Fuel Cell Converter Regenerative Power Control
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Solution Overview
Problem
Conventional fuel cell systems face issues with insufficient consumption of regenerative power, leading to increased operating frequencies and vibrations in auxiliary machines, which results in noise and inefficiency.
Innovation Solution
A fuel cell system with a controller that manages electric power distribution by discharging from the secondary battery during power-running operations when a deceleration instruction is given, increasing power loss in the converter and allowing more efficient consumption of regenerative power by auxiliary machines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative power is consumed by auxiliary machines with restrictions on secondary battery charging, then regenerative power consumption is achieved, but auxiliary machines operate at increased frequencies causing vibrations and noise
Solution Approach 1:
The converter is used as an intermediary device to consume regenerative power through controlled voltage conversion losses. The controller adjusts the converter's operation to create power losses that match the regenerative power available, thereby consuming the regenerative power without requiring auxiliary machines to operate frequently.
Solution Approach 2:
The controller changes the operating parameters of the converter to optimize power loss characteristics. By adjusting voltage conversion ratios and operating conditions, the system maximizes regenerative power consumption through the converter while minimizing the need for auxiliary machine operation.
2Quantity of substance
If the secondary battery charge rate is maintained at high levels, then battery capacity is preserved, but regenerative power cannot be effectively consumed leading to auxiliary machine operation increases
Solution Approach 1:
The system converts what would be wasted regenerative power into useful energy losses through the converter. By intentionally creating power losses in the voltage conversion process, the system effectively consumes regenerative power that would otherwise require auxiliary machines to handle, turning a potential waste product into a beneficial energy sink.
3Loss of energy
If auxiliary machines are operated frequently to consume regenerative power, then regenerative power is utilized, but system complexity and maintenance requirements increase
Solution Approach 1:
The converter serves multiple functions: it performs voltage conversion between the fuel cell and secondary battery, and simultaneously acts as a controllable power sink to consume regenerative power. This multi-functionality eliminates the need for dedicated auxiliary machines solely for regenerative power consumption, reducing system complexity.
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 reduces the frequency of auxiliary machine operation and increases the capacity for regenerative power charging by lowering the secondary battery's charge rate and enhancing power loss in the converter, thereby improving energy efficiency and reducing noise.
Implementation Method 1
a fuel cell for generating electric power by using reactant gas
Implementation Method 2
a secondary battery capable of charging and discharging electric power
Implementation Method 3
a converter electrically connected between a drive motor for driving the vehicle and the secondary battery to perform voltage conversion between the drive motor and the secondary battery
Data Source
AI summary
A fuel cell system to be mounted on a vehicle includes: a fuel cell for generating electric power by using reactant gas; a secondary battery capable of charging and discharging electric power; a converter electrically connected between a drive motor for driving the vehicle and the secondary battery to perform voltage conversion between the drive motor and the secondary battery; and a controller for controlling the fuel cell system. The controller exerts such control that when an accelerator for accepting a speed control instruction for the vehicle has accepted a deceleration instruction under a condition that a charge rate of the secondary battery is equal to or more than a preset value, or when the accelerator has accepted a deceleration instruction under a condition that a chargeable electric power of the secondary battery is equal to or less than a preset value, electric power is discharged from the secondary battery during a period of power-running operation lasting until the drive motor with its torque being decreased shifts to regenerative operation. Thus, increases in frequency at which the auxiliary machine is operated to consume regenerative power can be suppressed.