Matrix Converter Control Using Current Flow Ratio Correction
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Solution Overview
Problem
Existing matrix converter control methods are complex due to the need for ripple computation and carrier amplitude modulation, which complicates the control configuration and computation.
Innovation Solution
A matrix converter and control method that simplifies the control-related circuit construction by using a current flow ratio to correct the output voltage command signal, generating a PWM conversion signal based on the corrected signal and a carrier signal, thereby maintaining a constant average virtual DC link voltage without ripple computation or carrier amplitude modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ripple computation and carrier amplitude modulation are used to control the matrix converter, then the output voltage can be accurately controlled, but the control configuration and computation become more complex
Solution Approach 1:
The patent extracts and eliminates the complex ripple computation and carrier amplitude modulation processes from the control system. Instead of using these complex methods, the invention directly uses the output voltage command signal combined with input current information to generate PWM signals, thereby simplifying the control configuration while maintaining accurate output voltage control
Solution Approach 2:
The patent changes the control parameters from requiring ripple computation and variable carrier amplitude to using a constant amplitude carrier signal combined with corrected output voltage command signals. This parameter change simplifies the control system by eliminating the need for complex real-time computations while maintaining control accuracy
2Measurement precision
If ripple computation and carrier amplitude modulation are used to control the matrix converter, then the output voltage can be accurately controlled, but the computational complexity increases
Solution Approach 1:
The patent removes the computationally intensive ripple computation and carrier amplitude modulation steps from the control process. The simplified method directly computes PWM signals using basic arithmetic operations on the output voltage command signal and input current information, significantly reducing computational complexity while preserving control accuracy
Solution Approach 2:
The patent replaces complex, resource-intensive computation methods with simpler, more efficient computational approaches. By using straightforward signal correction and constant amplitude modulation, the system achieves the same control accuracy with much lower computational cost, making it suitable for digital control systems with limited processing power
3Measurement precision
If variable amplitude carrier signal is used for PWM modulation, then the output voltage can be controlled, but the PWM modulation resolution varies
Solution Approach 1:
The patent changes the carrier signal parameter from variable amplitude to constant amplitude. By maintaining a constant amplitude carrier signal while correcting the output voltage command signal, the system ensures consistent PWM modulation resolution throughout the modulation process, eliminating the resolution variations that occur with variable amplitude carriers
Data Source
Figure 1
Figure 2
Figure 3A~3F
AI summary
An output voltage command signal for outputting a specified three-phase ac output voltage is generated by a line voltage control command signal generating section 11, and a signal representing a current flow ratio is generated by a current flow ratio generating section 12 based on a specified input current command signal. The output voltage command signal is corrected by a command signal computing section 13 based on the output voltage command signal generated by the line voltage control command signal generating section 11 and the signal representing the current flow ratio generated by the current flow ratio generating section 12. A PWM conversion signal is generated by a PWM conversion signal generating section 15, 17 based on the corrected output voltage command signal and a carrier signal. Based on the generated PWM conversion signal, a three-phase ac input voltage is converted into a specified three-phase ac input voltage by a conversion section.