Regenerative Braking Power Switching for Stable Auxiliary Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In regenerative braking systems, rapid voltage fluctuations occur when switching between regeneration and non-regeneration periods due to the slower response of auxiliary-machine generators compared to DC/DC converters, potentially hindering normal operation of auxiliary machines, and large-capacitance smoothing capacitors increase system size and cost while prolonging initial charging and discharging times.
Innovation Solution
A regenerative braking system with a controller that manages the switching between generators and power storage, deactivating the auxiliary-machine generator during regeneration and activating it during non-regeneration, and using a DC/DC converter to stabilize voltage, ensuring a predetermined voltage value is maintained across the auxiliary-machine DC line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a large-capacitance smoothing capacitor is connected to the auxiliary-machine DC line to reduce voltage fluctuations, then voltage stability is improved, but system size and cost increase, and initial charging and discharging times are prolonged
Solution Approach 1:
The patent introduces a control device as an intermediary that coordinates between the DC/DC converter and the auxiliary-machine generator. This control mediator manages power distribution and voltage regulation without requiring large capacitance components, thereby achieving voltage stability while maintaining compact system size and avoiding prolonged charging/discharging times associated with large capacitors.
2Loss of energy
If the auxiliary-machine generator is deactivated during regeneration period, then energy conservation is improved, but voltage fluctuations occur during transient states due to slower response compared to DC/DC converter
Solution Approach 1:
The control device performs preliminary action by predicting the end of the regeneration period and activating the auxiliary-machine generator in advance before the DC/DC converter completes its transition. This anticipatory activation ensures that the generator is ready to immediately support voltage regulation, preventing voltage fluctuations during the transient state while maintaining energy conservation benefits throughout the regeneration period.
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 voltage fluctuations during regeneration operation switching, enhances energy conservation, and minimizes system size and cost by optimizing power distribution and reducing the need for large capacitors.
Implementation Method 1
a DC/DC converter that converts electric power of the first DC line, and supplies the electric power to the second DC line
Implementation Method 2
a first rectifier circuit that is connected to the first generator, rectifies output of the first generator, and outputs the output of the first generator as direct current electric power
Data Source
AI summary
When regeneration operation is being performed, electric power on a main-machine side is supplied to an auxiliary-machine side, a voltage on the auxiliary-machine side is controlled to become a first voltage value predetermined on the basis of operating voltage specifications of an auxiliary apparatus, a generator on the auxiliary-machine side is deactivated to stop supply of electric power to the auxiliary-machine side, and electric power on the auxiliary-machine side is supplied to a power storage apparatus. When the regeneration operation is ended, the supply of the electric power from the main-machine side to the auxiliary-machine side is stopped, the generator on the auxiliary-machine side is activated, the generator on the auxiliary-machine side is controlled such that a voltage on the auxiliary-machine side becomes the first voltage value, electric power of the power storage apparatus is supplied to the auxiliary-machine side, and the voltage on the auxiliary-machine side is controlled to become a second voltage value higher than the first voltage value. This enables reduction of fluctuations of a voltage supplied to auxiliary machines at a time of switching of regeneration operation by travel motors.