Voltage Source Converter Gate Drive for Integrated DC Voltage Sensing
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Solution Overview
Problem
Existing voltage source converters for high-power applications, such as in railway vehicles, require accurate DC voltage measurement to prevent semiconductor device overload and optimize switching, but existing solutions involve costly separate measurement devices and complex insulation, leading to high costs and electromagnetic interference.
Innovation Solution
Integration of a voltage divider within a single gate drive unit for both current valves, with an electrically isolating two-way communication link, allowing the converter control device to calculate and send control signals based on measured DC voltage, reducing component count and eliminating the need for separate voltage sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate voltage measurement devices are used to determine DC voltage, then measurement accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The voltage measurement function is merged into the gate drive unit by integrating a voltage divider that measures DC voltage across the capacitor. This eliminates the need for separate voltage measurement devices and reduces overall system complexity while maintaining measurement accuracy through the shared measurement infrastructure.
Solution Approach 2:
The gate drive unit is designed to perform multiple functions: controlling the semiconductor device switching and measuring DC voltage. The voltage divider integrated in the gate drive unit serves both the measurement purpose and provides information to the converter control device, making the gate drive unit a multi-functional component that reduces overall system complexity.
2Reliability
If separate voltage measurement devices are used, then measurement reliability is improved, but cost and power supply requirements increase
Solution Approach 1:
The voltage measurement function is merged into the gate drive unit, eliminating redundant components. The same gate drive unit that controls semiconductor switching also performs voltage measurement through the integrated voltage divider, reducing the total number of components while maintaining measurement reliability through the shared measurement infrastructure.
3Object-affected harmful factors
If electrically insulating communication channels are used between converter control device and gate drive members, then electromagnetic interference is reduced, but device complexity increases
Solution Approach 1:
The patent uses an electrically insulating communication channel as an intermediary between the converter control device and gate drive members. This intermediary provides galvanic isolation that blocks electromagnetic interference while allowing control signals and measurement data to pass through, protecting the control system from high-voltage transient effects without significantly increasing complexity.
4Reliability
If redundant measurement devices are used to guarantee converter operation, then reliability is improved, but cost and complexity increase
Solution Approach 1:
The voltage measurement function is merged into the gate drive unit, creating a unified measurement and control system. This integration reduces the number of separate measurement devices needed while maintaining reliability through the shared measurement infrastructure that is inherently protected by the galvanic isolation of the communication channel.
Data Source
AI summary
A voltage source converter has a half bridge (18) with two current valves (19, 20) connected in series and an arrangement configured to carry out voltage measurements for determining a value of the DC voltage between opposite poles (21, 22) of a DC side of the converter. Each current valve comprises a semiconductor device (23, 24) controlled by an associated gate drive member (29, 30), each forming gate drive parts of one gate drive unit (28) in common to both current valves. The gate drive unit (28) comprises an isolated two-way communication link (33) between the gate drive members. The arrangement is included in the gate drive unit and configured to measure the entire DC voltage between said opposite poles (21, 22). A converter control device (31) calculates and sends control signals to the gate drive unit based on the result of the voltage measurement.