Inverter Power Control for Low Idle Current Off-Grid AC Supply
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Solution Overview
Problem
Off-grid power systems face inefficiencies due to high idle current consumption by DC/AC inverters, leading to excessive battery usage and bulkier systems, and existing solutions either reserve battery capacity or manually switch off the inverter, which are not practical.
Innovation Solution
A method and system that measure electrical currents and voltages to determine AC output power demand, controlling the inverter unit's power consumption and selecting between low-level and high-level modes based on a threshold, using a switching element to connect/disconnect inverters accordingly, optimizing energy usage and reducing battery capacity requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the DC/AC inverter is kept on continuously to be ready to produce electricity on demand, then the system can respond immediately to AC load requirements, but the inverter consumes high amount of energy due to significant idle current even when no load is connected
Solution Approach 1:
The inverter is switched on and off periodically based on the presence of AC load. The controller detects when AC load is connected and switches the inverter on only when needed, rather than keeping it continuously on. This periodic operation eliminates idle current consumption while maintaining the ability to supply power when required.
2Use of energy by moving object
If the inverter is switched off temporarily to sense voltage load, then the idle current consumption is reduced, but this causes serious problems with modern appliances that cycle on and off within certain periods
Solution Approach 1:
The controller uses feedback from voltage sensing to detect AC load presence. When voltage is detected on the AC output line, the controller determines that a load is connected and switches the inverter on. When no voltage is detected, the inverter is switched off. This feedback mechanism allows the system to reduce idle consumption while reliably detecting when modern appliances are connected and need power.
3Ease of operation
If extra battery capacity is reserved to cover inverter idle current consumption, then the system can maintain continuous operation without manual intervention, but the system becomes bulkier and heavier
Solution Approach 1:
By switching the inverter on and off periodically based on actual AC load presence, the system eliminates the need for reserved battery capacity to cover continuous idle consumption. The battery only needs to supply power when the inverter is actually operating with a load, significantly reducing the required battery capacity and overall system weight while maintaining automatic 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
This approach minimizes fuel consumption, reduces battery size and weight, enables longer continuous AC output without engine generators, and integrates seamlessly into existing systems, optimizing power supply efficiency.
Implementation Method 1
DC power received via the internal DC bus is inverted to AC power by the inverter unit to supply AC output power
Implementation Method 2
values of electrical currents and/or voltages within the system are measured by an energy measurement device
Implementation Method 3
The switching element is controlled by the controller. In the method step the switching element accomplishes a step wherein the switching element connects the low-level inverter on the AC output line and disconnects the high-level inverter from the AC output line
Data Source
AI summary
The invention relates to a system and method for supplying AC output power to at least one desired AC load. Values of electrical currents and/or voltages are measured by an energy measurement device within the system and an AC output power demand of the AC load is determined. An inverter unit inverts DC power received via the internal DC bus to AC power to supply AC output power to the connected AC load. The invention further comprises that the controller controls the electrical energy consumption of the inverter unit based on the AC output power demand.