Vehicle Start-Stop System Dual Inverter Architecture
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Solution Overview
Problem
Conventional start-stop systems are inefficient due to the need for additional circuitry and costly components like voltage stabilizers and pre-charge circuits, and the DC/DC converter often lacks sufficient power capability.
Innovation Solution
A start-stop system incorporating two DC-to-AC inverters and a starter/alternator, with a controller managing the energy storage devices to determine whether the starter motor or starter/alternator starts the vehicle based on the state of charge, eliminating the need for additional conversion stages and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a DC/DC converter is used to charge the secondary battery from the main battery, then the secondary battery can be charged, but the conversion stage does not provide sufficient power capability and adds system cost
Solution Approach 1:
The patent removes the DC/DC converter from the system architecture. Instead of using a separate conversion stage to charge the secondary battery, the system directly connects the main battery to the secondary battery through a switch, eliminating the conversion stage that limited power capability and added cost.
Solution Approach 2:
The main battery serves multiple functions: it powers the starter motor for cold starts and directly charges the secondary battery through the switch. This multi-functional approach eliminates the need for dedicated conversion equipment, increasing overall system power capability while reducing complexity.
2Reliability
If voltage stabilizers and pre-charge circuits are added to maintain main battery voltage and store energy, then system reliability improves, but system cost and complexity increase
Solution Approach 1:
The patent eliminates voltage stabilizers and pre-charge circuits from the system. The simple switch-based architecture between the main and secondary batteries provides sufficient reliability for the intended application without requiring these additional components, thereby reducing system complexity and cost.
Solution Approach 2:
The system uses the inherent electrical properties of the battery connection to automatically manage voltage and energy transfer. The switch-based direct connection allows the batteries to self-regulate energy flow without requiring external control circuitry for voltage stabilization or pre-charging.
3Use of energy by moving object
If the engine is shut off during temporary stops to reduce fuel consumption, then fuel efficiency improves, but the system requires additional circuitry to function properly
Solution Approach 1:
The patent removes the additional circuitry typically required for start-stop systems by using a simple switch-based architecture. The system achieves engine shutdown during temporary stops for fuel savings while maintaining a minimal, cost-effective electrical system without complex conversion stages or stabilization circuits.
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
This configuration enhances efficiency by minimizing conduction losses and eliminating the need for costly pre-charge circuits, allowing for improved power generation and reduced active switch ratings, thus enhancing overall system performance.
Implementation Method 1
a first DC-to-AC inverter coupled to the first energy storage device, a starter/alternator coupled to the first DC-to-AC inverter, and a second DC-to-AC inverter coupled to the starter/alternator
Data Source
AI summary
According to some embodiments, a start-stop system for a vehicle is disclosed. The start-stop system includes a first energy storage device coupled to a starter motor. The start-stop system also includes a first DC-to-AC inverter coupled to the first energy storage device, a starter/alternator coupled to the first DC-to-AC inverter, and a second DC-to-AC inverter coupled to the starter/alternator. The start-stop system further includes a second energy storage device coupled to the second DC-to-AC inverter. The start-stop system finally includes a controller configured to control the two DC-to-AC inverters such that either the starter motor or starter/alternator starts the vehicle based on the state of charge of the second energy storage device.