The EC-C1200 inverter's connections include a SYNC link, which allows a fast data transfer directly between two inverters. The main purpose for the SYNC connection is resolver signal sharing, for example in a dual motor inverter setup. The SYNC link allows the inverter which has a resolver connected (referred to as the "resolver master") to share the measured resolver signal also to the other inverter ("resolver slave"). This allows running both inverters in closed-loop control, improving the operation and efficiency of the system. In a quad winding/inverter setup, two separate SYNC links can be used to form two pairs of inverters, each with their own resolver (+RES2 option required for the motor) to have full closed-loop control for all four inverters running the motor.
Setting up the resolver signal sharing can be done via the inverter parameters:
- In firmware version 11, the resolver sharing is enabled by setting the parameter Synchronization mode (1.4.1.1) in parameter group 1.4 Converter paralleling to "Resolver sharing master" for the inverter which has the resolver connected, and "Resolver sharing slave" for the other inverter.
- In firmware version 7, the resolver sharing setting can be found in parameter group system under the parameter sync_mode (1001.1029) and can be enabled by choosing "Synchronization master" for the inverter with the resolver connected and "Synchronization slave" for the other inverter.
In case the motor is running in high field weakening, and a difference between the master and slave inverters' torque or current is observed, the sync link delay can be compensated to reduce the difference.
For the physical connections and instructions for wiring of the SYNC link, see the SYNC link physical layer article. Note that the SYNC cable between inverters has a maximum length of 0,5 meters.
A full guide for the resolver calibration is available from Danfoss Editron.