Motor Neutral-Point Charging Circuit for Variable Voltage Battery Input
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Solution Overview
Problem
Existing charging systems using stator coils and switching elements of an inverter as a boost converter cannot effectively adjust voltage levels to charge a battery when the power supply has either a lower or higher output voltage than the battery.
Innovation Solution
A charging system that utilizes stator coils as a reactor, incorporating a controller to manage neutral point switching elements and inverters to either boost or step down the power supply voltage based on its output relative to the battery voltage, allowing charging from power supplies with varying voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a boost converter using stator coils and switching elements is used to charge a battery, then the battery can be charged by a power supply with lower output voltage, but the system cannot step down voltage to charge from a power supply with higher output voltage
Solution Approach 1:
The charging system is designed to perform multiple functions: it can operate as a boost converter when the power supply voltage is lower than the battery voltage, and as a buck converter when the power supply voltage is higher than the battery voltage. This multi-functionality allows a single system to handle different voltage scenarios without requiring separate charging circuits, thereby improving adaptability while managing device complexity.
2Loss of energy
If the power supply voltage is higher than the battery voltage, then charging can proceed directly, but voltage mismatch causes charging losses
Solution Approach 1:
The system dynamically adjusts its operation mode based on the relationship between power supply voltage and battery voltage. When the power supply voltage is higher, the system activates the buck converter function with appropriate switching element control to step down the voltage. When the power supply voltage is lower, it switches to boost converter mode. This dynamic adaptation minimizes voltage mismatch losses while maintaining reasonable system complexity through unified control logic.
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 charging of batteries from power supplies with either lower or higher output voltages by adjusting voltage levels, reducing charging losses and enhancing motor performance.
Implementation Method 1
A charging system is configured to transform a voltage of a power supply to charge a battery by using stator coils of a motor as a voltage converter
Implementation Method 2
an inverter with a direct current end that is connected to the battery and an alternating current end that is connected to first ends of the stator coils; a plurality of neutral point switching elements each of which connects a second end of a corresponding one of the stator coils to the neutral point
Data Source
AI summary
A charging system includes: a motor including a plurality of stator coils; a power receiving terminal including a power receiving positive end and a power receiving negative end, the power receiving negative end being connected to a battery negative end, and the power receiving positive end being connected to a neutral point of the motor; a capacitor; an inverter; a plurality of neutral point switching elements each of which connects a second end of a corresponding one of the stator coils to the neutral point; and a plurality of diodes, an anode of each of the diodes being connected to the power receiving negative end, and a cathode of each of the diodes being connected to the second end of a corresponding one of the stator coils.