What is the Steady Speed Mode of Micro Pump?

This paper focuses on the speed stabilization mode of brushless motor micropump. Compared with the brushed motor pump, the brushless DC motor pump has the advantages of small electromagnetic interference, long life and low noise. From the aspect of steady speed, it also has the characteristics of high steady speed accuracy, which is directly related to the stable accuracy and adjustment accuracy of the output flow of the micro pump. Steady speed method of brushless motor micropump:

1. The voltage stability mode is to stabilize the input voltage at a constant value by installing the voltage stabilizer and other equipment with a large voltage fluctuation to ensure the constant speed of the brushless motor. This way is simple to operate, but if the voltage stabilizer fails, it will reduce the performance of the brushless motor.

2. Electronic speed regulation Using advanced electronic technology to adjust the driving current of the motor to control the speed of the motor. This method has the advantages of high accuracy, good effect and high reliability, but it requires professional maintenance and debugging.

3. Mechanical transmission mode is mainly to control the speed of the brushless motor by increasing or reducing the gear diameter of the pump. This way is simple to operate, but the accuracy is not high, easy to fluctuate.

The brush DC motor is directly driven by the DC power supply. When the steady speed is required, a special integrated block can be used, and the feedback signal is taken from the reverse potential of the rotor of the micro pump motor. When the steady speed is needed, the drive IC with steady speed function can be used, or the steady speed stabilization circuit FG (Frequency Generator) with steady speed function IC can be used, called the frequency generator. It is actually a device that transforms the magnetic pulse signal into synchronous electrical signal, and plays the role of electromagnetic coding. This paper introduces the speed stabilization principle of using brushless motor micropump.

Speed stability principle in the use of micro gas pump, micro water pump, with brushless motor as the pump speed feedback signal can form a voltage servo circuit or locked servo circuit, also can form a mixed speed stability circuit with voltage servo and locked servo at the same time, which depends on the whole system on the flow stability accuracy requirements.

(1) The speed stabilization principle of the same voltage and service circuit

It is an important electronic circuit, which can keep the output voltage stable. It is achieved by making a comparison and feedback on the phase difference between input and output. This circuit can be applied in many different applications, such as DC voltage power, AC power, AC voltage power, etc. The principle of steady speed is to compare the reference voltage with the output voltage, and to adjust the output voltage according to the comparison results to reach the desired stable voltage level. This comparison can be done in a variety of different ways, common ways including phase comparison and voltage comparison. The output frequency of the micropump pulse signal is proportional to the speed of the pump motor. The signal works through the frequency and voltage converter, and the voltage is proportional to the speed. The level enters the comparator for comparison with the reference voltage. The comparison result is calculated and the control signal is adjusted to achieve the purpose of steady speed.

(2) Steady speed principle of the locked servo circuit

It is a common feedback control system, which realizes the control of the system stability through the phase difference between the feedback signal and the reference signal. The stability principle is based on the basic principle of signal phase comparison and feedback control to realize the synchronous stability of circuit output waveform. The reference and feedback signals undergo phase comparison through the phase detector to obtain the phase difference signal. The phase difference signal is then amplified by the control circuit and applied on the output signal so that it remains in phase with the reference signal. In this way, a synchronous and stable control of the output signal can be achieved. Based on the idea of signal synchronization control, the parameters such as frequency and phase can be accurately controlled and adjusted. The signal frequency of the micropump is directly proportional to the rotational speed of the pump motor. The signal is entered into the phase comparator through the waveform shaping circuit and compares with the reference frequency, and the comparison result is sent through the integration circuit into the amplifier to adjust the control signal, so as to achieve the purpose of steady speed.

Features and Applications

(1) Using speed feedback principle to stabilize speed is a classic theory, using speed generator in the early years is a typical example. At present, there are often a speed sensor to obtain the pump speed signal example, but this speed stabilization method is relatively cumbersome, the volume is large, the volume of the speed stabilization method is significantly reduced, and the signal frequency can be done very high, which is easy to effectively ensure the accuracy of speed stability.

(2) the steady speed mode of brush motor micro pump is not widely used, because the poor steady speed effect, large electromagnetic interference, short life and many other defects cannot be overcome. At present, the volume of DC brushless motor can be very small, like our brushless motor, the life and speed accuracy can be improved by an order of magnitude, as for electromagnetic interference performance and brush motor pump is a world of difference.

The above are some professional knowledges on the steady speed of the micro pumps by VSD Motors. For more relevant information, please contact us.