A motor servo power drive circuit

Abstract

The present invention relates to the technical field of antennas in motion, and in particular to a motor servo power drive circuit, comprising a power supply circuit, a main control single chip microcomputer, a triangular wave generating circuit, a current sampling circuit, a MOSFET drive circuit and a PWM wave generating circuit; the power supply circuit is used to provide power; the main control single chip microcomputer is used to output a control voltage; the triangular wave generating circuit is used to generate a triangular wave signal; the current sampling circuit is used to detect the current flowing through the circuit inside the motor and output two detection voltages; the MOSFET drive circuit is used to drive the motor to rotate; the PWM wave generating circuit is used to generate two limit signals after superimposing the input two detection voltages with the control voltage, and then compare the two limit signals with the triangular wave signal, and finally generate two PWM signals and output them to the MOSFET drive circuit. The present invention has a fast response speed for driving the motor and high precision.

Description

Technical Field

[0001] The invention relates to the technical field of servo circuits, and in particular to a motor servo power drive circuit. Background Art

[0002] Satellite communication systems are divided into two categories. One is the static communication system, which is mainly used for receiving satellite digital television. The other is the mobile satellite communication (i.e., mobile communication) system, which is used for communication between vehicles, ships, aircraft and other constantly moving antenna carriers and satellites. The former is mainly used in areas where cable digital TV signals cannot cover, or as a satellite TV signal transmission master station. In these applications, since the antenna is always in a static state, the fixed satellite antenna receiving system only needs to adjust the azimuth and elevation angle of the antenna to align the antenna with the satellite to conveniently receive satellite signals. In the latter, since the antenna carrier is always in constant motion, the antenna posture is constantly changing. Under these circumstances, the antenna on the carrier cannot be accurately aligned with the satellite and cannot receive satellite signals. In order to ensure uninterrupted and stable communication between the receiving station and the satellite, mobile communication technology is the most important, and the key technology of mobile communication technology is a fast, stable and reliable servo control system.

[0003] The core of the servo control system is to construct a stable platform so that the antenna on the moving carrier can be unaffected by external disturbances and always keep the spatial pointing direction of the antenna unchanged. The movement of the carrier is mainly disturbed by two aspects: 1) angular motion interference of the carrier; 2) long-distance linear motion interference of the carrier. The perturbation of the satellite can be tracked through the satellite downlink signal, while the movement of the carrier is mainly achieved by tracking the isolation of the carrier movement and tracking and capturing the satellite signal on the basis of stability, so as to achieve reliable satellite communication during the movement of the carrier. Therefore, the quality of the servo control system directly affects the communication quality of the entire vehicle-mounted mobile communication system.

[0004] Disadvantages of existing servo drive technology:

[0005] 1. The existing technology realizes PWM wave output through software programming, and requires a driver to drive the external MOS tube. The tracking accuracy of the driving circuit to control the DC motor in this solution is relatively poor and cannot meet the tracking accuracy requirements. At the same time, the software programming requirements are high (poor accuracy).

[0006] 2. The existing technology is that the motor driver directly drives the DC motor after the control signal output by the MCU is processed by calculation. During the control process, the response speed of the motor cannot keep up and the tracking performance is poor (poor response speed). Summary of the invention

[0007] The present invention provides a motor servo power drive circuit for solving the problems in the prior art. The present invention has fast response speed and high precision.

[0008] In order to solve the above technical problems, the present invention adopts the following technical solutions: 1. It includes a power supply circuit, a main control microcontroller, a triangular wave generating circuit, a current sampling circuit, a MOSFET driving circuit and a PWM wave generating circuit; the power supply circuit is used to provide power; the main control microcontroller is used to output a control voltage; the triangular wave generating circuit is used to generate a triangular wave signal; the current sampling circuit is used to detect the current flowing through the circuit inside the motor and output two detection voltages; the MOSFET driving circuit is used to drive the motor to rotate; the PWM wave generating circuit is used to superimpose the two input detection voltages with the control voltage to generate two limit signals, and then compare the two limit signals with the triangular wave signal, and finally generate two PWM signals and output them to the MOSFET driving circuit.

[0009] Preferably, the MOSFET driving circuit is connected to a flying car protection circuit, the input end of the flying car protection circuit is used to receive the speed signal of the motor, and the output end of the flying car protection circuit is respectively connected to the main control microcontroller and the MOSFET driving circuit.

[0010] Preferably, a voltage discharge circuit is provided between the power supply circuit and the MOSFET drive circuit, and the voltage discharge circuit is used to eliminate the reverse electromotive force generated when the motor stops rotating.

[0011] Preferably, the MOSFET driving circuit is connected to a voltage protection circuit, the input end of the voltage protection circuit is connected to a main control microcontroller, and the output end of the voltage protection circuit is connected to the MOSFET driving circuit.

[0012] Preferably, the power supply circuit is connected to an over-temperature protection circuit, and the over-temperature protection circuit is used to disconnect the power supply circuit when the circuit environment temperature is too high.

[0013] Preferably, the output end of the MOSFET driving circuit is provided with two filter circuits, and the two filter circuits are used to reduce the noise of the motor and reduce the heat generated by the motor.

[0014] Preferably, the power supply circuit includes a second step-down circuit, which is used to provide a 5V DC power supply. The second step-down circuit is connected to a 5V voltage monitoring circuit, the input end of the 5V voltage monitoring circuit is connected to the second step-down circuit, and the output end of the 5V voltage monitoring circuit is connected to the MOSFET drive circuit.

[0015] Preferably, the output end of the MOSFET driving circuit is connected to a relay control circuit, and the relay control circuit is used to prevent the motor from rotating due to external force.

[0016] Preferably, the power supply circuit also includes a 48V input power supply, a first step-down circuit and a third step-down circuit, the first step-down circuit is used to step down the 48V input power supply and output a 28V voltage, the second step-down circuit is used to step down the first step-down circuit and output a 5V voltage, and the third step-down circuit is used to step down the second step-down circuit and output a 2.5V voltage.

[0017] The beneficial effects of the present invention are as follows: the present invention does not require a special driver to drive the motor, and does not require software to be designed to generate PWM waves. Instead, a pure hardware circuit is used to generate PWM waves. Therefore, the motor has a fast response speed and high response accuracy. That is, when it is necessary to track a satellite, the present invention can quickly drive the motor to rotate, thereby driving the antenna to track the satellite, and can accurately control the motor speed, thereby accurately driving the antenna to track the satellite. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is the overall principle diagram of the present invention;

[0019] Figure 2 The circuit diagram of the triangle wave generating circuit;

[0020] Figure 3 is a circuit diagram of a current sampling circuit;

[0021] Figure 4 is the circuit diagram of the MOSFET driving circuit;

[0022] Figure 5 This is the circuit diagram of the PWM wave generating circuit;

[0023] Figure 6 This is the circuit diagram of the flying car protection circuit;

[0024] Figure 7 A circuit diagram of a voltage discharge circuit;

[0025] Figure 8 is a circuit diagram of a voltage protection circuit;

[0026] Fig. 9 This is a circuit diagram of an over-temperature protection circuit;

[0027] Fig.10 This is the circuit diagram of the 5V voltage monitoring circuit;

[0028] Fig.11 is a circuit diagram of a relay control circuit;

[0029] Fig.12 is a circuit diagram of a first step-down circuit;

[0030] Fig.13 is a circuit diagram of a second step-down circuit;

[0031] Fig.14 is a circuit diagram of a third step-down circuit.

[0032] Figure numerals: 1, first step-down circuit; 2, second step-down circuit. DETAILED DESCRIPTION

[0033] In order to facilitate the understanding of those skilled in the art, the present invention is further described below in conjunction with the embodiments and drawings, and the contents mentioned in the embodiments are not intended to limit the present invention. The present invention is described in detail below in conjunction with the drawings.

[0034] like Figure 1-Figure 5 As shown, a motor servo power drive circuit includes a power supply circuit, a main control single chip microcomputer, a triangular wave generating circuit, a current sampling circuit, a MOSFET drive circuit and a PWM wave generating circuit; the power supply circuit is used to provide power; the main control single chip microcomputer is used to output a control voltage; the triangular wave generating circuit is used to generate a triangular wave signal; the current sampling circuit is used to detect the current flowing through the circuit inside the motor and output two detection voltages; the MOSFET drive circuit is used to drive the motor to rotate; the PWM wave generating circuit is used to generate two limit signals after superimposing the two input detection voltages with the control voltage, and then compare the two limit signals with the triangular wave signal, and finally generate two PWM signals and output them to the MOSFET drive circuit.

[0035] like Figure 1-Figure 5 As shown, the main control microcontroller inputs the control voltage V_in to the PWM wave generating circuit, the triangular wave generating circuit outputs the triangular wave signal and outputs it to the PWM wave generating circuit, the current sampling circuit detects the current flowing through the circuit inside the motor, and then outputs two detection voltages and outputs them to the PWM wave generating circuit. The PWM wave generating circuit includes a PI adjustment circuit, such as Figure 1As shown, the PI circuit is composed of an operational amplifier DA4B, a resistor R17, a resistor R21 and a capacitor C16. The PWM wave generating circuit superimposes two detection voltages and control signals into a voltage signal, and then after proportional amplification and integral regulation by the PI regulating circuit, two limit signals are output after voltage division by resistors R15 and R26. The two limit signals are compared and superimposed with the triangular wave signals in operational amplifiers DA6A and DA6B respectively, and then two PWM signals are generated and output to the MOSFET driving circuit. The two PWM signals are PWM_IN1 and PWM_IN2 respectively. PWM_IN1 and PWM_IN2 are regulated by driving chips DA1 and DA9 respectively, and then two complementary PWM signals are output respectively, which are used to control MOS tubes VT1, VT2, VT3 and VT4. When VT1 and VT4 are turned on, the motor rotates forward; when VT2 and VT3 are turned on, the motor rotates reversely, and the speed of the motor is determined by the control voltage of the main control microcontroller. The models of DA1 and DA9 are L6384D.

[0036] The present invention does not require a special driver to drive the motor, and does not require software to generate PWM waves. Instead, a pure hardware circuit is used to generate PWM waves. Therefore, the motor has a fast response speed and high response accuracy. That is, when it is necessary to track a satellite, the present invention can quickly drive the motor to rotate, thereby driving the antenna to track the satellite, and can accurately control the motor speed, thereby accurately driving the antenna to track the satellite.

[0037] like Figure 6As shown, the MOSFET driving circuit is connected with a flying car protection circuit, the input end of the flying car protection circuit is used to receive the speed signal of the motor, and the output end of the flying car protection circuit is respectively connected to the main control microcontroller and the MOSFET driving circuit. When the motor is out of control and its speed is not controlled by the main control microcontroller, resulting in an excessively fast speed, the rotary encoder installed on the motor sends the speed frequency to the converter DA14, and the converter DA14 is used to convert the speed frequency into a voltage signal, which is then input into the operational amplifier DA15A, so that the operational amplifier DA15A outputs a high level and sends it to the chip DA16, so that the chip DA16 outputs a high level, thereby turning on the triodes VT9 and VT10, and the turning on of VT9 and VT10 turns on the chips DA17 and VT8, and the collector of VT8 is connected to the DT / ST interface of the driving chips DA1 and DA9, and VT8 sends a high level to the DT / ST interface, so that the driving chips DA1 and DA9 do not output PWM signals, thereby stopping the motor from rotating. At the same time, VT9 and VT10 are turned on to turn on MOS tube V9, and the drain of MOS tube V9 is connected to the M_STOP pin of the main control microcontroller. When the M_STOP pin receives a high-level signal input from the drain of MOS tube V9, the main control microcontroller will not output the control voltage, thereby ensuring that the motor will stop rotating. The overrunning protection circuit can stop the motor with out-of-control speed, thereby protecting the antenna.

[0038] like Figure 7 As shown, a voltage discharge circuit is provided between the power supply circuit and the MOSFET drive circuit, and the voltage discharge circuit is used to eliminate the reverse electromotive force generated when the motor stops rotating. When the voltage discharge circuit is not provided, when the motor stops, the internal circuit of the motor will generate reverse electromotive force. In serious cases, the reverse electromotive force will increase the input voltage of the MOSFET drive circuit, thereby burning the electronic components of the MOSFET drive circuit. When the voltage discharge circuit is provided, when the internal circuit of the motor generates reverse electromotive force, the voltage of the inductor L4 is greater than 48V, and the conduction voltage VEB of VT5 will increase. When the conduction voltage VEB is greater than 0.7, VT5 will be turned on, and then VT7 will be turned on. Finally, the reverse electromotive force is discharged and cleared through the resistor R44 and the resistor R45, thereby preventing the MOSFET drive circuit from being burned and playing a protective role.

[0039] like Figure 8As shown, the MOSFET driving circuit is connected to a voltage protection circuit, the input end of the voltage protection circuit is connected to the main control microcontroller, and the output end of the voltage protection circuit is connected to the MOSFET driving circuit. When the control voltage input by the main control microcontroller is too large, the monitor DA3B will output a high level signal, so that the comparators DA7A and DA7B output a high level, and the output ends of the comparators DA7A and DA7B are connected to the DT / ST interfaces of the driving chips DA1 and DA9. After the DT / ST interface receives the high level output by the monitor DA3B, the driving chips DA1 and DA9 will not output a PWM signal, so that the motor cannot rotate, preventing the MOSFET driving circuit from being burned out, thereby protecting the overall circuit and the motor.

[0040] like Fig. 9 As shown, the power supply circuit is connected to an over-temperature protection circuit, and the over-temperature protection circuit is used to disconnect the power supply circuit when the temperature is too high. The model of the thermistor RT1 is NTCS0805E3103JMT, and its sensitivity is -4% / °C. Its critical temperature is 81°C, that is, when the temperature rises to 81°C, when the overall circuit runs for too long, or is affected by the external environment, it will cause the temperature to exceed 81°C. The over-temperature protection circuit will send a command level to the power supply circuit to disconnect the power supply circuit, thereby protecting the overall circuit to prevent components or motors from being burned out due to excessive temperature.

[0041] like Figure 4 As shown, the output end of the MOSFET drive circuit is provided with two filter circuits, and the two filter circuits are used to reduce the noise of the motor and reduce the heat generated by the motor. The two filter circuits include a first filter circuit 1 and a second filter circuit 2. The first filter circuit 1 includes an inductor L1, a capacitor C8 and a resistor R5, and the second filter circuit 2 includes an inductor L2, a capacitor C19 and a resistor R8. The models of the inductors L1 and L2 are SER2918H-153KL. The first filter circuit 1 and the second filter circuit 2 can convert the two PWM signals into DC voltages respectively, thereby reducing the impedance of the motor, thereby reducing the heat generated by the motor, protecting the motor, and reducing the noise emitted by the motor.

[0042] like Fig.10 and Fig.13As shown, the power supply circuit includes a second step-down circuit, the second step-down circuit is used to provide a 5V DC power supply, the second step-down circuit is connected to a 5V voltage monitoring circuit, the input end of the 5V voltage monitoring circuit is connected to the second step-down circuit, and the output end of the 5V voltage monitoring circuit is connected to the MOSFET drive circuit. When the second step-down circuit is abnormal, the 5V voltage monitoring circuit will detect whether the voltage input to the second step-down circuit is greater than 5V. If it is greater than 5V, the 5V voltage monitoring circuit will send an instruction to the chip DA9 in the MOSFET drive circuit to control the chip DA9 not to output a telecommunications signal, so that the motor does not rotate, thereby protecting the motor and the overall circuit.

[0043] like Fig.11 As shown, the output end of the MOSFET driving circuit is connected to a relay control circuit, and the relay control circuit is used to prevent the motor from rotating due to external force. The relay control circuit includes a relay K1. When the MOSFET driving circuit is energized, the relay K1 is energized, the coil of the motor is closed, and the motor rotates. When the MOSFET driving circuit is not energized, the coil of the motor is not induced, so that the motor cannot rotate under the action of external force. Since the rotation of the antenna is driven by the motor, the relay control circuit locks the motor, thereby preventing the motor from rotating due to external force when the circuit is not energized, thereby protecting the antenna.

[0044] like Figure 12-14 As shown, the power supply circuit also includes a 48V input power supply, a first step-down circuit and a third step-down circuit. The first step-down circuit is used to step down the 48V input power supply and output a 28V voltage. The second step-down circuit is used to step down the first step-down circuit and output a 5V voltage. The third step-down circuit is used to step down the second step-down circuit and output a 2.5V voltage. The first step-down circuit includes a voltage regulator chip DA13, whose model is LM5576MH. The step-down chip DA13 can directly step down the 48V input voltage to a 28V voltage; the second step-down circuit includes a voltage regulator chip DA8, whose model is LM78M05. The voltage regulator chip DA8 can directly step down the input 28V voltage to a 5V voltage; the third step-down circuit includes an operational amplifier DA3A, whose model is LMC6482IM. The operational amplifier DA3A can directly step down the input 5V voltage to a 2.5V voltage. Stepping down the 48V input power supply and outputting three different voltages can meet the input voltage requirements of each circuit.

[0045] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with the profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments according to the technology of the present invention are within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.

Claims

1. A motor servo power drive circuit, characterized in that: It includes a power supply circuit, a main control single chip computer, a triangular wave generating circuit, a current sampling circuit, a MOSFET driving circuit and a PWM wave generating circuit; the power supply circuit is used to provide power; the main control single chip computer is used to output a control voltage; the triangular wave generating circuit is used to generate a triangular wave signal; the current sampling circuit is used to detect the current flowing through the circuit inside the motor and output two detection voltages; the MOSFET driving circuit is used to drive the motor to rotate; the PWM wave generating circuit is used to generate two limit signals after superimposing the two input detection voltages with the control voltage, and then compare the two limit signals with the triangular wave signal, and finally generate two PWM signals and output them to the MOSFET driving circuit; The main control microcontroller inputs the control voltage V_in to the PWM wave generating circuit, the triangular wave generating circuit outputs the triangular wave signal and outputs it to the PWM wave generating circuit, the current sampling circuit detects the current flowing through the circuit inside the motor, and then outputs two detection voltages and outputs them to the PWM wave generating circuit. The PWM wave generating circuit includes a PI adjustment circuit, which is composed of an operational amplifier DA4B, a resistor R17, a resistor R21 and a capacitor C16. The PWM wave generating circuit superimposes the two detection voltages and the control signal into one voltage signal, and then passes through the resistor R15 and the resistor R26 after proportional amplification and integral adjustment of the PI adjustment circuit. After voltage division, two limit signals are output. The two limit signals are compared and superimposed with the triangle wave signal in the operational amplifier DA6A and the operational amplifier DA6B, respectively, to generate two PWM signals and output them to the MOSFET drive circuit. The two PWM signals are PWM_IN1 and PWM_IN2. PWM_IN1 and PWM_IN2 are adjusted by the drive chips DA1 and DA9 respectively, and then two complementary PWM signals are output respectively to control the MOS tubes VT1, VT2, VT3, and VT4. When VT1 and VT4 are turned on, the motor rotates forward; when VT2 and VT3 are turned on, the motor rotates reversely. The MOSFET driving circuit is connected to a flying car protection circuit, the input end of the flying car protection circuit is used to receive the speed signal of the motor, and the output end of the flying car protection circuit is respectively connected to the main control single chip computer and the MOSFET driving circuit; When the motor is out of control and its speed is not controlled by the main control microcontroller, resulting in an excessively fast speed, the rotary encoder installed on the motor sends the speed frequency to the converter DA14. The converter DA14 is used to convert the speed frequency into a voltage signal, which is then input into the operational amplifier DA15A, so that the operational amplifier DA15A outputs a high level and sends it to the chip DA16, so that the chip DA16 outputs a high level, thereby turning on the transistors VT9 and VT10. The turning on of VT9 and VT10 turns on the chips DA17 and VT8, and the collector of VT8 is connected to the DT / ST interface of the driver chips DA1 and DA9. VT8 sends a high level to the DT / ST interface, so that the driver chips DA1 and DA9 do not output PWM signals, thereby stopping the motor from rotating; at the same time, the turning on of VT9 and VT10 turns on the MOS tube V9, and the drain of the MOS tube V9 is connected to the M_STOP pin of the main control microcontroller. When the M_STOP pin receives a high level signal input from the drain of the MOS tube V9, the main control microcontroller will not output the control voltage, and the motor will stop rotating; A voltage discharge circuit is provided between the power supply circuit and the MOSFET drive circuit, and the voltage discharge circuit is used to eliminate the reverse electromotive force generated when the motor stops rotating; When the voltage discharge circuit is not set, when the motor stops, the internal circuit of the motor will generate reverse electromotive force; when the internal circuit of the motor generates reverse electromotive force, the voltage of the inductor L4 is greater than 48V, and the conduction voltage VEB of VT5 will increase. When the conduction voltage VEB is greater than 0.7, VT5 will be turned on, and then VT7 will be turned on, and finally the reverse electromotive force will be discharged and cleared through the resistors R44 and R45; The output end of the MOSFET driving circuit is provided with two filter circuits, and the two filter circuits are used to reduce the noise of the motor and reduce the heat generated by the motor; The two filter circuits include a first filter circuit and a second filter circuit. The first filter circuit includes an inductor L1, a capacitor C8 and a resistor R5. The second filter circuit includes an inductor L2, a capacitor C19 and a resistor R8. The inductors L1 and L2 are of the SER2918H-153KL type. The first filter circuit and the second filter circuit can convert two PWM signals into DC voltages respectively, thereby reducing the impedance of the motor, thereby reducing the heating of the motor, and reducing the noise emitted by the motor. The power supply circuit includes a second step-down circuit, the second step-down circuit is used to provide a 5V DC power supply, the second step-down circuit is connected to a 5V voltage monitoring circuit, the input end of the 5V voltage monitoring circuit is connected to the second step-down circuit, and the output end of the 5V voltage monitoring circuit is connected to the MOSFET driving circuit; When the second step-down circuit is abnormal, the 5V voltage monitoring circuit will detect whether the voltage input to the second step-down circuit is greater than 5V. If it is greater than 5V, the 5V voltage monitoring circuit will send an instruction to the chip DA9 in the MOSFET drive circuit to control the chip DA9 not to output a telecommunication signal, thereby preventing the motor from rotating. The output end of the MOSFET driving circuit is connected to a relay control circuit, and the relay control circuit is used to prevent the motor from rotating due to external force; The relay control circuit includes a relay K1. When the MOSFET drive circuit is energized, the relay K1 is energized, the coil of the motor is closed, and the motor rotates. When the MOSFET drive circuit is not energized, the coil of the motor is not induced, so that the motor cannot rotate under the action of external force, and the relay control circuit locks the motor.

2. The motor servo power drive circuit according to claim 1, characterized in that: The MOSFET driving circuit is connected to a voltage protection circuit, the input end of the voltage protection circuit is connected to a main control microcontroller, and the output end of the voltage protection circuit is connected to the MOSFET driving circuit.

3. The motor servo power drive circuit according to claim 1, characterized in that: The power supply circuit is connected to an over-temperature protection circuit, and the over-temperature protection circuit is used to disconnect the power supply circuit when the circuit environment temperature is too high.

4. The motor servo power drive circuit according to claim 1, characterized in that: The power supply circuit also includes a 48V input power supply, a first step-down circuit and a third step-down circuit. The first step-down circuit is used to step down the 48V input power supply and output a 28V voltage. The second step-down circuit is used to step down the first step-down circuit and output a 5V voltage. The third step-down circuit is used to step down the second step-down circuit and output a 2.5V voltage.

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