Automatic Start-Stop Control for Engine Generators Without Relays
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Solution Overview
Problem
Existing automatic start/stop devices for engine-driven power generators require large-capacity relays due to high generator voltages, leading to layout and cost issues.
Innovation Solution
An automatic start/stop device with a load detection circuit connected in parallel to the inverter output line via a resistor, using a power supply circuit and decision circuit to detect load presence without relays, allowing the engine to start or stop based on load detection signals, and utilizing a battery-powered system for independent load monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a relay is used to switch the load connection terminal in existing automatic start/stop devices, then the engine can be automatically started or stopped based on load detection, but a large-capacity relay is required due to high generator voltage, causing layout and cost problems
Solution Approach 1:
The patent introduces a load detection circuit as an intermediary component that detects load presence through current flow measurement rather than directly switching high-voltage circuits. This mediator circuit includes a current detection unit that monitors current through the load connection terminal, a comparison unit that compares detected current against threshold values, and a control unit that generates start/stop signals based on comparison results, thereby eliminating the need for large relays while maintaining automatic control functionality
Solution Approach 2:
The patent replaces the mechanical relay switching system with an electronic control system. Instead of using a mechanical relay to physically open/close high-voltage circuits, the invention uses electronic components (current detection circuit, comparison circuit, and control circuit) to detect load conditions and generate control signals, substituting mechanical action with electronic signal processing to achieve the same automatic start/stop function without requiring large-capacity mechanical relays
2Extent of automation
If a relay is used to switch the load connection terminal, then the engine can be automatically started or stopped, but the cost increases due to the requirement for a large-capacity relay
Solution Approach 1:
The patent replaces the expensive large-capacity relay with a combination of lower-cost electronic components including current detection circuits, comparison circuits, and control logic implemented using affordable electronic elements. This substitution uses cheaper, readily available components to achieve the same automatic control function, significantly reducing manufacturing cost while maintaining the automatic start/stop capability
3Loss of energy
If the engine is stopped when the load is absent, then fuel consumption and noise are reduced, but the operator must manually stop the engine each time the load stops, which is complicated especially when the operator is at a distant place
Solution Approach 1:
The patent implements a self-service automatic control system that autonomously monitors load conditions through current detection and automatically generates engine start/stop commands based on detected load presence or absence. The system serves itself by continuously monitoring its own operational state and making independent control decisions without requiring operator intervention, thereby achieving automatic fuel savings and noise reduction while eliminating the complexity of manual operation especially when the operator is at a distant location
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
Eliminates the need for large-capacity relays by using a high-resistance load detection circuit, enabling automatic engine start and stop based on load presence, and allowing continuous load monitoring regardless of engine operation, with the alternator serving as a starter motor.
Implementation Method 1
the resistor is set at a resistance value which does not influence a load to which the generator output is supplied
Data Source
AI summary
Starting and stopping an engine is automatically controlled based on a load without using a relay. An inverter engine-driven power generator has an alternator, a rectifying circuit, a DC/DC converter, and an inverter circuit. A load detection circuit is connected to an output of the inverter circuit in parallel. A load detection line of the load detection circuit is connected to an output line of the inverter circuit in parallel via resistors. A power supply formed of a battery is connected to the load detection line. A decision circuit outputs a load detection signal when a current having a preset value or more flows through the load detection line. A drive/stop CPU starts the engine in response to the load detection. The resistors are set at a resistance value which does not influence a load to which a generator output is supplied.