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OpenVVVF Documentation

OpenVVVF is an open-source Variable Voltage Variable Frequency (VVVF) traction inverter platform. A single control module runs the motor-control firmware and talks to one of several power-stage chassis. The same hardware can serve very different applications - motorcycle, passenger car, industrial drive, or rail - by selecting the right power stage and configuring the safety profile.

This site is the single source of truth for OpenVVVF hardware documentation (including the control-assembly software manual), safety analyses, and validation evidence.

Documentation sections

System architecture

Major blocks

• Control module / control assembly - The reusable dual-MCU control board that runs OpenVVVF firmware. It handles field-oriented motor control, state estimation, diagnostics, and safety monitoring.
• Power stage - The physical inverter assembly that contains the IGBTs, DC-link capacitors, gate drivers, current sensors, and thermal hardware.
• C2 - mid-size, 150 / 200 / 400 V class per DC-link capacitor selection, ~465 A continuous / 600 A peak (60 s).
• Main MCU software - The primary microcontroller firmware; runs the real-time motor-control loop, PWM generation, ADC sampling, communication stacks, and application logic.
• Safety coprocessor software - A separate microcontroller that independently monitors safety-critical outputs and can bring the system to a safe state.
• RTE Studio - The host-side Real-Time Examiner and tuning tool. It connects to the inverter over CAN or Ethernet to log variables, adjust parameters, and run calibration routines.
• Codegen tools - Code and parameter generation tools that keep firmware data structures in sync with the hardware model.

Data flow at a glance

RTE Studio / Codegen
       |
       | CAN / parameter files
       v
Control Module (Main MCU + Safety Coprocessor)
       |
       | PWM / gate-drive / sensor signals
       v
    Power Stage
       |
       | Three-phase output
       v
     Motor

Glossary

General terms

• OpenVVVF - Open-source Variable Voltage Variable Frequency traction inverter platform.
• VVVF - Variable Voltage Variable Frequency. A method for controlling AC motors by adjusting voltage and frequency.
• Traction inverter - A power-electronics converter that turns a DC bus into variable-frequency AC to drive a motor.
• Chassis - A mechanical/electrical form-factor family for power stages (currently C2).

Software terms

• MCU - Microcontroller Unit. The main processor running the motor-control firmware.
• Main MCU - The primary microcontroller on the control module; runs the motor-control loop.
• Safety coprocessor - A separate microcontroller that independently monitors safety-critical outputs.
• RTE - Real-Time Examiner. The host-side tool for logging, tuning, and calibrating the inverter over CAN or Ethernet.
• Codegen - Code/parameter generation tools that keep firmware data structures in sync with the hardware model.
• FOC - Field-Oriented Control. The motor-control algorithm used to drive AC machines.
• PWM - Pulse-Width Modulation. The technique used to synthesize variable voltages from a fixed DC bus.
• VCU - Vehicle Control Unit. A higher-level controller that commands the inverter in a vehicle.

Safety and compliance terms

• HARA - Hazard Analysis and Risk Assessment. A process for identifying hazardous events and assigning safety goals.
• TARA - Threat Analysis and Risk Assessment. The cybersecurity counterpart to HARA.
• FMEA - Failure Mode and Effects Analysis. A bottom-up method for analyzing how component failures affect the system.
• ISO 26262 - Automotive functional-safety standard.
• IEC 61800-5-2 - Industrial-drive safety standard.
• ASIL - Automotive Safety Integrity Level. A risk classification from A (lowest) to D (highest).
• HVIL - High-Voltage Interlock Loop. A safety circuit that detects when HV connectors are unmated.
• Safe state - A defined low-risk state the system enters after a fault.

Electrical / mechanical terms

• DC link - The DC bus capacitors and connections between the battery/supply and the inverter bridge.
• IGBT - Insulated-Gate Bipolar Transistor. The power switch used in the inverter bridge.
• Vdc - DC-link voltage.
• Vll - Line-to-line AC voltage.
• DCR - DC Resistance. The resistance measured at DC, typically used for motor phase resistance.
• LCR meter - Instrument for measuring inductance, capacitance, and resistance.
• Heatsink / baseplate - The metal surface that conducts heat away from the IGBT modules.