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Inverter Modeling

The Inverter device composes a Node (as a DC bus junction) with an implicit Connection to model bidirectional DC/AC power conversion with separate efficiency and power limits per direction.

Model Elements Created

graph LR
    subgraph "Device"
        SS["Node<br/>(is_source=false, is_sink=false)"]
        Conn["Connection<br/>{name}:connection"]
    end

    DCDevices["DC Devices<br/>(Battery, PV)"]
    ACNode["Connection Target<br/>(AC Bus)"]

    DCDevices -->|connect to| SS
    SS <-->|linked via| Conn
    Conn <-->|connects to| ACNode
Model Element Name Parameters From Configuration
Node {name} is_source=false, is_sink=false (pure junction)
Connection {name}:connection efficiency, power limits per direction

Devices Created

Inverter creates 1 device in Home Assistant:

Device Name Created When Purpose
Primary {name} Always DC/AC conversion tracking and DC bus monitoring

Parameter Mapping

The adapter transforms user configuration into model parameters:

User Configuration Model Element Model Parameter Notes
efficiency_dc_to_ac PowerConnection efficiency_source_target Efficiency when inverting (DC to AC)
efficiency_ac_to_dc PowerConnection efficiency_target_source Efficiency when rectifying (AC to DC)
max_power_dc_to_ac PowerConnection max_power_source_target Maximum inverting power (optional)
max_power_ac_to_dc PowerConnection max_power_target_source Maximum rectifying power (optional)
connection PowerConnection target AC side node to connect to
— Node is_source=false DC bus is not a power source
— Node is_sink=false DC bus is not a power sink

Sensors Created

Inverter Device

Sensor Unit Update Description
power_dc_to_ac kW Real-time Power flowing from DC to AC (inverting)
power_ac_to_dc kW Real-time Power flowing from AC to DC (rectifying)
power_active kW Real-time Net power (DC to AC - AC to DC)
dc_bus_power_balance $/kW Real-time DC bus power balance shadow price
max_power_dc_to_ac_price $/kW Real-time Max DC to AC power shadow price
max_power_ac_to_dc_price $/kW Real-time Max AC to DC power shadow price

The max_power_*_price sensors are only created when the corresponding limit is configured.

See Inverter Configuration for detailed sensor and configuration documentation.

Configuration Examples

Basic Hybrid Inverter

Field Value
Name Main Inverter
AC Connection Home Bus
DC to AC Efficiency 97.0
AC to DC Efficiency 97.0

With Power Limits

Field Value
Name Hybrid Inverter
AC Connection Home Bus
DC to AC Efficiency 96.0
AC to DC Efficiency 95.0
Max DC to AC Power 5.0
Max AC to DC Power 5.0

Typical Use Cases

Hybrid Inverter Systems: Connect batteries and solar panels to the inverter's DC bus, with the AC side connecting to the home bus where loads and grid are attached.

DC-Coupled Solar + Battery: When solar and battery share a DC bus, the inverter handles all DC/AC conversion. This models systems where solar feeds the battery directly on the DC side.

Asymmetric Power Ratings: Some inverters have different power ratings for inverting vs. rectifying. Configure separate max_power_dc_to_ac and max_power_ac_to_dc to model this.

Physical Interpretation

The Inverter represents a power electronics device that converts between DC and AC power. The DC bus acts as a junction point where DC devices (batteries, solar panels with DC output) connect, while the AC side connects to your home's AC network.

Configuration Guidelines

  • Efficiency Values: Typical modern inverters achieve 95-98% efficiency. Set slightly lower values to account for real-world losses.
  • Separate Efficiencies: Rectifying (AC to DC) efficiency may differ from inverting (DC to AC). Measure or consult specifications for accurate values.
  • Power Limits: Configure limits matching your inverter's continuous power rating. Peak/surge ratings should not be used as they are not sustainable.
  • DC Bus Connections: Other elements (batteries, PV) should connect to the inverter's DC bus by specifying the inverter name as their connection target.

Next Steps