Engineering category

Solid-State Power Systems: Definition, Architecture and Taxonomy

A solid-state power system converts energy into electrical power and delivers it to a load, with the direct conversion step performed without a conventional rotating electromechanical generating stage. The term describes how the conversion path is built, not where the energy comes from, and it is not a synonym for a solid-state battery. One subclass is electrodynamic; VENDOR.Energy’s development is focused on that subclass.

What a solid-state power system is

The defining property of the class is the architecture of the conversion stage — solid-state energy conversion — rather than the origin of the energy being converted.

A solid-state power system converts energy into electrical power using stationary materials, structures or electronic devices. No conventional rotating electromechanical converter appears in that stage.

A note on the term itself

Solid-state energy conversion is well established in the scientific literature, where it covers photovoltaic, thermoelectric, thermophotovoltaic and solid-oxide electrochemical converters. The broader superclass solid-state power system has no formal industry standard. This page uses it as a taxonomic framework for architectures that share a common conversion-stage architecture, and proposes it in that capacity.

Two consequences follow. Two systems can obtain energy in entirely different ways and still belong to the same class if they share the same conversion-stage architecture. Conversely, a shared energy source does not by itself place two systems in the same class.

Solid-state energy conversion is not solid-state energy storage

Solid-state power generation is one function of solid-state energy conversion. Solid-state energy storage is a function of a different kind. In the current search environment the two are conflated almost automatically, which is why the distinction gets a section of its own.

TermWhat it denotes
Solid-state energy conversionThe direct conversion of energy into electrical power by stationary materials, structures or electronic devices
Solid-state power systemA system that converts energy into electrical power and delivers it to a load, in which the direct conversion into electrical power is performed by stationary materials, structures or electronic devices, without a conventional rotating electromechanical converter
Solid-state power generationThe function of producing electrical power within a solid-state power system
Solid-state power conversionThe conditioning of already available electrical power by power electronics
Solid-state energy storageA class of storage technologies in which the key functional storage elements are implemented in solid-phase materials
Solid-state batteryA rechargeable electrochemical battery that uses a solid electrolyte in place of a liquid or gel electrolyte
Solid-state transformerA power-electronic converter performing transformation and power-flow control; neither an energy source nor an energy-storage device
Solid-state relayA power-electronic switching element; neither an energy source nor an energy-storage device

An energy storage system answers the question of how energy is taken in, retained over time and then returned to the system. A power system, in this taxonomy, answers the question of how conversion and power delivery are performed. These are different functions, and placing them in one class is a terminological error rather than a shorthand.

What makes a power system solid-state

An architecture belongs to the class when all five conditions hold.

  1. The direct conversion into electrical power is performed by stationary materials, structures or electronic devices, without a conventional rotating electromechanical converter.
  2. The system presents an electrical output interface to a user load.
  3. The dominant function of the path is conversion and delivery of power, not the storage of previously received electrical energy.
  4. A buffering or storage element is permitted; its presence neither places a system in the class nor excludes it from it.
  5. The class does not determine the energy source; the source is not a classification criterion.

The third condition carries most of the weight. Without it the definition immediately absorbs storage systems, which formally satisfy every other point, and the distinction drawn in the previous section collapses.

A system is classified by the dominant function of its path, not by an inventory of the elements it contains.

A separate note on combustion. The absence of a combustion cycle is characteristic of most architectures in the class but is not a defining property: a thermal subclass converts a heat flow regardless of how that heat was produced. The property belongs to particular architectures, not to the class.

A solid-state power system is a class, not a single physical mechanism

The class contains several subclasses. What they share is the architecture of the conversion stage, not a common physical effect.

SubclassConversion mechanismCharacteristic application
PhotovoltaicPhotovoltaic effectDistributed generation
ThermoelectricSeebeck effectWaste-heat recovery, autonomous sensors
ThermophotovoltaicPhotovoltaic conversion of thermal radiationHigh-temperature heat conversion
Solid oxide fuel cellElectrochemical conversionStationary generation
ElectrodynamicElectrodynamic conversionInfrastructure power

The list is open. A new subclass does not change the definition of the class, because the class is set by the architecture of the conversion stage rather than by a predefined list of physical effects.

The electrodynamic subclass

The electrodynamic subclass covers architectures in which the conversion stage is built on electrodynamic interaction rather than on a photovoltaic, thermoelectric or electrochemical effect. The term is used here as a taxonomic label, not as a description of the internal construction of any particular system.

VENDOR.Energy’s development is focused on the electrodynamic subclass of solid-state power systems.

Everything specific to the system itself is set out on the pages that own it:

VENDOR System
Canonical classification of the system, product-level naming and current status
How it works
Functional route through the conversion path and product interfaces
Where the energy comes from
Energy attribution and the list of what the source is not
Technology validation
Verification protocol, device boundary and acceptance criteria

How the class differs from adjacent architectures

The table distinguishes functions within a system. It does not assess suitability and does not compare performance.
ArchitectureDominant functionRotating generating stageMeans of electrical conversion
Battery, BESSStorage and subsequent returnNoneElectrochemical storage with power electronics
Diesel gensetGenerationPresentMechanical to electrical
Photovoltaic installationConversion and power deliveryNonePhotovoltaic
Solid-state electrodynamic systemConversion and power deliveryNoneElectrodynamic

Detailed comparisons are held elsewhere: comparisons, including against diesel and against solar plus battery.

Where solid-state conversion systems are used

The field of application is set by the physical subclass rather than by the class as a whole. Photovoltaic, thermoelectric, thermophotovoltaic, electrochemical and electrodynamic architectures address different problems and operate at different scales, from a single autonomous sensor to grid-scale installations.

For infrastructure power, the relevant sites are those where distributed placement, the absence of a conventional rotating generating stage, and direct electrical output into a local power system all matter.

  • Telecom infrastructure
  • Edge sites and distributed computing
  • Utility and water infrastructure
  • Remote industrial assets
  • Local DC infrastructure

Sector scenarios are developed under Solutions. The economic framework is set out on the Economics page.

VENDOR.Energy products

The product layer is kept separate from the taxonomy.

Current classification and system status — VENDOR System.

Fit between the architecture and a specific site is assessed through a structured questionnaire.