User Manual

Motor Operating Features and Options
86 Advanced Digital Motor Controller User Manual V2.0, July 8, 2019
Global Power Configuration Parameters
PWM Frequency
The power MOSFETs are switched at 16kHz by default. This frequency can set to another
value ranging from 10 kHz to 30 kHz. Increasing the frequency reduces efficiency due to
switching losses. Lowering the frequency eventually creates audible noise and can be in-
efficient on low inductance motors.
Changing the PWM frequency typically results in no visible change in the motor operation
and should be left untouched.
Overvoltage Protection
The controller includes a battery voltage monitoring circuit that will cause the output
transistors to be turned Off if the main battery voltage rises above a preset Over Voltage
threshold. The value of that threshold is set by default and may be adjusted by the user.
The default value and settable range is given in the controller model datasheet.
This protection is designed to prevent the voltage created by the motors during regenera-
tion to be “amplified” to unsafe levels by the switching circuit.
The controller will resume normal operation when the measured voltage drops below the
Over Voltage threshold minus a user definable hysteresis voltage.
The controller can also be configured to trigger one of its Digital Outputs when an Over
Voltage condition is detected. This Output can then be used to activate a Shunt load
across the VMot and Ground wires to absorb the excess energy if it is caused by regen-
eration. This protection is particularly recommended for a situation where the controller is
powered from a power supply instead of batteries.
Undervoltage Protection
In order to ensure that the power MOSFET transistors are switched properly, the control-
ler monitors the internal preset power supply that is used by the MOSFET drivers. If the
internal voltage drops below a safety level, the controller’s output stage is turned Off. The
rest of the controller’s electronics, including the microcomputer, will remain operational as
long as the power supply on VMot is above the minimum voltage specified in the product
datasheet or if Power Control is above 7V.
Additionally, the output stage will be turned off when the main battery voltage on VMot
drops below a user configurable level that is factory preset at 5V.
Temperature-Based Protection
The controller features active protection which automatically reduces power based on
measured operating temperature. This capability ensures that the controller will be able to
work safely with practically all motor types and will adjust itself automatically for the vari-
ous load conditions.
When the measured temperature reaches 5
o
C below the Over temperature limit, the con-
troller’s maximum allowed power output begins to drop by 20% for every degree until the
temperature reaches the Over temperature limit. Above this limit, the controller’s power
stage turns itself off completely. The same applies to MCU Temp at 90
o
C - 95
o
C degrees.
Note that the measured temperature is measured on the heat sink near the Power Transis-
tors and will rise and fall faster than the outside surface.