Preliminary Result
Through out this project, i have already obtain the primary result by simulate the new gate driver with optocoupler.
This is a figure of lead-acid battery used in the project. The battery specification are as follow:
Nominal voltage : 12 V
Capacity : 7 AH
This figure shows the DC motor used in this project. The specification of the motor are as follows.
Operating voltage : 24 V
No load speed : 3000 rpm
Rated current : 10 A
Rated output power : 135 W
Arduino Mega ADK as a microcontroller to provide PWM signal and interfacing between controller circuit with DC motor.
Existing Gate Drive Circuit
This is a circuit of an existing gate driver installed in the electric skateboard. As shown in the figure, the controller which is an arduino side is connecting the same grounding with the high side of the circuit. This may cause problems as the current will flow in the same loop and can cause the gate driver IC overheated.
Another problem about this circuit is, there is no resistor connected at the gate terminal of the MOSFET. The resistor purposely to limit the current flow into the MOSFET as the high current may damage it.
New Gate Driver Design
The figure shows a new design of a gate driver circuit with optocoupler to establish a galvanic isolation between the microcontroller and the DC motor.
This is the PWM signal generated from the pulse generator to represent the Arduino microcontroller. It is shown that the voltage peak is 5 V and the duty cycle is about 80%.
This waveform represent the signal of PWM from the output of the gate driver. From the figure, it is shown that the voltage has been amplify to 12 V from 5 V. This circuit can be use as the new gate driver to substitute the old one that lacking in some features.