Referring to Unicycle Electrical block diagram, both Control Board(CB) and Drive board(DB) needs 12V source.
So what options we have.

1) Method-1 Tap from the 60V battery pack.
Pros: > Available from the battery, no need of extra electronics.

Cons: > Tough to tap from a battery pack..( Alex is it ??? )
> If not done properly leads to ugly looking wiring and loose connections..!!!!
> NO Isolation between CB and DB.
(Alex is it really required, need to validate. My opinion, if routing of tracks and wires of the entire system is done properly it would not be required. But generally its preferred.)

2) Method - 2 60V to 12V Non-isolated buck converter
Pros: > No need to tap from the battery.
60Volts from the battery is converted to 12V and fed to both CB and DB.
Cons: Still no isolation between CB and DB.

3) Method - 3: 60 V to 12V isolated power supply and 60V to 12V non isolated power supply.
Pros: > Isolation between CB and DB is achieved. :-)
Cons: > Extra hardware and cost (Not too much. Worth it for the piece of mind.)

4) Method - 4: 60V to 12 dual isolated power supply.
Pros: >Still Isolation between CB and DB is achieved. :-)
> If designed properly this method would cost us little cheaper compared to Method-3. :-)
> This keeps the 12V line going to the Driver Board also little cleaner.
Cons: > Dont think of any compared to Method-3.

My opinion
If isolation required between CB and DB I prefer Mehod-3 or 4.

If isolation NOT required I prefer at least Method-2, as a worst and last option method-1.

Whats your opinion folks..????

Referring to Unicycle Electrical block diagram, both Control Board(CB) and Drive board(DB) needs 12V source.
So what options we have.

1) Method-1 Tap from the 60V battery pack ...

Control board and Driver board interface
(Referring to the figure attached)

Functionality of each board in brief.
Control Board(CB):
> Reads the signal from the Gyro and calculates the voltage to be applied to the motor using closed loop control.
> Sends this voltage to the Driver board.

Driver Board(DB):
> Decodes the voltage value communicated by CB and applies it to the BLDC motor in the right direction.

The attached image shows the
>Power distribution and
>Signal Interface
between different components.

How should CB communicate with DB????
- The figure shows 2 ways to communicate.
1) PWM and Direction (DIR)
With these 2 lines CB can send voltage and Direction info to the drive.
> Voltage is sent in the form of PWM signal with Duty Cycle changing from 10% (0V to motor) and 90%(Max 60V to motor)
> Direction is sent in the form of binary for CW or CCW.
Pros:
-Less processing either side.
Cons:
-Only voltage and DIR can be communicated.
-Unidirectional

2) UART (Tx and Rx)
>Voltage and DIR info can also be sent using UART lines.
>Data needs to be packed in a particular format in CB and sent to DB.

Pros:
- Data can be bidirectional.
DB can send other data like Motor current and Error status of DB.
Cons:
- Adds processing delay in packing and decoding the data.(in both CB and DB)
- Serial communication itself will have the delay of sending data bit after bit.

So which is best for Volt and DIR communication??
>Among these shortlisted 2 options we need to choose anyone to start with based on some calculations and simplicity to implement.
-Though technically both are simple to implement PWM and DIR method will take less time to complete.
To get the benefit of PWM & DIR(METHOD -1) method over UART (METHOD -2) we need to select the appropriate PWM frequency.
Minimum of 1Khz has to maintained to gain the control loop effectiveness at 1Khz.

Control board and Driver board interface
(Referring to the figure attached)

Functionality of each board in brief.
Control Board(CB):
> Reads the signal from the Gyro and calculates the voltage ...

Please refer to the image

Please refer to the image

MOSFETs used in the Chinese unicycle are SSF7509

MOSFETs used in the Chinese unicycle are SSF7509

Total cost - Rs 5430
1.2 usd per unit
27 usd shipping
There was no customs duty charged on it as it was a small purchase.

Total cost - Rs 5430
1.2 usd per unit
27 usd shipping
There was no customs duty charged on it as it was a small purchase.

Just testing

Just testing

We should be able to set battery low voltage cutoff on the motor driver.

We should be able to set battery low voltage cutoff on the motor driver.

The motor driver should be capable of handling regenerative braking. This will be the way the motor decelerate. If the rate of deceleration is very high, we should be able to burn the power up on a high wattage resistor

The motor driver should be capable of handling regenerative braking. This will be the way the motor decelerate. If the rate of deceleration is very high, we should be able ...

This motor is supposed to work for BLDC motors with 3 sense wires

This motor is supposed to work for BLDC motors with 3 sense wires

One channel PWM to represent the voltage that needs to be applied to the motor.

On digital pin to represent what direction to rotate the motor

One channel PWM to represent the voltage that needs to be applied to the motor.

On digital pin to represent what direction to rotate the motor

The motor driver will receive inputs in the form of SPI data[TTL] or PWM input.

The input signal is supposed to represent the voltage that needs to be applied to the motor.

The motor driver will receive inputs in the form of SPI data[TTL] or PWM input.

The input signal is supposed to represent the voltage that needs to be applied ...

We will have a small MCU on the controller. It will be used for setting the safety parameters specific to each motor. This unit will be controlling the switching the phases for the bldc motor.

It will also be monitoring current drawn by the motors and keeping them under control.

The MCU can also be used for defining custom torque profiles for the controller.

It can be fine tuned for various use cases - like a certain torque profile while running on mud etc.

We will have a small MCU on the controller. It will be used for setting the safety parameters specific to each motor. This unit will be controlling the switching the ...

We want to build a modular hardware. So ideally we want a generic motor driver.

It should be able to run 48V and 60V motors.

It should be able to handle 500Watt motor to 1500watt motor. If possible stretch it to 2000W.

We want to build a modular hardware. So ideally we want a generic motor driver.

It should be able to run 48V and 60V motors.

It should be able to ...

Reliable source (atleast you can order 24 from this based on the price breakout)
1)
http://www.futureelectronics.com/en/technologies/semiconductors/discretes/transistors/mosfets/Pages/5140173-IRFB4110PBF.aspx?IM=0

2) Cheaper option (you can order from this immediately)
https://www.verical.com/html/#!/catalog/product-detail/248053/IRFB4110PBF

Other sources:
1)
http://www.ebay.com/itm/2pcs-IRFB4110-FB4110-POWER-MOSFET-Transistor-TO-220-/191228130255?pt=LH_DefaultDomain_0&hash=item2c8615b3cf#shpCntId

2)
http://www.aliexpress.com/item/10PCS-IRFB4110-TO-220/32214455729.html

3) (cheapest option)
http://www.aliexpress.com/item/Free-Shipping-50PCS-LOT-IRFB4110PBF-IRFB4110-TO-220-100-new-and-original/32235824334.html

Reliable source (atleast you can order 24 from this based on the price breakout)
1)
http://www.futureelectronics.com/en/technologies/semiconductors/discretes/transistors/mosfets/Pages/5140173-IRFB4110PBF.aspx?IM=0 ...