Power Conversion Control Apparatus Synchronizing Switching Speed
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional power conversion systems face challenges in properly adjusting switching speed for inverter elements to prevent breakdown and reduce losses, as existing techniques lack timely control over switching speed changes, leading to potential element breakdown due to reaction delays.
Innovation Solution
A power conversion control apparatus that includes a control ECU to output both input voltage change and switching speed change commands, allowing for synchronized adjustments to prevent breakdown and minimize losses by varying switching speed based on input voltage changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the switching speed is increased to reduce loss in switching elements, then loss reduction is achieved, but the surge voltage increases which may cause breakdown of the switching elements
Solution Approach 1:
The patent applies dynamics by making the switching speed variable rather than fixed. The control ECU dynamically adjusts the switching speed of the inverter based on the input voltage level, allowing the system to optimize between loss reduction and breakdown prevention under different operating conditions. This is achieved through a switching speed change command that varies the gate resistor values or gate voltage levels in response to input voltage changes.
Solution Approach 2:
The patent changes the parameter of switching speed based on the input voltage parameter. When the input voltage increases, the control ECU reduces the switching speed to prevent surge voltage from causing breakdown. When the input voltage decreases, the switching speed is increased to reduce losses. This parameter coupling ensures that the switching elements operate within safe voltage margins while minimizing energy loss.
2Reliability
If the switching speed is reduced to prevent breakdown of switching elements, then breakdown prevention is achieved, but loss in switching elements increases
Solution Approach 1:
The system dynamically adjusts switching speed based on real-time input voltage conditions. Rather than operating at a fixed low speed that would prevent breakdown but increase losses, the control ECU continuously adapts the switching speed to match the input voltage level, optimizing the trade-off between reliability and efficiency.
Solution Approach 2:
The switching speed parameter is changed in response to input voltage parameter changes. When input voltage is low, the switching speed is increased to reduce losses while remaining within safe operating limits. When input voltage is high, the switching speed is reduced to prevent breakdown, thus dynamically optimizing the parameter combination for each operating condition.
3Speed
If the switching speed is changed without considering timing coordination with input voltage changes, then switching speed adjustment is achieved, but high input voltage and high switching speed situation occurs due to reaction delay which may cause breakdown
Solution Approach 1:
The control ECU takes preliminary action by issuing the switching speed change command simultaneously with or in coordination with the input voltage change command. This ensures that the switching speed is adjusted in advance or at the same time as the input voltage changes, preventing the dangerous condition where high input voltage coincides with high switching speed due to reaction delays.
Solution Approach 2:
The system uses feedback by monitoring the input voltage level and using this information to control the switching speed. The control ECU receives feedback about the input voltage state and adjusts the switching speed accordingly, ensuring that the switching elements are protected from surge voltage even during transient conditions. This closed-loop control coordinates the timing of switching speed changes with input voltage changes.
Data Source
AI summary
In a power conversion control apparatus incorporated in a power conversion system for converting a direct current (DC) voltage output from a converter into an alternating current (AC) using an inverter. The power conversion control apparatus includes a converter drive circuit configured to drive the converter, an inverter drive circuit, and a control electronic control unit (ECU). The inverter drive circuit operates a plurality of switching elements forming the inverter at a variably set switching speed. The control ECU outputs to the converter drive circuit an input voltage change command for changing an input voltage command for an input voltage to be output from the converter and input to the inverter. The control ECU outputs to the inverter drive circuit a drive command for driving the plurality of switching elements and a switching speed change command for changing the switching speed for the plurality of switching elements.