EPE Association: EPE 1985 - 15 - Lecture Session 3.01: MICROPROCESSOR CONTROL FOR AC DRIVES (I)

EPE 1985 - 15 - Lecture Session 3.01: MICROPROCESSOR CONTROL FOR AC DRIVES (I)
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1985 - Conference > EPE 1985 - 15 - Lecture Session 3.01: MICROPROCESSOR CONTROL FOR AC DRIVES (I)

   [return to parent folder]

   A.C. DRIVE WITH THREE-LEVEL VOLTAGE SOURCE INVERTER AND HIGH DYNAMIC PERFORMANCE MICROPROCESSOR CONTROL
By R. Joetten; M. Gekeler; J. eibel [View]
[Download]

Abstract: A controlled a.c. drive system is described, which contains a three-level voltage source inverter feeding an induction machine. Superimposed to the control of the inverter is a speed control system designed for high dynamic performance and covering a large speed range. Field weakening is included as well as positioning speeds near zero. The control system is realized by three microprocessors. The consequences of the three-level principle are evaluated regarding switching frequency, additional machine losses due to the current harmonics and control.

   DIRECT CONTROL OF INDUCTION MOTOR CURRENTS - DESIGN AND EXPERIMENTAL RESULTS
By H. R. Mayer; G. Pfaff [View]
[Download]

Abstract: The paper deals with a method for a direct control of the stator currents of an induction motor fed from a VSI-inverter. The design of a suitable control algorithm for direct affecting the three phases of the inverter is explained. The development of the control concept is conducted in the time domain taking as a basis the differential equation system of the machine and the special features of the inverter. By an online solution of these equations an optimal voltage vector is obtained and an appropriate switching sequence for the inverter is calculated. An additional aim consists of the demand for keeping the mean switching frequency of the inverter as low as possible. Since the control coefficients are depending on the speed an adaptive control is necessary. Experimental results obtained from a 70 kVA inverter drive controlled by a fast signal processor are presented demonstrating the performance of the control concept.

   POSITION CONTROL OF AN ASYNCHRONOUS MACHINE FED BY PWM CONVERTER
By B. De Fornel; M. Pietrzak-David; J. C. Hapiot [View]
[Download]

Abstract: In this paper, the authors present a study concerning a position control of an asynchronous machine fed by a pulse width modulated inverter. This "machine - converter" set present an example of an a.c. actuator. Firstly, a mathematical model is presented in order to analyse the dynamic behaviour of the system. Then an optimal position control with a quadratic criterion has been chosen in view to ensure the best system performances. The process for the whole system "asynchronous machine-converter" is then simulated, in a very precise way, in order to verify acceptable operation of this set during the different transient states in all four quadrants of the torque-speed plane.

   A PWM INVERTER DRIVE SYSTEM WITH ON-LINE OPTIMIZED PULSE PATTERNS
By J. Holtz; S. Stadtfeld [View]
[Download]

Abstract: A novel approach to the PWM problem is described which performs an on-line minimization of the inverter switching sequence. An algorithm implemented in a microcomputer is used to predict the future trajectories of the stator current space vector in the complex plane as functions of all posslble inverter switching states. This information is used to select the optimal switching state such that the switching frequency is minimized. The computing time for the optimization is a few tens of microseconds. The method is applicable to thyristor inverters having a switching frequency of a few hundred hertz. An extended algorithm is proposed for the applicatlon in fast switching power transistor or GTO lnverters. lt predicts the dynamic state of the drive system for the time instant at which the optimization will have to be made. This enables to complete the optimization just before the result is actually needed to control the system.

   AC ELECTRIC DRIVE SYSTEM FOR HYBRID VEHICLES
By A. Bobbio; C. Calcagno; L. Fiore Donati; S. Sironi [View]
[Download]

Abstract: This paper describes the electric drive system of the hybrid vehicle developed in Italy by Alfa Romeo and Ansaldo, financed by the Natjonal Council of Research (CNR). The hybrid vehicle electric powerplant consists of an induction motor, a transistor inverter and a 96 Volt Ni-Cd battery pack. The propulsion electric motor is a special purpose three-phase asynchronous machine. With forced air cooling it produces 6 Kw continuously and 12 Kw overload. The inverter utilizes high speed power darlington transistors to pulse the battery voltage and obtain a PWM waveshape. The electric power plant includes a microprocessor system dedicated to determine the available capacity of the Ni-Ci batteries. The system design, with particular consideration for the transistor inverter, and the results of some experimental testes are described.

EPE 1985 - 15 - Lecture Session 3.01: MICROPROCESSOR CONTROL FOR AC DRIVES (I)
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1985 - Conference > EPE 1985 - 15 - Lecture Session 3.01: MICROPROCESSOR CONTROL FOR AC DRIVES (I)
	[return to parent folder]

	A.C. DRIVE WITH THREE-LEVEL VOLTAGE SOURCE INVERTER AND HIGH DYNAMIC PERFORMANCE MICROPROCESSOR CONTROL By R. Joetten; M. Gekeler; J. eibel	[View] [Download]
Abstract: A controlled a.c. drive system is described, which contains a three-level voltage source inverter feeding an induction machine. Superimposed to the control of the inverter is a speed control system designed for high dynamic performance and covering a large speed range. Field weakening is included as well as positioning speeds near zero. The control system is realized by three microprocessors. The consequences of the three-level principle are evaluated regarding switching frequency, additional machine losses due to the current harmonics and control.

	DIRECT CONTROL OF INDUCTION MOTOR CURRENTS - DESIGN AND EXPERIMENTAL RESULTS By H. R. Mayer; G. Pfaff	[View] [Download]
Abstract: The paper deals with a method for a direct control of the stator currents of an induction motor fed from a VSI-inverter. The design of a suitable control algorithm for direct affecting the three phases of the inverter is explained. The development of the control concept is conducted in the time domain taking as a basis the differential equation system of the machine and the special features of the inverter. By an online solution of these equations an optimal voltage vector is obtained and an appropriate switching sequence for the inverter is calculated. An additional aim consists of the demand for keeping the mean switching frequency of the inverter as low as possible. Since the control coefficients are depending on the speed an adaptive control is necessary. Experimental results obtained from a 70 kVA inverter drive controlled by a fast signal processor are presented demonstrating the performance of the control concept.

	POSITION CONTROL OF AN ASYNCHRONOUS MACHINE FED BY PWM CONVERTER By B. De Fornel; M. Pietrzak-David; J. C. Hapiot	[View] [Download]
Abstract: In this paper, the authors present a study concerning a position control of an asynchronous machine fed by a pulse width modulated inverter. This "machine - converter" set present an example of an a.c. actuator. Firstly, a mathematical model is presented in order to analyse the dynamic behaviour of the system. Then an optimal position control with a quadratic criterion has been chosen in view to ensure the best system performances. The process for the whole system "asynchronous machine-converter" is then simulated, in a very precise way, in order to verify acceptable operation of this set during the different transient states in all four quadrants of the torque-speed plane.

	A PWM INVERTER DRIVE SYSTEM WITH ON-LINE OPTIMIZED PULSE PATTERNS By J. Holtz; S. Stadtfeld	[View] [Download]
Abstract: A novel approach to the PWM problem is described which performs an on-line minimization of the inverter switching sequence. An algorithm implemented in a microcomputer is used to predict the future trajectories of the stator current space vector in the complex plane as functions of all posslble inverter switching states. This information is used to select the optimal switching state such that the switching frequency is minimized. The computing time for the optimization is a few tens of microseconds. The method is applicable to thyristor inverters having a switching frequency of a few hundred hertz. An extended algorithm is proposed for the applicatlon in fast switching power transistor or GTO lnverters. lt predicts the dynamic state of the drive system for the time instant at which the optimization will have to be made. This enables to complete the optimization just before the result is actually needed to control the system.

	AC ELECTRIC DRIVE SYSTEM FOR HYBRID VEHICLES By A. Bobbio; C. Calcagno; L. Fiore Donati; S. Sironi	[View] [Download]
Abstract: This paper describes the electric drive system of the hybrid vehicle developed in Italy by Alfa Romeo and Ansaldo, financed by the Natjonal Council of Research (CNR). The hybrid vehicle electric powerplant consists of an induction motor, a transistor inverter and a 96 Volt Ni-Cd battery pack. The propulsion electric motor is a special purpose three-phase asynchronous machine. With forced air cooling it produces 6 Kw continuously and 12 Kw overload. The inverter utilizes high speed power darlington transistors to pulse the battery voltage and obtain a PWM waveshape. The electric power plant includes a microprocessor system dedicated to determine the available capacity of the Ni-Ci batteries. The system design, with particular consideration for the transistor inverter, and the results of some experimental testes are described.