Voltage Source Converter DC Measurement Without Physical Sensors
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Solution Overview
Problem
Existing voltage source converters rely on physical DC voltage sensors for redundancy and accuracy, which are costly, space-consuming, and weighty, and their accuracy can be compromised by parasitic inductances and rapid current changes.
Innovation Solution
Incorporating a calculating unit that receives digital signals from gate drive units, performs quality estimation, and calculates a weighted average DC voltage value, eliminating the need for physical sensors and enhancing accuracy by mitigating the effects of parasitic inductances and signal irregularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If physical DC voltage sensors are used for redundancy and accuracy, then measurement reliability is improved, but device complexity, cost, weight, and space increase
Solution Approach 1:
The patent creates a virtual copy of the voltage measurement function by using the existing gate drive units to measure DC voltage through voltage dividers. Instead of adding physical sensors, the system copies the measurement capability from the gate drive circuitry, eliminating the need for separate sensor hardware while maintaining measurement functionality.
Solution Approach 2:
The gate drive units are made multi-functional by enabling them to perform both their original function of controlling semiconductor devices and the additional function of measuring DC voltage. This universal approach allows the same hardware to serve multiple purposes, reducing the need for dedicated components.
2Reliability
If physical DC voltage sensors are used, then measurement redundancy is improved, but weight and space consumption increase
Solution Approach 1:
The measurement redundancy is achieved by having multiple gate drive units (at least two) each capable of measuring voltage independently. These virtual measurement copies replace physical sensor redundancy, providing the same fault tolerance and measurement verification without the weight of additional sensor hardware.
3Reliability
If physical DC voltage sensors are used, then measurement redundancy is improved, but cost increases
Solution Approach 1:
The patent eliminates the need for expensive physical voltage sensor hardware by copying the measurement function into the gate drive units. This software/firmware-based approach replaces costly hardware components, reducing bill of materials costs while maintaining measurement redundancy through multiple virtual sensors.
Solution Approach 2:
The gate drive units perform self-service by measuring the DC voltage themselves using their existing circuitry and voltage dividers. This self-measurement capability eliminates the need for separate sensor components, reducing overall system cost while providing redundant measurement paths through multiple gate drive units.
4Speed
If voltage measurements are taken during rapid current changes, then real-time voltage monitoring is improved, but measurement accuracy deteriorates due to parasitic inductances
Solution Approach 1:
The patent uses feedback from multiple gate drive units to monitor and detect measurement anomalies. By comparing voltage readings from multiple sources and monitoring the consistency of measurements, the system can identify when parasitic inductance effects are corrupting readings during rapid switching, and take corrective action or use alternative measurement data.
Solution Approach 2:
The system performs more measurements than strictly necessary by using multiple gate drive units to measure voltage. This excessive measurement approach provides redundant data that can be used to filter out erroneous readings caused by parasitic inductances, ensuring accurate voltage monitoring even during rapid current changes.
Data Source
AI summary
A voltage source converter includes two half bridges each having two current valves connected in series to be connected to opposite poles of a DC source/load. A gate drive unit controls a semiconductor device of a current valve. An arrangement carries out voltage measurements for providing a value of DC voltage between the opposite poles. A voltage divider connected across the two current valves measures DC voltage between opposite poles and each voltage divider has an output connected to processing parts delivering a digital signal representing a value of the DC voltage between the poles. Two gate drive units send a digital signal to a calculating unit to carry out a quality estimation of the digital signals and to calculate a DC voltage value from the signals while giving each signal a weight corresponding to the quality value adhered thereto and then forming a weighted average value.