Vehicle Power Distribution Module With Linear Pre-Charge Control
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Solution Overview
Problem
Existing power distribution modules (PDMs) for vehicles face inefficiencies in pre-charging motor controllers, resulting in non-linear voltage increase and variable pre-charge times due to quiescent current consumption and load dynamics, which limits the maximum attainable charge voltage and increases pre-charge time variability across different platforms.
Innovation Solution
A pre-charge circuit configured to increase output voltage linearly from zero to operating voltage, utilizing a series configuration of a P-Channel MOSFET, PTC thermistor, and power resistor, and a contactor drive circuit with a high inductance coil and PWM voltage controller to modulate battery voltage, ensuring consistent pre-charge across multiple controllers and reducing power dissipation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional pre-charge circuit is used, then the voltage increases non-linearly, but this results in variable pre-charge times and limits the maximum attainable charge voltage
Solution Approach 1:
The patent employs a dynamic control approach where the pre-charge circuit adjusts its operation based on real-time voltage feedback. The controller modulates the power switch duty cycle to maintain a substantially linear voltage increase profile, adapting the charging rate to achieve consistent pre-charge times across different load conditions while reaching the target voltage threshold reliably
2Loss of energy
If quiescent current consumption is present in existing PDMs, then the system operates continuously, but this increases power dissipation and reduces efficiency
Solution Approach 1:
The patent implements periodic action by using pulse-width modulation (PWM) to switch the pre-charge power device on and off in controlled cycles. This allows the system to deliver power in discrete pulses rather than continuous flow, reducing average power dissipation while maintaining effective pre-charge capability through cumulative energy delivery over the periodic cycles
Solution Approach 2:
The system dynamically changes operational parameters including voltage threshold levels, current limiting values, and duty cycle percentages based on detected load conditions. The controller adjusts these parameters in real-time to optimize the balance between power efficiency and pre-charge reliability, modifying the pre-charge profile to match actual system needs
3Loss of time
If the pre-charge circuit does not account for load dynamics, then the circuit design is simpler, but this causes variable pre-charge times across different platforms
Solution Approach 1:
The patent incorporates feedback mechanisms where the controller continuously monitors voltage levels, current flow, and load conditions during pre-charge operation. Based on this feedback, the controller dynamically adjusts switching parameters and power delivery to compensate for variations in load capacitance and platform characteristics, ensuring consistent pre-charge timing across different applications without requiring complex hardware modifications for each platform
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 solution achieves consistent pre-charge to 95% of battery voltage in under 2 seconds, independent of load capacitance, and reduces power dissipation, enhancing reliability and efficiency while maintaining thermal protection and backward compatibility with existing systems.
Implementation Method 1
a series configuration of a P-Channel MOSFET, PTC thermistor, and power resistor
Implementation Method 2
a contactor drive circuit with a high inductance coil and PWM voltage controller to modulate battery voltage
Implementation Method 3
a contactor drive circuit with a high inductance coil
Data Source
AI summary
A power distribution module (PDM) for a vehicle is discussed. PDMs discussed herein can comprise one or more improvements that are related to the pre-charge circuit, the contactor drive circuit, or both. One example embodiment is a PDM comprising: a pre-charge circuit configured to increase an output voltage to one or more motor controllers from zero to an operating voltage, wherein the pre-charge circuit is configured to increase the output voltage linearly; and a contactor drive circuit comprising a contactor coil, wherein the contactor drive circuit is configured to control activation of the pre-charge circuit.