ELECTRONIC SPEED CONTROLLERS

In this tutorial about electronic speed controllers (ESC) for drones is expalined. It is a hard-working, powerful component in the drone. It is an electronic circuit that controls and regulates the speed of a motor. It connects the flight controller and a brushless motor. As the brushless motor lacks the brush, they use a different way to turn direct current (DC)into alternating current (AC). This is performed by externally, through the use of an ESC.

ESC FIRMWARE:

Most of ESC’s runs on 3 major firmware – Blheli, SimonK, and KISS. SimonK is outdated firmware so that it is not used anymore. But some airplane ESC’s still use thisfirmware. KISS firmware is a closed source ESC which means that KISS firmware is only for KISS ESCs. whereas other firmware is open source. So the most popular choice nowadays is BLheli, as it is a user-friendly interface, oneshot125, and active braking.

As the voltage rating increases the total power of a motor will increase and thus the drone will fly faster as compared to low voltage drone.

COMPARISON BETWEEN BLheli_S and BLheli_32

BLheli_S is the second generation of BLheli firmware developed for ESCs. they are 8bit processors. It has a small step resolution varying from between 512 to 2048 steps. The Signal response delay of BLhelli_S is 1-2ms.

BLheli_32 is the third generation of BLheli firmware. It is the latest firmware written for ESCs. they are 32bit MCU (microcontroller unit) and it is a closed source.

These 32 bit MCU has more processing power compared to the 8-bit processor, so they can achieve faster input signals and lower latencies.

These ESC’s also include a current sensor where you can monitor your current consumption during flight. ESC’s are also capable of other features like controlling light-emitting diode (LED) and changing the direction of motor rotation.

FACTORS TO BE CONSIDERED WHILE CHOOSING ESPs:

Individual or 4 in1 ESCs:

As the name suggests there are typically two types of ESC’s individual and 4 in 1 ESCs.

4 in 1 ESC’s are a combination of 4 individual ESCs. these ESC’s are manufactured to reduce the complexity in wiring and to reduce the overall weight of the drone.

The 4 in 1 ESC’s are low in cost compared to 4 individual ESC’s like the cost of a 4 in 1 ESC is about $50 and cost an individual ESC is $15.

But replacing a 4 in 1 ESC is better than replacing a single individual ESC.

If you are a beginner I recommend you use an individual ESC’s. As your drone might crash often. So you need to replace ESCs. since replacing a single ESC is more cost-effective than replacing 4 in 1 ESC.

Voltage and Current Rating:

The size of a motor decides the current rating of ESCs. So if 2207 sized motor draws a 40A current at full throttle at the ground condition.

The current draw is approximately 20 – 25% lower in air. i.e. if current draw at ground condition is 40A then in the air it draws 32A. But you will not be flying with full throttle whole time. So ESC’s have something called Burst rating.

Burst rating is the maximum amount of current the ESC can handle for a small amount of time without damaging itself.

It is better to get an ESC capable of high current at the cost of size and expense than an ESC that might be damaged by the large current.

Voltage rating determines the maximum amount of voltage an ESC can handle. Low-cost ESC’s are rated up to 4S. But nowadays most ESC’s are rated up to 6S.

Capacitors:

Before few years ESC’s often comes with included electrolytic capacitors. As mini quads gain huge popularity.The size of ESC is reduced, so most ESCs no longer came with large electrolytic capacitors.

Capacitors act to smooth out the power to the drones. Adding a capacitor to PDB (power distribution board) will help absorb power spikes generated by the brushless motors during braking.

The most commonly used capacitors are low ESR capacitors. Adding a capacitor to the battery leads at the PDB can improve performance.

CONCLUSION:

The Electronic Speed Controllers are crucial component of drones. There are hundreds of ESC’s to choose from in the markets. All perform exceptionally with one better over the other. Unless you buy older generation ESC’s you won’t face any problems.