Discharge Control Apparatus for Power Converters
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Solution Overview
Problem
Conventional power converting systems face challenges in accurately controlling the heat generated in switching elements during discharge control, due to variations in switching element characteristics and driver voltages, leading to inconsistent current flow and heat management.
Innovation Solution
A discharge control apparatus that adjusts the voltage applied to the conduction control terminals of high- and low-side switching elements to maintain a current in the non-saturation region of one element lower than the other, using a manipulator to control the heat generated based on discharge current, thereby preventing excessive heat buildup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the voltage applied to the gate of the switching element is reduced to limit the current, then the heat generated in the switching element is reduced, but the current control accuracy deteriorates due to variations in switching element characteristics and driver voltages
Solution Approach 1:
The patent employs feedback control by measuring the actual current flowing through the switching element and adjusting the gate voltage accordingly. The controller monitors the current and modifies the gate voltage to maintain the current within the desired range, compensating for variations in switching element characteristics and driver voltages. This feedback mechanism resolves the contradiction by enabling accurate current control while preventing excessive heat generation.
Solution Approach 2:
The patent dynamically changes the gate voltage parameter based on real-time current measurements and switching element characteristics. By adjusting the gate voltage rather than using a fixed reduced voltage, the system can adapt to individual differences and aging variations in switching elements, maintaining both current control accuracy and heat management.
2Loss of energy
If the voltage applied to the gate of the switching element is reduced to prevent excessive current, then the heat generation is controlled, but the ability to control current accurately deteriorates due to individual differences and aging variations
Solution Approach 1:
The feedback control mechanism continuously monitors the actual current and adjusts the gate voltage to maintain desired current levels despite individual differences and aging variations in switching elements. This enables accurate current control while preventing excessive heat generation, resolving the contradiction between energy loss control and operational ease.
Solution Approach 2:
The patent transitions from a static gate voltage approach to a dynamic adjustment mechanism that adapts gate voltage in real-time based on measured current and switching element characteristics. This dynamic approach maintains current control accuracy and ease of operation while controlling heat generation across different operating conditions and component variations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for precise control of heat in switching elements, enhancing reliability by reducing the risk of excessive heat generation and improving controllability of current flow, even with individual differences and aging variations.
Implementation Method 1
the amount of heat generated in the switching element (IGBT) may be excessively increased. Because the amount of heat depends on the amount of current flowing through the switching element
Data Source
AI summary
A discharge controller carries out discharge control by determining a voltage to be applied to a conduction control terminal of each of switching elements such that a current in a non-saturation region of one of the switching elements is lower than a current in a non-saturation region of the other thereof, and applying the voltage to the conduction control terminal of each switching element with an opening-closing member opening an electrical path to turn on the switching elements, resulting in short-circuit of both electrodes of a capacitor so that a discharge current is outputted from the capacitor based on the discharge control. A manipulator manipulates, based on a value of the discharge current, how to apply the voltage to the conduction control terminal of the one of the switching elements, thus controlling an amount of heat to be generated in the one of the switching elements.