Power Converter Switching Control Using Integrated Voltage Values
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Solution Overview
Problem
Existing direct switching control schemes for electrical power conversion devices face limitations in reducing switching losses and simplifying switching state determination, particularly due to complex calculations and parameter errors.
Innovation Solution
The proposed electrical power conversion device determines switching states based on integrated voltage values of each phase and a voltage reference or instruction value, using an integration value calculation unit and a switching determination unit to minimize switching losses and simplify calculations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If model predictive control is used to calculate switching states based on state equations, then pulsation of electric current and torque can be reduced, but the amount of calculations becomes significantly large
Solution Approach 1:
The patent extracts only the essential integration values needed for switching state determination from the complex model predictive control calculations. Instead of calculating all state variables, it selectively integrates voltage values to obtain switching state information, significantly reducing computational burden while maintaining control effectiveness.
Solution Approach 2:
The patent performs preliminary integration of voltage values during the calculation process to obtain integration values that directly inform switching state determination. This preliminary action allows the system to prepare switching state information in advance without requiring full model predictive control calculations at each switching instant.
2Loss of energy
If model predictive control is used to determine switching states, then switching losses can be reduced, but parameter errors have significant influence on control accuracy
Solution Approach 1:
The patent uses inexpensive integration calculations instead of complex model predictive control that is sensitive to parameter errors. The integration-based approach is computationally simpler and less dependent on accurate machine parameters, providing robust control even with parameter variations.
3Object-generated harmful factors
If direct torque control is used to suppress pulsation of magnetic flux and torque, then the number of switching state transitions is reduced, but switching losses are not minimized
Solution Approach 1:
The patent implements feedback by integrating voltage values and using these integration values to determine switching states. This feedback mechanism allows the system to adapt switching states based on accumulated voltage information, minimizing switching transitions while maintaining suppression of magnetic flux and torque pulsation.
Data Source
AI summary
A power conversion device comprises: power conversion circuitry for converting DC power into AC power and supplying it into a load according to a switching state quantity defined by combinations among switching parameters of switching devices; a voltage output calculation device for calculating a voltage output value on the power conversion circuitry, based on the switching state quantity; an integration value calculation device for acquiring a voltage reference integration value and a voltage output integration value by integrating a voltage reference value and the calculated voltage output value; a switching update-determination unit for outputting an update signal of the switching state quantity, based on the voltage reference integration value, its allowance value, and the voltage output integration value; and a switching determination table for determining a switching state quantity of the switching devices, based on the voltage reference integration value, the voltage output integration value and the update signal.