Inverter Apparent Power Detection for Low-Load Energy Storage Output
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Solution Overview
Problem
Existing load connection state detection methods for energy storage power supplies face challenges in accurately identifying load connections without increasing hardware cost, volume, or introducing instability, particularly when low-power loads are connected, leading to potential power failures and reduced portability.
Innovation Solution
A software-based load connection state detection method that involves sampling output voltage and current to calculate apparent power, using an active load online detection algorithm to inject voltage excitation and detect voltage responses, determining load connection based on timing and power thresholds, and implementing automatic power-on/off control without additional hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If a specialized load detection circuit is designed, then the load connection state can be automatically identified and power-on/off control can be realized, but the hardware cost increases, volume and weight increase, and portability is reduced
Solution Approach 1:
The patent replaces the mechanical/electrical load detection circuit with a software-based detection algorithm. The controller uses software to sample output current and voltage, calculate apparent power, and determine load connection status through algorithmic processing rather than dedicated hardware circuits. This substitution eliminates the need for additional detection hardware while achieving the same automatic load identification function.
Solution Approach 2:
The patent makes the existing controller perform multiple functions: it not only controls the inverter operation but also serves as the load detection device through its built-in sampling and processing capabilities. The controller uses its existing ADC and processing units to detect load status, eliminating the need for separate detection hardware and reducing overall system complexity.
2Extent of automation
If a specialized load detection circuit is designed, then the load connection state can be automatically identified and power-on/off control can be realized, but the hardware cost and volume increase
Solution Approach 1:
The patent replaces the mechanical/electrical load detection circuit with a software-based detection algorithm. The controller uses software to sample output current and voltage, calculate apparent power, and determine load connection status through algorithmic processing rather than dedicated hardware circuits. This substitution eliminates the need for additional detection hardware while achieving the same automatic load identification function.
Solution Approach 2:
The patent merges the load detection function with the existing controller by integrating the detection algorithm into the controller's software. The sampling circuit, processing unit, and control functions are combined into a single integrated controller system, eliminating separate detection circuits and reducing overall device complexity.
3Device complexity
If output power sampling is used to detect no-load state, then no additional hardware is needed, but the power sampling accuracy is limited and low-power loads may be misidentified as no-load
Solution Approach 1:
The patent applies a preliminary filtering action by comparing apparent power against a predetermined threshold before making load detection decisions. This threshold-based preliminary assessment filters out noise and minor fluctuations, ensuring that only significant power draw events are recognized as actual load connections, thereby improving detection accuracy without requiring complex hardware.
Solution Approach 2:
The patent implements a feedback mechanism where the controller continuously monitors output current and voltage, calculates apparent power, compares it with the threshold, and adjusts its operation accordingly. This closed-loop feedback ensures accurate detection of load connections and prevents misidentification of low-power loads as no-load conditions.
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
Accurately detects load connections, reduces no-load loss, and enables automatic startup without hardware additions, improving portability and reducing power consumption by minimizing no-load losses to nearly zero.
Implementation Method 1
actively injecting a voltage excitation to an output port of the inverter power supply, detecting the voltage response at the output port
Implementation Method 2
controlling a driving of the inverter bridge to initiate waveform generation
Implementation Method 3
the AC output filter circuit includes a filter capacitor and a discharge resistor connected in parallel with the filter capacitor
Data Source
AI summary
A load connection state detection method for an energy storage power supply. The energy storage power supply comprises an inverter power supply. The method comprises the following steps: sampling an output voltage and an output current of the inverter power supply, and calculating output apparent power (S1); and determining whether the apparent power is less than a preset power threshold; if the apparent power is greater than the preset power threshold, a detection result being that a load is connected to the energy storage power supply; and if the apparent power is less than the preset power threshold, executing an active load online detection algorithm for secondary detection, and according to the secondary detection result, determining whether a load is connected (S2).