Power Controller Reverse Flow Isolation Switch

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Solution Overview

Problem

Conventional power controllers for grid interconnection of distributed power sources face inadequate power control performance during reverse power flow to the electric grid, necessitating a more convenient solution for managing multiple types of power sources.

Innovation Solution

A power controller that includes a switch and controller to manage the interconnection of at least one distributed power source capable of reverse power flow and one not capable, switching between parallel and off states to prevent reverse power flow, and a sensor to detect output reversals, allowing for efficient power storage and supply management based on generation and storage schedules.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple distributed power sources are interconnected to the grid in parallel, then the power supply capacity and versatility are improved, but the control complexity and reliability during reverse power flow deteriorate

Engineering Contradiction:

Improvepower source interconnection capabilityVSAvoidcontrol system complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The system segments the parallel-connected power sources into two groups: those capable of reverse power flow (first type) and those not capable (second type). The controller independently manages each group's connection status to the grid, applying different control strategies to each segment based on their reverse power flow capabilities, thereby simplifying the overall control logic while maintaining versatility

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The controller dynamically adjusts the connection state of the second type power sources based on real-time detection of reverse power flow conditions. When reverse power flow is detected from first type sources, the controller automatically switches second type sources to parallel off state, and when reverse power flow stops, it restores them to parallel state, making the system adaptable to changing conditions without increasing permanent complexity

Inventive Principle:

Principle #15Dynamics

2Ease of operation

If all distributed power sources remain interconnected during reverse power flow, then the system simplicity is maintained, but the power control performance and reliability deteriorate

Engineering Contradiction:

Improvesystem operation simplicityVSAvoidpower control performance

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The controller extracts or isolates the second type power sources from the parallel connection during reverse power flow events. By switching these sources to parallel off state when reverse power flow occurs, the system maintains simple operation for first type sources while protecting the reliability and control performance by excluding incompatible second type sources from the reverse power flow condition

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The controller acts as an intermediary that monitors the grid connection status and automatically switches the parallel state of second type power sources based on reverse power flow detection. This intermediary function maintains system simplicity by providing automated control without requiring manual intervention, while ensuring reliability through appropriate isolation of incompatible power sources

Inventive Principle:

Principle #24Intermediary (Mediator)

3Device complexity

If the switch is placed after power conversion, then the device complexity is reduced, but the measurement precision of reverse power flow detection deteriorates

Engineering Contradiction:

Improveswitch placement simplicityVSAvoidreverse power flow detection accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system uses sensor units to detect reverse power flow in the electrical parameter space (current direction and magnitude) at the point of common coupling, rather than trying to physically position switches at ideal locations. This dimensional approach to detection allows accurate measurement of reverse power flow conditions regardless of the physical switch placement location in the circuit

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS10511173B2Power controller, power control method, and power control system

Publication Date: 2019.12.17 KYOCERA CORP

AI summary

A power controller capable of grid interconnection of at least one distributed power source of a first type and at least one distributed power source of a second type together includes: a switch configured to switch between a parallel state in which the at least one distributed power source of the second type is interconnected to a grid together with the at least one distributed power source of the first type and a parallel off state in which the at least one distributed power source of the second type is independent of the at least one distributed power source of the first type and is paralleled off from the grid; and a controller configured to cause the switch to be in the parallel off state when reverse power flow occurs.