KR100304056B1 - Control Circuit of Direct Motor Operating Device - Google Patents

Abstract

The present invention relates to a control circuit of a small and medium-sized DC motor drive device capable of reversible operation, and receives a control force signal (Ts) from a torque sensor and supplies a current capable of determining the rotation direction, speed, and force to an EPS motor. The present invention relates to a control circuit of a device, and is applicable to a driving motor driving device that receives an accelerator signal (Ts) and forwards or reverses a towing vehicle of class 100 to 300 kg. At the analog input of the 8-bit one-chip controller (MPU), the control force signal (Ts) is connected to the input terminal (ADO) through a known buffer and voltage divider circuit, and the main power supply (48V DC) is divided by the resistors (R4, R5) and input. It is connected to the terminal AD1, and the output current signal of the driving device is detected by a shunt, amplified by a known amplifier circuit, and input to the input terminal AD2 through a buffer. The output current signal is detected by a known comparison circuit and connected to the intercept terminal INT of the MPU by detecting an overcurrent state of the output. On the other hand, the output terminal PWM output terminal of the MPU outputs a PWM pulse with the PWM pulse width necessary for motor speed control, and the other two output terminals output drive outputs of FET1 and FET2 that can determine the reversible direction of the motor's forward and backward operation directions. do. When the key switch (KS) is turned on, the MPU executes a built-in program and executes each process.The direct current of the steering device or traction device, such as auxiliary power transistor drive, initial self-diagnosis, PWM output control, current limit in case of overload and sensor failure detection. It is possible to implement the control operation which is basically required for motor driving.

Description

Control circuit of DC motor driving device

The present invention relates to a control circuit of a small and medium-sized DC motor drive device capable of reversible operation, and receives a control force signal (Ts) from a torque sensor and supplies a current capable of determining the rotation direction, speed, and force to an EPS motor. The present invention relates to a control circuit of a device, and is applicable to a driving motor driving device which receives an accelerator signal (Ts) and forwards or reverses a towing vehicle of class 100 to 300 kg.

In the past, hydraulic steering devices have been used as steering devices for electric cars or fork-lifts. However, the electric steering system (EPS) not only saves energy by operating the motor when the steering wheel is operated, but also produces low noise and steering. Hydraulic steering devices are being replaced by electric steering devices because they have excellent sense and strong power, and the demand for small and medium-sized DC motor drives is increasing.

In addition, there is an increasing demand for a driving motor driving apparatus capable of reversible driving used in 100 to 300 kg class towing vehicles (Golf Carts or handicapped vehicles).

As shown in FIG. 1, the electric steering device includes a steering motor (EPS Motor), a motor driving device, a sensor, an actuator or a steering gear, a reduction gear, and the like. The control force signal (Ts) is sent to the motor drive, and the drive device determines the rotation direction, speed, and force of the EPS motor based on this signal (Ts), and supplies the current necessary for steering to the EPS motor. It rotates in the direction of rotation, and this force is transmitted to the actuator or steering gear which moves the direction of the wheel through the reduction gear, which is converted into linear motion and operates the steering axle.

As shown in FIG. 2, the control circuit of the motor driving apparatus includes a hardware circuit including a known operational amplifier, a level comparator, a logic gate, and an auxiliary power supply for controlling the functions and speed required for driving the motor. It is composed of supply circuit, initial driving circuit, over current shut down circuit, PWM generating circuit and control force sensor (Ts) fault detection circuit.

In the initial driving circuit, when + 48V or + 24V DC power is applied to the terminal 1 (in the drawing, the original letter is indicated in original letters), the base signal of the driving transistor is output through the terminal 2 to drive the relay X1, and the DC 48V or 24V is transmitted to the terminal 3, and an external power supply IC is driven to supply the driving voltage Vcc of the control circuit to the terminal 4.

Terminals 23 and 24 are made of an oscillating circuit by making a PWM field having an ON cycle of about 30% as an auxiliary power circuit output to drive a transistor to make an auxiliary power source of the FET driving circuit.

In addition, the control force sensor Ts fault detection circuit receives the control force signal Ts and is a level comparator in the range where the sensor cannot be output in the normal state when the power supply Vcc of the control force sensor is 12V. If Ts) detects a level below 1V or above 11V and detects this signal, it is regarded as sensor failure and generates a fault signal.

The PWM generation circuit outputs the minimum PWM pulse width between P1 (usually 5V) and P3 (usually 7V) where the control force signal (Ts) is at the center level, so that the current flowing through the motor is 0 (zero) and P1, P2 (3.3). In V) or P3, P4 (8.7V) section, the FET drive circuit input that drives FET1, 2, 3, 4 of the FET module so that current proportional to the magnitude of the control force signal (Ts) can flow in the motor in the forward or reverse direction. Generate and apply each PWM pulse. When current is generated in the forward direction, FET1 is continuously turned ON and pulses with PWM periods in proportion to the magnitude of the control force signal (Ts) are applied to FET4 to adjust the output of both output terminals (A-AA) of the drive to which the motor is connected. . When current is generated in the reverse direction, the FET2 is continuously turned on, and a PWM pulse adjusted in proportion to the magnitude of the control force signal Ts is applied to the FET3.

In addition, if the maximum current is supplied to the motor when the control force signal Ts value is input in the P2 level or above the P4 level for more than 3 seconds, the steering wheel is in the maximum position or the steering system is broken. Immediately block the PWM output applied to the FET drive to block the output to prevent the motor drive and the motor from overheating (see Figure 5).

Shut-down circuit overload is amplified to several V level through amplifier if DC current flowing to EPS motor flows in the direction of the arrow in Fig. 2 and through logic circuit when this signal is detected through level comparison detector. Block the PWM waveform output for driving the FET.

However, since the control circuit of the conventional motor drive device is composed only of hardware, the circuit is too complicated to cause a cost increase, and there is a disadvantage that parts must be replaced when adding a function or modifying a detection level.

In particular, when overload due to increased friction of steering wheel, overload due to motor restraint or short circuit due to motor failure, the maximum current flows within the overload capacity limit of the motor drive when overload due to normal operation of EPS system. Since the PWM output must be shut down immediately in the case of a motor restraint or failure due to an error in the steering system, it was difficult to implement this with the hardware described above.

The present invention is to solve the above disadvantages of the auxiliary power transistor driving circuit and the initial driving circuit, the overload current limiting circuit, the sensor failure detection circuit and PWM generation circuit, the abnormality detection and display circuit of various operating conditions such as the abnormality of the driving device (CHOPPER) All functions are implemented in software using an 8-bit one chip controller (hereinafter referred to as MPU) to greatly simplify the control circuit of the DC motor drive, reducing costs, overcurrent detection level, sensor fault level, etc. Various detection operation levels can be easily modified and described in detail with reference to FIG. 3 as follows.

1 is an electric steering system schematic diagram.

2 is a control circuit block diagram of a motor drive device.

Is a control circuit diagram of the present invention.

4A to 4C are flowcharts of the MPU built-in program of the present invention.

5 is a table and a graph of a control force signal Ts voltage.

At the analog input of the 8-bit one-chip controller (MPU), the control force signal (Ts) is connected to the input terminal (ADO) through a known buffer and voltage divider circuit, and the main power supply (48 VDC) is divided by the resistors (R4, R5). Connected to AD1), the output current signal of the driving device is detected by a classifier (Shun t), amplified by a known amplifier circuit, and input to the input terminal (AD2) through a buffer.

In addition, the output current signal is detected by a known comparison circuit and connected to the intercept terminal INT of the MPU by detecting an overcurrent state of the output. On the other hand, the output terminal PWM output terminal of the MPU outputs a PWM pulse with the PWM pulse width necessary for motor speed control, and the other two output terminals output drive outputs of FET1 and FET2 that can determine the reversible direction of the motor's forward and backward operation directions. do.

On the other hand, the drive transistors of the FET1 and FET2 drive circuits are connected to another PWM output terminal of the MPU so that they can be used as the switching signals of the main switching elements of the auxiliary circuits of the drive circuits of the FET1 and FET2.

When the external interrupt signal is input to the MPU, a program is built in the MPU, and an interrupt routine for overcurrent limiting operation is performed, and a timer interrupt routine is executed when detecting a timer interrupt signal determined during initialization. It is configured to execute the routine by setting the PWM control pattern according to the level of).

Referring to the control circuit of the drive device configured as described in accordance with the operation sequence as follows.

When the key switch (KS) of the main power supply (main DC) is turned on to operate the drive system, the MPU receives a signal generated by dividing the main power supply voltage level with the resistors R4 and R5 connected in series and receives an error of the main power supply (usually 48V). The main circuit contactor (MS) is connected by detecting the presence and absence of the initial abnormal state of the FET device. The control force signal Ts is input in the range of 0 to 12V. The control force signal Ts is input to the analog input terminal AD0 of the MPU after being divided to 0 to 5V level by a known buffer circuit composed of integrated circuit IC1A and IC1B.

The FET1 and FET2 of the FET module determine the direction of rotation of the motor before and after. In the driving circuit configuration, two sets of power (15V) isolated from the control power supply (Vcc) are required. A PWM pulse with an ON cycle of about 30% is generated in the MPU at the base of the juice switching transistor Q5 of the power supply and applied through the PWM output port 2.

When FET1,3 or FET2,4 of the FET module are simultaneously turned on to produce an arm short-circuit current or when the motor's operating current increases above the allowable value (around 130%) and an overcurrent occurs, the shunt is the maximum. Another analog input terminal (AD2) of the MPU through a buffer consisting of integrated circuit IC2A, resistor R12, and capacitor C6 after amplifying to several V levels with a known associative amplification circuit consisting of integrated circuit IC1C and IC1D. It is input to and performs overcurrent limiting operation preferentially.

In addition, when the current signal amplified to several V levels continuously rises to a level higher than 150% in the comparison circuit composed of IC2B and resistors R13, 14, and 15, an external interrupt signal is provided to the MPU, and the PWM output of the FET module is about 10 times later. The power supply is cut off for a while and the contactor (MS) of the main circuit is turned off.

In the case of arm short of the FET module or short circuit of the motor, the current of the classifier increases rapidly in an instant. Therefore, when the peak value of the current is 200% or more, a comparison circuit composed of the integrated circuit IC2C and the resistors R18, 19, 20, and 21 If the controller detects this and outputs a low output (Curr. INT), the outputs of the logic gates of the integrated circuits IC3C and IC3D go low, and the known FET drive circuit blocks instantly, preventing the current from increasing beyond the set level.

Each output port of the MPU is arranged to perform the functions and roles described above, and is amplified by the transistor array integrated circuit IC4 to be connected to the final output signal stage. It outputs PWM pulse that can rotate the motor in the same state as the hardware circuit, and shuts down properly when the motor is in a restraint state or failure, and fault conditions such as 'CHOPPER ERROR', 'MP ON', 'Overcurrent', 'Ts ERROR', etc. Can be displayed simply by LED. In addition, when the control force signal Ts from the torque sensor is replaced with the accelerator signal Ts, the control circuit of the EPS motor drive device is a drive motor control circuit for advancing the towing vehicle 100 to 300 kg. Can be used

The program execution process in the MPU is as follows.

First, as shown in FIG. 4A, when the power is applied, the MPU performs an initializing process. In this routine, the initial output state of each port of the MPU, that is, '1' or '0', is determined and input or output. It designates each port to be used and decides each bit value of special register necessary for A / D conversion of A / D converter built in MPU. In addition, the detection period of the timer interleave of FIG. 4C is also determined during the initialization process.

When the initialization process⑴ is finished, the timer interleave is enabled and the control force signal Ts detection process is started. The timer interleave of FIG. 4C is performed every timer interleave period set in the initialization process of FIG. 4A. This means that the interlept should perform the timer interleave even during the execution of the main routine. Therefore, the control force signal (Ts) is detected at the analog input terminal AD0 at each timer interleave cycle, and the motor drive current is detected at the analog input terminal AD2. 4C adjusts a PWM control variable (PWM ERROR) value according to the current limit value of FIG.

When the control force signal Ts or the voltage detected by the classifier is converted in detail through the analog input terminals AD0 to AD2 of the MPU, the A / D converter has several channels in the MPU. In order to recognize the control force signal (Ts) value, the MPU first changes the channel to connect the multiplexer (MUX) to the analog input terminal AD0, and usually uses the sample hold time of 30usec to receive the correct value. This is the time it takes for the control force signal (Ts) to stabilize to the value currently being input to the capacitor inside the MPU.

The voltage level signal of the driving circuit output terminals A and AA is input to the analog input terminals AD3 and 4, and receives the channel control signal of the multiplexer and is connected to the A / D converter. The analog values connected to the AD converters by the multiplexer (MUX) are each converted into 8-bit digital signal values.

On the other hand, when the initialization process ⑴ is completed, the external interrupt is also enabled. When the 'HIGH' signal is input from the external interleave terminal INT, the external interrupt routine of FIG. 4C is performed. This is described in detail in the current limit operation.

After the initialization process, the MPU executes self-diagnosis routine, which is the process of ⑵ ~ ⑸. First, the voltage level of the main power is distributed by R4 and R5 and detected through the analog input terminal AD1, and then normal (usually 24V). If abnormal), turn on the MP LED (MAIN POWER LED) and proceed to the next step. If abnormal, do not perform any further program without turning on the MP LED.

After that, the MPU performs a diagnosis process for the abnormality of CHOPPER. When the 'HIGH' signal is applied to the forward rotation selection output terminal PORT6 of the driving device in Fig. 3 for a diagnosis time (a few μs), the 'LOW' signal is output from the output terminal O1 of the integrated circuit inverting buffer IC4 and the known FET drive circuit Since FET1 is driven by operating the photon coupler PC2, the voltage at the 'A' point of one of the motors becomes 48V (24V), and about 5V signal is converted to the level through the resistance divider of R42 and R43, so that the analog input terminal AD3 Check if 'HIGH' is detected. When the 'HIGH' signal is applied to the reverse rotation selection output port PORT7 for the diagnosis time, FET2 is turned on through the same process. Therefore, the voltage at the 'AA' point is converted into a 5V signal through the resistance divider of R44 and R45. Determine if it is detected as 'HIGH' through AD4.

In addition, when the 'HIGH' signal is applied to the PWM output terminal PORT1 and the forward rotation selection output terminal PORT6, the outputs of the integrated circuit gate IC3B and IC3D become 'HIGH', and the FET4 is conducted through a known driving circuit. 0V is detected through the analog input terminal AD4. In the same principle, if the 'HIGH' signal is applied to the PWM output terminal PORT1 and the reverse rotation selection output terminal PORT7, FET3 is conducted through the same process, and the voltage at the 'A' point should be detected at 0V through the analog input terminal AD3. . If all four conditions are satisfied, the FET module is normal, so to turn on the MS by outputting 'HIGH' to the relay drive output terminal PORT8 to turn on the main power contactor (hereinafter referred to as MS). If all of the above 4 conditions are not satisfied, the FET module is not normal and the CHOPPER ERROR LED is turned on and the program does not proceed any further.

After completing the above self-diagnosis process, the MPU detects the control force signal Ts and executes the main program below to control the PWM output to flow the current specified in the voltage current graph for the Ts voltage shown in FIG. Will run. First, the control force signal Ts is recognized at the analog input terminal AD0 through the resistor voltage divider and the buffer circuit of R2 and R3, and the control force signal Ts is checked in the ALU in the MPU to be within the normal range of 1.0V to 11V. If it is out of the above range, the torque sensor that outputs the control force signal (Ts) is bad, so give a signal to the inverting buffer IC4 input terminal I6 to turn on the TS ERROR LED, and the program will remain in the normal range as shown in Fig. 4a. Instead of proceeding to the next step 된다, the processes ⑹ through ⑺ of FIG. 4A are repeated.

When the control force signal Ts voltage is in the normal range, the following steps are performed. The FET driving and operation according to the control force signal Ts voltage will be described in detail with reference to FIG. 5.

First, when the control force signal Ts is in the range of P1 to P3 (5V to 7V), the FETs 1, 2, 3, and 4 are all turned off because the motor is stopped. At this time, if the range of P1, P3 is set large, the play of the steering wheel is increased.

Second, since the motor is running in the forward direction when the control force signal Ts is within the range of 7V to 8.7V, the forward rotation selection output terminal PORT6 outputs 'HIGH' and the reverse rotation selection output terminal PORT7 outputs 'LOW'. Through the furnace, FET2 is turned off and FET3 is also turned off because the integrated circuit IC3A and IC3C outputs are 'LOW'. Since the output terminal O1 of the integrated circuit inverting buffer IC4 is 'LOW', FET1 is turned on and FET4 is driven by the controlled PWM generated from the PWM output terminal PORT1 so that the motor rotates forward. At the moment, the PWM output PWM pulse width generated in PORT1 is controlled in accordance with the control signal (Ts) to the value obtained by the level '(TS voltage -7V) × K _P' K _P is in the range of 5 7V~11V First-order function corresponding to the slope.

Third, if the control force signal Ts is in the range of 3.3V to 5V, the motor rotates in reverse direction. Therefore, the forward rotation selection output terminal PORT6 outputs 'LOW' and the reverse rotation selection output terminal PORT7 outputs 'HIGH'. In the same principle, through the output terminals 01 and 02 of the integrated circuit inverting buffer IC4, FET1 and FET4 are turned OFF, FET2 is turned ON, and FET3 is driven by the PWM output whose pulse width generated from the PWM output terminal PORT1 is controlled. Done. Again, it is controlled according to the control force signal (Ts) level generated from the PWM output terminal PORT1. The PWM pulse width is obtained by '5V-TS voltage × K _P ', and K _P is in the range of 3.3V to 5V in FIG. The corresponding function.

Fourth, when the control force signal Ts is 8.7V to 11V and 1V to 3.3V, the maximum current is supplied to the motor while the current limit operation in the forward or reverse direction is activated. As described above, the steering wheel Is in the maximum position or the steering wheel is broken. If this condition persists for more than 3 seconds, the PWM output is turned off immediately, all the FETs are turned off, the overcurrent LED is turned on, and the program is terminated.

In the present invention, the current limit (Current Limit) function is controlled by double control of the software and hardware to prevent burnout of the drive device under any conditions, the hardware current limit (Current Limit) function as described above the current flowing in the motor Is detected by the classifier at 0 ~ 150mV level and it is amplified to several V level by a known operational amplifier circuit composed of IC1C, IC1D, and resistors R6 ~ 11. When increasing, the comparison circuit composed of integrated circuit IC2C and resistors R18, 19, 20, and 21 senses this, and when its output becomes 'LOW', the outputs of the logic gates of IC3C and IC3D become 'LOW'. Known FET drive circuits are blocked so that the current does not increase beyond the set level even at the moment.

On the other hand, if the current signal amplified by a known operational amplifier circuit is always sensed over the value specified in the analog input terminal AD2 of the MPU through the integrated circuit IC2A buffer and recognized as overcurrent, the MPU reduces the PWM value of the PWM output terminal PORT1. The current limiting operation of ⑽ or less is performed. In the following process, the current (CURR) of the analog input terminal AD2 is compared with the current limit value (LIMIT) set in the register in the MPU, and if the detection current (CURR) is larger, the error value corresponding to the difference between the two currents is increased. This function reduces the PWM pulse width output from the PWM output terminal PORT1. If this condition persists for more than 15 seconds, the PWM output is immediately turned off due to overload due to increased friction of the steering wheel or overload due to motor restraint. Turn off all FETs, turn on the overcurrent LED, and then finish program execution. Lastly, if the current surges, such as a short circuit due to a motor failure, the output must be shut down immediately. Therefore, when the output of the integrated circuit IC1D has risen more than 200% compared to the comparison circuit consisting of the integrated circuit IC2B and R13-15, After outputting HIGH 'signal and applying' HIGH 'signal to MPU external interrupt input terminal INT, MPU immediately executes external interrupt routine of Fig. 4C to stop PWM pulse generation of PWM output terminal PORT1, turn off all FETs, and overcurrent LED. After the program is turned on, the program should be terminated to prevent damage to the driving device. In this case, the program execution is completed. Therefore, turn off the power and start again from the beginning.

In addition, the driving circuits of FET1 and FET2 require two sets of auxiliary power (15V) generation circuits insulated from the control power supply (Vcc), so that the base of the juice switching element transistor Q5 of the auxiliary power supply circuit is connected to another PWM output terminal PORT2 of the MPU. When the MPU executes the initialization process, it assigns a bit value to the special raster in the MPU so that a 2KHz PWM pulse with a 30% ON cycle is continuously output to the auxiliary output PWM output terminal PORT2.

As described above, when the key switch KS is turned on, the MPU executes a program as shown in the pro chart of FIG. 4 and executes each process, so that the auxiliary power transistor drive, initial self-diagnosis, PWM output control, current limit in case of overload, and sensor failure are performed. It can realize the control operation basically necessary for driving DC motor of sensing light steering device or traction device, and can get the necessary functions for various self-diagnosis by adding simple program, which can reduce the cost by simplifying the hardware circuit. Since overcurrent detection and sensor failure detection are obtained by executing software, the detection level can be easily modified for the purpose of using without modifying the hardware, and the functions necessary for various self-diagnosis can be easily installed without adding much hardware. Will have the advantage.

Claims (3)

In the control circuit of the small and medium-sized DC motor drive device capable of reversible operation of the motor by configuring the abnormal function of various operation states and the display circuit as hardware, the one-chip controller (MPU) is used to perform the role according to the execution of the program embedded therein. At the analog input of the MPU, a control signal (TS) through a known buffer and voltage divider circuit, a main power supply (DC) divided by resistors R4 and R5, and a divider are detected and amplified by a known amplification circuit and driven through a buffer. The output current signal is input to each input terminal AD0 to AD2 of the MPU, and the output current signal is connected to the interrupt terminal INT of the MPU by detecting the current state of the output as a known comparison circuit, and the motor is connected to the output terminal of the MPU. FE that allows PWM pulses with PWM pulse width necessary for speed control to be output from the PWM output terminal, and determines the forward and backward operation directions of the motor from the other two output terminals. A control circuit for a small and medium-sized DC motor drive device, characterized in that the drive output of the T1, FET2 is connected directly to the MPU built-in program by connecting each input and output port of the MPU. The driving circuit of claim 1, wherein the driving transistors of the driving circuits driving the FET1 and FET2 are connected to another PWM output terminal of the MPU to generate PWM pulses having a pulse width of about 30% during initialization. Control circuit for small and medium-sized DC motor drive device characterized in that used as the switching signal of the juice switching device of the auxiliary power supply. The MPU built-in program performs an interrupt routine for the overcurrent limiting operation when an external interrupt signal is input to the interrupt terminal (INT) of the MPU, and performs a control force signal (A ₀ AD ₂ ) at the analog input terminal (AD ₀ AD ₂ ) of the MPU. In order to detect Ts) and the motor current signal, Timer interrupt luton is performed at every timer interrupt period determined during initialization, and by setting the PWM control pattern according to the level of the detected control signal TS, Control circuit of a small and medium-sized DC motor drive device characterized in that the reversible operation control of the.