Inverter Test Apparatus Using Virtual AC Load Simulation

Solution Overview

Problem

In dispersed power supply systems, existing methods for conducting anti-islanding tests on inverters require large AC loads, which increase costs and circuit complexity as inverter capacity increases, making it inefficient to simulate and test large-capacity inverters effectively.

Innovation Solution

An inverter test apparatus that simulates an AC load using an AC power output unit and controller to control AC power, allowing for the simulation of inductance, capacitance, or resistance, thereby conducting anti-islanding tests without the need for large reactors or capacitors, reducing the required circuit scale and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a large-capacity AC load is used to conduct anti-islanding tests on high-capacity inverters, then the test accuracy is improved, but the circuit scale and cost increase

Engineering Contradiction:

Improvetest accuracyVSAvoidcircuit scale

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent applies the copying principle by creating a virtual model of the AC load through software simulation rather than using physical hardware. The AC load simulation unit replicates the electrical characteristics (impedance, power factor, resonance) of a large-capacity AC load through computational algorithms, allowing accurate anti-islanding testing without constructing actual large-capacity load circuits. This reduces circuit scale and cost while maintaining test accuracy.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent substitutes the mechanical/electrical system (physical AC load circuits with reactors and capacitors) with an information-processing system (software-based simulation). The control unit executes simulation programs to generate virtual load characteristics, replacing the need for physical electrical components. This substitution dramatically reduces circuit complexity while preserving the ability to conduct accurate anti-islanding tests.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If a large-capacity AC load is used to conduct anti-islanding tests on high-capacity inverters, then the test accuracy is improved, but the cost increases

Engineering Contradiction:

Improvetest accuracyVSAvoidcost

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent applies the copying principle by creating a virtual model of the AC load through software simulation rather than using physical hardware. The AC load simulation unit replicates the electrical characteristics (impedance, power factor, resonance) of a large-capacity AC load through computational algorithms, allowing accurate anti-islanding testing without constructing actual large-capacity load circuits. This reduces circuit scale and cost while maintaining test accuracy.

Inventive Principle:

Principle #26Copying

Solution Approach 2:

The patent substitutes the mechanical/electrical system (physical AC load circuits with reactors and capacitors) with an information-processing system (software-based simulation). The control unit executes simulation programs to generate virtual load characteristics, replacing the need for physical electrical components. This substitution dramatically reduces circuit complexity while preserving the ability to conduct accurate anti-islanding tests.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If parallel operations of AC power system and inverter are used to supply power to AC load, then the inverter can be tested under grid-connected conditions, but the AC load capacity must match the inverter capacity

Engineering Contradiction:

Improvegrid-connected test capabilityVSAvoidAC load capacity requirement

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies the dynamics principle by making the AC load characteristics adjustable and configurable through software control. The AC load simulation unit can dynamically change its electrical parameters (impedance magnitude, power factor angle, resonance frequency) based on test requirements. This allows the same simulation unit to adapt to different inverter capacities and test scenarios, eliminating the need for fixed large-capacity physical loads while maintaining grid-connected test capability.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies the universality principle by designing a software-based AC load simulation unit that can serve multiple functions: simulating various load types (resistive, inductive, capacitive), adjusting power consumption levels, and adapting to different inverter capacities. This single multi-functional simulation unit replaces the need for multiple fixed-capacity physical load banks, reducing overall system complexity while maintaining versatility for grid-connected testing.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS9459310B2Inverter test apparatus

Publication Date: 2016.10.04 TMEIC CORP

AI summary

There is provided an inverter test apparatus for testing an inverter interconnected with an alternating-current power system, the apparatus including an alternating-current power output unit configured to output alternating-current power, and an alternating-current power controller configured to control the alternating-current power output from the alternating-current power output unit to simulate an alternating-current load of the inverter.