IR2110 drive control design and DSP implementation of DC motor
With the development of power electronics technology and new permanent magnet materials, DC motors are characterized by their good linearity and excellent control performance in most variable speed motion control and closed-loop servo control systems (such as robots, precision machine tools, automotive electronics, home appliances). Widely used in the field of electrical appliances and industrial processes.
At present, DC motor control digitization has become the mainstream trend, and high-performance motor control algorithms are mostly realized by the main control chip. With the emergence of high-speed, multi-function digital signal processor (DSP), more complex motors are made. Control strategies are implemented. In this paper, TMS320F28335 is the main control chip, IRF530 is the driving chip, and IR2110 is the driving control chip. The H-bridge driving control design is applied to the DC motor. This control has achieved good results and has high use value.
1, DC motor drive principle
2, hardware circuit design
The overall idea of the hardware circuit design is: use PWM wave to control the switch K1, K4 and K2, K3 in Figure 1 to control the forward and reverse of the motor, and change the duty cycle of the PWM wave to make the motor get different voltage. Thereby controlling the speed of the motor.
2.1, the choice of switching components
The switching element can be selected from a bipolar transistor or a field effect transistor. Since the power FET is a voltage controlled component, it has the characteristics of large input impedance, fast switching speed, no secondary breakdown, and the like, and can meet the requirements of high-speed switching action. In this design, all four switches use IR's N-channel enhancement type power MOSFET tube IRF530, which has a drain current of 14A and can withstand a single pulse current of 49A. The maximum voltage is 100V, and its on-resistance is not more than 0.16Ω. Meet the drive requirements.
2.2, the choice of MOSFET gate drive device
IR offers a variety of bridge driver ICs, typically IR2110. The chip is a monolithic integrated driver module for dual-channel, gate-driven, high-voltage, high-speed power devices. The highly integrated level-shifting technology in the chip greatly simplifies the control requirements of the power device for logic circuits. Improve the reliability of the drive circuit. In particular, the upper tube is powered by an external bootstrap capacitor, which greatly reduces the number of driving power sources compared to other IC drivers. This design uses IR's IR2110 as the driver chip.
2.3, the choice of switching frequency
The frequency of the PWM wave will affect whether the motor can output the maximum torque and the smoothness of the torque. The maximum torque is mainly considered here. In order to obtain the maximum output torque, it is necessary to know the direction of the rotor pole, that is, to determine the position of the rotor, which can be ignored for the small DC motor of this design. In order to avoid relatively large noise from the motor, the PWM wave frequency should be outside the range of the acoustic wave as much as possible. On the other hand, due to the inductive nature of the motor winding, the higher the frequency, the greater the inductive reactance, and the higher the frequency will cause the torque of the motor. Become smaller [9]. After analysis and comparison, the final motor frequency determined in this paper is 250Hz. Although there is a certain low frequency noise, the output torque effect is very good.
2.4, the choice of controller
At present, there are many ways to generate PWM waves, which can be generated by a special PWM wave generating chip, or by a microcontroller (such as a single chip microcomputer, ARM, DSP, FPGA, etc.). In this paper, the microcontroller uses TI's TMS320F28335 type DSP, which is the core part of the whole control system. Its performance determines the stability of the whole hardware system to some extent. The TMS320F28335 is a 32-bit floating-point DSP with a working frequency of 150MHz and 12 PWM outputs. 6 of them are high-precision PWM channels, which are ideal for motor control.
2.5, the overall design of the drive control circuit
According to the selection of the above key components, the circuit diagram of the drive control hardware shown in FIG. 3 is designed.
The PWM wave is generated by the PWM of the DSP and then sent to the optocoupler TLP521 via a 180 ohm resistor R5. Since the PWM frequency of this design is not high, the common optocoupler TLP521 has met the requirements.
3, circuit testing
The overall test results show that the DC motor runs smoothly and the control is accurate, meeting the design requirements.
In this paper, the whole process design of H-bridge drive control is applied to DC motor. Power MOSFET chip IRF530 is used as the switching component. IR2110 is used as the gate drive control of MOSFET. PWM signal is generated by DSP and sent to IR2110 through optocoupler and logic control. The floating control of the upper arm driving voltage is successfully performed, and the start-stop and forward-reverse control can be conveniently performed, and the motor runs smoothly and well, and the design purpose is achieved. The drive control circuit presented in this paper is also suitable for other similar applications, and has a large practical reference value.
