KR101626762B1 - Motor driver - Google Patents

Abstract

(assignment)
The present invention can easily determine whether to notify only the short-circuit current protection signal as an error signal to the microcomputer which is a higher-order device, or not to notify the overcurrent protection signal due to the detection of the current in addition to the short-circuit current protection signal as an error signal Provides a motor driver.
(Solution)
When the current detection value LS exceeds the overcurrent reference value Vocp, the overcurrent protection signal ERR2 is output and when the current detection value LS exceeds the overcurrent reference voltage Vscp higher than the overcurrent reference value Vocp An error detection circuit 44 for outputting a short-circuit current protection signal ERR1 and a short-circuit protection circuit for outputting a short-circuit current protection signal ERR1 as a low-level error signal from the error terminal TO to the microcomputer 3, The signal ERR2 outputs a high level voltage value divided by the voltage divider circuit (a series circuit of the resistor R2 and the resistor R3) to the microcomputer 3 from the error terminal TO as a low level error signal And an error signal output circuit 45 for outputting an error signal.

Description

Motor driver {MOTOR DRIVER}

The present invention relates to a motor driver for driving a motor.

A driving command from a microcomputer as a host device is converted into a driving signal having an optimum voltage and switching speed and the built-in inverter circuit is driven by a drive A motor driver for outputting a drive voltage for driving the motor is known. Such a motor driver includes, for example, an overcurrent protection circuit (overcurrent protection circuit) for detecting an overcurrent such as a motor overload and stopping the switching operation, a shortcurrent protection circuit for detecting a shortcurrent and stopping the switching operation (See, for example, Patent Document 1).

Patent Document 1; Japanese Patent Application Laid-Open No. 2002-369542

However, in the prior art, it is necessary to notify (notify) only the short-circuit current protection signal due to the detection of the short-circuit current to the microcomputer as the upper apparatus as an error signal, It has not been determined whether to notify the signal as an error signal. Therefore, there has been a problem that it is necessary to prepare a type of notifying only the short-circuit current protection signal as an error signal, and a type of motor driver notifying as an error signal the overcurrent protection signal by detecting the current in addition to the short-circuit current protection signal.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the problems of the prior art in view of the above problems and to provide a microcomputer which is an upper apparatus to notify only a shortcurrent protection signal as an error signal, And to provide a motor driver capable of easily selecting whether to notify an overcurrent protection signal due to an overcurrent protection signal as an error signal.

The motor driver of the present invention includes a driver circuit that drives an inverter circuit based on a drive command input from an upper apparatus and drives the motor by a drive voltage generated by driving the inverter circuit, And outputs an overcurrent protection signal when the circuit current of the circuit exceeds an overcurrent reference value and outputs a shortcircuit current protection signal when the circuit current of the inverter circuit exceeds a shortcircurrent reference voltage higher than the overcurrent reference value, And an error signal output circuit for outputting the short-circuit current protection signal to the host device as a low-level error signal and for outputting the overcurrent protection signal to the host device as an error signal of a higher level than the low level Characteristic It shall be.

According to the present invention, whether or not a short-circuit current protection signal is to be notified as an error signal to the microcomputer, which is a higher-order device, depending on whether a pull-up resistor is connected to the error terminal or not, It is possible to simply select whether to notify the signal as an error signal.

1 is a circuit configuration diagram showing a configuration of an embodiment of a motor control apparatus using a motor driver according to the present invention.
2 is a circuit configuration diagram showing the configuration of the FO circuit shown in Fig.
Fig. 3 is a diagram showing signal waveforms and operation waveforms of respective portions of the motor driver shown in Fig. 1. Fig.
Fig. 4 is a circuit diagram showing another example of connection between the motor driver and the microcomputer shown in Fig. 1. Fig.
5 is a diagram showing signal waveforms and operation waveforms of respective portions of the motor driver shown in Fig. 1. Fig.
Fig. 6 is a diagram showing signal waveforms and operation waveforms of respective portions of the motor driver shown in Fig. 1. Fig.
7 is a diagram showing an example of setting an overcurrent reference voltage to be compared with a current detection value in the abnormality detection circuit shown in Fig.

 BEST MODE FOR CARRYING OUT THE INVENTION Next, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same components are denoted by the same reference numerals, and a description thereof is omitted.

The motor control device of the present embodiment is a device for controlling the driving of a three-phase brushless motor 1. As shown in FIG. 1, the motor control device includes a DC power source, A microcomputer 3, a motor driver 4, a current detection resistor RS, a pull-up resistor R1, .

The DC power supply 2 is constituted by a storage battery or a power supply circuit formed by combining an AC power source and a converter circuit.

The microcomputer 3 outputs an external command or a drive command (movement command) (Hin1, Hin2, Hin3, Lin1, Lin2, Lin3) from the brushless motor 1 according to positional information or the like.

The motor driver 4 includes an inverter circuit 41, a driver circuit 42, and an FO circuit 43.

The inverter circuit 41 is a circuit in which a series circuit provided in a high side arm and a low side arm to which a switching element is connected corresponds to each of the U, And is connected between a positive direct current bus and a negative direct current bus connected to the direct current power source 2. The inverter circuit 41 outputs a driving voltage for driving the brushless motor 1 by on / off-controlling the switching elements.

The driver circuit 42 outputs the drive signals Ho1, Ho2, and Lin3 obtained by converting the drive commands Hin1, Hin2, Hin3, Lin1, Lin2, and Lin3 input from the microcomputer 3 to the optimal (optimal) Ho3, Lo1, Lo2, and Lo3) to the inverter circuit 41. The drive signals Ho1, Ho2 and Ho3 are drive signals for driving the switching elements of the high side arms of the U, V and W phases in the inverter circuit 41, And the switching elements of the low-side arms of the U, V, and W phases in the circuit 41, respectively. In this embodiment, the high side drive commands Hin1, Hin2 and Hin3 for driving the switching elements of the high side arm are chopped by the PWM control and the low side drive commands Lin1, Lin3) is turned on without chopping (always on high level during input).

The current detection resistor RS is provided on a grounded negative direct current bus as shown in Fig. 1 and detects a circuit current flowing from the direct current power source 2 to the inverter circuit 41 as a voltage value Output value) LS (hereinafter referred to as LS).

The FO circuit 43 detects an overcurrent based on the current detection value LS and outputs an overcurrent protection signal ERR2 and detects an overcurrent to output an overcurrent protection signal ERR1 An error signal output circuit 44 for outputting an error signal to the microcomputer 3 from an error terminal TO provided in the motor driver 4 45).

The abnormality detecting circuit 44 compares the current detection value LS with the overcurrent reference voltage Vocp and outputs the overcurrent protection signal ERR2 to the driver circuit 35 when the current detection value LS exceeds the overcurrent reference voltage Vocp. (42) and an error signal output circuit (45). The abnormality detecting circuit 44 also compares the current detection value LS with the short circuit current reference voltage Vscp set at a voltage value higher than the overcurrent reference voltage Vocp so that the current detection value LS becomes short- And outputs the short-circuit current protection signal ERR1 to the driver circuit 42 and the error signal output circuit 45 when the reference voltage Vscp is exceeded.

The error signal output circuit 45 includes resistors R2 and R3 and switch elements Q1 and Q2. A series circuit composed of a resistor R2 and a resistor R3 and a switch element Q1 is connected between the internal voltage Reg and the ground terminal and the switch element Q2 is connected in parallel with the resistor R3 and the switch element Q1. Are connected. The connection point A of the resistor R2 and the resistor R3 is connected to the error terminal TO of the motor driver 4. [ The switch element Q1 is a switch that is turned on by the output of the overcurrent protection signal ERR2 and the switch element Q2 is a switch that is turned on by the output of the shortcircuit current protection signal ERR1. Therefore, when neither the overcurrent protection signal ERR2 nor the short-circuit current protection signal ERR1 is outputted, the internal voltage Reg is output from the error terminal TO as a voltage corresponding to the high level of the error signal FO do. When the short-circuit current protection signal ERR1 is outputted, approximately 0 V is outputted from the error terminal TO as a voltage corresponding to the low level of the error signal FO. When the overcurrent protection signal ERR2 is outputted, a voltage obtained by dividing the internal voltage Reg by the resistor R2 and the resistor R3 is outputted from the error terminal TO.

Next, the overcurrent detecting operation in the motor driver 4 of the present embodiment will be described in detail with reference to Fig. 3 shows signal waveforms and operation waveforms of respective portions of the motor driver 4 when an overcurrent is detected. Fig. 3 (a) shows the drive command Hin, Fig. 3 (b) shows the drive command Lin, The overcurrent protection signal ERR1 and the overcurrent protection signal ER are represented by the short-circuit current protection signal ERR1 and the short-circuit current protection signal ER respectively. 3, the drive command (Hin) of the drive command (Lin) and the drive command (Lo) of the drive signal (Ho) Data are not controlled but data is controlled at the same timing.

The abnormality detecting circuit 44 compares the current detection value LS detected by the current detection resistor RS with the overcurrent reference voltage Vocp and the time ta1 as shown in Figure 3 (e) When the current detection value LS exceeds the overcurrent reference voltage Vocp at the overcurrent filter time Ta during the overcurrent filter time Ta for preventing erroneous detection LS) exceeds the overcurrent reference voltage (Vocp). If the state in which the current detection value LS exceeds the overcurrent reference voltage Vocp continues for the overcurrent filter time Ta, the abnormality detecting circuit 44 determines that the overcurrent filter time Ta has elapsed from the time Ta1 At time Ta2, the overcurrent protection signal ERR2 is inverted to output or high level as shown in Fig. 3 (g).

The overcurrent protection signal ERR2 is input to the driver circuit 42. The driver circuit 42 outputs a drive command Hin, Lin from the microcomputer 3 as shown in Figs. 3A and 3B The drive of the inverter circuit 41 is stopped by interrupting the low side drive signal Lo as shown in Fig. 3 (d). The cutoff of the drive signal Lo by the driver circuit 42 is performed during the overcurrent protection period Tocp (for example, several tens of microseconds) in which the overcurrent protection signal ERR2 is output (determined as high level). The overcurrent protection period (Tocp) is set to, for example, one carrier (one carrier) of the PWM frequency.

The switch element Q1 is turned on by the output of the overcurrent protection signal ERR2 and the voltage of the connection point A of the resistor R2 and the resistor R3 is outputted from the error terminal TO. When the pull-up resistor R1 is connected between the error terminal TO and an external voltage having the same potential as the internal voltage Reg as shown in Fig. 2, If the override the resistance component is a Reg * R3 / {R1 · R2 / (R1 + R2) + R3}. Therefore, by setting the resistance value of the pull-up resistor R1 equal to or higher than the resistance R3, the voltage of the connection point A is not recognized as a low level in the microcomputer 3 by more than half of the internal voltage Reg It can be a middle level. For example, when the internal voltage Reg is 5V, the resistor R1 is 3kΩ, the resistor R2 is 60kΩ, and the resistor R3 is 6kΩ, the voltage at the connection point A becomes a middle level of almost 3.4V.

On the other hand, as shown in Fig. 4, when the error terminal TO and the microcomputer 3 are connected without connecting the pull-up resistor R1, the voltage at the connection point A becomes the resistance component of the switch element Q1 If it is ignored, it becomes Reg * R3 / (R2 + R3). Therefore, by setting the resistance value of the resistor R2 to a value sufficiently larger than the resistor R3 (for example, 10 times or more), the voltage of the connection point A is set to a low level . For example, when the internal voltage Reg is 5V, the resistance R2 is 60kΩ, and the resistance R3 is 6kΩ, the voltage at the connection point A becomes a low level of approximately 0.45V. Whether or not to connect the pull-up resistor R1 to the error terminal TO as described above allows the user to select whether or not to output the overcurrent protection signal ERR2 to the microcomputer 3 as the error signal FO.

The output of the overcurrent protection signal ERR2 is inverted to the low level at the time Ta3 at which the overcurrent protection period Tocp has elapsed from the time Ta2 and then the driver circuit 42 sets the error signal filter time The low side drive signal Lo is cut off at the time ta4 after the elapse of the time Tb. When the overcurrent protection signal ERR2 is not outputted to the microcomputer 3 as the error signal FO, the microcomputer 3 outputs the overcurrent protection signal ERR2 ) And continues to output the drive commands (Hin, Lin). Therefore, the brushless motor 1 is rotated by inertia during the overcurrent protection period Tocp, and after the elapse of the overcurrent protection period Tocp, the inverter circuit 4, which is driven by the drive signals Ho and Lo, The drive of the drive motor 41 is restarted.

3 (g), a pulse signal of an overcurrent protection period (Tocp) width is output from the abnormality detection circuit 44 as the overcurrent protection signal ERR2, and the overcurrent protection signal ERR2 is output from the overcurrent protection signal ERR2, It is possible to cancel the blocking of the low side drive signal Lo after counting the overcurrent protection period Tocp at the driver circuit 42 side .

Next, a short-circuit current detection operation in the motor driver 4 of the present embodiment will be described in detail with reference to Figs. 5 and 6. Fig. 5 and 6 show signal waveforms and operation waveforms of respective portions of the motor driver 4 when a short-circuit current is detected. 5 and 6A show a drive command Hin, Fig. 5B shows a drive command Lin, Fig. 5C shows a drive signal Ho, Fig. 6D shows a drive signal Lo, The current detection values LS and f are the short-circuit current protection signals ERR1 and G and the overcurrent protection signals ERR2 and h are the output waveforms of the error signal FO, respectively. 5 and 6, the drive signal (Lo) of the drive command (Hin) and the drive command (Lin) of (b) Data are not controlled but data is controlled at the same timing.

The abnormality detecting circuit 44 compares the current detection value LS detected by the current detection resistor RS with the shortcircuit current reference voltage Vscp and compares the time tb1 When the current detection value LS exceeds the short-circuit current reference voltage Vscp, the current detection value LS is continuously supplied to the short-circuit current reference voltage Vscp ) Is exceeded. The short-circuit current filter time Tc is set to a time shorter than the overcurrent filter time Ta. If the state where the current detection value LS exceeds the short-circuit current reference voltage Vscp continues for the short-circuit current filter time Tc, the abnormality detecting circuit 44 outputs the short-circuit current filter time Tc At the elapsed time Tb2, the short-circuit current protection signal ERR1 is inverted to the output or high level as shown in Fig. 5 (f).

The short-circuit current protection signal ERR1 is input to the driver circuit 42 and the driver circuit 42 outputs the high-side and low-side drive signals Ho and Lo as shown in Figs. 3 (c) and 3 (d) The drive of the inverter circuit 41 is stopped.

The switching element Q2 is turned on by the output of the short-circuit current protection signal ERR1 and the voltage at the connection point A between the resistors R2 and R3 becomes almost 0 V, (TO). Thus, the microcomputer 3 recognizes the short-circuit current and stops the output of the drive command (Hin, Lin) as shown in Figs. 5 (a) and 5 (b).

The abnormality detection circuit 44 outputs a pulse signal of a short-circuit current protection period Tscp set at a time (for example, several ms) longer than the overcurrent protection period Tocp as the short-circuit current protection signal ERR1. When the output of the short-circuit current protection signal ERR1 is ended and inverted to the low level at the time Tb3, as shown in Figs. 5A and 5B, the drive command Hin, Lin from the microcomputer 3 The output of the drive signals Ho and Lo by the driver circuit 42 is resumed as shown in Figs. 5 (c) and 5 (d). The driver circuit 42 also includes a latch circuit (latch circuit) which is not released unless all of the drive instructions (Hin, Lin) inputted from the microcomputer 3 become low level, The output of the drive signals Ho and Lo is resumed on condition that all of the drive commands Hin and Lin input from the microcomputer 3 are at a low level. 6 (f), even if the short-circuit current protection signal ERR1 is outputted at the time tb2, as shown in Figs. 6 (a) and 6 (b) In the case where the commands (Hin, Lin) are continuously input, destruction or congestion of the microcomputer 3 can be considered. Therefore, even if the output of the short-circuit current protection signal ERR1 is ended and inverted to the low level at the time tb3, the driver circuit 42 outputs the drive signals Ho and Lo as shown in Figs. 6 (c) and 6 (d) The secondary output is prevented from being restarted.

The overcurrent reference voltage Vocp to be compared with the current detection value LS in the abnormality detection circuit 44 is set at a high temperature (for example, 100 deg. C) as shown in Fig. 7 (a) So that the switching element of the inverter circuit 41 can be utilized to an extreme limit within a range where heat is not destroyed. The generation (generation) of the overcurrent reference voltage Vocp is performed by using a thermal monitor circuit (a subtraction circuit) in which the output voltage changes according to the temperature as shown in Fig. 7 (b) Thereby generating the characteristic X shown in Fig. 7 (b). By subtracting the characteristic X from a predetermined constant potential, an overcurrent reference voltage Vocp which falls at a constant gradient at a high temperature can be generated. 7 (d), the overcurrent reference voltage Vocp which falls at a constant slope at a constant temperature (for example, 0 ° C) may be used. Alternatively, as shown in FIG. 7 an overcurrent reference voltage Vocp which falls at a constant slope at a constant temperature (for example, 0 ° C) and declines at a constant slope at a high temperature (for example, from 100 ° C) may be used as shown in FIG.

As described above, the present embodiment includes the driver circuit 42 that drives the inverter circuit 41 based on the drive command (Hin, Lin) input from the microcomputer 3 as the host device, The motor driver 4 drives the brushless motor 1 by the drive voltage generated by the drive of the inverter 41. The current detection value LS which is the circuit current of the inverter circuit 41 is the overcurrent reference value Vocp, And outputs an overcurrent protection signal ERR2 and outputs a shortcircuit current protection signal ERR1 when the current detection value LS exceeds a shortcurrent reference voltage Vscp higher than the overcurrent reference value Vocp Circuit 44 and the short-circuit current protection signal ERR1 as a low-level error signal FO to the microcomputer 3, And an error signal output circuit 45 for outputting the signal ERR2 to the microcomputer 3 as an error signal FO having a level higher than the low level (the error signal FO of the short-circuit current protection signal ERR1) have. The overcurrent protection signal ERR2 is a voltage value obtained by dividing the high level by a voltage dividing circuit (a series circuit of the resistor R2 and the resistor R3) .

According to this configuration, since the low-level error signal FO is generated by the voltage divider circuit (the series circuit of the resistor R2 and the resistor R3), the pull-up resistor R1 is connected to the error terminal TO It is possible to simply generate a middle level error signal that the microcomputer 3 does not recognize as a low level. Therefore, whether or not to notify (notify) only the short-circuit current protection signal ERR1 to the microcomputer 3 which is an upper apparatus as the error signal FO, depending on whether or not the pull-up resistor R1 is connected to the error terminal TO, It is possible to simply select whether to notify the overcurrent protection signal ERR2 in addition to the short-circuit current protection signal ERR1 as an error signal.

According to the present embodiment, the driver circuit 42 stops the drive of the inverter circuit 41 when the overcurrent protection signal ERR2 is outputted from the abnormality detecting circuit 44, and after the elapse of the overcurrent protection period Tocp, (41) is restarted. According to the present embodiment, the driver circuit 42 stops the drive of the inverter circuit 41 when the short-circuit current protection signal ERR1 is outputted from the abnormality detection circuit 44 and outputs a short circuit longer than the overcurrent protection period Tocp The drive of the inverter circuit 41 is restarted on the condition that all the drive commands Hin, Lin inputted from the microcomputer 3 are stopped once the current protection period Tscp has elapsed.

According to this configuration, secondary failure can be prevented even in a state in which the error signal FO can not be recognized due to destruction or runaway of the microcomputer 3.

It is to be understood that the present invention is not limited to the above-described embodiments, and that the embodiments can be appropriately changed within the scope of the technical idea of the present invention. Further, the number, position, shape, and the like of the constituent members are not limited to the above-described embodiment, but may be a number, a position, a shape, and the like suitable for carrying out the present invention. In the drawings, the same components are denoted by the same reference numerals.

One ; Brushless motor
2 ; DC power
3; Microcomputer
4 ; Motor driver
RS; Current detection resistor
R1; Pull-up resistor
41; Inverter circuit
42; Driver circuit
43; FO circuit
44; The abnormal detection circuit
45; Error signal output circuit
R2, R3; resistance
Q1, Q2; Switch element
Reg; Internal voltage

Claims (3)

(Driver circuit) that drives an inverter circuit (inverter circuit) based on a drive command (motion command) input from a host device (host device) A motor driver for driving the motor by the motor,
Circuit current of the inverter circuit exceeds the over-current reference value (過電流基準値) over current protection signal through output and at the same time, the circuit current is a high short-circuit current reference value (短絡電流基準値) than the over-current threshold value of the inverter circuit to exceeding An abnormality detection circuit (abnormality detection circuit) for outputting a short-circuit current protection signal,
A. a first switch element (Q1) turned on by the output of the overcurrent protection signal and a second switch element (Q2) turned on by the output of the shortcurrent protection signal,
B. When both the overcurrent protection signal and the short-circuit current protection signal are not output, the first voltage is outputted,
C. When the overcurrent protection signal is output, a second voltage lower than the first voltage is output,
D. When the short-circuit current protection signal is outputted, it is configured to output a third voltage lower than the second voltage
The error signal output circuit
And the motor driver.
The method according to claim 1,
Wherein the driver circuit stops the drive of the inverter circuit when the overcurrent protection signal is outputted from the abnormality detection circuit and resumes the drive of the inverter circuit after the overcurrent protection period elapses.
3. The method of claim 2,
The drive circuit stops the drive of the inverter circuit when the short-circuit current protection signal is outputted from the abnormality detection circuit, and after all of the drive commands inputted from the host apparatus after the lapse of the short- The drive of the inverter circuit is restarted.

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