EPE Association: EPE 1991 - 35 - Session 4.2: RENEWABLE ENERGY SOURCES

EPE 1991 - 35 - Session 4.2: RENEWABLE ENERGY SOURCES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 35 - Session 4.2: RENEWABLE ENERGY SOURCES

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   500 kW INVERTER IN "HYBRID-CONCEPT" FOR A LARGE PHOTOVOLTAIC POWER STATION
By Markus Meyer [View]
[Download]

Abstract: Self-commutated inverters for large photovoltaic power stations have to satisfy two contradictory requirements: high efficiency (i.e. a low switching frequency) and low harmonic distortion of voltage and current in the mains (high switching frequency). The "hybrid-inverter" represents a new concept especially developed for large photovoltaic plants. It produces only low distortions, but has a high efficiency over the whole operation range. It will be realized in "PHALK Mont-Soleil", Europe's largest photovoltaic power plant. The inverter consists of two parallel inverters of different size and switching frequency, i.e. an asymmetrical arrangement which offers new possibilities for operation and optimization. One of the inverters can work as an active filter. This paper presents the design of such an inverter. lts working modes, power ratings and attainable efficiency are explained and discussed. Problems of control and optimized pulse-width-modulation are treated.

   UTILITY INTERACTIVE PHOTOVOLTAIC GENERATION SYSTEM USING A SINGLE PHASE IGBT PWM CURRENT SOURCE INVERTER
By S. Nonaka; K. Kesamaru; K. Yamasaki; H. Uchiyama [View]
[Download]

Abstract: This paper deals with a utility interactive photovoltaic (PV) generation system with a single phase IGBT PWM current source inverter. This system should provide the utility with sinusoidal current and voltage at unity power factor. Owing to the newly added instantaneous current control, the output current of single phase current source inverter contains low harmonics, and the size of the reactor is substantially decreased. Moreover, the problem of islanding, the continued operation of a group of utility interactive PV systems even after loss of the utility power is examined. A change in the parameters of the inverter output voltage before and after the utility interruption is investigated, and the possibility of detecting the interruption by sensing the variation is discussed.

   PROPERTIES OF A THREE PHASE PULSE WIDTH MODULATED CURRENT SOURCE INVERTER FOR CONVERSION OF PHOTOVOLTAIC ENERGY IN GRID CONNECTED OPERATION
By Arie T. Veltman; Sjoerd W.H. de Haan [View]
[Download]

Abstract: A 3-phase transformerless power electronic conversion system is used as an interface between a photovoltaic array and the utility line. Because of the absense of a power transformer, and because of a high array voltage, the efficiency is high. An MPPT is used for optimal utilisation of the PV-array, which results in a high yield of the system. The power electronic converter is based on the topology of a Pulse Width Modulated Current Source Inverter (PWM-CSI). The inverter is operated at a high switching frequency (20 kHz), so that waveforms with a low distortion are generated, while the power factor is near unity. Both on the ac side as well as on the dc side the harmonics and the ripple components are considered. Performance measurements of a 1 kVA-prototype system shown that the efficiency of the system increases from 65 % at 20 % load to 85 % at full load. From 20 % to full load, the power factor exceeds 0.95.

   CONTROL AND DEVELOPMENT OF A NOVEL 2 kVA COMPOUND CONVERTER FOR REMOTE PHOTOVOLTAIC SYSTEMS
By S.J.B. Hartman; D. B. Snyman; J.H.R. Enslin [View]
[Download]

Abstract: A novel photovoltaic converter system, previously proposed by Snyman (1989), has been implemented with a power rating of 2 kVA. The converter system combines the functions of inversion, battery regulation and maximum power point tracking (MPPT) into a single cost effective converter. Maximum power point tracking is performed by controlling the voltage (and frequency) of the AC output. A description of this converter, and explanation of the control strategy employed is given together with practical results measured on the prototype converter.

   CONTROL STRATEGY FOR LOCAL ENERGY STORAGE SYSTEMS FOR DECOUPLED MANAGING OF REAL AND REACTIVE POWER
By M. Carpita; P. Pozzobon; G. Sciutto [View]
[Download]

Abstract: In this paper the authors present how to control real and reactlve power flow between an energy storage device (accumulator batteries) and a power three phase network, in order to perform local load compensation on the same network. Three modulation and control systems are proposed: hysteresis current modulation, sliding-mode voltage control and stepped wave modulation, with different features and power magnitude levels. Operation of the system is investigated by means of digital simulation: relevant results are raported and discussed.

   OPERATION AND CHARACTERISTICS OF DIRECT CURRENT MOTORS DIRECTLY POWERED BY PHOTOVOLTAIC GENERATORS
By A. Abete; F. Cane; R. Tommasini [View]
[Download]

Abstract: An analytical-numerical procedure gives the characteristics, the operating modes and the daily performance of DC motors with seperated (or permanent magnets), shunt and series excitation, directly powered by PV generators. It is so possible to make a comparative analysis of the DC motor behavior.

EPE 1991 - 35 - Session 4.2: RENEWABLE ENERGY SOURCES
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1991 - Conference > EPE 1991 - 35 - Session 4.2: RENEWABLE ENERGY SOURCES
	[return to parent folder]

	500 kW INVERTER IN "HYBRID-CONCEPT" FOR A LARGE PHOTOVOLTAIC POWER STATION By Markus Meyer	[View] [Download]
Abstract: Self-commutated inverters for large photovoltaic power stations have to satisfy two contradictory requirements: high efficiency (i.e. a low switching frequency) and low harmonic distortion of voltage and current in the mains (high switching frequency). The "hybrid-inverter" represents a new concept especially developed for large photovoltaic plants. It produces only low distortions, but has a high efficiency over the whole operation range. It will be realized in "PHALK Mont-Soleil", Europe's largest photovoltaic power plant. The inverter consists of two parallel inverters of different size and switching frequency, i.e. an asymmetrical arrangement which offers new possibilities for operation and optimization. One of the inverters can work as an active filter. This paper presents the design of such an inverter. lts working modes, power ratings and attainable efficiency are explained and discussed. Problems of control and optimized pulse-width-modulation are treated.

	UTILITY INTERACTIVE PHOTOVOLTAIC GENERATION SYSTEM USING A SINGLE PHASE IGBT PWM CURRENT SOURCE INVERTER By S. Nonaka; K. Kesamaru; K. Yamasaki; H. Uchiyama	[View] [Download]
Abstract: This paper deals with a utility interactive photovoltaic (PV) generation system with a single phase IGBT PWM current source inverter. This system should provide the utility with sinusoidal current and voltage at unity power factor. Owing to the newly added instantaneous current control, the output current of single phase current source inverter contains low harmonics, and the size of the reactor is substantially decreased. Moreover, the problem of islanding, the continued operation of a group of utility interactive PV systems even after loss of the utility power is examined. A change in the parameters of the inverter output voltage before and after the utility interruption is investigated, and the possibility of detecting the interruption by sensing the variation is discussed.

	PROPERTIES OF A THREE PHASE PULSE WIDTH MODULATED CURRENT SOURCE INVERTER FOR CONVERSION OF PHOTOVOLTAIC ENERGY IN GRID CONNECTED OPERATION By Arie T. Veltman; Sjoerd W.H. de Haan	[View] [Download]
Abstract: A 3-phase transformerless power electronic conversion system is used as an interface between a photovoltaic array and the utility line. Because of the absense of a power transformer, and because of a high array voltage, the efficiency is high. An MPPT is used for optimal utilisation of the PV-array, which results in a high yield of the system. The power electronic converter is based on the topology of a Pulse Width Modulated Current Source Inverter (PWM-CSI). The inverter is operated at a high switching frequency (20 kHz), so that waveforms with a low distortion are generated, while the power factor is near unity. Both on the ac side as well as on the dc side the harmonics and the ripple components are considered. Performance measurements of a 1 kVA-prototype system shown that the efficiency of the system increases from 65 % at 20 % load to 85 % at full load. From 20 % to full load, the power factor exceeds 0.95.

	CONTROL AND DEVELOPMENT OF A NOVEL 2 kVA COMPOUND CONVERTER FOR REMOTE PHOTOVOLTAIC SYSTEMS By S.J.B. Hartman; D. B. Snyman; J.H.R. Enslin	[View] [Download]
Abstract: A novel photovoltaic converter system, previously proposed by Snyman (1989), has been implemented with a power rating of 2 kVA. The converter system combines the functions of inversion, battery regulation and maximum power point tracking (MPPT) into a single cost effective converter. Maximum power point tracking is performed by controlling the voltage (and frequency) of the AC output. A description of this converter, and explanation of the control strategy employed is given together with practical results measured on the prototype converter.

	CONTROL STRATEGY FOR LOCAL ENERGY STORAGE SYSTEMS FOR DECOUPLED MANAGING OF REAL AND REACTIVE POWER By M. Carpita; P. Pozzobon; G. Sciutto	[View] [Download]
Abstract: In this paper the authors present how to control real and reactlve power flow between an energy storage device (accumulator batteries) and a power three phase network, in order to perform local load compensation on the same network. Three modulation and control systems are proposed: hysteresis current modulation, sliding-mode voltage control and stepped wave modulation, with different features and power magnitude levels. Operation of the system is investigated by means of digital simulation: relevant results are raported and discussed.

	OPERATION AND CHARACTERISTICS OF DIRECT CURRENT MOTORS DIRECTLY POWERED BY PHOTOVOLTAIC GENERATORS By A. Abete; F. Cane; R. Tommasini	[View] [Download]
Abstract: An analytical-numerical procedure gives the characteristics, the operating modes and the daily performance of DC motors with seperated (or permanent magnets), shunt and series excitation, directly powered by PV generators. It is so possible to make a comparative analysis of the DC motor behavior.