BDS4A-240J-0001\604C2 Kollmorgen Brushless Drive Sinewave Servo Amplifier

The Danaher Motion / Kollmorgen BDS4 Brushless Drive Sinewave Servo Amplifier is divided into four (4) main sections:

1. Fault Diagnostics monitor various signal leads. When a fault condition occurs the fault circuit will become latched, the BDS4will become internally inhibited, the appropriate red LED will become illuminated, and the Drive-Up contact will open indicating that the BDS4 is in its Inhibit mode.

2. The Input/Output interface circuitry is divided into two functions:

(A) Signals to and from the motor andBDS4.These signals are associated with the motor system resolver. A 7.0 kHz excitation signal is generated in theBDS4 and sent to the resolver. Two resolver feedback signals (sine and cosine) are received by the BDS4 and processed by an R/D (resolver-to-digital) converter. The R/D unit generates a digital position word used in electronically commutating the motor and an analog velocity (internal tach) signal to close the servo loop.

(B) Signals to and from the signal source (PLC, CNC, etc.) and BDS4.

There are numerous signals that may interface between the signal source (PLC, CNC, etc.) and the BDS4. These inputs and modes of operation differ with each application.

3. The BDS4 consists of a single velocity loop and three inner current loops. To give precise velocity control, the velocity loop is normally configured as a proportional, plus an integral, plus a derivative gain servo loop. The output of the velocity loop is the current command for the three microprocessor-based current loops.

The heart of the BDS4 is its microprocessor which receives and processes the current command (velocity error) signal from the output of the velocity loop circuit, the position information from the resolver-to-digital converter, and several other signals. After receiving the velocity error, the microprocessor generates three sinusoidal current commands. These current commands are forwarded to the three proportional plus integral current loops, one for each of the three motor phases.

The microprocessor is the key element in the Industrial Drives patented torque angle technique. The microprocessor varies the phase of the currents with respect to motor flux and significantly improves the motor speed-vs-torque profile.

4. The outputs from the three current loop circuits are converted into a 10 kHz pulse width modulation scheme. The modulation is such that the 10 kHz PWM results in 20kHz current ripple in the motor, resulting in very quiet motor operation.

The PWM switching signals are optically coupled to the power stage gate drive hardware for complete electrical isolation. The BDS4 uses IGBT's (Isolated Gate Bipolar Transistors) for the output power stage; allowing high frequency operation.