EPE Association: EPE 1985 - 07 - Lecture Session 1.07: SWITCHED MODE, HIGH FREQUENCY APPLICATIONS

EPE 1985 - 07 - Lecture Session 1.07: SWITCHED MODE, HIGH FREQUENCY APPLICATIONS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1985 - Conference > EPE 1985 - 07 - Lecture Session 1.07: SWITCHED MODE, HIGH FREQUENCY APPLICATIONS

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   A COMPERATIVE STUDY OF DELTA AND SINE PULSE WIDTH MODULATED INVERTERS
By M. A. Rahman; J. E. Quaicoe; M. A. Choudhury [View]
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Abstract: This paper presents a brief analysis of a delta modulated (DM) and sine pulse width modulated inverter. The performances of two types of inverters are compared. Use of delta modulation in generating inverter switching waveforms has several advantageous characteristics over the sine pulse width modulation technique. Analog implementation of delta modulation is relatively easy. lt provides low harmonics at the inverter output and has easy control of the inverter output voltage, commutations and harmonic contents. Some features of delta modulation are very much desirable for variable voltage variable frequency ac drives. ln both sine and delta modulated inverters, the fundamental voltage increases linearly with the increase of frequency. But in the case of delta modulation, the inverter output has a transition from PWM mode to square wave mode of operation at high frequency. This feature may allow ac drives to operate in constant torque and constant power mode without additional controls in logic circuits.

   CONVERTER WITH HIGH DYNAMIC PROPERTIES IN FET TECHNOLOGY
By E. Hebenstreit [View]
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Abstract: An experimental converter (3-phase, 220 V, about 6-8 kVA) was used to demonstrate the characteristics of FET technology in its high voltage region. When utilizing the inverse diode specific to FETs, a configuration without protection circuits can be realized using FRED FETs. The dynamic properties obtained are such that the switching and insertion losses are equal between 80 and 120 kHz, depending upon the driving speed, and minimum turn-on times of around 0.5 us with a resulting linear distortion of only 10%. A low-inductance design reduces overshoots so far as to allow approximately 90% utilization of the transistor blocking capability. This also applies in the case of short-circuiting. An inductance of 2uH is sufficient to maintain the short-circuit currents in the permissible region for the transistors. Guidelines can be derived from this example for converters of other types also, such as DC/DC converters and sine-wave generators.

   MEDIUM FREQUENCY INVERTER UTILISED IN THERMIC TREATMENTS
By Danut Ilea; Marius Georgescu [View]
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Abstract: A medium frequency inverter which is used in thermic treatments is described. It is shown the block diagram and the stages diagram during the operation. A set of valid equations for each working stage was solved with the computer by Runge-Kutta method. For a 100 kW and 10 kHz inverter, theoretical and experimental investigations were made. By power automatic control can be eliminated the tension and current jumps which can appear in the inverter load, when takes place an abrupt passing from load operation to idle operation and the reverse. Best inverter maximum load operation was simulated by the computer and practical implemented.

   SWITCHED MODE POWER SUPPLY FOR BATTERY POWERED VEHICLES AND ROBOTS
By Philippe Lataire; Gaston Maggetto [View]
[Download]

Abstract: To allow quick recharging of the batteries of electric vehicles or mobile autonomous robots, on board switched-mode power supplies have been developed. These supplies meet the particular requirements for compacity, highpower, solidity and controleability. To meet these requirements a forward converter has been developed.

EPE 1985 - 07 - Lecture Session 1.07: SWITCHED MODE, HIGH FREQUENCY APPLICATIONS
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1985 - Conference > EPE 1985 - 07 - Lecture Session 1.07: SWITCHED MODE, HIGH FREQUENCY APPLICATIONS
	[return to parent folder]

	A COMPERATIVE STUDY OF DELTA AND SINE PULSE WIDTH MODULATED INVERTERS By M. A. Rahman; J. E. Quaicoe; M. A. Choudhury	[View] [Download]
Abstract: This paper presents a brief analysis of a delta modulated (DM) and sine pulse width modulated inverter. The performances of two types of inverters are compared. Use of delta modulation in generating inverter switching waveforms has several advantageous characteristics over the sine pulse width modulation technique. Analog implementation of delta modulation is relatively easy. lt provides low harmonics at the inverter output and has easy control of the inverter output voltage, commutations and harmonic contents. Some features of delta modulation are very much desirable for variable voltage variable frequency ac drives. ln both sine and delta modulated inverters, the fundamental voltage increases linearly with the increase of frequency. But in the case of delta modulation, the inverter output has a transition from PWM mode to square wave mode of operation at high frequency. This feature may allow ac drives to operate in constant torque and constant power mode without additional controls in logic circuits.

	CONVERTER WITH HIGH DYNAMIC PROPERTIES IN FET TECHNOLOGY By E. Hebenstreit	[View] [Download]
Abstract: An experimental converter (3-phase, 220 V, about 6-8 kVA) was used to demonstrate the characteristics of FET technology in its high voltage region. When utilizing the inverse diode specific to FETs, a configuration without protection circuits can be realized using FRED FETs. The dynamic properties obtained are such that the switching and insertion losses are equal between 80 and 120 kHz, depending upon the driving speed, and minimum turn-on times of around 0.5 us with a resulting linear distortion of only 10%. A low-inductance design reduces overshoots so far as to allow approximately 90% utilization of the transistor blocking capability. This also applies in the case of short-circuiting. An inductance of 2uH is sufficient to maintain the short-circuit currents in the permissible region for the transistors. Guidelines can be derived from this example for converters of other types also, such as DC/DC converters and sine-wave generators.

	MEDIUM FREQUENCY INVERTER UTILISED IN THERMIC TREATMENTS By Danut Ilea; Marius Georgescu	[View] [Download]
Abstract: A medium frequency inverter which is used in thermic treatments is described. It is shown the block diagram and the stages diagram during the operation. A set of valid equations for each working stage was solved with the computer by Runge-Kutta method. For a 100 kW and 10 kHz inverter, theoretical and experimental investigations were made. By power automatic control can be eliminated the tension and current jumps which can appear in the inverter load, when takes place an abrupt passing from load operation to idle operation and the reverse. Best inverter maximum load operation was simulated by the computer and practical implemented.

	SWITCHED MODE POWER SUPPLY FOR BATTERY POWERED VEHICLES AND ROBOTS By Philippe Lataire; Gaston Maggetto	[View] [Download]
Abstract: To allow quick recharging of the batteries of electric vehicles or mobile autonomous robots, on board switched-mode power supplies have been developed. These supplies meet the particular requirements for compacity, highpower, solidity and controleability. To meet these requirements a forward converter has been developed.