Variable frequency motor control circuit for Toyota radiator fan
The application of Toyota radiator fans is very common in life, so what is the inverter motor? Is there a close connection with the cooling fan?
The variable frequency motor has DC motor characteristics but uses an AC motor structure. That is to say, although the external access is direct current, the DC-AC variable-voltage inverter control technology is purchased, and the motor body completely works according to the principle of communication. Therefore, the variable frequency motor is also called "self-controlled variable frequency synchronous motor", and the motor has the speed N depending on the set frequency F of the controller.
The drive circuit of the variable frequency motor consists of two parts: the main circuit and the control circuit. Now the two parts have been integrated into the same chip, so that all the control functions of the variable frequency motor can be realized by using one device, which simplifies the circuit structure. With the increasing emphasis on energy saving and noise suppression in the industry, many industrial products tend to adopt brushless motors, which puts higher demands on motor microcontrollers. As a new generation of motor control DSP chips, the cost-effective TMS320C240 is very suitable for this. task.
The three-phase star connection method of the Toyota radiator fan has a variable frequency motor control circuit, and the DC power supply is supplied to the three windings of the motor by the three-phase inverter circuit composed of the MOS tube. At each moment, only one of the three pairs of windings has electricity passing through, generating a magnetic field, then stopping supplying power to the pair of windings, and supplying power to the adjacent pair of windings such that the axis of the magnetic field in the stator rotates in space 120. °, the rotor is subjected to a magnetic force to follow the stator magnetic field for 120° rotation. The voltage is sequentially applied to A+B-, A+C-, B+C-, B+A-, C+A-, C+B-, and a rotating magnetic field is formed in the stator, so that the motor continuously rotates.
Experts in cooling fans know that as long as we disassemble the motor of the Toyota radiator fan, we can see that the Toyota radiator fan is a variable frequency motor, which can be identified from the position of the coil. The inverter motor control circuit board, the control chip will integrate the DSP function and the drive device, simplifying the circuit structure. The motor speed can be changed by programming the control chip.