High power DC Servo Drive for underwater vehicles

The i146 is a high-performance custom servo drive, developed to meet requirements of Marine & Subsea market

It has been specially designed for BLDC servo motor control on thrusters and electric propulsion systems on board of subsea vehicles such as manned submersibles, AUV’s, or ROV’s. i146 delivers up to 12 kW continuous power operating with a voltage range between 180 VDC to 300 VDC.

The i146 Servo Drive has been designed as an integral part of a complete underwater propulsion module working in a one (1) atmosphere housing.

Ultra-high efficiency for undersea operation

One of its key features is an optimized 4 Quadrants Non-Simultaneous IGBT commutation algorithm which helps to minimize both switching losses and EMIs. This power stage scheme together with state of the art IGBT modules allows to achieve an overall efficiency > 98%

A special requirement is that the PWM frequency is greater than 16 kHz, avoiding in this way to generate audible noise and providing a smooth operation.

The driver is optimized to operate with a single battery supply for power and logic; it includes a controlled capacitor pre-charge and allows regenerative braking.

It uses digital Hall sensors for both servo motor commutation and velocity feedback loop, avoiding using external feedback devices and therefore simplifying wiring and enhancing durability. Hall sensor inputs are high noise tolerant, allowing reliable operation even when feedback and power cables need to be wired closely in hermetic subsea connectors.

Reliability in mind

Reliability is critical for subsea operations. i146 has been designed for long term operation, selecting the best electronic components according to customer MTBF’s specifications.

The i146 DC Servo Drive incorporates all the power stage, control blocks, communications and I/O boards in a single PCB. Each electronic section has been carefully designed for ruggedness and performance in subsea operation conditions. To minimize EMI and safety issues, the different sections (power, control, feedbacks and I/O) are fully isolated.

Advanced Product features

Feedback:

High noise tolerant Digital Hall sensors

Servo control:

Advanced IGBT’s switching algorithm

PWM frequency 16 kHz for low acoustic noise generation

Communications

CANopen DS301 and DS402 motion profile

CAN isolated port. No need for external power supply

Redundancy: External analog operation for safety control (network failure)

RS485 isolated port for configuration

Rugged design

Power stage, control board and I/O’s are fully isolated

Customer-specific mechanical shape to meet space constraints

Easy maintenance and wiring. Design based on single PCBs