30kVA 3 Phase Static Inverter + AVR


The 30kVA Inverter is an AC to AC Module capable of producing a 400VAC line-line sine-wave, nominal 50-60Hz, 3 phase output from a 3 phase 35-115Hz variable frequency, variable voltage input.

The Inverter has an optional front end Automatic Voltage Regulator (AVR) Module. This enables the system to regulate the output voltage of a Diesel Machine by directly driving the generator field excitation current.

Note that the Inverter output is not an MEN equivalent supply.

The system is non-isolated and supports external serial port (RS232) access.

This system is ideally suited to traction environments, where it can either control the auxiliary diesel generator, or alternatively regulate an alternator connected to the main traction engine to ensure a stable supply for all in-carriage/railcar auxiliary 230V/400V loads. It is also readily adaptable to other applications.

The inverter and all associated components are rated for a 1200V DC bus, with the Static Inverter IGBT modules rated at 1700V. This is required to handle the load/speed changes on the main traction engine as the driver adjusts speed throughout the journey.

The Inverter's communications can be adapted to interface with any on-board/external monitoring systems as a dedicated add-on.

The Inverter + AVR contain live data logging for both normal operating behaviour and also recording any observed trips/external aberrant conditions. All faults/trips are recorded and accessible.

The system includes a Differential Filter Block and a Common Mode Filter Block.

    Technical Features

    • Automatic Voltage Regulator (AVR) for 3-phase Alternator
    • 1200V DC bus withstand
    • 1700V IGBT 3-phase Power Stage
    • 400V 50Hz Sinusoidal Output Waveform, with output good LED indicator
    • Fan Forced Cooling
    • DC link voltage monitoring
    • Low losses & hence high efficiency operation
    • Modular design for easy maintenance
    • Enhanced DC protection through Communications between AVR and Inverter
    • Galvanic Isolation between External Control and Power Circuitry
    • Comprehensive Internal Registers containing Inverter Parameters
    • 3 Level Security Protection of Inverter Parameters
    • USB 2.0 full speed serial port
    • LED Status
    • Differential Filter Block
    • Common Mode Filter Block
    • Optional interface support for on-board data communications systems

    In-built Protection

    • Input current limiting facility
    • Input and Output Over Current Protection
    • Output Short-Circuit Protection
    • Input Under & Over Voltage Protection
    • Heatsink Over Temperature Protection
    • Provision of fault memory recording for diagnosis & subsequent fault analysis
    • Fault Lockout on Permanent Fault Detection with external Fault Indicator
    • Auto-restart on fault elimination (dependent on fault type and frequency of recurrence)
    • Internal Contactor(s) Failure
    • Communications Failure (RS485 mode)
    • DC Bus to AC Voltage imbalance
    • Fast Reaction to Input DC over voltage to enable ride-through
    • Power Stage Gate Fault Detection


Technical Specifications


Inverter + Automatic Voltage Regulator (AVR)
Input (AC I) Voltage 350 Vrms Minimum, 1200 Vpeak Maximum, 3 Phase
(400 V +/- 15%, 415 V +/- 15%)
Input Frequency 35-115 Hz
Power Rating 30 kVA maximum
Voltage Output 400 Vrms nominal, 3 Phase (open loop - load Regulation 5%)
Sinusoidal output with Differential Filter Block and Common Mode Block
Output Frequency 50 Hz ± 0.5 Hz
Power Factor Control Fully controllable from 0 to 1, leading and lagging
DC Bus Voltage 550-750 V (supports 150 V DC Start in Modes: OL, CL Only)
Switching Frequency 10 kHz
Inverter Efficiency >98%
AVR - Output Voltage 0 - 110 VDC
AVR - Output Current 0 - 2 ADC
Battery Input 10 - 35 VDC, with On/Off clean contact input
Auxiliary Supply 0 - 300 VAC, 1 Phase, 35 - 115 Hz (alternator auxiliary output)
External Communications USB 2.0 (panel access - via Lexan panel))
Differential Mode Filter Block
Definition 3-phase LC (Inductor-Capacitor) Filter Module
Inductors 700 μH, 40 A
Capacitors 20 μF, 310 V X2
DC Bus Capacitance Block
Definition 6 off Series Connected DC Bus Capacitors
Connected in a series (3 off) / parallel (2 strings) configuration
Capacitance 3300 μF, 450 V
Discharge Resistors 10 kΩ, 10 W
Common Mode Filter Block
Definition 3-phase Common Mode Filter Module
Inductors ~10 mH, 40 A
Capacitors 0.047 μF, 310 V X2


Main Enclosure - Inverter + AVR
Dimensions (mm) L: 520 mm
W: 408 mm
H: 250 mm
Weight 18 kg (Approx.)
Cooling Medium  Forced air cooling
Mounting 6 x M8 holes at 320 x 130 mm Separation
Differential Mode Filter Block
Dimensions (mm) L: 340 mm
W: 158 mm
H: 171 mm
Weight 10 kg (Approx.)
Cooling Medium  Natural cooling
Mounting 4 x M8 holes
DC Bus Capacitance Module
Dimensions (mm) L: 400 mm
W: 200 mm
H: 400 mm
Weight 4 kg (Approx.)
Cooling Medium  Natural cooling
Mounting Underslung - flexible depending on application
Common Mode Filter Module
Dimensions (mm) L: 225 mm
W: 150 mm
H: 149.6 mm
Weight 6 kg (Approx.)
Cooling Medium  Natural cooling
Mounting 4 x M8 Holes


Operational Status
Active Monitoring / Software Protection Current Limiting
Input (AVR Mode)
Over Current Input + Output
Short Circuit Output Protection
Over Voltage Input
Under Voltage Input
Voltage Control Input (AVR), Output (Inverter)
Heatsink Over Temperature Hysteresis Protection
DC Link Voltage Imbalance Optional (only 1 voltage input available)
SMPS Failure Detection Yes
Gate Driver Failure Detection Yes
Semiconductor Device Failure Detection Yes
Alternator Phase Loss Yes
Contactor Failure Detection Yes
DC / AC Voltage Imbalance Checks for No DC when both AC and contactors closed
Field Supply Over Voltage Detection (AVR) Yes
Field Over Current Detection (AVR) Yes
Battery Voltage Detection Over and Under
Generator Speed Optional Over-speed detection
Communications Inter-processor failure
Status LEDs - Inverter 30kVA_LED_INV
Status LEDs - AVR 30kVA_LED_VRC


Operating Temperature Range -20°C to 55°C
Humidity 5% - 95% non-condensing
Cooling Fan Forced
IP Rating 20