configurations and a special current control method for brushless dc motors are described. lf a negative current component in the direct axis is applied and the permanent excited rotor has a reactance Xq > Xd, an additional torque is developed in such a way that the total armature current can be reduced and the power factor is improved. The steady-state operation curves are described and the influence of the rotor design is discussed. The dynamic equations of the two-axis theory are applied to the brushless dc motor. A special decoupled current control scheme is developed. The dynamic behaviour of the brushless dc motor including inverter and controller is investigated numerically integrating the state form of the dynamic equations using the Runge-Kutta algorithm. The theoretical results are verified by measurements and experimental investigations.