Reconnaissance Vehicle — One Panel in Place of an Inverter, DC-DC Converters and a Distribution Panel

A leading Turkish manufacturer of electro-optical surveillance systems approached TEDEG Defence for the power conversion and distribution subsystem of its 4×4 reconnaissance and surveillance vehicle programme. The vehicle powers an electro-optical / infrared surveillance head on a telescopic mast, military radios, a mission computer and the 220 VAC office and test equipment in the operator compartment, all at the same time. Between them these loads called for six voltage levels: 12, 24, 28 and 36 VDC plus 120 and 220 VAC.

On the first prototype vehicle each voltage level came from a separate device: a commercial inverter, several DC-DC converters and a separate fuse and distribution panel. The manufacturer sent TEDEG the field observation report from the prototype vehicle together with the vehicle's electrical architecture requirements. The request was for a military power conversion unit that runs from the vehicle battery, delivers all six voltage levels from one panel, produces pure sine AC and can be blacked out with a single switch on night missions.

Field trials of the prototype vehicle and the integration team's observation report showed clearly where the scattered power architecture fell short:

• Space, weight and cabling: a separate inverter, separate DC-DC converters and a separate distribution panel meant three mounting points and three harnesses in the operator compartment. Each device had its own input cable run back to the battery line.
• Modified sine: the commercial inverter's modified sine output caused heating and noise in the surveillance head's power supply and in the measurement equipment; the sensitive electro-optical electronics needed grid-quality AC.
• Light signature at night: every device had its own status LED, and they could not be switched off together. In surveillance and ambush scenarios the indicator lights in the operator compartment were a risk in themselves.
• Protection and failure points: each device protected itself with its own thresholds; finding out which device an overcurrent on one line had affected meant working at the vehicle.
• Isolation: the DC output returns were bonded to the chassis differently in each device, and ground-loop noise had been reported on the sensor lines.
• Maintenance: replacing a failed converter meant disturbing the wiring of three separate devices.

The manufacturer decided to have TEDEG build a single military panel that would cover all of these requirements.

TEDEG Defence brought the manufacturer's requirements together in the PowerGuard TPS-24DCAC Power Conversion Unit: four regulated DC levels, two pure sine AC outputs, a circuit breaker on every line and BLACKOUT mode in one aluminium panel. The output connector set and the mounting layout were defined to match the vehicle harness and the panel bay in the operator compartment.

The TPS-24DCAC was delivered to the manufacturer's reconnaissance and surveillance vehicle programme and replaced the inverter, DC-DC converters and distribution panel of the prototype vehicle.

• One 17–20 kg panel in place of three separate devices; a single mounting point and a single input cable in the operator compartment.
• Six voltage levels (4 DC + 2 AC) from one panel, each with its own circuit breaker and connector.
• Pure sine AC supplies the surveillance head and the measurement equipment at grid quality.
• With the BLACKOUT switch every indicator is extinguished in one action on night missions, with no interruption to power.
• The removable front panel and modular boards allow maintenance on the vehicle.