Multilevel Converter Gate Drive Using DC Link Capacitive Coupling
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Solution Overview
Problem
Existing motor driving devices for air conditioners face challenges in efficiently generating gate drive signals for multi-level converters, leading to increased manufacturing costs and complexity due to the need for high-voltage gate drive signals and additional power supply channels.
Innovation Solution
A motor driving device with a gate drive signal generator that includes a gate drive power source, a gate driver, a gate capacitor, and a gate switching element, which stores and generates gate drive signals without requiring high voltage supply or additional power supply channels, simplifying the design and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-voltage gate drive signals are used for multi-level converters, then the switching elements can be properly controlled, but the device complexity and manufacturing cost increase due to additional power supply channels
Solution Approach 1:
The patent combines the gate drive power supply function with the existing DC link power supply system. The gate drive signals are generated by capacitive coupling from the DC link voltage, eliminating the need for separate high-voltage power supply channels. This merging approach maintains reliable gate drive control while significantly reducing device complexity.
Solution Approach 2:
The DC link power supply system is made multi-functional by using it to provide both the main power to the converter and the gate drive signals for switching elements. The same power supply infrastructure serves dual purposes, reducing the overall number of power supply channels needed in the system.
2Reliability
If high-voltage gate drive signals are used for multi-level converters, then proper switching control is achieved, but manufacturing cost increases
Solution Approach 1:
By merging the gate drive power supply with the DC link power supply, the patent eliminates the need for separate high-voltage power supply components and channels. This reduction in component count and system complexity directly lowers manufacturing costs while maintaining reliable switching element control through capacitive coupling.
3Reliability
If additional power supply channels are added for gate drive signals, then gate drive capability is improved, but the overall system efficiency decreases
Solution Approach 1:
The patent makes the DC link power supply multi-functional, using it to provide both main converter power and gate drive signals. This eliminates redundant power supply channels and reduces energy losses associated with multiple separate power conversion paths, thereby improving overall system efficiency while maintaining gate drive capability.
Data Source
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AI summary
A motor driving device and an air conditioner including the same are disclosed. The disclosed motor driving device includes a multi-level converter to receive AC power, thereby outputting multi-level power, the multi-level converter including plural diodes and plural switching elements, plural capacitors for storing the multi-level power from the multi-level converter, and a gate drive signal generator to generate gate drive signals for the switching elements of the multi-level converter. The gate drive signal generator includes a gate drive power source to supply a gate drive voltage, a gate driver to generate the gate drive signals, using the gate drive voltage, a gate capacitor connected to both terminals of the gate driver, and a gate switching element connected between one end of the gate capacitor and one end of one of the plural capacitors. Accordingly, gate drive signals for the multi-level converter can be generated.