Matrix Convertor Intermediate Voltage Phase Control
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Solution Overview
Problem
Conventional matrix convertors face challenges in efficiently controlling the connection periods of input phases to output phases, leading to suboptimal power conversion and potential surge voltages due to the lack of precise control over the intermediate voltage phase connections.
Innovation Solution
A matrix convertor system with a controller that generates a control command with a lower limit for the connection period of the intermediate voltage phase, ensuring stable output by restricting the ratio of output vectors and adding the intermediate voltage phase to switching patterns, thereby preventing abrupt changes between maximum and minimum voltage phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the connection period of the intermediate voltage phase is not controlled with a lower limit, then the switching frequency can be reduced, but surge voltages occur and output voltage accuracy deteriorates
Solution Approach 1:
The patent applies parameter changes by establishing a lower limit for the connection period (duty ratio) of the intermediate voltage phase. This parameter constraint prevents the duty ratio from becoming too small, thereby avoiding surge voltages and maintaining output voltage accuracy without requiring complex additional control mechanisms.
Solution Approach 2:
The patent implements preliminary action by pre-defining the lower limit threshold for the intermediate voltage phase connection period before operation. This preventive measure ensures that the control system avoids problematic operating conditions (surge voltages) by design, rather than reacting to them after they occur.
2Object-affected harmful factors
If the intermediate voltage phase connection period is restricted with a lower limit, then surge voltages are prevented, but the switching pattern complexity increases
Solution Approach 1:
The patent uses parameter changes by modifying the switching pattern to incorporate a minimum duty ratio constraint for the intermediate voltage phase. This parameter-based approach simplifies the overall control strategy compared to complex multi-variable control methods, while effectively preventing surge voltages through the established lower limit.
3Stability of the object's composition
If the connection period of the intermediate voltage phase is extended, then output voltage stability improves, but the response speed to voltage changes decreases
Solution Approach 1:
The patent applies parameter changes by setting an optimal lower limit for the intermediate voltage phase connection period. This parameter optimization balances stability and response speed: the duty ratio is constrained to be sufficiently large to ensure stability, but not excessively large to prevent sluggish response, achieving an optimal compromise through parameter tuning.
Data Source
AI summary
A matrix convertor includes a power convertor and a controller. The power convertor includes a plurality of bidirectional switches disposed between a plurality of input phases and a plurality of output phases. The controller is configured to generate a control command and control the power convertor based on the control command. The control command includes a switching pattern that causes a first input phase among the input phases to be connected to one output phase among the output phases and that causes connection of the input phases to be switched between a rest of the output phases. In generating the control command, the controller is configured to set a lower limit to a period of time during which a second input phase among the input phases that corresponds to an intermediate voltage is connected to the rest of the output phases.