EPE Association: EPE 1987 - 04 - Lecture Session 1.04: MOSFET

EPE 1987 - 04 - Lecture Session 1.04: MOSFET
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1987 - Conference > EPE 1987 - 04 - Lecture Session 1.04: MOSFET

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   FUTURE OF POWER MOSFET
By Pierre Aloisi [View]
[Download]

Abstract: The industrial use of power MOSFET started around five years ago. For the semiconductor market this is the end of the first part of the learning curve. It is time "to take the ship's bearing":
-Utilization of power mosfet as:
- main switch in many systems
- driver for large semiconductor devices
- How to drive a power mosfet
- Ruggedness and protection
- New products: cells density - sensefet - logicfet - smart power.
With these guidelines where are the theorical and technological limitations?

   CONTRIBUTION TO THE COMPARISON OF POWER MOSFET AND CONDUCTIVITY ENHANCED MOSFET
By E.-K. Behr; R. Hanitsch [View]
[Download]

Abstract: The paper deals with the comparison of two different power electronic switches with respect to different parameters. In comparison to power MOSFETs conductivity enhanced FETs show a significant reduction in conduction loss and this especially in high voltage applications. However switching loss is increased because of slow turn off behaviour. There is no integral diode within the conductivity enhanced FET. Whether this is a bonus or a malus depends very much on the application. Using the integral diode of a power MOSFET as a free-wheeling path may cause large electrical stress for the switches involved. It is shown that conductivity enhanced FETs combined with external fast recovery diodes can have lower overall switching loss than power MOSFET with speed optimized integral diodes. With an experimental investigation such parameters as switching energies, switching times, peak power, peak current, conduction loss and loss vs. switching frequency were looked at and typical characteristics are presented.

   A NOVEL PWM INVERTER USING TRANSFORMER-ISOLATED POWER MOSFETS
By M. A. Preston; J. D. Edwards; G. Williams [View]
[Download]

Abstract: Transformer isolation of semiconductor switching devices is desirable, but difficult to implement with PWM control. These difficulties can be overcome with MOSFETs as a result of their gate characteristics of capacitance in parallel with a high resistance, by storing 'on' and 'off' states on the gate capacitance. Current techniques for accomplishing this are limited. An improved technique and an associated design method are presented along with experimental results. The design method is used to show that it is possible to design a general-purpose drive which will work with a wide variety of MOSFETs if a suitable series gate resistance is chosen.

   DETERMINATION AND MINIMIZATION OF THE POWER-LOSSES IN A 1 KVA PULSE-WIDTH-MODULATED INVERTER
By H. Kuyken; D. Baert [View]
[Download]

Abstract: Energy transformations with high efficiency become more and more important in DC/AC power conversion. In this paper, the basic converter of a 1kVA pulse-width-modulated inverter is examined. First, a selection is made between several possible DC/DC converters. The classic comparison between the converter types is partially reviewed for the use of MOSFETs instead of bipolars. A comparison of the highest achievable efficiency and output power for each converter type was made. Furtheron, after a converter type was actually selected, a calculation of the different sources of power losses has been made. These calculations show how to increase the total efficiency with about 8% by minimizing the discussed losses.

   HIGH POWER HIGH VOLTAGE GENERATOR
By I. Bonanni, L. Cristofoli [View]
[Download]

Abstract: This paper describes a compact high voltage generator suitable to feed a high power X-ray tube (150 KV - 50 Kw). Both the ultrasonic converter and the high voltage transformer are completely solid-state. The new "Injected MOS devices" (COMFET) are employed in the 60 KHz fixed frequency operating inverter. The requested high voltage DC output is directly supplied from an epoxy encapsuled high frequency transformer able to generate without capacitive multipliers up to 200 KV.

EPE 1987 - 04 - Lecture Session 1.04: MOSFET
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 1987 - Conference > EPE 1987 - 04 - Lecture Session 1.04: MOSFET
	[return to parent folder]

	FUTURE OF POWER MOSFET By Pierre Aloisi	[View] [Download]
Abstract: The industrial use of power MOSFET started around five years ago. For the semiconductor market this is the end of the first part of the learning curve. It is time "to take the ship's bearing": -Utilization of power mosfet as: - main switch in many systems - driver for large semiconductor devices - How to drive a power mosfet - Ruggedness and protection - New products: cells density - sensefet - logicfet - smart power. With these guidelines where are the theorical and technological limitations?

	CONTRIBUTION TO THE COMPARISON OF POWER MOSFET AND CONDUCTIVITY ENHANCED MOSFET By E.-K. Behr; R. Hanitsch	[View] [Download]
Abstract: The paper deals with the comparison of two different power electronic switches with respect to different parameters. In comparison to power MOSFETs conductivity enhanced FETs show a significant reduction in conduction loss and this especially in high voltage applications. However switching loss is increased because of slow turn off behaviour. There is no integral diode within the conductivity enhanced FET. Whether this is a bonus or a malus depends very much on the application. Using the integral diode of a power MOSFET as a free-wheeling path may cause large electrical stress for the switches involved. It is shown that conductivity enhanced FETs combined with external fast recovery diodes can have lower overall switching loss than power MOSFET with speed optimized integral diodes. With an experimental investigation such parameters as switching energies, switching times, peak power, peak current, conduction loss and loss vs. switching frequency were looked at and typical characteristics are presented.

	A NOVEL PWM INVERTER USING TRANSFORMER-ISOLATED POWER MOSFETS By M. A. Preston; J. D. Edwards; G. Williams	[View] [Download]
Abstract: Transformer isolation of semiconductor switching devices is desirable, but difficult to implement with PWM control. These difficulties can be overcome with MOSFETs as a result of their gate characteristics of capacitance in parallel with a high resistance, by storing 'on' and 'off' states on the gate capacitance. Current techniques for accomplishing this are limited. An improved technique and an associated design method are presented along with experimental results. The design method is used to show that it is possible to design a general-purpose drive which will work with a wide variety of MOSFETs if a suitable series gate resistance is chosen.

	DETERMINATION AND MINIMIZATION OF THE POWER-LOSSES IN A 1 KVA PULSE-WIDTH-MODULATED INVERTER By H. Kuyken; D. Baert	[View] [Download]
Abstract: Energy transformations with high efficiency become more and more important in DC/AC power conversion. In this paper, the basic converter of a 1kVA pulse-width-modulated inverter is examined. First, a selection is made between several possible DC/DC converters. The classic comparison between the converter types is partially reviewed for the use of MOSFETs instead of bipolars. A comparison of the highest achievable efficiency and output power for each converter type was made. Furtheron, after a converter type was actually selected, a calculation of the different sources of power losses has been made. These calculations show how to increase the total efficiency with about 8% by minimizing the discussed losses.

	HIGH POWER HIGH VOLTAGE GENERATOR By I. Bonanni, L. Cristofoli	[View] [Download]
Abstract: This paper describes a compact high voltage generator suitable to feed a high power X-ray tube (150 KV - 50 Kw). Both the ultrasonic converter and the high voltage transformer are completely solid-state. The new "Injected MOS devices" (COMFET) are employed in the 60 KHz fixed frequency operating inverter. The requested high voltage DC output is directly supplied from an epoxy encapsuled high frequency transformer able to generate without capacitive multipliers up to 200 KV.