Matrix Converter Control Method Minimizing Switching Losses
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Solution Overview
Problem
Existing matrix converter control methods do not achieve optimal reduction of switching losses and common mode voltages, as the blocked cell does not systematically impose the lowest total sum of input voltages to the other cells, leading to suboptimal performance when current and output voltage are in phase.
Innovation Solution
A control method for a matrix converter that removes the zero phase from the duty cycle matrix and positions a new zero phase to minimize switching losses and common mode voltages by determining the input voltage vector and adjusting the zero phase location based on its position relative to the input voltages, using intersective type modulation with triangular carriers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a zero phase is introduced to block one cell over a switching period, then the modulation depth increases to maximum (0.86) and switching losses are reduced, but the total sum of input voltages to the switching cells is not systematically minimized
Solution Approach 1:
The patent applies dynamics by making the zero phase position variable rather than fixed. The control method dynamically adjusts which switching cell receives the zero phase based on real-time evaluation of input voltage magnitudes, ensuring optimal performance under varying operating conditions while maintaining reduced switching losses.
Solution Approach 2:
The patent changes the parameter of zero phase position from a static configuration to a dynamically adjustable parameter. By modifying which cell is blocked based on input voltage conditions, the system optimizes the trade-off between modulation depth and switching losses under different operating scenarios.
2Loss of energy
If the number of active states is limited to eight over a switching period, then switching losses and common mode voltages are reduced, but the optimum reduction of switching losses when current and output voltage are in phase is not achieved
Solution Approach 1:
The patent optimizes switching losses by dynamically changing which switching cell is blocked based on the relationship between current and output voltage phase. When current and output voltage are in phase, the method selectively blocks the appropriate cell to minimize switching losses while maintaining the required eight active states for reliable operation.
Solution Approach 2:
The control method dynamically adjusts the blocking strategy based on real-time phase relationship between current and output voltage. This dynamic adaptation ensures optimal switching loss reduction while maintaining system reliability through proper selection of active states.
3Device complexity
If a fixed zero phase position is used in the duty cycle matrix, then the control structure is simplified, but switching losses and common mode voltages are not systematically minimized
Solution Approach 1:
The patent resolves the contradiction between control simplicity and energy efficiency by implementing a dynamic zero phase positioning strategy. The control structure remains relatively simple while adding intelligence to automatically select the optimal zero phase position based on input voltage conditions, achieving both simplicity and optimization.
Solution Approach 2:
The control method enables the system to self-optimize by automatically determining the optimal zero phase position based on measured input voltages. The system serves itself by making intelligent decisions about switching cell blocking without requiring complex external control, thereby reducing switching losses while maintaining manageable control complexity.
Data Source
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AI summary
The invention relates to a control method implemented in a variable speed device of the matrix converter type, comprising: three input phases (u, v, w) connected to an AC voltage source and three output phases (a, b, c) connected to an electrical load, nine two-way current and voltage electronic switches (fau, fav, faw, fbu, fbv, fbw, feu, fev, fcw) intended to be individually controlled in order to connect an output phase to any one of the input phases, the operation of switching the switches of the converter obeying a duty cycle matrix for obtaining an output voltage at the load, said duty cycle matrix including a zero phase, the method including a step of suppressing the zero phase in the duty cycle matrix and a step of positioning a new zero phase in the duty cycle matrix so as to minimize the switching losses and the common-mode voltages.