Inverter Control Device Minimizing Output Power Fluctuations
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Inverters experience significant fluctuations in output power due to changes in pulse patterns, which reduces responsiveness in controlling output power, especially when switching between different modulation factors and synchronous numbers.
Innovation Solution
A control device for an inverter that includes a pattern storage unit and a pattern selecting unit, which stores and selects operation patterns to minimize changes between current and next pulse patterns, ensuring consistent output power by choosing patterns with the smallest change from the current setting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If pulse pattern switching is performed to control output power from the inverter, then the output power control capability is improved, but significant fluctuations in output power occur due to large differences between adjacent pulse patterns
Solution Approach 1:
The patent changes the selection criterion for pulse patterns from using adjacent modulation factors to using modulation factors with smaller parameter differences. Specifically, when switching from a first pulse pattern to a second pulse pattern, the patent selects the second pattern based on minimizing the difference in modulation factors rather than simply using adjacent values, thereby reducing output power fluctuations while maintaining control capability
Solution Approach 2:
The patent creates multiple pulse patterns associated with the same modulation factor (e.g., first through fourth patterns for modulation factors M1-M4). This allows the system to have redundant pattern options that can be selected based on minimizing change from the current pattern, rather than being constrained to a single pattern per modulation factor
2Stability of the object's composition
If wait time is provided for pulse pattern switching to limit output power fluctuations, then output power stability is improved, but responsiveness for controlling output power is reduced
Solution Approach 1:
The patent pre-calculates and stores multiple pulse patterns associated with each modulation factor in advance. When switching is needed, the system can immediately select from these pre-prepared patterns based on the minimum difference criterion, eliminating the need for wait time or real-time calculation while maintaining both stability and responsiveness
Data Source
AI summary
A control device stores a plurality of operation patterns associated with each of synchronous numbers and modulation factors, and the synchronous numbers each define the upper limit of the number of switching operations for each switch constituting an inverter. The control device selects an appropriate operation pattern from among the stored operation patterns, and operates each switch on the basis of the selected operation pattern. The control device stores a plurality of operation patterns associated with the same modulation factor for the same synchronous number. In a case where there is a plurality of next patterns as operation patterns corresponding to a next modulation factor, the control device selects, from among the next patterns, an operation pattern with a small change from a currently set operation pattern.