Motor control

Development of electronics for commutator, DC, BLDC and asynchronous motors.

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One of our basic development and production programs is the development of electronics for commutator, direct current, BLDC and asynchronous motors, used in electric and battery tools. Electronics are produced in the form of modules embedded in plastic trays and inserted into a variety of electrical tools, e.g. angle and straight grinders, drills, circular and oscillating saws, planers, slotting machines, drilling and demolition hammers.

The vast majority of electronics use a microprocessor to control the required functions of the electronics, for which programmers create software according to the customer's requirements. The basic functions of the modules produced by us include soft start, no-load speed limit, speed regulation, motor winding temperature monitoring with a PTC/NTC sensor, motor shutdown in case of overcurrent, switching to cooling speed, monitoring of supply voltage failure, network undervoltage monitoring, LED signaling of functional states, etc.

Nabíječka

Which motors can we control?

Used with most small plug-in power tools

  • Advantages: compact dimensions and ease of regulation, relatively cheap
  • Disadvantages: lower efficiency of the drive and commutator (necessary replacement of carbons)

This is a solution that has already been replaced, but it is still used in applications where there is a requirement for a higher engine torque when the rotor is stationary. Such a start-up is often difficult for drives with a synchronous motor.

  • Advantages: ease of regulation where the motor rotates in one direction
  • Disadvantages: lower efficiency of the drive and commutator (necessary replacement of carbons)
Řízení motorů

These motors are called BLDC or PMSM. The BLDC motor has a trapezoidal voltage waveform and its control is simpler (so-called 6-step). A PMSM motor has a sinusoidal voltage waveform and a vector control method based on the mathematical model of the motor is used to regulate it. It is more efficient than BLDC and its efficiency reaches over 90% in our applications, with large drives efficiency over 95% can be achieved.

  • Advantages : Unlike DC motors, they have no brushes. If the engine is well constructed, it has a very long life. Thanks to the lower voltage, it is possible to achieve very compact dimensions of the control electronics (typically 50 x 50 mm).
  • Disadvantages: problematic start-up when starting up to a heavy load, relative complexity of control electronics, more expensive compared to other types of regulation.

Despite the above-mentioned disadvantages, BLDC and PMSM motors are among the most efficient and are currently widely used in high-quality battery tools due to their long service life and low consumption.

This is another type of brushless motor. Unlike the PMSM motor, it does not have magnets installed in the rotor, but the cage is short-circuited. Thanks to this design solution, this motor is cheaper.

  • Advantages : Longer service life than PMSM because it does not have permanent magnets, which risk demagnetization if improperly controlled. Thanks to its design, it has a high torque even when the rotor is stationary. This is one of the most used drives in households and industry for three-phase machines, as it enables start-up without control electronics.
  • Disadvantages: lower efficiency compared to PMSM motors. Dimensional electronics that have the same properties as electronics for PMSM motors powered from the mains.

Our electronics not only control the motors, they also protect them.

Functions and protections of TESLA control electronics

Žena
Slow start
It serves to limit the currents through the motor during start-up, which increases its service life. The ramp speed can be varied depending on the current flowing through the motor.
Setting the speed with a potentiometer
Regulation depending on the motor speed sensor
Regulation using a virtual speed sensor
Such sensor is usually sensorless algorithms, but it can also be, for example, a motor load map.
Motor cooling mode
In this special mode, the motor will reduce the speed so that the winding can be cooled by the integrated propeller on the motor.
Status signaling
We use operational or service signaling. Operational signaling using LEDs, when the current state of the electronics is displayed. Service signaling informs about a possible HW error. It is possible to use an LCD or OLED display for both types.
Customer-defined actions
The action that occurs is the result of the reaction of one of the protections. This is usually by stopping the motor, going into cooling mode, or stopping and restarting.
Communication
Using communication protocols, it is possible to read and set motor parameters. A common protocol is e.g. MODBUS.
Dust protection
Electronics are normally potted to protect against conductive dust and external environmental influences.
Overcurrent protection
Protects electronics from instant overload.
Short circuit protection
Quick evaluation of the high current flowing through the motor. The response of electronics is usually in microseconds.
Long-term overload protection
The electronics allow a defined short-term overload, but if it lasts for a certain time, the electronics will react to the overload according to the settings.
Thermal protection of electronics
The temperature of semiconductors is monitored using a thermistor. If the value exceeds the limit, the electronics will react in such a way that it is not destroyed by thermal overload.
Motor thermal protection
A temperature sensor is placed in the motor winding. If the given sensor allows temperature monitoring, the electronics can detect it - this can be used to define other advanced functions. More often, however, only information is available if the temperature determined by the sensor's properties has been reached. As soon as the motor overheats, the electronics react accordingly and protect the motor from destruction.

The architecture of the control processors and the circuit solution is crucial for our developers and allows them to adapt to your requirements.

Our priority is to find a quick and quality solution.

We take thorough testing for granted.

All our electronics undergo during production

three-phase testing process

1.Test in the un-soldered state, when the voltage state in the electronics is checked and programming is carried out with the final SW;
2.Test after filling with insulating PU material at mains voltage;
3.Statistical selection of electronics and their control through the Quality Control Department.

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