Predictive Inverter Capacitor Pre-Charge Without Isolated Hardware
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Solution Overview
Problem
Existing pre-charge solutions for battery power supplies in electrical circuits are costly, complex, and require specialized components like bulky resistors and high-voltage isolated power supplies, making them inefficient and difficult to implement.
Innovation Solution
A software-based predictive active pre-charge system that uses low-frequency voltage measurements in a slow control loop to determine buck converter power switch duty cycles over defined intervals, eliminating the need for SMPS control hardware and isolated power supplies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive pre-charge systems are used, then circuit damage is prevented, but specialized and expensive components like bulky resistors and contactors are required
Solution Approach 1:
The patent replaces passive mechanical pre-charge components (resistors, contactors) with an active electronic control system using a microcontroller and power switch. The microcontroller monitors battery voltage and capacitor voltage, then controls the power switch to actively regulate charging current, eliminating the need for bulky passive components while maintaining circuit protection functionality.
Solution Approach 2:
The system uses existing voltage measurement circuitry within the battery management system to provide feedback for pre-charge control, rather than requiring separate measurement circuits. The microcontroller utilizes these existing resources to make pre-charge decisions, reducing overall system complexity and component count.
2Reliability
If active pre-charge systems are used, then improved performance is achieved, but SMPS control hardware and high-voltage isolated power supply are required, adding cost and complexity
Solution Approach 1:
The microcontroller serves multiple functions: it performs existing battery management tasks including voltage measurements, and simultaneously provides pre-charge control functionality. By integrating pre-charge control into the existing battery management microcontroller, the patent eliminates the need for separate SMPS control hardware and isolated power supplies, reducing overall system complexity.
Solution Approach 2:
The patent combines the pre-charge control function with the existing battery management system. The same microcontroller that manages battery operations also controls the pre-charge process, and the existing voltage measurement circuitry serves both battery monitoring and pre-charge control purposes, merging multiple functions into a single integrated system.
3Reliability
If traditional active pre-charge systems are used, then pre-charge functionality is provided, but component cost and system complexity increase
Solution Approach 1:
The system leverages existing components and circuitry within the battery management system (voltage measurements, microcontroller) to provide pre-charge functionality, rather than requiring additional dedicated components. This self-service approach reduces component count and system cost while maintaining pre-charge operation.
Solution Approach 2:
Existing battery management components are made multi-functional by having them perform both their original battery management tasks and pre-charge control. The microcontroller and voltage measurement circuitry serve dual purposes, eliminating the need for separate pre-charge components and reducing overall system cost.
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
Reduces system costs and complexity by leveraging existing voltage measurement circuitry, providing efficient pre-charging without the need for expensive components and complex hardware.
Implementation Method 1
a switched bypass pre-charging path having one or more power switches for selectively connecting and disconnecting the battery and the inverter capacitor in response to one or more first switching control signals
Data Source
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AI summary
A device and method for actively pre-charging an inverter capacitor includes a switched bypass pre-charging path having one or more power switches for selectively connecting and disconnecting the battery and the inverter capacitor in response to one or more first switching control signals having a configurable duty cycle, where one or more processor units are configured with a predictive active pre-charging module to control active pre-charging of the inverter capacitor from the battery by using low-frequency measurements of a battery voltage and an inverter capacitor voltage to periodically determine the configurable duty cycle for the one or more first switching control signals that is applied over a plurality of specified charging intervals to actively pre-charge the inverter capacitor to the battery voltage.