EPE Association: EPE 2017 - LS3b: Measurement Techniques, Estimation, Sensors

EPE 2017 - LS3b: Measurement Techniques, Estimation, Sensors
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 03: Measurement and Control > EPE 2017 - LS3b: Measurement Techniques, Estimation, Sensors

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   Accuracy Analysis of UCE(on)-based Measurement of the Inverter Output Current at Higher Motor Speeds
By Marco DENK [View]
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Abstract: This paper presents a new gate driver concept that consists of an integrated measurement of the junction temperature and the load current of a power module during inverter operation. For junction temperature measurement the gate driver identifies the temperature sensitive on-chip internal gate resistor by means of a small identification signal that is modulated onto the positive gate voltage. To determine the current through the power semiconductor the new gate driver also measures the highly current sensitive on-state collector-emitter voltage drop UCE(on) and compensates the impact of the junction temperature on driver level. This combined measurement of a temperature-sensitive and a current-sensitive parameter enables accurate current measurement with lowest costs. From today's point of view accuracies of 1-5\% can be reached with reasonable efforts, but it's hard to predict whether UCE(on)-based current measurement can ever cope with the stationary accuracy stated in the datasheets of conventional current sensors. However, it is found that the overall accuracy of UCE(on)-based current measurement profits from very good dynamic properties that become increasingly important in case of high motor speeds and fundamental frequencies. This paper investigates the overall accuracy of a current sensor system to measure a certain load current pointer at a motor speed of 3000 rpm. In d/q-coordinates the low-pass character of a conventional current sensor is found to be responsible for a deviation of the measured current pointer of up to 3.6\%. In contrast, UCE(on)-based current measurement only deviates 0.4\%. In this aspect, the better dynamic properties partially compensate the poorer stationary accuracy of UCE(on)-based current measurement and makes it interesting for lower performance control tasks in high motor speed drives.

   Delta-Sigma Modulated Voltage and Current Measurement for Medium-Voltage DC Applications
By Jan GOTTSCHLICH [View]
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Abstract: This paper presents a galvanically isolated two channel measurement system for voltage and current measurement in medium-voltage dc-dc converters with more than 1 kV operating voltage. The system uses delta-sigma modulation and signal multiplexing to transmit the digitalized signals over fiber optical cables. In combination with a current-loop power supply, high noise immunity and excellent electrical isolation is achieved.

   Design and Measurement Considerations for WBG Switching Circuits
By TIANQI ZHANG [View]
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Abstract: Wide Band Gap (WBG) transistors using materials such as Gallium Nitride (GaN) and Silicon Carbide (SiC) offer superior electrical and thermal properties, as well as fast switching capability. However, the high dv/dt and high di/dt may cause ringing with the parasitic inductances and capacitances in the switching loop, increasing overshoot voltages and reducing confidence in the design. Also, making accurate measurements of the switching behaviour without unduly loading the circuit under test is challenging and further impedes the development of WBG applications. This paper presents a prototype WBG Development Platform, built around a half-bridge switched inductive load test circuit. Additional circuits are integrated on to the main PCB for test and measurement purposes: These include a high bandwidth linear current gate-drive circuit and a high bandwidth on-board measurement system. These sub-circuits are described in detail in this paper, together with the switching waveforms that have been achieved during tests with SiC MOSFETs. The authors demonstrate a practical implementation for high frequency WBG power circuits.

   Resolver-to-Digital Converter with Synchronous Demodulation for FPGA based Low-Latency Control Loops
By Alessandro LIDOZZI [View]
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Abstract: This paper deals with a synchronous demodulation scheme to be used to obtain the speed and position from resolver position sensor. Proposed algorithm is intended to be implemented on a FPGA to provide the elaborated information for very low latency control loops. Moreover, resolver excitation circuit has been simplified working directly with a square wave signal. Resolver frequency behavior has been also taken into account due to the non-sinusoidal excitation.

EPE 2017 - LS3b: Measurement Techniques, Estimation, Sensors
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2017 ECCE Europe - Conference > EPE 2017 - Topic 03: Measurement and Control > EPE 2017 - LS3b: Measurement Techniques, Estimation, Sensors
	[return to parent folder]

	Accuracy Analysis of UCE(on)-based Measurement of the Inverter Output Current at Higher Motor Speeds By Marco DENK	[View] [Download]
Abstract: This paper presents a new gate driver concept that consists of an integrated measurement of the junction temperature and the load current of a power module during inverter operation. For junction temperature measurement the gate driver identifies the temperature sensitive on-chip internal gate resistor by means of a small identification signal that is modulated onto the positive gate voltage. To determine the current through the power semiconductor the new gate driver also measures the highly current sensitive on-state collector-emitter voltage drop UCE(on) and compensates the impact of the junction temperature on driver level. This combined measurement of a temperature-sensitive and a current-sensitive parameter enables accurate current measurement with lowest costs. From today's point of view accuracies of 1-5\% can be reached with reasonable efforts, but it's hard to predict whether UCE(on)-based current measurement can ever cope with the stationary accuracy stated in the datasheets of conventional current sensors. However, it is found that the overall accuracy of UCE(on)-based current measurement profits from very good dynamic properties that become increasingly important in case of high motor speeds and fundamental frequencies. This paper investigates the overall accuracy of a current sensor system to measure a certain load current pointer at a motor speed of 3000 rpm. In d/q-coordinates the low-pass character of a conventional current sensor is found to be responsible for a deviation of the measured current pointer of up to 3.6\%. In contrast, UCE(on)-based current measurement only deviates 0.4\%. In this aspect, the better dynamic properties partially compensate the poorer stationary accuracy of UCE(on)-based current measurement and makes it interesting for lower performance control tasks in high motor speed drives.

	Delta-Sigma Modulated Voltage and Current Measurement for Medium-Voltage DC Applications By Jan GOTTSCHLICH	[View] [Download]
Abstract: This paper presents a galvanically isolated two channel measurement system for voltage and current measurement in medium-voltage dc-dc converters with more than 1 kV operating voltage. The system uses delta-sigma modulation and signal multiplexing to transmit the digitalized signals over fiber optical cables. In combination with a current-loop power supply, high noise immunity and excellent electrical isolation is achieved.

	Design and Measurement Considerations for WBG Switching Circuits By TIANQI ZHANG	[View] [Download]
Abstract: Wide Band Gap (WBG) transistors using materials such as Gallium Nitride (GaN) and Silicon Carbide (SiC) offer superior electrical and thermal properties, as well as fast switching capability. However, the high dv/dt and high di/dt may cause ringing with the parasitic inductances and capacitances in the switching loop, increasing overshoot voltages and reducing confidence in the design. Also, making accurate measurements of the switching behaviour without unduly loading the circuit under test is challenging and further impedes the development of WBG applications. This paper presents a prototype WBG Development Platform, built around a half-bridge switched inductive load test circuit. Additional circuits are integrated on to the main PCB for test and measurement purposes: These include a high bandwidth linear current gate-drive circuit and a high bandwidth on-board measurement system. These sub-circuits are described in detail in this paper, together with the switching waveforms that have been achieved during tests with SiC MOSFETs. The authors demonstrate a practical implementation for high frequency WBG power circuits.

	Resolver-to-Digital Converter with Synchronous Demodulation for FPGA based Low-Latency Control Loops By Alessandro LIDOZZI	[View] [Download]
Abstract: This paper deals with a synchronous demodulation scheme to be used to obtain the speed and position from resolver position sensor. Proposed algorithm is intended to be implemented on a FPGA to provide the elaborated information for very low latency control loops. Moreover, resolver excitation circuit has been simplified working directly with a square wave signal. Resolver frequency behavior has been also taken into account due to the non-sinusoidal excitation.