EPE Association: EPE 2007 - Subtopic 06-2 - LS: Converter control sets and modulation strategies I

EPE 2007 - Subtopic 06-2 - LS: Converter control sets and modulation strategies I
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 06: 'Modulation strategies and specific control methods for static converter' > EPE 2007 - Subtopic 06-2 - LS: Converter control sets and modulation strategies I

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   Variable Sampling Quasi Multirate Deadbeat Control Method for PWM Inverter in Low Carrier Frequency
By Suguru Tahara; Tomoki Yokoyama [View]
[Download]

Abstract: A new approach for real time digital feedback control of single phase and three phase PWM inverter is proposed, in which a quasi multirate deadbeat control combined with variable sampling method using FPGA based hardware controller. It was reported that the deadbeat control method with FPGA based hardware controller had the very good transient response for various loads, but these reports were mainly focused on a few KW class PWM inverter system, so the high carrier frequency were adopted for evaluation. But in MW class PWM inverter system, the carrier frequency is limited up to 2kHz range, because of the performance of the switching devices and the trade off against the efficiency of the inverter. In this condition, the controllability of the PWM inverter is not so much expected. In the proposed method, to ensure the tracking accuracy of the output voltage to the reference voltage, more than two sampled data is used while one carrier interval. The proposed method is applied to single phase system and then expanded to three phasePWMinverter system. The control characteristics of the proposed variable sampling deadbeat control were verified through simulations and experiments.

   Harmonic Distortion of Multicarrier PWM Strategies in Cascaded Multilevel Converters with Unequal DC Sources
By Niklas E. RUEGER; Harald KUHN; Axel MERTENS [View]
[Download]

Abstract: Calculating in an analytical way the influence of modulation strategies for multilevel converters is a challenging topic, especially if the theoretical and ideal assumptions are not valid. In this paper, a modular multilevel converter, consisting of three H-Bridges is analysed. Based on analytical formulas, a numerical approach is shown to handle the risen complexity due to the risen number of output levels. The influence on the harmonic content of the output voltage is investigated assuming non-ideal DC sources.

   PERFORMANCE CHARACTERISTICS OF THE REDUCED COMMON MODE VOLTAGE NEAR STATE PWM METHOD
By HAVA Ahmet; ÃœN Emre [View]
[Download]

Abstract: The Near State PWM (NSPWM) method, which has low common mode voltage/current is proposed for three-phase voltage source inverter drives. The method is described and its voltage linearity, output current ripple, DC bus current ripple, common mode voltage and output line-to-line pulse patterns are thoroughly studied and compared with classical PWM methods. The theory, simulation, and laboratory experiments illustrate that NSPWM has low common mode voltage, results in less common mode current, has low switching losses comparable to those of DPWM methods, has low current ripple compared to the classical methods, and exhibits no significant overvoltage problems in long cable applications as its pulse pattern involves a sufficient distance between the polarity reversing voltage pulses.

EPE 2007 - Subtopic 06-2 - LS: Converter control sets and modulation strategies I
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2007 - Conference > EPE 2007 - Topic 06: 'Modulation strategies and specific control methods for static converter' > EPE 2007 - Subtopic 06-2 - LS: Converter control sets and modulation strategies I
	[return to parent folder]

	Variable Sampling Quasi Multirate Deadbeat Control Method for PWM Inverter in Low Carrier Frequency By Suguru Tahara; Tomoki Yokoyama	[View] [Download]
Abstract: A new approach for real time digital feedback control of single phase and three phase PWM inverter is proposed, in which a quasi multirate deadbeat control combined with variable sampling method using FPGA based hardware controller. It was reported that the deadbeat control method with FPGA based hardware controller had the very good transient response for various loads, but these reports were mainly focused on a few KW class PWM inverter system, so the high carrier frequency were adopted for evaluation. But in MW class PWM inverter system, the carrier frequency is limited up to 2kHz range, because of the performance of the switching devices and the trade off against the efficiency of the inverter. In this condition, the controllability of the PWM inverter is not so much expected. In the proposed method, to ensure the tracking accuracy of the output voltage to the reference voltage, more than two sampled data is used while one carrier interval. The proposed method is applied to single phase system and then expanded to three phasePWMinverter system. The control characteristics of the proposed variable sampling deadbeat control were verified through simulations and experiments.

	Harmonic Distortion of Multicarrier PWM Strategies in Cascaded Multilevel Converters with Unequal DC Sources By Niklas E. RUEGER; Harald KUHN; Axel MERTENS	[View] [Download]
Abstract: Calculating in an analytical way the influence of modulation strategies for multilevel converters is a challenging topic, especially if the theoretical and ideal assumptions are not valid. In this paper, a modular multilevel converter, consisting of three H-Bridges is analysed. Based on analytical formulas, a numerical approach is shown to handle the risen complexity due to the risen number of output levels. The influence on the harmonic content of the output voltage is investigated assuming non-ideal DC sources.

	PERFORMANCE CHARACTERISTICS OF THE REDUCED COMMON MODE VOLTAGE NEAR STATE PWM METHOD By HAVA Ahmet; ÃœN Emre	[View] [Download]
Abstract: The Near State PWM (NSPWM) method, which has low common mode voltage/current is proposed for three-phase voltage source inverter drives. The method is described and its voltage linearity, output current ripple, DC bus current ripple, common mode voltage and output line-to-line pulse patterns are thoroughly studied and compared with classical PWM methods. The theory, simulation, and laboratory experiments illustrate that NSPWM has low common mode voltage, results in less common mode current, has low switching losses comparable to those of DPWM methods, has low current ripple compared to the classical methods, and exhibits no significant overvoltage problems in long cable applications as its pulse pattern involves a sufficient distance between the polarity reversing voltage pulses.