PLC Supervisor Time Slot Allocation for Solar Inverter Collision Prevention

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Solution Overview

Problem

In solar module systems, existing power line communication (PLC) protocols face challenges in efficiently managing shared power line access among multiple inverters and supervisors, leading to potential collisions and data loss due to the lack of effective coordination and jamming mechanisms.

Innovation Solution

A system comprising a supervisor with a line interface, processor, and program memory that determines shared power line availability, allocates unicast transmission time slots, broadcasts messages, and transmits jam signals when necessary to prevent collisions, ensuring efficient communication on the shared power line.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If multiple inverters communicate on a shared power line without coordination, then communication coverage is extended, but data collisions and loss occur due to lack of access management

Engineering Contradiction:

Improvecommunication coverageVSAvoiddata integrity

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The shared power line communication medium is segmented into distinct unicast transmission time slots allocated to different inverters. Each inverter is assigned specific time windows for communication, dividing the shared resource into manageable segments that prevent collisions while maintaining extended coverage across multiple devices.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The supervisor performs preliminary actions by allocating unicast transmission time slots to each inverter before communication begins. This advance scheduling and reservation of communication resources ensures that when inverters transmit, they do so in predetermined slots, preventing data collisions and maintaining reliability.

Inventive Principle:

Principle #10Preliminary action

2Device complexity

If power line communication is used without jamming mechanisms, then device complexity is reduced, but unauthorized access and collisions cannot be prevented

Engineering Contradiction:

Improvecommunication protocol simplicityVSAvoidcollision prevention

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

A supervisor device acts as an intermediary between multiple inverters on the shared power line. The supervisor manages communication by allocating time slots and transmitting jam signals to prevent unauthorized access. This intermediary approach maintains protocol simplicity while ensuring reliable collision-free communication through centralized control.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The supervisor transmits jam signals as a preliminary anti-action to prevent unauthorized inverters from accessing the shared power line. By detecting inactive time slots and responding with jam signals before other devices can transmit, the system proactively prevents collisions and unauthorized access while maintaining overall protocol simplicity.

Inventive Principle:

Principle #9Preliminary anti-action

3Reliability

If unicast transmission time slots are allocated to each inverter, then data collisions are prevented, but communication coordination complexity increases

Engineering Contradiction:

Improvecollision-free communicationVSAvoidcoordination mechanism complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

Each inverter is configured to listen for and respond to the supervisor's unicast transmission time slot allocations. The inverters self-organize by monitoring the supervisor's scheduling messages and automatically transmitting in their assigned slots without requiring complex peer-to-peer coordination mechanisms, thus achieving reliable collision-free communication with minimal coordination overhead.

Inventive Principle:

Principle #25Self-service

4Reliability

If jam signals are transmitted when inverters do not communicate in their allocated slots, then unauthorized access is prevented, but energy consumption increases

Engineering Contradiction:

Improveunauthorized access preventionVSAvoidsupervisor energy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The supervisor transmits jam signals selectively only when an inverter fails to communicate in its allocated unicast time slot, rather than continuously. This partial action approach provides sufficient unauthorized access prevention by responding only to anomalies while avoiding excessive energy consumption that would result from constant jam signal transmission.

Inventive Principle:

Principle #16Partial or excessive action

Data Source

PatentUS9634723B1Communication between photovoltaic devices on a shared power line

Publication Date: 2017.04.25 ENPHASE ENERGY INC

AI summary

An electric system, method, and computer-readable medium facilitate shared access to a shared power line for communication using a PLC protocol. The electric system, method, and computer-readable medium may determine when the shared power line is available for a transmission, allocate unicast transmission time slots to each of a plurality of inverters, transmit a multicast message requesting that each of the plurality of inverters communicate information during its allocates transmission time slot, determine whether a first inverter in the plurality of inverters did not communicate using the shared power line during its allocated unicast transmission time slot, and if the first inverter did not communicate information during its allocated unicast transmission time slot, transmit with the line interface a jam signal during the first inverter's unicast transmission time slot.