Programmable AC Load with Regenerative Inverter for Diverse Load Profiles
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Solution Overview
Problem
Current programmable AC loads are limited in generating a wide variety of load profiles, particularly steady-state, harmonic, transient, and modulation profiles, and are often purely dissipative, leading to inefficiencies and energy wastage.
Innovation Solution
A programmable AC load system incorporating an active load profiler with a voltage source inverter, grid-connected inverter, and operational mode selector, allowing for regenerative or dissipative modes, which enables the generation of diverse load profiles and efficient energy management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If passive components and power semiconductors are used in programmable AC loads, then the device can generate load profiles, but the number of achievable load profile types is limited
Solution Approach 1:
The patent replaces passive mechanical/electrical components (resistors, inductors, capacitors, diode bridges) with an active power electronic system based on IGBTs and MOSFETs. This substitution enables generation of diverse load profiles (steady-state, transient, harmonic, modulation) through controlled switching operations rather than physical component reconfiguration, thereby increasing adaptability without proportionally increasing device complexity.
Solution Approach 2:
The programmable AC load is designed as a universal device capable of generating multiple types of load profiles (steady-state, transient, harmonic, modulation) through a single integrated power electronic circuit. The system can perform various functions by changing control parameters rather than physical configuration, making it adaptable to different testing requirements while maintaining a fixed hardware architecture.
2Adaptability or versatility
If diode bridge rectifiers are used to generate harmonic load profiles, then harmonic profiles can be produced, but the harmonic patterns are very limited and passive components must be adjusted to vary magnitude and phase
Solution Approach 1:
The patent replaces diode bridge rectifiers with controllable power semiconductor switches (IGBTs, MOSFETs) that can generate harmonic load profiles through programmed switching sequences. This eliminates the need for passive component adjustment and enables flexible control of harmonic magnitude and phase through digital control signals, significantly improving ease of operation and harmonic pattern variety.
3Adaptability or versatility
If motor loads are used to achieve low frequency current modulation profiles, then modulation can be produced, but the modulation pattern is limited in terms of programmable current modulation magnitude and frequency
Solution Approach 1:
The patent replaces motor loads with a power electronic circuit using IGBTs and MOSFETs that can generate current modulation profiles through controlled switching. This substitution expands the programmable range of modulation magnitude and frequency while simplifying control through digital signal processing, as the solid-state switches respond more precisely and rapidly than motor mechanical systems.
4Loss of energy
If programmable AC loads operate in purely dissipative mode, then energy can be dissipated as heat, but electrical energy is wasted unnecessarily especially during long duration tests
Solution Approach 1:
The patent converts the previously harmful energy dissipation into a beneficial regenerative process. The power electronic circuit is designed to operate in bidirectional mode, allowing it to absorb energy from the equipment under test and return it to the grid or store it in DC link capacitors. This transforms wasted heat energy into recoverable electrical energy, reducing overall energy loss and improving testing efficiency during long duration tests.
5Use of energy by moving object
If passive components are used in programmable AC loads, then the load can process energy, but the energy is dissipated by heat which is not cost-effective
Solution Approach 1:
The patent transforms the energy processing function from a dissipative process to a regenerative process. Instead of converting electrical energy to heat through passive resistors, the power electronic circuit converts electrical energy to electrical energy, enabling energy to be returned to the grid or stored for later use. This maintains the energy processing capability while eliminating harmful heat dissipation and associated costs.
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 effectively generates a wide range of load profiles, including steady-state, harmonic, and transient profiles, while offering a regenerative mode that reduces energy wastage by sending power back to the grid, enhancing efficiency and cost-effectiveness.
Implementation Method 1
The ALP includes a voltage source inverter, a control module in operative communication with the voltage source inverter of the ALP
Implementation Method 2
The grid-connected inverter provides a regulated DC voltage source to the voltage source inverter of the ALP
Implementation Method 3
a dissipative mode where the equipment under test voltage is dissipated by heat
Data Source
AI summary
A programmable alternating current (AC) load in communication with an equipment under test (EUT) is disclosed, where the EUT generates an equipment under test voltage. The programmable AC load includes an active load profiler (ALP) for creating current modulation load profiles that are sent to the EUT. The ALP includes a voltage source inverter, a control module in operative communication with the voltage source inverter of the ALP, and a grid-connected inverter having an AC side and a direct current (DC) side. The AC side of the voltage source inverter is in communication with the EUT for receiving the equipment under test voltage. The control module sends a control duty signal to the voltage source inverter indicating a switching frequency and a duty cycle of the current modulation load profiles.