Dual Power Supply Control for Inverter Back-EMF Suppression
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Solution Overview
Problem
Existing power source systems face issues with parasitic capacitance, unintentional operation of load devices during external charging, noise generation from switching power sources, and high-voltage back EMF causing equipment failure and unintended torque in vehicles with motors and inverters.
Innovation Solution
A power source system with a motor, inverter, switching control unit, first and second power sources, and voltage control unit that performs short-circuit control using the second power source when the first fails, and adjusts voltage levels to stabilize switching control during external charging.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the first power source operates intermittently or at reduced voltage during external charging to reduce noise, then noise is reduced, but the power source may fail to provide sufficient power for reliable switching control
Solution Approach 1:
The power source system is divided into two independent power sources: the first power source for normal operation and the second power source for backup during external charging. This segmentation allows each power source to be optimized independently - the first can operate at reduced voltage to minimize noise, while the second ensures reliable switching control power is always available.
Solution Approach 2:
The system changes the operating parameters of the first power source during external charging by reducing its output voltage or operating intermittently. This parameter change reduces noise generation while the second power source compensates to maintain sufficient total power for reliable switching control.
2Power
If the first power source supplies power at high voltage in normal state, then sufficient power is provided for reliable operation, but noise is generated during external charging
Solution Approach 1:
The first power source dynamically adjusts its operating mode based on the charging state. During normal operation, it supplies high voltage for sufficient power. During external charging, it automatically reduces voltage or operates intermittently to minimize noise, while the system transitions to using the second power source for switching control.
3Device complexity
If the switching control unit uses only the first power source during external charging, then the system is simpler, but noise is generated and power may be insufficient
Solution Approach 1:
The power supply function is segmented between two power sources with distinct roles. The first power source handles general power needs with reduced voltage during charging to minimize noise, while the second power source is dedicated to switching control, ensuring sufficient power without contributing to noise issues.
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
The system effectively suppresses back EMF and reduces noise, ensuring stable switching control during external charging by utilizing a backup power source, even when the primary power source fails.
Implementation Method 1
an inverter, including a series-connected element of a upper arm switch and a lower arm switch, that converts power between a battery and the motor
Implementation Method 2
when the rotation speed of a motor increases, a reverse electromotive voltage generated in the coil by a magnetic flux of a permanent magnet of the motor may become larger than the voltage of the battery
Data Source
AI summary
The power source system includes a motor, an inverter, a switching control unit, a first power source that supplies power to the switching control unit, and a second power source that supplies power to the switching control unit when a short-circuit control is performed. The first power source provides power at a higher voltage than a first threshold value during normal states, while the switching control unit intermittently provides power, or provides power at a reduced voltage, or stops supplying power during an external charging. The switching control unit controls the inverter using the power supplied from the higher output voltage of the first power source and the second power source or by power supplied from the second power source during the external charging, while the switching control unit performs the short-circuit control using the power supplied from the second power source when the first power source fails.