Double-Ended Inverter System Operating Point Optimization
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Solution Overview
Problem
The complexity and cost of electrical systems in hybrid vehicles are increased due to the use of both power inverters and power converters, which convert DC power to AC power and manage power from multiple voltage sources, leading to high power loss and system inefficiency.
Innovation Solution
A double-ended inverter system is controlled to determine an optimal operating point that minimizes power loss by using a constant power line and modulating voltage commands, allowing for efficient power flow between energy sources while maintaining the benefits of a dual inverter system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If both power inverters and power converters are used to manage multiple voltage sources, then power management capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines the power converter and power inverter into a single integrated double-ended inverter system. The first inverter operates as a power converter when converting DC from the first voltage source to DC for the second voltage source, and as a power inverter when converting DC to AC for motor operation. This merging eliminates the need for separate DC/DC converter and inverter components, reducing system complexity while maintaining the ability to manage multiple voltage sources and provide regenerative braking functionality.
2Adaptability or versatility
If both power inverters and power converters are used, then power management capability is improved, but overall cost and weight increase
Solution Approach 1:
The patent integrates the functions of separate power converter and inverter into a single double-ended inverter system, eliminating redundant components. The first inverter serves dual purposes: converting DC to DC for battery charging from the fuel cell (power converter function) and converting DC to AC for motor operation (inverter function). This component consolidation directly reduces the overall weight of the vehicle by removing the need for separate converter and inverter hardware.
3Power
If traditional dual inverter system operates without optimization, then motor performance is maintained, but power loss increases
Solution Approach 1:
The patent implements dynamic operating point optimization for the double-ended inverter system. The controller dynamically determines the optimal operating point on the constant power line by evaluating multiple candidate points and selecting the one that minimizes total power loss. This dynamic adjustment of operating parameters (voltage commands for first and second inverters) allows the system to maintain required motor performance while minimizing energy losses in the inverter components through real-time optimization.
Solution Approach 2:
The patent changes the operating parameters of the inverter system by determining optimal voltage commands (V1 and V2) for the first and second inverters. The controller evaluates multiple operating points by varying the angle parameter relative to the vector corresponding to required output current, and selects the operating point that minimizes power loss. This parameter optimization maintains the required voltage for motor performance while reducing energy losses through optimized voltage combination selection.
Data Source
AI summary
Systems and methods are provided for controlling a double-ended inverter system coupled to a first energy source and a second energy source. The method comprises determining a constant power line associated with operation of the double-ended inverter system, the constant power line representing a desired power flow to the second energy source. The method further comprises determining an operating point on the constant power line, the operating point producing a minimum power loss in the double-ended inverter system for a required output current, and modulating the double-ended inverter system using a first voltage command and a second voltage command corresponding to the operating point.