Bidirectional AC-DC Converter Control for Mobile Load Sharing
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Solution Overview
Problem
The 12-volt DC electrical systems in vehicles limit the development of practical and efficient electrically driven equipment for mobile applications, as they require high current for short durations, leading to battery drain and equipment failure, and rely on internal combustion engines or generators that are noisy, polluting, and maintenance-intensive.
Innovation Solution
A mobile power system with a bidirectional AC-DC converter that converts grid AC to a power-limited DC charging signal, a battery module, and a controller to selectively switch between charging and power delivery states, allowing concurrent charging and load power delivery, and managing battery health and load distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If internal combustion engines or generators are used to provide power for mobile applications, then sufficient power can be provided, but the system becomes noisy, polluting, and maintenance-intensive
Solution Approach 1:
The patent replaces internal combustion engines (mechanical system) with an electrical power system consisting of a bidirectional AC-DC converter and battery module. The converter can operate in two modes: rectifying mode to charge the battery from grid AC power, and inverting mode to convert battery DC power to AC power for loads. This substitution eliminates noise, pollution, and maintenance issues associated with combustion engines while providing sufficient power for mobile applications
Solution Approach 2:
The bidirectional AC-DC converter serves multiple functions: it can convert AC to DC for battery charging, convert DC to AC for power delivery to loads, and provide bidirectional power flow control. This multi-functionality replaces the need for separate generators and charging systems, providing a unified solution that addresses both power generation and energy storage needs
2Use of energy by moving object
If the vehicle is connected to grid power, then the battery can be charged, but the batteries cannot be used for power delivery simultaneously
Solution Approach 1:
The patent implements a dynamic power management system where the bidirectional AC-DC converter can dynamically switch between different operational states based on real-time conditions. The controller monitors battery charge level, load requirements, and grid availability to determine the optimal operating mode. This allows the system to simultaneously accept charging power from the grid while delivering power to loads when needed, maximizing both charging efficiency and power delivery capability
Solution Approach 2:
The power management system segments the power flow into distinct controllable paths: one path for AC-to-DC conversion and battery charging, another path for DC-to-AC conversion and load power delivery. The bidirectional converter can independently control these paths, allowing simultaneous charging and power delivery operations by directing power flows through different conversion modes
3Power
If the vehicle relies on generator or grid power, then power can be supplied, but the system becomes dependent on unreliable availability
Solution Approach 1:
The patent implements parameter-based state switching where the controller monitors key parameters including battery state of charge, load power requirements, and grid availability. Based on these parameter thresholds, the system automatically transitions between different operational states: grid-charging mode, grid-power-delivery mode, battery-power-delivery mode, and standby mode. This parameter-driven control ensures reliable power supply by seamlessly switching between power sources based on real-time conditions, eliminating dependence on单一 power source availability
Solution Approach 2:
The bidirectional AC-DC converter acts as an intermediary between the grid power system and the battery module. It mediates power flow in both directions, enabling the system to buffer and manage power transitions smoothly. This intermediary function allows the system to maintain power delivery to loads even when grid availability changes, by coordinating battery charge/discharge operations through the converter's controlled power flow management
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 efficiently manages battery charging and load power, extending battery life, reducing reliance on generators, and providing reliable power without grid availability, while minimizing environmental impact and maintenance.
Implementation Method 1
a bidirectional alternating current-direct current (AC-DC) converter configured to convert a grid AC signal to a power limited DC charging signal
Implementation Method 2
a battery module configured to provide a DC power signal
Implementation Method 3
concurrently converting the DC power signal with the bidirectional AC-DC converter into a battery AC signal for delivery to the load
Data Source
AI summary
A mobile power system may include a bidirectional AC-DC converter configured to convert a grid AC signal to a power limited DC charging signal with a threshold level, a battery module configured to provide a DC power signal, and a controller coupled to the battery module and the bidirectional AC-DC converter and configured to selectively switch the bidirectional AC-DC converter between a first state and a second state. The first state may include, when a load power level is less than the threshold level, concurrently charging the battery module using the power limited DC charging signal and delivering the grid AC signal to a load. The second state may include, when the load power level is greater than the threshold level, concurrently converting the DC power signal with the bidirectional AC-DC converter into a battery AC signal for delivery to the load, and delivering the grid AC signal to the load.