CN202495903U - Brushless dc motor driver with medium voltage and high rotating speed - Google Patents

Abstract

The utility model provides a medium-voltage high-speed brushless DC motor driver, which drives the motor to rotate through a high-frequency PWM modulation signal. The motor transmits the collected motor rotor information to the MCU microprocessor through the detection circuit. The MCU microprocessor can accurately collect the rotor position signal and the PWM duty cycle adjustment with a frequency not less than 1KHz by using a sampling signal with a frequency not less than 120KHz. signal, the system can precisely control the motor speed by controlling the duty cycle of the PWM modulation signal. A gate drive circuit that is turned on or off, so that the power MOSFET can be turned on or off quickly under the drive of a high-frequency PWM modulation signal. The utility model not only has a simple structure, but also has good control characteristics and high work efficiency, so that the maximum rotating speed of the motor is improved.

Description

Medium Voltage High Speed Brushless DC Motor Driver

technical field

The utility model relates to a medium-voltage high-speed brushless DC motor driver.

Background technique

The brushed DC motor has the characteristics of large torque, hard mechanical properties, and high efficiency, but its speed is generally not very high due to the existence of brushes and commutators. Although the speed of induction motors can reach very high, the torsional torque of such motors is generally relatively small. Since the brushless DC motor has no limitations of brushes and commutators, it has the characteristics of large torsional torque, hard mechanical characteristics, high efficiency and high speed of the induction motor of the brushed DC motor, so there is no Brushed DC motors have become one of the most promising motor products. Most of the common high-speed motor controllers are realized by changing the frequency of the driving voltage through a frequency converter. This kind of frequency converter has the disadvantages of low efficiency and low control motor speed. At present, domestic research on brushless DC motor drivers mainly focuses on low- and medium-speed brushless DC motor drivers, while there are not many studies involving high-speed brushless DC motor drivers. The medium-voltage high-speed brushless DC motor driver is mainly realized by selecting power electronic devices with higher switching frequency and withstand voltage value, more advanced hardware circuit design and more reasonable control algorithm.

Contents of the invention

The purpose of the utility model is to provide a medium-voltage high-speed brushless DC motor driver, which uses pulse width modulation technology to control the brushless DC motor. Its overall structure is simple, its control characteristics are good, and its work efficiency is high. The maximum speed of the motor.

The technical scheme provided by the utility model is:

A medium-voltage high-speed brushless DC motor driver, which includes an MCU microprocessor, a high-speed optocoupler circuit, a gate drive circuit, an inverter circuit, a motor, a detection circuit, and a rectifier circuit, and the MCU microprocessor sends a pulse width The modulation signal is sent to a high-speed optocoupler circuit, and the high-speed optocoupler circuit is used to isolate the gate drive circuit from the MCU microprocessor. The gate drive circuit sends a drive control signal according to the received pulse width modulation signal, and the drive The control signal is sent to the inverter circuit, and the AC power is rectified by the rectifier circuit and then input to the inverter circuit. The inverter circuit sends a drive voltage to the motor according to the received drive control signal to drive the motor to work. The detection circuit detects the motor The speed signal and the motor rotor position signal are sent to the MCU microprocessor.

The system can detect the position of the motor rotor through the detection circuit, then the MCU microprocessor determines the commutation time, calculates the rotor speed, and then sends out the corresponding pulse width modulation signal (PWM modulation signal) for controlling the rotor speed, PWM modulation After the signal passes through the gate drive circuit, it can quickly drive the MOSFET device in the inverter circuit to turn on and off. The AC power is rectified by the rectifier circuit and then becomes a DC power source. The PWM modulation signal sends out the driving voltage to drive the motor to work, ensuring that the motor works at a stable speed, and the speed can be accurately controlled by the MCU microprocessor by controlling the duty cycle of the PWM modulation signal.

As a supplement to the above technical solution, the electronic device in the inverter circuit is a MOSFET device with a relatively high driving voltage, the sampling frequency of the detection circuit is not less than 120KHz, and the frequency of the PWM modulation signal is not less than 1KHz.

As a supplement, the high-speed optocoupler circuit includes a high-speed optocoupler, and the speed of the high-speed optocoupler is not lower than 10Mbit/s.

Compared with the solutions in the prior art, the utility model has the advantages of:

1. The utility model drives the motor through a high-frequency PWM modulation signal. The motor transmits the collected motor rotor information to the MCU microprocessor through the detection circuit. The MCU microprocessor can accurately collect the rotor position signal by using a sampling signal with a frequency of not less than 120KHz. The MCU microprocessor generates a frequency of not less than 1KHz. PWM duty cycle adjustment signal, the system can precisely control the motor speed by controlling the duty cycle of the PWM modulation signal, and realize high-frequency sampling and low-frequency control of the motor speed. To work normally at high switching frequency, a gate drive circuit that can quickly drive MOSFET on or off is added to the front end of the inverter circuit, so that the power MOSFET can be quickly turned on or off under the drive of high frequency PWM modulation signal broken. The utility model not only has a simple structure, but also has good control characteristics and high work efficiency, so that the maximum speed of the motor is improved;

2. The utility model adds a high-speed optocoupler circuit between the gate drive circuit and the MCU microprocessor, and the high-speed optocoupler circuit isolates the PWM modulation signal output by the MCU microprocessor from the high-voltage part, reducing the high-voltage part The interference to the control signal improves the stability and reliability of the system work.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the utility model is further described:

Fig. 1 is a structural principle block diagram of the utility model.

Detailed ways

The above solution will be further described below in conjunction with specific embodiments. It should be understood that these examples are used to illustrate the present invention and not to limit the scope of the present invention. The implementation conditions used in the examples can be further adjusted according to the conditions of specific manufacturers, and the implementation conditions not indicated are usually the conditions in routine experiments.

Example:

The medium-voltage high-speed brushless DC motor driver described in this embodiment includes an MCU microprocessor, a high-speed optocoupler circuit, a gate drive circuit, an inverter circuit, a motor, a detection circuit, and a rectifier circuit. The pulse width modulation signal sent by the device is sent to the high-speed optocoupler circuit, the high-speed optocoupler circuit is used to isolate the gate drive circuit from the MCU microprocessor, and the gate drive circuit sends a drive control signal according to the received pulse width modulation signal , the drive control signal is sent to the inverter circuit, the AC power is rectified by the rectifier circuit and then input to the inverter circuit, and the inverter circuit sends a drive voltage according to the received drive control signal and sends it to the motor to drive the motor to work. The detection circuit detects the motor speed signal and the motor rotor position signal and sends the obtained signal to the MCU microprocessor.

The electronic device in the inverter circuit is a MOSFET device with a relatively high driving voltage.

The motor transmits the collected motor rotor position information to the MCU microprocessor through the detection circuit. In the MCU microprocessor, two kinds of interrupts with different priorities are used to realize the sampling frequency interrupt (sampling signal) and the pulse duty cycle adjustment interrupt (PWM duty cycle modulation signal). Higher priority interrupts can generate a sampling signal with a frequency not less than 120KHz. Through this high-frequency sampling signal, the position signal of the rotor can be accurately collected, which can not only achieve the purpose of quickly and accurately determining the commutation time of the motor, but also Real-time acquisition of motor speed can be realized; lower priority interrupts generate a PWM modulation signal with a frequency not less than 1kHz, and the system can precisely control the motor speed by controlling the duty cycle of the PWM modulation signal. In this way, the system can detect the position of the motor rotor through the detection circuit, and then the MCU microprocessor determines the commutation time, calculates the rotor speed, and then issues the corresponding speed control command to adjust the amplitude and output of the motor drive voltage output by the inverter circuit. Frequency, and finally achieve the purpose of adjusting the motor speed.

Since the MOSFET device in the inverter circuit requires a high driving voltage and has a certain capacitive input impedance, it is necessary to use a driving source with a small internal resistance to quickly charge and discharge the gate capacitance to ensure that the gate-source voltage is stable. Sufficiently steep front and rear edges, that is, to make the gate-source voltage reach above the threshold or drop below the threshold in the shortest possible time, so that it can achieve the purpose of fast turn-on or turn-off. In order to make the MOSFET device meet the above conditions, a gate drive circuit that can quickly drive the MOSFET device is added to the front end of the inverter circuit, so that the power MOSFET can be quickly turned on or off under the drive of the high-frequency PWM chopping signal.

A high-speed optocoupler circuit is added between the gate drive circuit and the MCU microprocessor to isolate the PWM modulation signal output by the MCU microprocessor from the strong current part, which reduces the interference of the strong current part on the control signal and improves the efficiency of the control signal. Stability and reliability of system work. Since the frequency of the output PWM signal is as high as 120KHz or more, the waveform of the high-frequency PWM signal will produce a certain degree of distortion when it passes through the optocoupler circuit. The smaller the impact on the system, the smaller the impact on the system. Therefore, in order to minimize the impact of the distortion of the PWM signal waveform on the system, the utility model uses a high-speed photocoupler with a speed of not lower than 10Mbit/s.

To sum up, in this embodiment, the motor is driven by a high-frequency PWM modulation signal. The motor collects the collected motor rotor information through the detection circuit. The MCU microprocessor uses a sampling signal with a frequency of not less than 120KHz to accurately collect the position signal of the rotor. The MCU microprocessor generates a PWM with a frequency of not less than 1KHz. Duty cycle adjustment signal, the system can precisely control the motor speed by controlling the duty cycle of the PWM modulation signal, realizing high-frequency sampling and low-frequency control of the motor speed, in order to enable the MOSFET device in the inverter circuit to operate at high To work normally at the switching frequency, a gate drive circuit that can quickly drive the MOSFET is added to the front end of the inverter circuit, so that the power MOSFET can be quickly turned on or off under the drive of the high-frequency PWM modulation signal. The utility model not only has a simple structure, but also has good control characteristics and high work efficiency, so that the maximum rotating speed of the motor is improved.

The above examples are only to illustrate the technical conception and characteristics of the present invention, and its purpose is to allow people familiar with this technology to understand the content of the present invention and implement it accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention shall fall within the protection scope of the present invention.

Claims (5)

1. press high rotating speed brshless DC motor driver in one kind; It is characterized in that; It comprises MCU microprocessor, high speed photo coupling circuit, gate drive circuit, inverter circuit, motor, testing circuit, rectification circuit; Said MCU microprocessor sends pulse-width signal and delivers to the high speed photo coupling circuit; Said high speed photo coupling circuit is used for gate drive circuit and MCU microprocessor are isolated; Said gate drive circuit sends drive control signal according to received pulse-width signal, and said drive control signal is sent into inverter circuit, and AC power is handled back input inverter circuit through the rectification of rectification circuit; Inverter circuit sends driving voltage according to received drive control signal and sends into motor in order to drive motors work, and said testing circuit detects rotating speed of motor signal and motor rotor position signal and the gained signal is sent to the MCU microprocessor.

2. press high rotating speed brshless DC motor driver in according to claim 1, it is characterized in that what electronic device was selected for use in the said inverter circuit is the MOSFET device with higher drive.

3. press high rotating speed brshless DC motor driver in according to claim 1, it is characterized in that the sample frequency of said testing circuit is not less than 120KHz.

4. press high rotating speed brshless DC motor driver in according to claim 1, it is characterized in that the frequency of said PWM modulation signal is not less than 1KHz.

5. press high rotating speed brshless DC motor driver in according to claim 1, it is characterized in that said high speed photo coupling circuit comprises high-speed photoelectric coupler, the speed of said high-speed photoelectric coupler is not less than 10Mbit/s.