Electric Vehicle Voltage Stabilization via Motor Power Feedback
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Solution Overview
Problem
Existing control apparatuses for electric vehicles face challenges in stabilizing voltage on the power supply line due to variations in the balance of power between AC motors, leading to potential damage to electronic equipment and increased costs with high-performance voltage converters and large capacitance smoothing capacitors, while also struggling to maintain a small size and low cost.
Innovation Solution
A control apparatus comprising a power conversion unit, motor driving unit, system voltage stabilization control unit, and conversion power control unit, which adjusts input power to stabilize system voltage and corrects conversion power errors, allowing for effective voltage stabilization without the need for high-performance converters and large capacitors, using a correction quantity computation unit and conversion power correction unit to refine control precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a voltage boosting converter with better performance and a smoothing capacitor with a larger capacitance are used to stabilize voltage, then voltage stabilization is improved, but cost and device size increase
Solution Approach 1:
The control apparatus uses a feedback mechanism where the control unit continuously monitors the balance of power between AC motors and adjusts the voltage boosting converter's operation accordingly. This feedback control enables effective voltage stabilization using a smoothing capacitor of standard capacitance, avoiding the need for oversized capacitors while maintaining reliability.
Solution Approach 2:
The system utilizes the AC motors themselves to help stabilize voltage by controlling their power balance. When voltage fluctuations occur, the control unit adjusts the power consumption of AC motors to compensate, allowing the system to self-regulate voltage without requiring high-performance expensive converters or large capacitors.
2Adaptability or versatility
If the balance of power between AC motors varies due to vehicle operating state changes, then adaptability is improved, but voltage stability deteriorates
Solution Approach 1:
The control unit implements feedback control by continuously monitoring the power balance between AC motors and adjusting the voltage boosting converter's duty ratio accordingly. This enables the system to adapt to changing vehicle operating states while maintaining voltage stability, as the converter dynamically responds to power balance variations.
Solution Approach 2:
The system employs dynamic control where the voltage boosting converter's operation is continuously adjusted based on real-time power balance conditions. The control unit modifies the converter's duty ratio dynamically in response to changing vehicle operating states, allowing the system to maintain voltage stability across varying conditions without sacrificing adaptability.
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 effectively stabilizes system voltage while meeting the demands for a small size and low cost, reducing the load on the stabilization control and preventing dynamic range narrowing, thus ensuring sufficient voltage stabilization functionality.
Implementation Method 1
a voltage boosting converter for raising a voltage generated by a DC power supply
Implementation Method 2
a smoothing capacitor connected to the power supply line smoothes the voltage appearing on the power supply line
Implementation Method 3
a smoothing capacitor connected to the power supply line smoothes the voltage appearing on the power supply line
Data Source
AI summary
In electric vehicle control, system voltage stabilization control is executed to reduce the difference between a target value and detected value of a system voltage generated by a voltage boosting converter for an AC motor. Further, conversion power control is executed to reduce the difference between a command value and detected value of the conversion power, which is defined as the output power of the voltage boosting converter. A conversion power correction quantity is computed from an input power operation quantity of the system voltage stabilization control and reflected in the conversion power control to correct the conversion power. Thus, variations in a system voltage caused by an error or the conversion power control can be reduced.