DC/DC Power Conversion Apparatus Voltage Equalization
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Solution Overview
Problem
Conventional DC/DC power conversion apparatuses face issues with device breakage due to overvoltage when switching devices and diodes are subjected to maximum input voltage, leading to increased costs and reduced efficiency, especially when control is stopped and input voltage is applied.
Innovation Solution
Incorporating a smoothing capacitor with voltage division capacitors connected in series and a switching device for voltage equalization between the charge-discharge capacitor and the voltage division capacitors, ensuring the inter-terminal voltage of the charge-discharge capacitor is maintained at a desired level, even when switching devices are in control stopped states, allowing the use of low-breakdown voltage semiconductor devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If switching devices and diodes are subjected to maximum input voltage in control stopped state, then device breakdown occurs, but increasing breakdown voltage of devices increases cost and reduces efficiency
Solution Approach 1:
A voltage equalization circuit is introduced as an intermediary between the input voltage source and the switching devices/diodes. This circuit includes a voltage equalization capacitor connected in parallel with the charge-discharge capacitor and a voltage equalization switch connected in series with the capacitor. The intermediary circuit equalizes the voltage distribution, preventing maximum input voltage from being applied directly to the switching devices and diodes during control stopped state, thereby protecting them from breakdown while allowing the use of lower breakdown voltage devices
Solution Approach 2:
The voltage equalization circuit changes the voltage parameter distribution across the circuit components. By controlling the voltage equalization switch to be in the ON state during control stopped state, the circuit transforms the voltage distribution such that the voltage across the switching devices and diodes is reduced from the maximum input voltage to a lower equalized voltage level, preventing breakdown while enabling the use of cost-effective lower breakdown voltage devices
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 configuration prevents device breakage, reduces costs, and enhances efficiency by equalizing voltages applied to switching devices and diodes, enabling the use of low-breakdown voltage components while maintaining stable operation.
Implementation Method 1
a smoothing capacitor on an output side, which is connected to the DC voltage conversion section and composed of a plurality of voltage division capacitors connected in series to each other
Implementation Method 2
a switching device for voltage equalization provided on a connection line provided between the negative terminal of the charge-discharge capacitor and a connection point between the voltage division capacitors
Implementation Method 3
a charge-discharge capacitor which is charged or discharged by ON/OFF operations of the switching devices
Implementation Method 4
a plurality of diodes which provide a charging route and a discharging route for the charge-discharge capacitor
Data Source
AI summary
A DC/DC power conversion apparatus includes a reactor connected to a DC power supply and a DC voltage conversion section connected to the reactor. The DC voltage conversion section includes a plurality of switching devices, a charge-discharge capacitor which is charged or discharged by ON/OFF operations of the switching devices, a plurality of diodes which provide a charging route and a discharging route for the charge-discharge capacitor. The DC/DC power conversion apparatus also includes a smoothing capacitor on an output side, which is connected to the DC voltage conversion section and including a plurality of voltage division capacitors connected in series to each other, and a switching device for voltage equalization provided on a connection line provided between the negative terminal of the charge-discharge capacitor and a connection point between the voltage division capacitors.