DC Link Voltage Detection in Current-Source Power Converters
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Solution Overview
Problem
Current power converting apparatus configurations require multiple current and voltage detection circuits, leading to complexity and reduced accuracy in monitoring power source malfunctions, especially when an inverter and PWM converter are connected in series.
Innovation Solution
A direct power converting apparatus with a current-source converter and voltage-source inverter operating in synchronization, using a simplified configuration to detect line voltages and currents between DC power supply lines, allowing for high-accuracy amplitude information and instantaneous waveform detection without additional power storage means.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple current and voltage detection circuits are used to monitor power source malfunctions, then detection accuracy is improved, but device complexity increases
Solution Approach 1:
The voltage detection circuit serves multiple functions: it detects the voltage between DC power supply lines, determines conduction patterns of switching elements, and monitors power source malfunctions. This multi-functionality eliminates the need for separate detection circuits while maintaining comprehensive monitoring capability.
Solution Approach 2:
The system uses its own internal voltage detection capability to monitor power source malfunctions without requiring external or additional dedicated detection circuits. The voltage detection results are reused for multiple control and monitoring purposes within the power converting apparatus.
2Loss of information
If separate current detection circuits are provided for PWM converter and inverter, then individual current monitoring is improved, but device complexity increases
Solution Approach 1:
The voltage between DC power supply lines serves as an intermediary parameter that provides information about the current conduction states. By detecting this voltage and analyzing the conduction pattern of switching elements, the system can infer current flow paths without requiring direct current measurement for each component.
Solution Approach 2:
The patent replaces direct current measurement (analogous to mechanical measurement) with voltage measurement and logical inference. Instead of using multiple current sensors, the system uses voltage detection combined with switching element state analysis to determine current flow, reducing the need for physical current measurement devices.
3Reliability
If voltage detection is performed at basic level for amplitude monitoring, then power source malfunction monitoring is enabled, but detection accuracy decreases
Solution Approach 1:
The system performs preliminary detection of the voltage between DC power supply lines and stores this information for subsequent analysis. By capturing the voltage information in advance and combining it with conduction pattern data, the system achieves accurate amplitude detection and comprehensive malfunction monitoring without requiring complex real-time measurement systems.
Data Source
AI summary
A current-source converter includes high-arm side switching elements and low-arm side switching elements. A voltage between the DC power supply lines is detected as a line voltage of an input line, based on a conduction pattern of the high-arm side switching elements and the low-arm side switching elements.