AC Power Inverter Control Module for Heavy-Duty Trucks
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Solution Overview
Problem
AC power inverters in heavy-duty trucks often deplete the batteries to the point where they cannot start the engine, leading to restrictions on their use or requiring high low-voltage set-points that cause premature shutdowns when high-power devices are used.
Innovation Solution
A control module that monitors battery voltage, shunt voltage, alternator status, and elapsed time to dynamically adjust the AC power inverter's operation, ensuring sufficient energy remains for starting the vehicle by calculating energy usage and adjusting the voltage shutoff point based on current draw.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the low-voltage set-point is set high to preserve power for starting the engine, then the battery can start the vehicle, but the AC power inverter turns off too soon when high-power devices are used
Solution Approach 1:
The patent implements dynamic adjustment of the low-voltage set-point based on real-time monitoring of battery state of charge, alternator charging status, and inverter power consumption. The control module continuously modifies the shutdown threshold voltage dynamically rather than using a fixed high set-point, allowing the system to adapt to changing conditions and prevent premature inverter shutdown while ensuring sufficient power remains for vehicle starting.
2Loss of energy
If a timer is used to limit inverter usage to a predetermined number of hours, then energy consumption is controlled, but the inverter may prohibit use of devices that require only small amounts of energy even when sufficient battery energy is available
Solution Approach 1:
The patent employs continuous feedback monitoring of battery voltage, current draw, and calculated state of charge to dynamically control inverter operation. The control module receives real-time data from voltage sensors and current shunts, processes this information to determine actual available battery energy, and adjusts inverter shutdown thresholds accordingly. This feedback mechanism replaces fixed timer limitations with intelligent energy-based control that accurately reflects actual battery capacity and charging status.
3Duration of action of moving object
If the inverter is allowed to run until batteries are nearly completely drained, then maximum usage time is achieved, but the vehicle cannot start due to insufficient battery energy
Solution Approach 1:
The patent implements preliminary monitoring and calculation of battery state of charge before complete depletion occurs. The control module continuously tracks energy consumption and maintains a dynamic threshold that ensures a minimum reserve of battery energy is preserved for vehicle starting. This preliminary action prevents the harmful effect of complete battery drainage by proactively shutting down the inverter when approaching unsafe energy levels, while still maximizing permissible usage time.
Data Source
AI summary
A system for controlling an AC power inverter has a charging power source (e.g., vehicle alternator), a battery (e.g., vehicle crank battery), a DC to AC power inverter, a shunt or current-measuring device (which may either be internal to, or external to, the AC power inverter), electrical connections (i.e., cables and connections between the charging power source, battery, AC power inverter, and shunt), and a control module; wherein the control module is capable of measuring shunt voltage, battery voltage, elapsed time, and is capable of turning the AC power inverter On and Off based upon certain criteria (i.e., control logic).