Electronic Speed Controllers, or ESCs, are essential components in the realm of electric propulsion systems and drones. These tiny gadgets function as the motor’s brain, calculating its rotational speed in response to instructions from the throttle controller. Let’s explore the world of electronic speed controller for drone, whether you’re a drone enthusiast or just interested in learning more about these intriguing devices.
What is an electronic speed controller for drone?
An essential part of controlling an electric motor’s speed is an Electronic Speed Controller (ESC). It serves as a bridge between the motor and the flight controller, also known as the transmitter, to provide exact control over the drone’s speed and functionality. Although ESCs are frequently connected to drones, they are also utilized in other applications, such as electric cars and remote-controlled vehicles (RC cars, boats, and planes). There are two types of electronic speed controller for drone: 4-in-1 ESC and Single ESC.
4-in-1 ESC
An 4-in-1 ESC combines four separate ESCs onto a single circuit board, each of which is in charge of managing a different motor. These ESCs and the flight controller frequently have comparable size, which makes stacking and installation simpler. They simplify the soldering and wiring procedure since they require fewer solder joints. The 4-in-1 ESC usually connects with a single wire harness and is mounted underneath the flight controller. However, it’s important to remember that the entire board needs to be replaced if one of the ESCs in the 4-in-1 unit malfunctions. These days, this convenience-tradeoff is less significant because 4-in-1 ESCs have established a solid reputation for dependability.
For different drone sizes with different mounting patterns, 4-in-1 ESCs come in three sizes: 30x30mm, 20x20mm, and 16x16mm. Because of their larger FETs, larger ESCs are often more robust and powerful. The most popular size for 5″ and larger FPV drones is 30x30mm.
Single ESC
Single ESCs are made to control a single motor; this is a less frequent arrangement that was once common. Since each ESC may be replaced separately in the event of damage, their main benefit is their simplicity of replacement. They have better cooling capabilities and enhanced airflow when put on the drone’s arms. However, connecting to a power distribution board (PDB) or “All-in-One (AIO) flight controller” for power supply is typically required when utilizing single ESCs. This method may result in an increase in the drone’s overall weight because it requires more soldering and wiring.
How Does an electronic speed controller Work?
Battery Power: Direct current (DC) from the battery powers the ESC. The motor cannot operate without this power.
Switching System: An alternating three-phase current is created from DC power inside the ESC using a switching system. Through this alternating current, the brushless motor is powered.
Throttle Control: The throttle controller on the car, which is often a component of the remote transmitter, modifies the speed of the motor. The rate at which the switches in the ESC’s circuit open and close is changed by increasing the throttle, which also changes the output power.
Signal Protocols: The ESC receives throttle information from the remote controller via a number of signal delivery protocols, including PWM, Oneshot, Multishot, and Dshot. The drone’s reaction time is impacted by the signal frequency differences between these protocols. Dshot, for example, transmits a digital signal, increasing its accuracy and dependability.
Microcontroller (MCU): The microcontroller of the ESC senses the throttle signal, monitors the motor’s position, and makes sure that acceleration happens smoothly. To get the intended motor command, it pulses the gate driver.
MOSFETs and gate drivers: Metal-oxide-semiconductor field-effect transistors, or MOSFETs, are managed by the gate driver. These parts change the direction and speed of the motor’s rotation by transferring the current to the coils.
I will give a summary of the most widely used ESC firmware in this part.
SimonK and BLHeli
BLHeli and SimonK are two of the most established open-source ESC firmwares for multirotors. Although these are out of date and not found in current ESCs, they should nonetheless be acknowledged for helping to establish the groundwork for FPV drones.
BLHeli_S and Bluejay
The second iteration of BLHeli firmware, known as BLHeli_S, was created especially for ESCs that use faster 8-bit “Busybee” processors. As development attention went to the newer BLHeli_32, the official BLHeli_S firmware is no longer being updated. However, unofficial firmware has surfaced to support the hardware that comes with BLHeli_S, delivering state-of-the-art features and performance on par with the newest and priciest BLHeli_32 ESCs. For best results, I strongly advise updating your BLHeli_S ESC with Bluejay, as he is a noteworthy example.
BLHeli_32
The third and most recent generation of the BLHeli firmware is BLHeli_32 ESC. This version, which was created especially for 32-bit processors, is no longer open source. Even though the BLHeli_32 ESC is significantly more expensive and does not significantly improve performance compared to the previous BLHeli_S ESC, many pilots still prefer to purchase the less expensive BLHeli_S ESC and flash them to Bluejay.
AM32
BLHeli_32 is rivaled by AM32, an open-source firmware that is quite recent. There are ESCs that come pre-installed with AM32 firmware. Now, if you’re curious about what AM32 brings to the table, here are some of its compelling features, straight from its official description:
Open Source firmware
Firmware upgradable via betaflight passthrough (only support G4, F4 and F7 FCs, and make sure your betaflight
firmware is up to date when you try to use passthrough)
Servo PWM, DShot300, DShot600 ESC protocol support
Bi-directional Dshot
KISS standard ESC telemetry
Variable PWM frequency
Sinusoidal startup mode, which is designed to get larger motors up to speed
Stuck motor protection
I think it’s only right to issue a warning before you run off to download the AM32 ESC firmware. Recall that this program is open-source. On the one hand, that’s fantastic as it’s always getting better and more sophisticated. However, as this is a relatively new firmware, there may be bugs and issues that need to be sorted out.
It may be best to continue with the reliable BLHeli32 ESC for the time being if you find debugging and problem-solving to be a little uncomfortable.
Which Firmware for an ESC Should You Select?
Either choice is good because there isn’t much of a performance difference between BLHeli_S ESC (flashed with Bluejay) and BLHeli_32 ESC. Bi-directional DShot is now supported by both firmware, allowing you to use any kind of ESC in Betaflight to enable RPM filtering.
The more recent iteration, BLHeli_32, has more sophisticated capabilities than BLHeli_S, like RGB LED support and ESC telemetry. These qualities are not necessary, though, as they have no effect on flight performance. If you want an ESC that is more future-proof, go for BLHeli_32; if you want value for your money, get BLHeli_S.
What is ESC Protocols?
The motor signal speed between the ESC and the flight controller (FC) is determined by ESC protocols. The following is a list of popular ESC protocols for FPV drones, sorted from the earliest to the newest:
Standard PWM
Oneshot125
Oneshot42
Multishot
DShot (DShot150, DShot300, DShot600)
Now, to save you from getting too lost in the details, the standard ESC protocol for FPV drones is called DShot. For best results with Betaflight, you should always utilize DShot.The number at the end of the names indicates the different speeds offered by DShot. The PID Loop Frequency that you specify in Betaflight determines the speed that you select.
Now that you have a solid understanding of ESC types, protocols, and firmwares, you can choose the best ESC for your FPV drone build. It’s crucial to understand that the newest ESCs available on the market typically offer comparable performance levels, making it difficult to choose incorrectly from the selections included in this guide. To find the ideal fit for your FPV drone, it’s important to put your own demands and preferences first.
