EPE Association: EPE 1991 - 13 - Session 2.2: DIGITAL CONTROL

EPE 1991 - 13 - Session 2.2: DIGITAL CONTROL
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 13 - Session 2.2: DIGITAL CONTROL

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   Comparison of Five Control Methods for Digitally Feedback Controlled PWM Inverters
By Atsuo Kawamura; Tomoki Yokoyama [View]
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Abstract: Five different schemes suitable for digital feedback control of PWM inverter are proposed, which are 1) resistance load based DB (deadbeat) control, 2) disturbance observer based DB control I, 3) disturbance observer based DB control Il, 4) internal model principle based pole placement, and 5) digital PI based DB control. From the view point of UPS applications, the advantages and disadvantages are discussed through simulations and experiments.

   DIRECT CONTROL OF INDUCTION MOTORS. A TIME DISCRETE STRATEGY RESPECTS TIME CONTINUOUS TRAJECTORIES
By H. Segerer [View]
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Abstract: The paper presents a new method to control high dynamic drives with induction motor fed by low switching voltage source lnverter. In opposition to the usually applied methods, the characteristics of the proposed one are advantageous in steady state as well as during transient operation throughout the whole operating range starting from zero frequency up into the field weakening range. The control is done by steps of milliseconds with a fast signal processor system. Therefore a complex strategy can be applied to generate directly the switching instructions for the bridge legs of the inverter. For this an extended time discrete controller and a strongly coupled voltage modulator are both influenced by the characteristics of the desired steady state voltage patterns and the corresponding flux trajectories. The generated switching sequence allows high dynamic response of electrical torque and corresponds in the special case of steady state operation to the desired synchronous (off-line optimized) or asynchronous voltage patterns.

   DIGITAL CONTROL OF A FOUR-QUADRANT CONVERTER USING PREDICTIVE CURRENT CONTROL
By Christian Endrikat [View]
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Abstract: For control of a four-quadrant converter (4QC), the paper analyzes the effect of a non-zero computation time of the digital control algorithm. As a result, a novel discrete-time control strategy for four-quadrant converters (4QC) is proposed. In order to compensate for computational delays, the new approach a) utilizes a sample strategy that is synchronized with the 4QC pulse-width modulator and b) features a predictive current control. Since the proposed strategy does not require extra fast hardware, costs might be saved without lowering performance. Alternatively, for a given fast hardware extra features could be added to the control algorithm.

   DIGITAL ADAPTIVE CONTROL OF A HIGH POWER HYBRID COMPENSATOR
By J. G. Roos; G. L. van Harmelen; J. H. R. Enslin [View]
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Abstract: A digital controller, based on the TMS320 series microprocessors, is proposed for a 100 kVA demonstration hybrid fictitious power compensator. The hybrid power compensator is to consist of a 60 kVA three-phase Static Var Compensator (SVC), in parallel with a 40 kVA three phase voltage-fed Dynamic Power Filter (DPF) system. This paper introduces and describes the characteristics of the digital adaptive control techniques implemented for both the SVC and the DPF. The hybrid compensator is to be controlled via a general time-domain compensation philosophy which is based on sound energy principles. Adaptive algorithms are employed in both the SVC and the DPF controllers so that optimum control is achieved.

   NOVEL DIGITAL CONTROLLER FOR INDUCTION MACHINES CONSIDERING THE INVERTER SWITCHING TIMES AND A FLUCTUATING DC-LINK VOLTAGE
By Thomas Kalker; Ansgar Ackva; Uwe Jansen [View]
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Abstract: A novel digital controller for variable speed drive applications with the PWM-inverter-fed induction machine is presented. The controller which is designated to provide the inverter-switching signals for switching frequencies of up to 20 kHz consists of an especially designed pulse pattern generator (PWM-ASIC) and a microcontroller. In a second part of the paper the influences of the transistor switching times and an oscillating DC-link voltage on the drive performance are analyzed and suitable compensation techniques are presented. This compensation leads to a linearization of the open-loop transfer function of the inverter. Measured results obtained from a test drive prove that the effects mentioned above can be compensated using the proposed techniques.

   ADVANCED DIGITAL CONTROL STRATEGIES FOR A POWER DC/DC CONVERTER
By Nicola De Angelis; Alessandro De Carli; Giovanni Mignano; Domenico Vivarelli [View]
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Abstract: A dc/dc converter is used in some ac traction drive to hold the input voltage of the inverter to the prefixed value. A dc/dc converter is realized by inserting a conventional chopper circuitry between two power filters, the first one connected to the contact line, the second one to the inverter. The dynamic behaviour of the chopper is highly influenced by these filters. The control of the inverter voltage is effected by applying a PWM technique. In this paper the procedure for designing the control strategy is illustrated. This paper deals with a step-up converter. The general model is firstly deduced and the static characteristics are presented. Subsequently, the linearized model is deduced: The control strategy is worked out so as to satisfy different requirements in the input-output and in the disturbance-output behaviour.

EPE 1991 - 13 - Session 2.2: DIGITAL CONTROL
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 13 - Session 2.2: DIGITAL CONTROL
	[return to parent folder]

	Comparison of Five Control Methods for Digitally Feedback Controlled PWM Inverters By Atsuo Kawamura; Tomoki Yokoyama	[View] [Download]
Abstract: Five different schemes suitable for digital feedback control of PWM inverter are proposed, which are 1) resistance load based DB (deadbeat) control, 2) disturbance observer based DB control I, 3) disturbance observer based DB control Il, 4) internal model principle based pole placement, and 5) digital PI based DB control. From the view point of UPS applications, the advantages and disadvantages are discussed through simulations and experiments.

	DIRECT CONTROL OF INDUCTION MOTORS. A TIME DISCRETE STRATEGY RESPECTS TIME CONTINUOUS TRAJECTORIES By H. Segerer	[View] [Download]
Abstract: The paper presents a new method to control high dynamic drives with induction motor fed by low switching voltage source lnverter. In opposition to the usually applied methods, the characteristics of the proposed one are advantageous in steady state as well as during transient operation throughout the whole operating range starting from zero frequency up into the field weakening range. The control is done by steps of milliseconds with a fast signal processor system. Therefore a complex strategy can be applied to generate directly the switching instructions for the bridge legs of the inverter. For this an extended time discrete controller and a strongly coupled voltage modulator are both influenced by the characteristics of the desired steady state voltage patterns and the corresponding flux trajectories. The generated switching sequence allows high dynamic response of electrical torque and corresponds in the special case of steady state operation to the desired synchronous (off-line optimized) or asynchronous voltage patterns.

	DIGITAL CONTROL OF A FOUR-QUADRANT CONVERTER USING PREDICTIVE CURRENT CONTROL By Christian Endrikat	[View] [Download]
Abstract: For control of a four-quadrant converter (4QC), the paper analyzes the effect of a non-zero computation time of the digital control algorithm. As a result, a novel discrete-time control strategy for four-quadrant converters (4QC) is proposed. In order to compensate for computational delays, the new approach a) utilizes a sample strategy that is synchronized with the 4QC pulse-width modulator and b) features a predictive current control. Since the proposed strategy does not require extra fast hardware, costs might be saved without lowering performance. Alternatively, for a given fast hardware extra features could be added to the control algorithm.

	DIGITAL ADAPTIVE CONTROL OF A HIGH POWER HYBRID COMPENSATOR By J. G. Roos; G. L. van Harmelen; J. H. R. Enslin	[View] [Download]
Abstract: A digital controller, based on the TMS320 series microprocessors, is proposed for a 100 kVA demonstration hybrid fictitious power compensator. The hybrid power compensator is to consist of a 60 kVA three-phase Static Var Compensator (SVC), in parallel with a 40 kVA three phase voltage-fed Dynamic Power Filter (DPF) system. This paper introduces and describes the characteristics of the digital adaptive control techniques implemented for both the SVC and the DPF. The hybrid compensator is to be controlled via a general time-domain compensation philosophy which is based on sound energy principles. Adaptive algorithms are employed in both the SVC and the DPF controllers so that optimum control is achieved.

	NOVEL DIGITAL CONTROLLER FOR INDUCTION MACHINES CONSIDERING THE INVERTER SWITCHING TIMES AND A FLUCTUATING DC-LINK VOLTAGE By Thomas Kalker; Ansgar Ackva; Uwe Jansen	[View] [Download]
Abstract: A novel digital controller for variable speed drive applications with the PWM-inverter-fed induction machine is presented. The controller which is designated to provide the inverter-switching signals for switching frequencies of up to 20 kHz consists of an especially designed pulse pattern generator (PWM-ASIC) and a microcontroller. In a second part of the paper the influences of the transistor switching times and an oscillating DC-link voltage on the drive performance are analyzed and suitable compensation techniques are presented. This compensation leads to a linearization of the open-loop transfer function of the inverter. Measured results obtained from a test drive prove that the effects mentioned above can be compensated using the proposed techniques.

	ADVANCED DIGITAL CONTROL STRATEGIES FOR A POWER DC/DC CONVERTER By Nicola De Angelis; Alessandro De Carli; Giovanni Mignano; Domenico Vivarelli	[View] [Download]
Abstract: A dc/dc converter is used in some ac traction drive to hold the input voltage of the inverter to the prefixed value. A dc/dc converter is realized by inserting a conventional chopper circuitry between two power filters, the first one connected to the contact line, the second one to the inverter. The dynamic behaviour of the chopper is highly influenced by these filters. The control of the inverter voltage is effected by applying a PWM technique. In this paper the procedure for designing the control strategy is illustrated. This paper deals with a step-up converter. The general model is firstly deduced and the static characteristics are presented. Subsequently, the linearized model is deduced: The control strategy is worked out so as to satisfy different requirements in the input-output and in the disturbance-output behaviour.