Quality Motor Controller

Votes: 0
Views: 196

Tired of needing to patch the machine so it is compliant? Using shielded cables and adding ferrite for EMC and additional external relays for safety, only to discover that you still need to add additional shielding to pass? This all comes after a long period of creating the movements (application software) and tuning the motor. Even the mechanical design had to change to add the necessary heat sink.

How about a motor drive that reduces all that? Or better still, tries to eliminate it. Meet the QD25M06ECA drive from QDrives. It has quality as the primary design requirement.

Quality, or the lack thereof, are generally noticed by many small issues. Let's take a look at four more distinct features.


Efficiency – saving energy. Not only for the environment, but also save money and reduce heat generation. The highest efficiency is gained not just in the drive, but taking the whole system – motor, drive, power supply and filters.

With 100kHz PWM and current loop, even motors with the lowest inductance can still be controlled smoothly. The high frequency reduces the ripple current that causes the motor to heat up. It also keeps the position more stable when stationary.


FOC (Field Oriented Control), used from low to high speeds, keeps the torque more constant and improves the speed and position accuracy. It also improves the efficiency of the motor and reduces noise and vibration.

What good is a high speed current loop without a fast velocity and position loop? So either 2kHz or 10kHz velocity loop is applied (depending on feedback resolution). Fieldbus communication (i.e. EtherCat, CANopen or ProfiNet) is processed in sub millisecond. On the fly changes of acceleration in an S-curve profile? No problem.


EMC (Electro Magnetic Compatibility) usually is checked at the end of the project. When the wiring, components and functionality is ready, the complete system can be tested. At that point, changes to the system take a lot of effort and are costly. Not to mention project delays.

Drives and motors are common sources for EMC noise. QDrives designs their drives to have very little EMC noise.


Last but not least – safety. Safety can be needed in different ways: simply switching off the supply (STO or Safe Torque Off) or actively stopping and either disabling the motor or keeping it in position. Naturally, there are other safety aspects such as over speed, over temperature, communication problems, etc. The QD25M06ECA has two microcontrollers and two STO inputs. Each microcontroller monitors one STO input and the other microcontroller. Both can switch off the drive, allowing SIL3 for STO. The STO inputs are configurable to allow the other types of safety.


Voting is closed!


  • Name:
    Rene De Nooijer
  • Type of entry:
  • Profession:
    Business Owner/Manager
  • Rene is inspired by:
    A lack of quality with existing motor drives. Manufactures not listening to customers with complaints about it.
  • Software used for this entry:
    LTSpice, Altium, GCC, SimScale, FreeCAD, Designspark Mechanical
  • Patent status: