Vehicle Power Management System With Bidirectional DC-AC Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current vehicle electrical systems face inefficiencies and reliability issues due to complex compressor installations, unreliable alternators, and the need for high engine idle to power air conditioning systems, which affects fuel economy and increases maintenance costs. Additionally, existing systems struggle to provide sufficient AC power for vehicle accessories and environmental control, especially in ambulances and other specialized vehicles.
Innovation Solution
A power management system that includes a high-voltage DC power bus, DC to AC inverters, bidirectional converters, and a controller to optimize power distribution and battery charging, allowing for flexible configuration and automatic engine start/stop functionality to provide reliable AC power to environmental control systems and vehicle accessories without the need for high engine idle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a mechanically-driven compressor is used in the air conditioning system, then the system can provide cooling capacity, but the mounting kit becomes complex and requires regular maintenance
Solution Approach 1:
The patent replaces the mechanically-driven compressor with an electrically-driven compressor. This substitution eliminates the need for a complex mounting kit that interfaces with the engine's mechanical system, while also reducing maintenance requirements and improving reliability. The electric compressor can be independently mounted and controlled, decoupling it from the engine's mechanical operations.
Solution Approach 2:
The electric compressor serves multiple functions: it provides cooling capacity for the air conditioning system, can be independently controlled regardless of engine operation, and can operate during engine idle or shutdown. This multi-functionality resolves the contradiction by providing reliable cooling without requiring a complex engine-integrated mounting system.
2Power
If the prime mover engine operates at high idle to power the compressor, then adequate cooling capacity is achieved, but fuel economy deteriorates
Solution Approach 1:
The electric compressor enables dynamic control of cooling capacity independent of engine speed. The compressor can be operated at optimal speeds for cooling efficiency rather than being tied to engine idle speed, allowing the engine to operate at fuel-efficient speeds while the electric motor provides the necessary power for adequate cooling capacity.
Solution Approach 2:
Replacing the engine-driven compressor with an electrically-driven compressor decouples the cooling system from engine operation. This allows the engine to operate at fuel-efficient speeds without being forced to maintain high idle for compressor operation, while the electric motor provides the necessary power for adequate cooling capacity.
3Reliability
If an alternator is used to charge the battery and power electrical fans, then the battery can be augmented and electrical loads can be powered, but the alternator becomes unreliable and expensive
Solution Approach 1:
The electric compressor motor serves as a dual-function device: it drives the compressor for cooling and simultaneously acts as a generator to charge the battery when the engine is running. This eliminates the need for a separate alternator, reducing system cost and improving reliability by removing a failure-prone component while maintaining electrical power generation capability.
4Adaptability or versatility
If electrically-driven air conditioning systems are used, then installation flexibility and reliability are improved, but additional DC electrical power capacity is required
Solution Approach 1:
The electric compressor system with battery integration provides self-service by using the compressor motor as a generator during engine operation to recharge the battery. This self-charging capability allows the system to sustain high DC power consumption for the electric compressor without requiring proportionally larger battery capacity, as the system replenishes its own energy stores during normal operation.
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 simplifies installation, improves reliability and efficiency, reduces engine run time, and enhances HVAC capacity, enabling instant-on heating and reduced thermal load on the engine, while also allowing for the integration of alternate power sources like solar and shore power, thereby improving fuel economy and reducing emissions.
Implementation Method 1
DC to AC inverters
Implementation Method 2
bidirectional converters
Implementation Method 3
electromagnetic machine both as a charging device and as a motor
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A power management system with DC/AC (20) converter for providing power to electrical heating, ventilating and air-conditioning system (28), having a first electrical power interface (EPI) and a second EPI. Optional DC/DC converter (24) having a third EPI and a fourth EPI, the third EPI being electrically coupled to the second EPI. A switching arrangement (18) of the system has a common connection (A), the common connection being configured to be coupled to an electromagnetic machine (12), a first connection (C) selectively electrically coupled to the common electrical connection (A), the first electrical connection further being electrically coupled to the second EPI and the third EPI, and a second electrical connection (B) selectively electrically coupled to the common electrical connection (A), the second electrical connection (B) further being electrically coupled to the fourth EPI. The first EPI, the second EPI, the third EPI, the fourth EPI and the common electrical connection are configurable as electrical power inputs and outputs.