Electric Vehicle Main Conversion Device Regenerative Power Control
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Solution Overview
Problem
In electric motor cars with an auxiliary power-supply device integrated with the main conversion device, regenerative power flowing to the overhead line must be restricted without shutting down the auxiliary power-supply device, as deactivating the first power converter leads to insufficient power supply to auxiliary devices, causing potential shutdowns due to harmonic component issues at the transforming station.
Innovation Solution
A main conversion device comprising a first power converter, a second power converter, an auxiliary power-supply device, and an operation controller that controls the first power converter's operation based on vehicle acceleration conditions, vehicle speed, necessary auxiliary power, and regenerative power restrictions to ensure the auxiliary power-supply device receives sufficient power while limiting regenerative power flowing to the overhead line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the first power converter is deactivated to restrict regenerative power flowing to the overhead line, then the adverse effects of harmonic components to the transforming station can be avoided, but the auxiliary power-supply device cannot receive sufficient power from the overhead line
Solution Approach 1:
The power supply system is segmented into two independent paths: one path through the first power converter for regenerative power control, and another path through the main transformer for auxiliary power supply. This segmentation allows the auxiliary power-supply device to receive power from the overhead line independently of the first power converter's operational state, resolving the contradiction between restricting regenerative power and ensuring auxiliary power supply.
2Volume of moving object
If the auxiliary power-supply device is provided integrally with the main conversion device, then the total size can be made compact, but the auxiliary power-supply device operates depending on the operation of the main conversion device
Solution Approach 1:
While maintaining physical integration for compactness, the patent segments the power supply paths by providing separate connection terminals. The auxiliary power-supply device has both a first connection terminal connected to the first power converter and a second connection terminal connected to the main transformer, enabling operational independence despite physical integration.
Solution Approach 2:
The auxiliary power-supply device is designed with multi-functionality to operate in two modes: it can receive power from the first power converter when the overhead line is not supplying power, or it can receive power directly from the overhead line through the main transformer when available. This universality allows the device to adapt to different operational conditions while maintaining compact integration.
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 allows for the restriction of regenerative power flowing to the overhead line without shutting down the auxiliary power-supply device, ensuring continuous power supply to auxiliary devices and reducing power consumption by electric motor cars.
Implementation Method 1
the first power converter converts AC power output by the main transformer to DC power
Implementation Method 2
the second power converter converts, at the time of power running, the DC power supplied from the intermediate link to AC power
Implementation Method 3
the AC power supplied from the overhead line is sequentially converted by a main transformer and a main conversion device both constructing the main circuit, and is output to the electric motor. Hence, the power is converted to motion energy
Implementation Method 4
there are electric motor cars which utilize, at the time of braking, the electric motor as a power generator to convert the motion energy of the vehicle to power through the main circuit thereby causing regenerative power to flow to the overhead line
Data Source
AI summary
The first power converter is connected with a circuit connected with an overhead line, and an intermediate link, and mutually converts power. The second power converter is connected with the intermediate link, and a circuit electrically connected with an induction motor, and mutually converts power. The auxiliary power-supply device receives power from the intermediate link, and supplies power to a load. The operation controller controls the operation/deactivation of the first power converter based on acceleration and speed of a vehicle, auxiliary source power, and a restriction value for regenerative power to the overhead line in such a way that the power to be supplied to the auxiliary power-supply device becomes equal to or larger than the auxiliary source power, and the regenerative power flowing to the overhead line 105 becomes equal to or smaller than the restriction value.