Busting three myths of chopper stabilization

 

Brushless DC (BLDC) motor manufacturers often think they need a chopper-stabilized magnetic sensor, but what they actually require is a high-sensitivity part. Joshua and Fred bust the three myths that have led designers to request latching sensors with chopper stabilization and explain why a high-sensitivity bipolar latching Hall effect sensor can increase BLDC motor efficiency.

Sensor manufacturers have historically achieved high sensitivity in bipolar latching Hall effect sensors for BLDC motor applications by using chopper stabilization, a technique used to mitigate sensitivity and stability over temperature for a Hall element. As a result, chopper stabilization has become synonymous with high sensitivity and stability in Hall effect sensors.

Today, with new technologies and processes, magnetic sensor manufacturers can achieve high sensitivity and magnetic stability without using chopper stabilization. This translates into improved sensor performance in terms of faster response time and better repeatability from the sensor.

BLDC motors are highly efficient, delivering more energy per unit compared to brush-type DC motors. These motors are growing in popularity due to the world’s need for greater energy efficiency. BLDC motors use electronic commutation versus mechanical commutation in brush-type DC motors to control power distribution to the motor. Latching Hall effect sensors measure the motor’s position, which is communicated to the electronic controller to apply energy to the motor at the right time and right orientation (see Figure 1). BLDC motors can be used in any application that needs an efficient and quiet motor, ranging from robotics and portable medical equipment to HVAC fans and appliances.

Figure 1: Latching Hall effect sensors can be placed directly inside the motor, at the end of a motor’s shaft, or around a ring magnet attached to the rotor shaft.

BLDC motor manufacturers have moved toward using chopper-stabilized latching sensors for electronic commutation, but what is actually required is a high-sensitivity part that is stable over its specified temperature range. The following discussion will bust three myths that have led designers to request chopper-stabilized bipolar latching Hall effect sensors instead of choosing several other options that can more efficiently commutate the motor.

refer: http://industrial-embedded.com/articles/busting-three-myths-chopper-stabilization/



ACROSSER has provided innovative embedded computer solutions and quality products to over thousands customers on helping them reduce the time-to-market to gain the higher competence and to win the market.