Fuel Cell Power Converter Switching for Fast Residual Charge Discharge
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Solution Overview
Problem
Existing power supply systems face challenges in quickly reducing terminal voltage without using a relay, which is space-constrained and increases manufacturing costs.
Innovation Solution
A power supply control apparatus and method that uses a switching control device to alternate the state of switching elements and control oxidant gas supply to discharge residual charge in a fuel cell, employing multiple short circuits followed by a normal short circuit to efficiently reduce terminal voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a relay is used to decrease voltage between terminals, then the voltage reduction speed is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent extracts and eliminates the relay component from the system by implementing voltage reduction control directly through the power converter's switching elements. The controller manages the switching elements to control current flow and discharge residual charge from the fuel cell, achieving voltage reduction without requiring a separate relay device.
Solution Approach 2:
The power converter's switching elements are made multi-functional by enabling them to perform both their primary power conversion function and the additional function of voltage reduction control. The same switching elements that convert electric power also control current flow to discharge residual charge and reduce terminal voltage, eliminating the need for dedicated relay components.
2Reliability
If a relay is mounted in the power supply system, then the voltage control capability is improved, but the space requirement and manufacturing cost increase
Solution Approach 1:
The patent merges the voltage control function with the existing power converter structure. The controller and switching elements of the power converter are integrated to perform both power conversion and voltage reduction control, combining multiple functions into a single system component and eliminating the need for separate relay mounting space.
Solution Approach 2:
The switching elements in the power converter are designed to perform multiple functions: primary power conversion and secondary voltage reduction control. This multi-functionality allows the system to achieve reliable voltage control without adding separate relay components that would require additional mounting space.
3Productivity
If the on time of switching elements is extended during residual charge discharge, then the voltage reduction efficiency is improved, but the risk of overcurrent increases
Solution Approach 1:
The controller implements feedback control by monitoring the discharge current and adjusting the on time of switching elements accordingly. When residual charge is being discharged, the controller extends the on time to improve voltage reduction efficiency while simultaneously monitoring current levels and reducing on time when approaching overcurrent thresholds, achieving both efficiency and safety.
Solution Approach 2:
The on time of switching elements is made dynamic rather than fixed. The controller continuously adjusts the on time based on real-time system conditions: extending it during residual charge discharge to improve efficiency, and dynamically reducing it when current levels approach dangerous thresholds, thereby balancing efficiency and overcurrent prevention.
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
The method quickly decreases terminal voltage within regulatory times without a relay, saving space and reducing costs by effectively discharging residual charge in the fuel cell.
Implementation Method 1
a power converter having a plurality of switching elements and configured to convert electric power output from the fuel cell
Implementation Method 2
The power supply has a fuel cell, a gas supply unit configured to supply oxidant gas to the fuel cell
Data Source
AI summary
A power supply control apparatus includes a switching control device configured to switch each of switching elements of a power converter between an on state and an off state alternately, and a discharge control device configured to, when residual charge of the fuel cell is discharged, control a gas supply unit such that oxidant gas is not supplied to the fuel cell, in a first period, control the switching control device such that an on time during which at least one switching element is maintained in the on state is longer than the on time during an operation of the fuel cell and the at least one switching element is switched between the on state and the off state alternately, and, in a second period subsequent to the first period, control the switching control device such that the at least one switching element continues to maintain the on state.