Matrix Converter Commutation Control via Phase Selection
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Solution Overview
Problem
Matrix converters face commutation failures such as circuit opening or short circuits due to delays or detection errors in current or voltage commutation methods, especially when the output current is small or the difference in input phase voltages is minimal.
Innovation Solution
A matrix converter with a controller that selects between a first and second commutation method based on the phase of the output electric current or input voltage, using a selector to choose the appropriate commutation method to prevent failures, employing a combination of four-step current and voltage commutation methods to accurately control bidirectional switches.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If current commutation method is used, then commutation control can be performed, but commutation failure occurs when output electric current is small due to delay of polarity switching or detection error
Solution Approach 1:
The patent changes the commutation control parameter from current-based to voltage-based when the output current magnitude falls below a threshold. This parameter switching allows the system to avoid detection errors inherent in current commutation at low currents, thereby resolving the contradiction between maintaining commutation reliability and dealing with detection precision limitations.
2Reliability
If voltage commutation method is used, then commutation control can be performed, but commutation failure occurs when difference in magnitude of input phase voltages is small due to delay of switching or detection error
Solution Approach 1:
The patent switches between voltage commutation and current commutation based on the magnitude relationship of input phase voltages. When the voltage difference is small and detection errors occur, the system transitions to current commutation mode, thereby resolving the contradiction between maintaining commutation reliability and overcoming voltage detection precision limitations.
3Device complexity
If single commutation method is used, then control is simple, but commutation failure occurs under certain conditions
Solution Approach 1:
The patent implements dynamic selection between voltage commutation and current commutation methods based on real-time detection of output current magnitude and input voltage relationships. This dynamic adaptation allows the system to maintain high commutation reliability across varying operating conditions while keeping the controller structure relatively simple through conditional logic.
Data Source
AI summary
A matrix converter includes: a power convertor that includes a plurality of bidirectional switches; and a controller configured to control the plurality of bidirectional switches. The controller includes: a first commutation controller configured to perform a commutation control with a first commutation method; a second commutation controller configured to perform a commutation control with a second commutation method different from the first commutation method; and a selector configured to select a commutation controller that is configured to execute a commutation control from the first commutation controller and the second commutation controller based on any one of a phase of an output electric current from the power convertor and a phase of an input voltage to the power convertor.