Semiconductor Drive Circuit Resonance Prevention
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Solution Overview
Problem
Existing power conversion devices in railway vehicles face malfunctions due to noise-induced erroneous turn-ons in high-speed semiconductor devices like IGBTs and SiC MOSFETs, which increase switching losses and reduce noise immunity, leading to reliability issues.
Innovation Solution
A semiconductor device signal transmission circuit with an inductor and impedance circuit connected in parallel, where the inductor is short-circuited in the counter arm during drive arm switching to prevent resonance and erroneous turn-ons, using diodes or resistors to manage impedance and reduce switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a gate drive resistor value is reduced to increase gate drive current and reduce switching loss, then switching loss is reduced, but noise immunity deteriorates and resonance is likely to occur causing voltage vibration that damages the semiconductor device
Solution Approach 1:
The patent applies dynamics by making the impedance circuit switchable between different impedance states. The switchable impedance circuit changes its impedance value dynamically based on operating conditions, allowing the system to optimize between switching loss reduction and noise immunity. This is achieved through a control circuit that adjusts the impedance circuit's state according to the switching element's operation phase.
Solution Approach 2:
The patent changes the impedance parameter of the signal transmission circuit dynamically. By adjusting the impedance circuit's resistance, inductance, or capacitance values based on operating conditions, the system can reduce switching loss when needed while maintaining noise immunity when required. The control circuit monitors switching states and modifies impedance parameters accordingly.
2Speed
If a gate drive resistor value is reduced to increase gate drive current, then switching speed is improved, but resonance occurs causing voltage vibration exceeding gate voltage rating
Solution Approach 1:
The patent introduces an impedance circuit as an intermediary element between the gate drive circuit and the switching element. This impedance circuit acts as a mediator that filters out harmful voltage vibrations and resonance while allowing the gate drive current to effectively switch the power semiconductor device. The impedance circuit absorbs and dampens the resonance without affecting the primary switching function.
Solution Approach 2:
The patent converts the harmful resonance and voltage vibration into a beneficial effect by using the impedance circuit to detect and respond to switching conditions. The control circuit utilizes feedback from the impedance circuit to adjust driving conditions, transforming what would be harmful vibrations into useful information for optimizing switching performance and protecting the device.
3Reliability
If switching time is increased to prevent resonance, then noise immunity is improved, but switching loss increases
Solution Approach 1:
The patent applies periodic action by using pulse-width modulation (PWM) to control the switching element. The gate drive circuit generates periodic gate drive signals with variable duty cycles, allowing the switching element to operate in continuous switching mode. This periodic switching action reduces average switching loss while the impedance circuit ensures noise immunity during each switching cycle.
Solution Approach 2:
The patent makes the impedance circuit dynamically adjustable to change its characteristics during different phases of operation. During switching transitions, the impedance circuit provides high impedance to prevent resonance, while during steady-state operation, it adjusts to minimize loss. This dynamic adaptation allows the system to achieve both noise immunity and low switching loss without extending switching time.
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 solution prevents malfunctions and reduces switching losses without increasing the semiconductor device's switching time, thereby enhancing the reliability of the power conversion device and electric system for railway vehicles.
Implementation Method 1
a signal transmission circuit for drive-control that is connected between a semiconductor device constituting an arm in a power conversion device and a drive circuit configured to drive the semiconductor device, and the semiconductor device signal transmission circuit for drive-control includes: an inductor; and an impedance circuit including a switch and connected in parallel with the inductor
Data Source
AI summary
To provide a semiconductor device signal transmission circuit for drive-control, a method of controlling a semiconductor device signal transmission circuit for drive-control, a semiconductor device, a power conversion device, and an electric system for a railway vehicle capable of preventing malfunction due to noise while speeding up or reducing loss of a switching operation. The semiconductor device signal transmission circuit for drive-control that is connected between a semiconductor device constituting an arm in a power conversion device and a drive circuit configured to drive the semiconductor device, including: an inductor; and an impedance circuit including a switch and connected in parallel with the inductor.