Power Control Module for Combined Starter Drive and Power Generation


Under a recent SBIR effort with the Air Force, IS4S developed and demonstrated the benefits of active rectification on paralleling high-frequency turbogenerators. IS4S designed, fabricated and tested a Power Conversion Module (PCM) for 2kW output. The PCM is a bi-directional motor drive and active rectifier module that uses field-oriented control (FOC) algorithms and MOSFET switching technology. The resulting PCM technology can be used for gas turbine engine startup as a motor drive, and it can be used to convert generator three-phase power to DC power for battery charging.

IS4S Flightworthy Turboalternator ECU and Monitoring Software

Synchronizer Power Control Module for Paralleling Multiple Power Generation Sources

    Under a recent SBIR effort with the Air Force and OSD, IS4S performed modeling and simulation of gas turbine power generation systems to determine innovative, efficient methods to synchronize and link multiple turbogenerators for scalable power generation and provide electrical power for ground forces or vehicles. IS4S developed embedded controls for synchronizing and controlling speed and load share between multiple turbogenerators in the presence of a changing load. The Synchronizer with load sharing control was first demonstrated with two sets of electric motor driven alternator (EMDA) hardware for emulating turbogenerator hardware. Subsequently, the Synchronizer Power Control Module was demonstrated using two commercial miniature turbogenerators. The miniature turbogenerators were tested on the bench and packaged in a compact generator chassis to demonstrate a scalable portable power system. The paralleling of generators was demonstrated in both the DC Parallel and Synchronized, Three-Phase configurations.

Electronic Control Unit for Miniature Turbojet Engines

For over two decades, IS4S engineers have been involved in missile and unmanned air vehicle propulsion including rocket engines, internal combustion engines and jet engines. IS4S engineers have developed gas turbine cycle modeling tools and transient simulation models in support of propulsion system development and mission simulation. IS4S performs thermodynamic cycle modeling for prediction of turbine power and fuel consumption at various off-design conditions (operating speed, power output, altitude and temperature). Leveraging this experience, IS4S is currently developing a military ruggedized ECU for a miniature turbojet engine for a ground application.

Power Electronics & Controls

IS4S Flightworthy Ignition Exciter Unit.

IS4S Thermodynamic Cycle Modeling of Turbojet Performance versus Altitude

  IS4S is heavily involved in the development of electronics for command and control purposes for decontamination, obscuration, ground power, and unmanned systems. IS4S specializes in electronics and control systems for gas turbine power generation and propulsion systems at the miniature to small scale. Compared to traditional generator sets, turboalternators offer advantages in size, weight, reliability and attenuated noise level. In support of these systems, IS4S has either developed or is currently developing the following power electronics for several military customers:

  • Remote command and control operability
  • Electronic control unit (ECU) for miniature turbojet engines
  • ECUs for miniature turboalternators (operating above 200k RPM)
  • High-energy ignition exciter for high-tension spark output
  • Power conversion modules (PCMs) for combined startup and power generation
  • Synchronizer power control module for paralleling multiple power generation sources
  • High-speed motor drives


IS4S uses a number of tools for development of power electronics, controls development and packaging. These are listed here:

  • Modeling and simulation of turboalternator and load transients – MatLab®/Simulink®
  • Thermodynamic cycle modeling – Graphical Engine Cycle Analysis Tool (GECAT)
  • Circuit board schematic and layout – KiCad
  • Mechanical design and data management – SolidWorks® CAD and PDM
  • Software development and source code management – Multiple tools used

IS4S Power Control Module for Combined Starter Drive and Power Generation.

​Electronic Control Units for Miniature Turboalternators

     Over the past six years, IS4S engineers have been involved in ECU development for miniature turboalternators for ground power and unmanned ground and air vehicles. Specifically IS4S has developed both ground test and flightworthy ECUs for 1 to 5 kW output turboalternators operating at speeds above 200,000 rpm. IS4S’ parameter-based ECUs are highly configurable (via the CAN bus), perform startup and control, and interface to a supervisory controller (e.g. flight or ground computer) and auxiliary PCM module via CAN communication. Other interfaces include thermocouple sensors, pressure sensors, ignition exciter module, and fuel system components.

High-Energy Ignition Exciter with High-Tension Spark Output

     IS4S developed the Ignition Exciter Module using capacitive-discharge technology to output a high-energy spark for ignition of a high-speed turboalternator. The spark output can be programmed for different spark energy and sparking rates. The spark can be enabled and triggered independently or automatically after power up. Combined with the matching Ignition High Tension Cable, the unit has the following performance attributes: 22-29 Vdc supply, 1.1 to 1.6 Joule output, and 2 to 4 sparks per second.

IS4S Compact and Scalable Three-Phase Power Generation