Station Building Auxiliary Power Unit for Regenerative AC Power
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Solution Overview
Problem
Existing technologies fail to efficiently utilize regenerative power in AC distribution line systems, particularly during peak usage hours when regenerative power is exchanged among electric vehicles, and are not applicable to AC distribution line systems due to reliance on ripple components from rectifiers.
Innovation Solution
A station building auxiliary power unit that determines power flow direction between an AC distribution line and a substation, generating control signals to transform AC power for efficient use in loads within the station building, avoiding storage or consumption during peak regenerative power exchange.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If regenerative power is stored in an electrical power storage apparatus during no-load hours, then the regenerative power can be utilized later, but cross current occurs when the distribution line voltage reaches the charge start voltage
Solution Approach 1:
The system performs preliminary detection of power flow direction before initiating charging operations. By detecting whether power is flowing from the distribution line to the substation or vice versa, the system determines the appropriate charge start voltage threshold in advance, preventing cross current conditions before they occur
Solution Approach 2:
The system continuously monitors the power flow direction between the distribution line and substation, using this feedback information to dynamically adjust charging operations. When power flow indicates regenerative power is being exchanged among electric vehicles, the system modifies the charge start voltage threshold to prevent unnecessary charging that would cause cross current
2Object-generated harmful factors
If the charge start voltage is set several volts higher than the average distribution line voltage, then cross current is avoided, but regenerative power cannot be utilized during peak usage hours when distribution line voltage is low
Solution Approach 1:
The system dynamically adjusts the charge start voltage threshold based on real-time power flow conditions rather than using a fixed voltage value. When power flow detection indicates regenerative power exchange among electric vehicles, the system lowers the charge start voltage threshold to enable regenerative power utilization even when distribution line voltage is low during peak usage hours
Solution Approach 2:
The system changes the charge start voltage parameter based on power flow direction detection. Instead of maintaining a static voltage threshold several volts above average, the system modifies this parameter dynamically according to whether the distribution line is supplying power to the substation or receiving regenerative power from electric vehicles
3Ease of operation
If a fixed charge start voltage is used, then the system is simple to operate, but regenerative power storage occurs during peak usage hours when it should be exchanged among electric vehicles
Solution Approach 1:
The system automatically detects power flow direction and determines appropriate charging operations without requiring manual intervention or complex voltage monitoring algorithms. The power flow detection mechanism enables the system to self-adjust its charging behavior based on real-time grid conditions, eliminating the need for fixed voltage thresholds set by operators
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
Enables efficient use of regenerative power in AC distribution line systems by transforming AC power for consumption in station building loads, preventing storage during peak usage hours and being applicable to AC systems without relying on ripple components.
Implementation Method 1
a power converter circuit to transform the first AC power into the second AC power
Data Source
AI summary
A station building auxiliary power unit includes a start-of-operation determination unit that determines, based on a first signal that represents information on a power flow direction indicating a direction of flow of electrical power between an AC distribution line electrically connecting to an electric vehicle and a substation for supplying AC power to the AC distribution line, whether first AC power on an AC distribution line side is to be transformed into second AC power usable by a load, and if it is determined that transformation is to be performed, generates and outputs a second signal, a voltage instruction value calculator that calculates and outputs a voltage instruction value corresponding to the second signal, and a PWM signal generator that generates a control signal for a power converter circuit operated upon transformation of the first AC power into the second AC power, and outputs the control signal.