JP2006238670A - Drive device for three-phase brushless motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To appropriately protect a motor in a drive device for a three-phase brushless motor. <P>SOLUTION: The driving device is provided with a three-phase drive circuit, constituted of a three-phase source transistor which discharges a drive current to a three-phase drive coil that the three phase brushless motor has, and of a three-phases sync transistor for, to which a drive current flows from the three-phase driving coil, and with a drive control circuit for controlling conduction/non-conduction of the source and sync transistors, based on the relative position of a rotor, with respect to a stator and supplying six drive control signals to the drive circuit. The drive device rotates and drives the three-phase brushless motor, by sequentially switching a conduction direction of the three-phase drive coil to a prescribed conduction direction which is to be set at each prescribed electrical angle, based on the six drive control signals. The device is also provided with a motor protecting circuit, performing motor protection control for stopping an operation of the drive circuit, when it decides that the six drive control signals received from the drive control circuit do not indicate a logical pattern at normal rotation drive, which corresponds to the prescribed conduction direction at each prescribed electrical angle. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a drive device for a three-phase brushless motor.

  The three-phase brushless motor includes a stator (armature) and a rotor (rotor) disposed around the stator. The stator is configured by repeatedly winding a plurality of iron cores arranged radially from the center in the order of a U-phase drive coil, a V-phase drive coil, and a W-phase drive coil. The rotor is configured as a permanent magnet having alternating N and S poles. The three-phase brushless motor sets the energization direction of the drive current flowing in the three-phase (U-phase, V-phase, W-phase) drive coils for each predetermined electrical angle based on the relative position of the rotor with respect to the stator. By sequentially switching in a predetermined energizing direction, a change in the magnetic field is generated between the stator and the rotor, and rotational driving is performed in accordance with the change in the magnetic field.

  A three-phase brushless motor includes a sensor-equipped motor having a position detection element (for example, a hall element) for detecting the relative position of the rotor with respect to the stator, and a counter electromotive force generated in a three-phase drive coil without providing the position detection element. And a sensorless motor that detects the relative position of the rotor with respect to the stator based on the voltage. In the case of a motor with a sensor, mainly as shown in FIG. 22, hall elements 101a to 101c for three phases are arranged around the rotor 107 at intervals of 120 degrees, so that hall elements 101a to 101 for three phases are arranged. A phase difference between the three position detection signals detected from 101c indicates a relationship of an electrical angle of 120 degrees. The example shown in FIG. 22 is a case of a three-phase, four-pole brushless motor, and a U-phase drive coil 105a, a V-phase drive coil 105b, and a W-phase drive coil 105c are respectively provided on three radial iron cores in the stator 106. A rotor 107 made of a permanent magnet having four poles is disposed around the stator 106. Recently, for example, as shown in FIG. 23, three-phase Hall elements 101a to 101c are arranged around the rotor 107 at intervals of 30 degrees, and detected from the three-phase Hall elements 101a to 101c. The case where the phase difference between the three position detection signals thus obtained indicates a relationship of an electrical angle of 60 degrees is also adopted.

  A driving device that rotationally drives a three-phase brushless motor includes a three-phase source transistor that discharges a driving current to a three-phase driving coil and a three-phase sink transistor into which the driving current flows from the three-phase driving coil. And at least a drive control circuit for supplying six drive control signals for controlling the conduction / non-conduction of the three-phase source transistors and the three-phase sink transistors to the drive circuit. Then, the drive device rotates the three-phase brushless motor by sequentially switching the energization directions of the three-phase drive coils as described above based on the six drive control signals.

  Here, when the motor is restrained, the source transistor and the sink transistor of a predetermined phase are turned on according to the rotor position restrained in the drive circuit, respectively, and a driving current flows in a predetermined driving coil of the motor. to continue. In this case, the temperature of the drive circuit and the temperature of the drive coil of the motor will increase. For this reason, the drive device needs a measure for protecting the event that is destroyed by the heat accompanying the temperature rise. FIG. 21 is a diagram showing the configuration of a conventional motor protection circuit which is a case of a motor with a Hall element and which a conventional drive device has. In addition, the conventional motor protection circuit is disclosed by FIG. 8 of the patent document 1 shown below, for example.

  The conventional motor protection circuit shown in FIG. 21 counts up based on a clock input signal and outputs an output signal C for notifying the latch circuit 2 as a latch clock signal when a predetermined count value is reached. When the power supply potential Vcc is latched at the H level at the counter 1 to be supplied and the rising edge (or falling edge) of the output signal C of the counter 1, the output signal OFF (H level: driving) for stopping the operation of the driving device An output signal S (L (L) for notifying the operation state of the three-phase brushless motor by a latch circuit 2 for generating a device operation stop) and an S / S (start / stop) input signal supplied from an external device (such as a microcomputer). Level: start, H level: stop) and edge of a position detection signal detected by a hall element (not shown) An edge detection circuit 4 that detects and generates a pulsed output signal RP indicating the detection, and calculates the logical sum of the output signal S from the S / S circuit 3 and the output signal RP from the edge detection circuit 4 And an OR element 5 for generating an output signal RST (H level: resets the states of the counter 1 and the latch circuit 2) for resetting the states of the counter 1 and the latch circuit 2 from the logical sum thereof.

  As the driving of the three-phase brushless motor starts, the counter 1 starts counting up the count value. At this time, the output signal S of the S / S circuit 3 is at L level (start). When the three-phase brushless motor is in a rotational drive state, a position detection signal generated in a hall element (not shown) is transmitted to the edge detection circuit 4, and as a result, an output signal RP is generated in the edge detection circuit 4. The OR element 5 has the output signal S from the S / S circuit 3 at the L level, but the output signal RP from the edge detection circuit 4 is at the H level by the pulse width. Supply to the counter 1 and the latch circuit 2. Therefore, since the state of the counter 1 is reset at a predetermined cycle, the count value of the counter 1 does not count up to a predetermined count value for generating the output signal C. Therefore, the latch circuit 2 does not generate the H level output signal OFF. That is, the output signal OFF is at the L level.

However, when the motor is restrained, the level of the position detection signal generated in the hall element (not shown) is fixed, so that the output signal RP is not generated in the edge detection circuit 4. The output signal RST of the OR element 5 becomes both L level by the L level output signal S and the output signal RP, and the counter 1 and the latch circuit 2 are not reset. As a result, the count value of the counter 1 continues to count up. When the count value of the counter 1 reaches a predetermined count value, the output signal C is supplied to the latch circuit 2 as a latch clock signal. As a result, based on the output signal OFF (H level) generated in the latch circuit 2, the rotational drive of the three-phase brushless motor is stopped. In this way, protection during motor restraint is achieved.
JP 2001-268971 A

  By the way, in the case of a motor with a Hall element, noise is often mixed in the position detection signal detected by the Hall element when the energization direction of the three-phase drive coil is switched. Further, if the motor is restrained when the energization direction of the three-phase drive coil is switched, chattering may occur in the Hall element position detection signal. Similarly, even in the case of a sensorless motor, a position detection signal indicating the relative position of the rotor with respect to the stator based on the back electromotive voltage generated in the three-phase drive coil when the energization direction of the three-phase drive coil is switched. In this case, there is a risk of noise mixing and chattering. In these cases, the output signal RP of the edge detection circuit 4 and the output signal RST of the OR element 5 form inappropriate signals, and there is a possibility that appropriate motor protection cannot be performed.

  The main present invention that solves the above-described problems is a three-phase source transistor that discharges drive current to a three-phase drive coil of a three-phase brushless motor, and a three-phase portion in which the drive current flows from the three-phase drive coil. And six drive control signals for controlling conduction / non-conduction of the source transistor and the sink transistor based on the relative position of the rotor with respect to the stator in the three-phase brushless motor, respectively. A drive control circuit for supplying the drive circuit to the drive circuit, and based on the six drive control signals, the energization direction of the three-phase drive coil is set to a predetermined energization direction to be set for each predetermined electrical angle. In the three-phase brushless motor drive device that rotationally drives the three-phase brushless motor by sequentially switching When the three-phase brushless motor is in a rotational drive state, the six drive control signals are received from the drive control circuit, and the received six drive control signals are transmitted in the predetermined energization direction for each predetermined electrical angle. A motor protection circuit that performs a motor protection control to stop the operation of the drive circuit when it is determined whether or not the logical pattern at the time of normal rotation driving is indicated and it is determined that the logical pattern is not indicated. And

  ADVANTAGE OF THE INVENTION According to this invention, the drive device of the three-phase brushless motor which performs motor protection appropriately can be provided.

<Configuration of 3-phase brushless motor drive device>
FIG. 1 is a diagram showing a configuration of a driving device for a three-phase brushless motor according to the present invention. In the present embodiment, the three-phase brushless motor is a motor with a Hall element.

  The three-phase brushless motor driving apparatus includes a motor circuit 10 and a motor protection circuit 20. The motor protection circuit 20 includes a latch control circuit 11, a latch circuit 12, an edge detection circuit 13, and an operation state detection circuit 14.

  First, the configuration of the motor circuit 10 will be described based on FIG. 2 with reference to FIGS. 3, 4, 5, 6, and 7 as appropriate.

  The drive circuit 104 for driving the three-phase brushless motor is composed of NPN transistors 104a to 104f.

NPN transistor 104a is a source transistor for discharging drive current from power supply line Vcc to U-phase drive coil 105a, and NPN transistor 104b is for drive current to flow from U-phase drive coil 105a to ground line Vss. It is a sink transistor. The NPN transistors 104a and 104b are connected in series between the power supply line Vcc and the ground line Vss, and the connection portion of the NPN transistors 104a and 104b is connected to one end of the U-phase drive coil 105a.
NPN transistor 104c is a source transistor for discharging drive current from power supply line Vcc to V-phase drive coil 105b, and NPN transistor 104d is for drive current to flow from V-phase drive coil 105b to ground line Vss. It is a sink transistor. The NPN transistors 104c and 104d are connected in series between the power supply line Vcc and the ground line Vss, and the connection portion of the NPN transistors 104c and 104d is connected to one end of the V-phase drive coil 105b.
The NPN transistor 104e is a source transistor for discharging drive current from the power supply line Vcc to the W-phase drive coil 105c, and the NPN transistor 104f is for drive current flowing from the W-phase drive coil 105c to the ground line Vss. It is a sink transistor. The NPN transistors 104e and 104f are connected in series between the power supply line Vcc and the ground line Vss, and the connection portion of the NPN transistors 104e and 104f is connected to one end of the W-phase drive coil 105c.

  Note that the source transistor and the sink transistor constituting the drive circuit 104 are not limited to the bipolar transistors as described above, and may be MOS transistors. Further, a preamplifier may be connected in front of the base electrodes of the source transistor and the sink transistor constituting the driving circuit 104.

  The U-phase drive coil 105a, the V-phase drive coil 105b, and the W-phase drive coil 105c are star-connected and wound around a radial iron core of the stator with a phase difference of 120 electrical degrees. A rotor (not shown) composed of permanent magnets having a predetermined number of poles is disposed around the stator.

  Further, around the rotor, a U-phase Hall element 101a, a V-phase Hall element 101b, and a W-phase Hall element 101c for detecting the relative position of the rotor with respect to the stator are disposed. As shown in FIG. 22, these three-phase Hall elements 101a to 101c are arranged at intervals of 120 ° around the rotor 107, and are detected at three positions detected from the three-phase Hall elements 101a to 101c. As shown in FIG. 23, when the phase difference of the detection signal indicates a relationship of 120 electrical angles, the detection signals are arranged around the rotor 107 at intervals of 30 ° and detected by the hall elements 101a to 101c for three phases. In some cases, the phase difference between the three position detection signals indicates a relationship of an electrical angle of 60 degrees.

  Here, the waveform of the Hall signal in the case of an electrical angle of 120 degrees output from the Hall elements 101a to 101c for three phases is shown in FIG. As shown in the figure, one hall signal HU1, HV1, HW1 output from the hall elements 101a to 101c for three phases has a phase difference of 120 degrees from each other, and the other hall signals HU2, HV2 , HW2 is in a reverse phase relationship. Here, the hall signals HU1 and HU2 are supplied to the U-phase zero-cross detection circuit 102a, the hall signals HV1 and HV2 are supplied to the V-phase zero-cross detection circuit 102b, and the hall signals HW1 and HW2 are supplied to the W-phase zero-cross detection circuit 102c.

  When the Hall signal HU1 is larger than the Hall signal HU2, the U-phase zero-cross detection circuit 102a outputs one logic value, for example, H level, and when the Hall signal HU1 is smaller than the Hall signal HU2, the other logic value is output. For example, L level is output. Here, the output signal of the U-phase zero-cross detection circuit 102a is referred to as a position detection signal IN1 detected by the U-phase Hall element 101a. The position detection signal IN1 is inverted at the point where the hall signal HU1 intersects the hall signal HU2, that is, the zero crossing point.

  When the hall signal HV1 is larger than the hall signal HV2, the V-phase zero-cross detection circuit 102b outputs, for example, an H level that is one of the logical values. When the hall signal HV1 is smaller than the hall signal HV2, the V-phase zero-cross detection circuit 102b For example, L level is output. Here, the output signal of the V-phase zero-cross detection circuit 102b is referred to as a position detection signal IN2 detected by the V-phase Hall element 101b. The position detection signal IN2 is inverted at the point where the hall signal HV1 intersects the hall signal HV2, that is, at the zero cross point.

  When the hall signal HW1 is larger than the hall signal HW2, the W-phase zero-cross detection circuit 102c outputs, for example, an H level that is one of the logical values. When the hall signal HW1 is smaller than the hall signal HW2, the other logical value. For example, L level is output. Here, the output signal of the W-phase zero-cross detection circuit 102c is referred to as a position detection signal IN3 detected by the W-phase Hall element 101c. The position detection signal IN3 is inverted at the point where the hall signal HW1 intersects the hall signal HW2, that is, the zero crossing point.

  Here, the position detection signals IN1 to IN3 correspond to the case where the phase difference indicates an electrical angle of 120 degrees as shown in FIG. 6 according to the arrangement positions of the hall elements 101a to 101c for the three phases, and FIG. In some cases, the phase difference indicates a relationship of an electrical angle of 60 degrees.

  Based on the position detection signal IN1 from the U-phase zero-cross detection circuit 102a, the position detection signal IN2 from the V-phase zero-cross detection circuit 102b, and the position detection signal IN3 from the W-phase zero-cross detection circuit 102c, the drive control circuit 103 In order to switch the energization direction of the drive current flowing through the phase drive coil 105a, V-phase drive coil 105b, and W-phase drive coil 105c to a predetermined energization direction that should be set for each predetermined electrical angle, the NPN transistors 104a to 104f are turned on. / Six drive control signals UH, UL, VH, VL, WH, WL for controlling non-conduction are generated.

  The drive control signal UH is supplied to the base electrode of the NPN transistor 104a to control conduction / non-conduction, and the drive control signal UL is supplied to the base electrode of the NPN transistor 104b to control conduction / non-conduction. The drive control signal VH is supplied to the base electrode of the NPN transistor 104c to control conduction / non-conduction, and the drive control signal VL is supplied to the base electrode of the NPN transistor 104d to control conduction / non-conduction. The drive control signal WH is supplied to the base electrode of the NPN transistor 104e to control its conduction / non-conduction, and the drive control signal WL is supplied to the base electrode of the NPN transistor 104f to control its conduction / non-conduction. Is.

  The drive control circuit 103 is configured as a logic circuit as shown in FIG. 4, for example, when the phase differences between the position detection signals IN1 to IN3 indicate a relationship of 120 electrical degrees. The energization logic of the drive control circuit 103 shown in FIG. 4 is shown as the truth table in FIG. As shown in the truth table of FIG. 5, the combination of the position detection signals IN1, IN2, and IN3 has six modes a to f for every 60 electrical angles. Further, in order of modes a to f, the V-phase drive coil 105b to the U-phase drive coil 105a, the W-phase drive coil 105c to the U-phase drive coil 105a, the W-phase drive coil 105c to the V-phase drive coil 105b, the U-phase The energization direction is switched from drive coil 105a to V-phase drive coil 105b, U-phase drive coil 105a to W-phase drive coil 105c, and V-phase drive coil 105b to W-phase drive coil 105c.

  Further, the drive control circuit 103 has a case where each phase difference between the position detection signals IN1 to IN3 is an electrical angle of 120 degrees even when each phase difference between the position detection signals IN1 to IN3 indicates a relationship of 60 electrical degrees. Although the combination of logic patterns is different from the above, it is realized by a logic circuit similar to the logic circuit shown in FIG. Specifically, when each phase difference between the position detection signals IN1 to IN3 is an electrical angle of 60 degrees, when the position detection signals IN1 to IN3 are in the mode a in the modes a to f shown in FIG. , L ”,“ b ”for mode b,“ H, H, H ”for mode c,“ L, H, H ”for mode d,“ L ”for mode e , L, H ”and mode f are different in that they are“ L, L, L ”. In this case, the logic patterns of the six drive control signals UH, UL, VH, VL, WH, WL are the same as the logic patterns shown in the modes a to f shown in FIG. That is, the drive control circuit 103 is configured as a logic circuit that realizes such a logic pattern using the position detection signals IN1 to IN3.

  The AND element 108a calculates a logical product of the drive control signal UL and a stop signal / OFF described later, and supplies the logical product to the base electrode of the NPN transistor 104b. The AND element 108b calculates a logical product of the drive control signal VL and a stop signal / OFF described later, and supplies this logical product to the base electrode of the NPN transistor 104d. The AND element 108c calculates a logical product of the drive control signal WL and a stop signal / OFF described later, and supplies this logical product to the base electrode of the NPN transistor 104f. That is, when a stop signal OFF (to be described later) is at an H level, the NPN transistors 104b, 104d, and 104f are all turned off all at once. This stops energization of the drive currents of the U-phase drive coil 105a, the V-phase drive coil 105b, and the W-phase drive coil 105c. The AND elements 108a to 108c may be provided on the source transistor side, that is, on the NPN type transistors 104a, 104c, and 104e side.

  Next, the configuration of the motor protection circuit 20 will be described with reference to FIG. 1, referring to FIGS. 5, 6, 7, 8, 9, 10, 10, 11, 12, 16, and 17 as appropriate. And explained.

  The motor protection circuit 20 receives six drive control signals UH, UL, VH, VL, WH, WL from the drive control circuit 103 when the three-phase brushless motor is in a rotational drive state, and receives these received six drives. Whether the control signals UH, UL, VH, VL, WH, WL indicate a logical pattern during normal rotation driving according to a predetermined energization direction for each predetermined electrical angle (for example, every 60 degrees electrical angle) When it is determined that the logic pattern during normal rotation driving is not indicated, motor protection control is performed to stop energization of the driving current of the U-phase driving coil 105a, V-phase driving coil 105b, and W-phase driving coil 105c. Is. In this motor protection control, an H level stop signal OFF is output from the operation state detection circuit 14, and then an L level stop signal / OFF logically inverted by an inverter element is supplied to the AND elements 108a to 108c. It is carried out.

  Here, the logic pattern during normal rotation driving of the six drive control signals UH, UL, VH, VL, WH, WL indicates a relationship in which each phase difference of the position detection signals IN1 to IN3 has an electrical angle of 120 degrees, for example. In this case, a logical pattern as shown in FIG. 6 is shown based on the modes a to f for every electrical angle of 60 degrees in the truth table shown in FIG. In addition, when each phase difference of position detection signals IN1-IN3 shows the relationship of 60 electrical degrees, it shows in FIG. 7 based on mode af for every electrical angle 60 degrees of the truth table shown in FIG. Such a logical pattern is shown. That is, when FIG. 6 is compared with FIG. 7, the logic pattern during normal rotation driving of the six drive control signals UH, UL, VH, VL, WH, WL is independent of the phase relationship of the position detection signals IN1 to IN3. A certain combination is shown for each predetermined electrical angle. Note that the logic pattern when the six drive control signals UH, UL, VH, VL, WH, WL are not in normal rotation drive is, for example, when the motor is restrained as shown in FIGS. It is a logical pattern.

  Therefore, the motor protection circuit 20 according to the present invention is significantly different from the conventional motor protection control using the position detection signals IN1 to IN3 whose phase difference is variable depending on the arrangement positions of the Hall elements 101a to 101c. The motor protection control according to the present invention is performed using six drive control signals UH, UL, VH, VL, WH, WL indicating combinations of constant logic patterns for each corner. That is, according to the present invention, general-purpose motor protection control can be performed regardless of the configuration of the motor circuit 10.

  The motor protection circuit 20 is configured by a stop reset signal generation circuit 30 and an operation state detection circuit 14 so that the stop signal OFF generation by the reset signal RST shown in FIG. By following this, it can be easily configured.

The stop reset signal generation circuit 30 receives six drive control signals UH, UL, VH, VL, WH, WL from the drive control circuit 103, and receives the received six drive control signals UH, UL, VH, VL, It is determined whether WH and WL indicate a logical pattern during normal rotation driving according to a predetermined energization direction for each predetermined electrical angle. When the stop reset signal generation circuit 30 determines that the logic pattern during normal rotation driving is indicated, the stop reset signal generation circuit 30 sequentially generates the stop reset signal RP and detects the operation state within a predetermined period (eg, electrical angle of 360 degrees). Transmit to circuit 14. The stop reset signal RP is a signal for setting whether to reset the generation of the stop signal OFF in the operation state detection circuit 14. On the other hand, the stop reset signal generation circuit 30 stops the generation of the stop reset signal RP and the transmission to the operation state detection circuit 14 when it is determined that the logic pattern during normal rotation driving is not indicated.
The stop reset signal generation circuit 30 includes a latch control circuit 11, a latch circuit 12, and an edge detection circuit 13.

  The latch control circuit 11 receives six drive control signals UH, UL, VH, VL, WH, WL from the drive control circuit 103, and receives the received six drive control signals UH, UL, VH, VL, WH, It is determined whether or not WL indicates a logical pattern during normal rotation driving corresponding to a predetermined energization direction for each predetermined electrical angle. When the latch control circuit 11 determines that the logic pattern during normal rotation driving is indicated, the latch control circuit 11 responds to the logic patterns of the six drive control signals UH, UL, VH, VL, WH, WL during normal rotation driving. The generated latch clock signal PN12 and latch reset signal PA3 are supplied to the latch circuit 12. On the other hand, when the latch control circuit 11 determines that the logic pattern at the time of normal rotation driving is not shown, the latch control circuit 11 is fixed to either the H level or the L level and does not generate an edge, or the H level. Alternatively, a latch reset signal PA3 fixed at one of the L levels is generated and supplied to the latch circuit 12.

  The latch circuit 12 is set at the edge of the latch clock signal PN12, and is reset by the H level (or L level) of the latch reset signal PA3. Then, the latch circuit 12 generates the pulse signal P with the switching from the set state to the reset state. Here, one configuration example of the latch circuit 12 is shown in FIG. As shown in FIG. 8, the latch circuit 12 can be configured by a D flip-flop 121. In the D flip-flop 121, the power supply potential Vcc is applied to the data input terminal D, the latch clock signal PN12 is supplied to the clock input terminal CL, the latch reset signal PA3 is supplied to the reset terminal R, and the output terminal Q Thus, a pulse signal P is output.

  In this configuration, for example, as shown in FIG. 9, when the latch clock signal PN12 is supplied to the clock input terminal CL, the output terminal Q becomes the H level (set state) at the falling edge of the latch clock signal PN12. . Further, when the latch reset signal PA3 is supplied to the reset terminal R, the output terminal Q becomes L level (reset state) when the latch reset signal PA3 is H level. That is, the output terminal Q latches the H level from the falling edge of the latch clock signal PN12 supplied to the clock input terminal CL to the rising edge of the latch reset signal PA3 supplied to the reset terminal R. As a result, , A pulse signal P is output.

  Here, even when the latch clock signal PN12 and the latch reset signal PA3 are, for example, as shown in FIGS. 6 and 7, the phase differences between the position detection signals IN1 to IN3 indicate a relationship of an electrical angle of 120 degrees. Even when a relationship of 60 electrical angles is shown, a constant logic pattern is shown for each predetermined electrical angle. This is because, as described above, there are six drive controls regardless of whether the phase differences of the position detection signals IN1 to IN3 indicate a relationship of 120 electrical degrees or a relationship of 60 electrical angles. This is because the logic patterns of the signals UH, UL, VH, VL, WH, WL are the same. The latch clock signal PN12 and the latch reset signal PA3 are always generated at least at every electrical angle of 360 degrees without overlapping timing.

  That is, when the three-phase brushless motor is normally driven, the latch circuit 12 sets the set state and the reset state every predetermined period (for example, electrical angle 360 degrees) by the latch clock signal PN12 and the latch reset signal PA3. It must be generated at different generation timings. As a result, the edge of the pulse signal P is always generated every predetermined period.

  On the other hand, when the operation of the three-phase brushless motor becomes abnormal, such as when the motor is restrained, the latch circuit 12 is fixed to either the H level or the L level, and the latch clock signal PN12 and the H level or L that do not cause an edge. The previous state is held by the latch reset signal PA3 fixed at one of the levels. As a result, the edge of the pulse signal P is not generated every predetermined period.

  Here, the latch clock signal and the latch reset signal generated according to the logic patterns of the six drive control signals UH, UL, VH, VL, WH, and WL in the latch control circuit 11 will be described in detail.

  First, the latch control circuit 11 is based on the six drive control signals UH, UL, VH, VL, WH, WL received from the drive control circuit 103, and is a logical product PA1 of the drive control signal UL and the drive control signal VH ( (UL and VH), a logical product PA2 (VL and WH) of the drive control signal VL and the drive control signal WH, and a logical product PA3 (WL and UH) of the drive control signal WL and the drive control signal UH. .

  Next, the latch control circuit 11 includes an inverted logical sum PN12 (PA1 nor PA2) of the logical product PA1 and the logical product PA2, an inverted logical sum PN13 (PA1 nor PA3) of the logical product PA1 and the logical product PA3, and a logical product PA2. And an inversion logical sum PN23 (PA2 nor PA3) of the logical product PA3.

  Then, the latch control circuit 11 selects any one of the logical products PA1 to PA3 and uses it as a latch reset signal, and any two of the logical products PA1 to PA3 that are not selected as the latch reset signal. One of the inverted logical sums PN12, PN13, and PN23 based on the above is selected and used as a latch clock signal. In the above-described embodiment, the logical product PA3 is selected as the latch reset signal, and the logical product PA1 and the inverted logical sum PN12 of the logical product PA2 that are not selected are selected as the latch reset signal as the latch clock signal. . That is, as other combinations other than the embodiment described above, a combination of the latch reset signal PA1 and the latch clock signal PN23 and a combination of the latch reset signal PA2 and the latch clock signal PN13 can be adopted.

  The edge detection circuit 13 receives the pulse signal P from the latch circuit 12 and detects the edge of the received pulse signal P. Then, a stop reset signal RP indicating that the edge has been detected is generated. Here, a configuration example of the edge detection circuit 13 is shown in FIG. As shown in FIG. 10, the edge detection circuit 13 can be configured by combining D flip-flops 131 and 132 and an AND element 133.

  In this configuration, for example, as shown in FIG. 11, the reset stop signal RP having a predetermined pulse width is generated by the rising edge of the pulse signal P. Specifically, first, the initial state of the output terminal Q of the D flip-flop 131 is L level, and the initial state of the output terminal Q of the D flip-flop 132 is H level. That is, the reset stop signal RP output from the AND element 133 is at the L level. Here, in the D flip-flop 131, when the pulse signal P supplied to the data input terminal D indicates a rising edge, the output terminal Q is set to the H level by the falling edge of the clock input signal supplied to the clock input terminal CL. (Set state). As a result, the reset stop signal RP output from the AND element 133 becomes H level.

  Next, in the D flip-flop 132, the inverted output of the D flip-flop 131 supplied to the data input terminal D, that is, the L level is set by the falling edge of the next cycle of the clock input signal supplied to the clock input terminal CL. Latched. For this reason, the reset stop signal RP output from the AND element 133 becomes L level. In this way, the reset stop signal RP is generated.

  Note that the edge detection circuit 13 is not limited to the configuration described above, and may be configured with, for example, a one-shot multivibrator. The edge detection circuit 13 may generate a stop reset signal RP indicating that the falling edge of the pulse signal P has been detected and indicate the detection, or both the rising edge and the falling edge of the pulse signal P. An edge may be detected and a stop reset signal RP indicating that each edge is detected may be generated. The circuit configuration can be simplified by detecting only one edge of the pulse signal P.

  As described above, the stop reset signal generation circuit 30 uses the latch clock signal PN12 and the latch reset signal PA3 that are generated by appropriately performing logical operations on the six drive control signals UH, UL, VH, VL, WH, and WL. Here, when the three-phase brushless motor is normally driven, that is, when the six drive control signals UH, UL, VH, VL, WH, WL indicate a normal logic pattern for each predetermined electrical angle, the latch clock The signal PN12 and the latch reset signal PA3 have a relationship that is always generated at different timings for each predetermined period. In the present invention, the stop reset signal generation circuit 30 is easily realized by utilizing this relationship.

  The operation state detection circuit 14 detects the operation state of the three-phase brushless motor. The operation state detection circuit 14 includes an S / S (L level: start, H level: stop) input signal instructed by an external device (such as a microcomputer) (not shown), and a stop reset generated by the stop reset signal generation circuit 30. A signal RP is input. Therefore, the operation state detection circuit 14 can detect whether or not an external device has instructed the drive device to rotate the three-phase brushless motor.

  The operation state detection circuit 14 detects the actual operation state of the three-phase brushless motor instructed from the external device based on the stop reset signal RP received from the stop reset signal generation circuit 30. More specifically, the operation state detection circuit 14 determines that the motor restraint or the like when the reception interval of the stop reset signal RP exceeds the generation interval of the stop reset signal RP when the stop reset signal generation circuit 30 is driven to rotate normally. It is determined that an abnormality has occurred, and a stop signal OFF for stopping the operation of the drive circuit 104 is generated and supplied to the drive circuit 104.

  FIG. 12 is a configuration example of the operation state detection circuit 14. The operation state detection circuit 14 shown in FIG. 12 starts counting when the driving of the three-phase brushless motor starts, and when the count value reaches a predetermined value (at least an appropriate value exceeding 360 electrical angles), this fact is indicated. A notification signal C is generated, and a counter circuit 141 that resets the count value when the stop reset signal RP is received. The notification signal C is received from the count circuit 141, and the stop signal OFF is turned on by the edge of the received notification signal C. A latch circuit 142 that generates an output signal SD (H level: drive stopped, L level: drive continued) for setting the stop signal OFF when the stop reset signal RP is received, 3 phase brushless by S / S (start / stop) input signal supplied from (microcomputer etc.) S / S circuit 143 for generating an output signal S (L level: start, H level: stop) for notifying the operation state of the data, output signal S from S / S circuit 143, and stop from edge detection circuit 13 An OR element 144 for calculating the logical sum of the reset signals RP and generating an output signal RST (H level: reset, L level: reset release) for resetting the state of the counter 141 and the latch circuit 142 from the logical sum; The OR element 145 generates a stop signal OFF by calculating the logical sum of the output signal S from the S / S circuit 143 and the output signal SD from the latch circuit 142. As described above, when detecting the operation state of the three-phase brushless motor, the counter 141 outputs the stop reset signal RP without depending on the predetermined relationship established between the latch clock signal PN12 and the latch reset signal PA3. By verifying the predetermined period that is not generated, the certainty of the motor protection control is increased.

  FIG. 13 shows another configuration example of the operation state detection circuit 14. The operation state detection circuit 14 shown in FIG. 13 starts charging the capacitive element 147 when the driving of the capacitive element 147 and the three-phase brushless motor starts instead of the counter 141 and the latch circuit 142 shown in FIG. In addition, the charge / discharge circuit 146 that stops charging and starts discharging when the stop reset signal RP is received is compared with the charge / discharge voltage of the capacitor 147 and a predetermined reference voltage Vref. And a comparator 148 that generates an output signal SD indicating that the charge / discharge voltage of the element 147 exceeds the reference voltage Vref. In this case, as compared with the configuration example shown in FIG. 12, the design timing constraint is relaxed, and therefore, it can be easily realized.

<Motor protection control of 3-phase brushless motor drive>
<< When each phase difference of position detection signal is electrical angle 120 degrees >>
=== In case of motor restraint at the rising edge of position detection signal ===
The motor protection control of the driving device for the three-phase brushless motor will be described with reference to FIG. 14 with reference to FIGS. 5, 6, and 16 as appropriate. It is assumed that the position detection signals IN1 to IN3 indicate a phase difference of 120 electrical degrees as shown in FIG.

  First, motor protection control when the motor is restrained when the position detection signal IN1 rises will be described.

  Here, the time of rising of the position detection signal IN1 corresponds to the mode a shown in FIG. Mode a is a case where the position detection signal IN1 is at the H level, the position detection signal IN2 is at the L level, and the position detection signal IN3 is at the H level. When the motor is restrained when the position detection signal IN1 rises, the position detection signal IN1 chatters repeatedly between H level and L level, and the other position detection signals IN2 and IN3 maintain the level. . That is, in this case, only mode a and mode f shown in FIG. 5 occur repeatedly.

  FIG. 14A shows position detection signals IN1 to IN3 and six drive control signals UH, UL, mode a and mode f when the motor is restrained (or mixed with noise) when the position detection signal IN1 rises. The logical levels of VH, VL, WH, WL, logical products PA1 to PA3, and inverted logical sums PN12, PN13, and PN23 are shown.

  As shown in FIG. 14A, in this case, the position detection signal IN1 and the drive control signals UL and WL are subject to chattering that repeats H level and L level. Meanwhile, the logical product PA3, that is, the latch reset signal PA3, remains at the L level in both the mode a and the mode f. Therefore, the latch circuit 12 is not reset by the latch reset signal PA3 remaining at the L level, and the power supply potential Vcc is always latched at the H level, so that the pulse signal P cannot cause an edge thereafter.

  Then, since the stop reset signal RP is not generated in the edge detection circuit 13, the operation state detection circuit 14 generates a stop signal OFF and transmits it to the drive circuit 104 after a predetermined period. As a result, the rotational driving of the three-phase brushless motor is reliably stopped, and the motor protection control is appropriately performed. The waveform diagram of the main signal described above is shown in FIG. 16 for reference.

  Next, similarly to the above, the motor protection control when the motor is restrained (or mixed with noise) when the position detection signal IN2 rises will be described.

  Here, the time of rising of the position detection signal IN2 corresponds to the mode c shown in FIG. Mode c is a case where the position detection signal IN1 is at the H level, the position detection signal IN2 is at the H level, and the position detection signal IN3 is at the L level. When the motor is restrained at the rising edge of the position detection signal IN2, the position detection signal IN2 chatters repeatedly between the H level and the L level, and the other position detection signals IN1 and IN3 maintain the level. . That is, in this case, only mode b and mode c shown in FIG. 5 occur repeatedly.

  FIG. 14B shows the position detection signals IN1 to IN3 and the six drive control signals UH, UL, VH, VL, and WH in the mode b and the mode c when the motor is restrained when the position detection signal IN2 rises. , WL, logical products PA1 to PA3, and logical levels of inverted logical sums PN12, PN13, and PN23.

  As shown in FIG. 14B, in this case, the position detection signal IN2 and the drive control signals UL and VL are chattered repeatedly between H level and L level. Meanwhile, the logical product PA3, that is, the latch reset signal PA3, remains at the L level in both the mode a and the mode f. Therefore, the latch circuit 12 is not reset by the latch reset signal PA3 remaining at the L level, and the power supply potential Vcc is always latched at the H level, so that the pulse signal P cannot cause an edge thereafter.

  Then, since the stop reset signal RP is not generated in the edge detection circuit 13, the operation state detection circuit 14 generates a stop signal OFF and transmits it to the drive circuit 104 after a predetermined period. As a result, the rotational driving of the three-phase brushless motor is reliably stopped, and the motor protection control is appropriately performed.

  Next, similarly to the above, the motor protection control when the motor is restrained (or mixed with noise) when the position detection signal IN3 rises will be described.

  Here, the rising edge of the position detection signal IN3 corresponds to the mode e shown in FIG. Note that the mode e is a case where the position detection signal IN1 is L level, the position detection signal IN2 is H level, and the position detection signal IN3 is H level. When the motor is restrained at the rising edge of the position detection signal IN3, the position detection signal IN3 chatters repeatedly between the H level and the L level, and the other position detection signals IN1 and IN2 are held at the level. . That is, in this case, only mode d and mode e shown in FIG. 5 are repeatedly generated.

  FIG. 14C shows the position detection signals IN1 to IN3 and the six drive control signals UH, UL, VH, VL, and WH in the modes d and e when the motor is restrained when the position detection signal IN3 rises. , WL, logical products PA1 to PA3, and logical levels of inverted logical sums PN12, PN13, and PN23.

  As shown in FIG. 14C, in this case, the position detection signal IN3 and the drive control signals VL and WL are chattered repeatedly between H level and L level. Incidentally, the logical product PA3, that is, the latch reset signal PA3, repeats the H level and the L level in the modes d and e. However, the inverted logical sum PN12, that is, the latch clock signal PN12 remains at the H level in the modes d and e.

  Therefore, the latch circuit 12 does not subsequently latch the power supply potential Vcc at the H level by the latch clock signal PN12 that cannot generate an edge while maintaining the H level, and the pulse signal P cannot subsequently generate an edge. Then, since the stop reset signal RP is not generated in the edge detection circuit 13, the operation state detection circuit 14 generates a stop signal OFF and transmits it to the drive circuit 104 after a predetermined period. As a result, the rotational driving of the three-phase brushless motor is reliably stopped, and the motor protection control is appropriately performed.

=== When the motor is restrained when the position detection signal falls ===
The motor protection control of the three-phase brushless motor driving device will be described with reference to FIG. 15 with reference to FIGS. 5, 6, and 16 as appropriate. It is assumed that the position detection signals IN1 to IN3 indicate a phase difference of 120 electrical degrees as shown in FIG. First, motor protection control when the motor is restrained when the position detection signal IN1 falls will be described.

  Here, the time of the fall of the position detection signal IN1 corresponds to the mode d shown in FIG. The mode d is a case where the position detection signal IN1 is L level, the position detection signal IN2 is H level, and the position detection signal IN3 is L level. When the motor is restrained at the time of the fall of the position detection signal IN1, the position detection signal IN1 is subject to chattering that repeats the H level and the L level, and the other position detection signals IN2 and IN3 are held at the level. Become. That is, in this case, only mode c and mode d shown in FIG. 5 occur repeatedly.

  FIG. 15A shows the position detection signals IN1 to IN3 and the six drive control signals UH and UL in the modes c and d when the motor is restrained (or mixed with noise) when the position detection signal IN1 falls. , VH, VL, WH, WL, logical products PA1 to PA3, and inverted logical sums PN12, PN13, and PN23.

  As shown in FIG. 15A, in this case, the position detection signal IN1 and the drive control signals UH and WH are chattered repeatedly between H level and L level. Incidentally, the logical product PA3, that is, the latch reset signal PA3, remains at the L level in both the mode c and the mode d. Therefore, the latch circuit 12 is not reset by the latch reset signal PA3 remaining at the L level, and the power supply potential Vcc is always latched at the H level, so that the pulse signal P cannot cause an edge thereafter.

  Then, since the stop reset signal RP is not generated in the edge detection circuit 13, the operation state detection circuit 14 generates a stop signal OFF and transmits it to the drive circuit 104 after a predetermined period. As a result, the rotational driving of the three-phase brushless motor is reliably stopped, and the motor protection control is appropriately performed.

  Next, similarly to the above, the motor protection control when the motor is restrained (or mixed with noise) when the position detection signal IN2 falls is described.

  Here, the time of the fall of the position detection signal IN2 corresponds to the mode f shown in FIG. The mode f is a case where the position detection signal IN1 is L level, the position detection signal IN2 is L level, and the position detection signal IN3 is H level. When the motor is restrained at the time of the fall of the position detection signal IN2, the position detection signal IN2 is subject to chattering that repeats the H level and the L level, and the other position detection signals IN1 and IN3 are held at the level. Become. That is, in this case, only mode e and mode f shown in FIG. 5 occur repeatedly.

  FIG. 15B shows the position detection signals IN1 to IN3 and the six drive control signals UH and UL in the mode e and the mode f when the motor is restrained (or mixed with noise) when the position detection signal IN2 falls. , VH, VL, WH, WL, logical products PA1 to PA3, and inverted logical sums PN12, PN13, and PN23.

  As shown in FIG. 15B, in this case, the position detection signal IN2 and the drive control signals UH and VH are chattered repeatedly between the H level and the L level. Incidentally, the logical product PA3, that is, the latch reset signal PA3, repeats the H level and the L level in the mode e and the mode f. However, the inverted logical sum PN12, that is, the latch clock signal PN12 remains at the H level in the mode e and the mode f.

  Therefore, the latch circuit 12 does not subsequently latch the power supply potential Vcc at the H level by the latch clock signal PN12 that cannot generate an edge while maintaining the H level, and the pulse signal P cannot subsequently generate an edge. Then, since the stop reset signal RP is not generated in the edge detection circuit 13, the operation state detection circuit 14 generates a stop signal OFF and transmits it to the drive circuit 104 after a predetermined period. As a result, the rotational driving of the three-phase brushless motor is reliably stopped, and the motor protection control is appropriately performed.

  Next, similarly to the above, the motor protection control when the motor is restrained when the position detection signal IN3 falls is described.

  Here, the time of the fall of the position detection signal IN3 corresponds to the mode b shown in FIG. Mode b is a case where the position detection signal IN1 is at the H level, the position detection signal IN2 is at the L level, and the position detection signal IN3 is at the L level. When the motor is restrained at the time of the fall of the position detection signal IN3, the position detection signal IN3 is subject to chattering that repeats the H level and the L level, and the other position detection signals IN1 and IN2 are held at the level. Become. That is, in this case, only mode a and mode b shown in FIG. 5 occur repeatedly.

  FIG. 15C shows the position detection signals IN1 to IN3 and the six drive control signals UH, UL, VH, VL, mode a and mode b when the motor is restrained when the position detection signal IN3 falls. The logical levels of WH and WL, logical products PA1 to PA3, and inverted logical sums PN12, PN13, and PN23 are shown.

  As shown in FIG. 15C, in this case, the position detection signal IN3 and the drive control signals VH and WH are subject to chattering that repeats H level and L level. Meanwhile, the logical product PA3, that is, the latch reset signal PA3, remains at the L level in both the mode a and the mode b. Therefore, the latch circuit 12 is not reset by the latch reset signal PA3 remaining at the L level, and the power supply potential Vcc is always latched at the H level, so that the pulse signal P cannot cause an edge thereafter.

  Then, since the stop reset signal RP is not generated in the edge detection circuit 13, the operation state detection circuit 14 generates a stop signal OFF and transmits it to the drive circuit 104 after a predetermined period. As a result, the rotational driving of the three-phase brushless motor is reliably stopped, and the motor protection control is appropriately performed.

<< When each phase difference of position detection signal is electrical angle 60 degrees >>
Next, refer to FIGS. 6 and 7 for motor protection control of the driving device for the three-phase brushless motor when the position detection signals IN1 to IN3 indicate a phase difference of 60 degrees as shown in FIG. However, a description will be given based on FIG.

  As described above, when comparing FIG. 6 and FIG. 7, even if the phase difference between the position detection signals IN1 to IN3 indicates an electrical angle of 120 degrees or an electrical angle of 60 degrees. When the three-phase brushless motor is driven to rotate normally, the logical patterns of the six drive control signals UH, UL, VH, VL, WH, WL, logical products PA1 to PA3, and inverted logical sums PN12, PN13, and PN23 match.

  Therefore, even when the motor is restrained at the rising or falling edge of any one of the position detection signals IN1 to IN3, as described above, the latch reset signal PA3 that remains at the L level. Alternatively, the pulse signal P output from the latch circuit 12 cannot generate an edge by the latch clock signal PN12 that remains at the H level and cannot generate an edge.

  Then, since the stop reset signal RP is not generated in the edge detection circuit 13, the operation state detection circuit 14 generates a stop signal OFF and transmits it to the drive circuit 104 after a predetermined period. As a result, the rotational drive of the three-phase brushless motor is surely stopped and the motor protection control is appropriately performed.

  Although the present embodiment has been described above, the above-described examples are for facilitating the understanding of the present invention, and are not intended to limit the present invention. The present invention can be changed / improved without departing from the spirit thereof, and the present invention includes equivalents thereof.

<Application example for sensorless motor>
The above-described embodiment shows a case of a motor with a sensor having position detection elements such as Hall elements 101a to 101c. However, the driving device for a three-phase brushless motor according to the present invention is applied to a sensorless motor. It is also possible. Hereinafter, application examples thereof will be described.

FIG. 18 is a diagram showing a configuration of a motor circuit 10 for a sensorless three-phase brushless motor.
The configuration of the motor circuit 10 shown in FIG. 18 is obtained by removing the Hall elements 101a to 101c from the motor circuit 10 with the sensor shown in FIG. Further, the coil voltage Vu generated at one end of the U-phase drive coil 105a, the coil voltage Vv generated at one end of the V-phase drive coil 105b, and the coil voltage Vw generated at one end of the W-phase drive coil 105c are converted into the U-phase zero-cross detection circuits 109a, V The phase zero cross detection circuit 109b and the W phase zero cross detection circuit 109c are supplied. Further, the neutral point voltage Vcom of the U-phase drive coil 105a, the V-phase drive coil 105b, and the W-phase drive coil 105c is supplied to the zero-cross detection circuits 109a to 109c for three phases.

  Here, the U-phase zero-cross detection circuit 109a compares the coil voltage Vu and the neutral point voltage Vcom, and when the coil voltage Vu is larger than the neutral point voltage Vcom, for example, outputs an H level as one logic level, When the coil voltage Vu is smaller than the neutral point voltage Vcom, for example, L level is output as the other logic level. Similarly, the V-phase zero-cross detection circuit 109b compares the coil voltage Vv and the neutral point voltage Vcom, and outputs, for example, an H level as one logic level when the coil voltage Vv is greater than the neutral point voltage Vcom. When the coil voltage Vv is smaller than the neutral point voltage Vcom, for example, L level is output as the other logic level. Similarly, the W-phase zero-cross detection circuit 109c compares the coil voltage Vw and the neutral point voltage Vcom, and when the coil voltage Vw is larger than the neutral point voltage Vcom, for example, outputs an H level as one logic level, When the coil voltage Vw is smaller than the neutral point voltage Vcom, for example, L level is output as the other logic level.

  FIG. 19 shows signals Vu, Vv, Vw, Vcom supplied to the zero-cross detection circuits 109a to 109c for three phases, and position detection signals Uo, which are outputs of the zero-cross detection circuits 109a to 109c for three phases. It is a figure which shows the waveform of Vo and Wo.

  FIG. 20 is a truth table showing an example of the energization logic of the drive control circuit 110 for the sensorless motor. The drive control circuit 110 for the sensorless motor has six drives corresponding to the truth table shown in FIG. 20 based on the position detection signals Uo, Vo, Wo output from the zero-cross detection circuits 109a to 109c for three phases. A logic pattern of the control signals UH, UL, VH, VL, WH, WL is generated. Then, the drive control circuit 110 for the sensorless motor, based on the generated six drive control signals UH, UL, VH, VL, WH, WL, U-phase drive coil 105a, V-phase drive coil 105b, W-phase drive The energizing direction of the drive current to the coil 105c is appropriately switched. As a result, the sensorless motor is driven to rotate.

  Therefore, when the motor protection control according to the present invention is applied to the sensorless motor driving device, the motor protection circuit 20 is driven by the drive control signals UH, UL, VH, VL generated by the sensorless motor driving control circuit 110. , WH, WL are used to generate a stop signal OFF for stopping the operation of the drive circuit 104, as in the above-described embodiment. As a result, even when the position detection signals Uo, Vo, Wo have noise or chattering at the start of driving the sensorless motor, appropriate motor protection is achieved.

It is a figure which shows the structure of the drive device of the three-phase brushless motor which concerns on one Embodiment of this invention. It is a figure which shows the structure of the motor circuit which concerns on one Embodiment of this invention. It is a figure which shows the waveform of the zero cross detection circuit output which concerns on one Embodiment of this invention. It is a figure which shows the structure of the drive control circuit which concerns on one Embodiment of this invention. It is a figure which shows the truth table according to operation | movement of the drive control circuit which concerns on one Embodiment of this invention. It is a figure which shows the waveform of the main signal in case the phase difference of the position detection signal for 3 phases which concerns on one Embodiment of this invention is an electrical angle of 120 degree | times. It is a figure which shows the waveform of the main signal in case the phase difference of the position detection signal for 3 phases which concerns on one Embodiment of this invention is an electrical angle of 60 degree | times. It is a figure which shows the structure of the latch circuit which concerns on one Embodiment of this invention. 6 is a timing chart showing an operation of the latch circuit according to the embodiment of the present invention. It is a figure which shows the structure of the edge detection circuit which concerns on one Embodiment of this invention. 3 is a timing chart showing an operation of the edge detection circuit according to the embodiment of the present invention. It is a figure which shows the structure of the operation state detection circuit which concerns on one Embodiment of this invention. It is a figure which shows the other structure of the operation state detection circuit which concerns on one Embodiment of this invention. FIG. 14A is a diagram showing a logical value calculated by the latch control circuit when the motor is constrained when the position detection signal IN1 rises, and FIG. 14B is a diagram when the motor is constrained when the position detection signal IN2 rises. FIG. 14C is a diagram showing a logical value calculated by the latch control circuit when the motor is restrained when the position detection signal IN3 rises. is there. FIG. 15A is a diagram showing a logical value calculated by a latch control circuit when the motor is restrained when the position detection signal IN1 falls, and FIG. 15B shows a motor value when the position detection signal IN2 falls. FIG. 15C is a diagram illustrating a logical value calculated by the latch control circuit when restrained, and FIG. 15C illustrates a logical value calculated by the latch control circuit when the motor is restrained by the falling edge of the position detection signal IN3. FIG. It is a figure which shows the waveform of the main signal when the phase difference of the position detection signal for 3 phases which concerns on one Embodiment of this invention is an electrical angle of 120 degree | times, and a motor is restrained. It is a figure which shows the waveform of the main signal in case the phase difference of the position detection signal for 3 phases which concerns on one Embodiment of this invention is an electrical angle of 60 degree | times, and a motor is restrained. It is a figure which shows the structure of the motor circuit in the case of the sensorless motor which concerns on other embodiment of this invention. It is a figure which shows the input-output waveform of the zero cross detection circuit for 3 phases which concerns on other embodiment of this invention. It is a figure which shows the truth table according to operation | movement of the drive control circuit which concerns on other embodiment of this invention. It is a figure which shows the structure of the protection circuit of the drive device of the conventional three-phase brushless motor. It is a figure which shows the structure of a motor with a Hall element in case the phase difference of the position detection signal for 3 phases is 120 degrees. It is a figure which shows the structure of a motor with a Hall element in case the phase difference of the position detection signal for 3 phases is 60 degrees.

Explanation of symbols

10 Motor circuit 101a, 101b, 101c Hall element 102a, 102b, 102c Zero cross detection circuit 109a, 109b, 109c Zero cross detection circuit 103, 110 Drive control circuit 104 Drive circuit 104a, 104b, 104c, 104d, 104e, 104f NPN transistor 105a U-phase drive coil 105b V-phase drive coil 105c W-phase drive coil 106 Stator 107 Rotors 108a, 108b, 108c, 133 AND element 14 Operation state detection circuit 1, 141 Counter 2, 142 Latch circuit 3, 143 S / S circuit 5, 144, 145 OR element 146 Charging / discharging circuit 147 Capacitance element 148 Comparator 11 Latch control circuit 12 Latch circuit 121, 131, 132 D flip-flop 4, 13 Edge detection circuit 20 MO Protection circuit 30 stops the reset signal generating circuit

Claims (9)

A drive circuit comprising a three-phase source transistor for discharging drive current to a three-phase drive coil of a three-phase brushless motor, and a three-phase sink transistor into which the drive current flows from the three-phase drive coil; A drive control circuit for supplying to the drive circuit six drive control signals for controlling conduction / non-conduction of the source transistor and the sink transistor based on the relative position of the rotor with respect to the stator in the three-phase brushless motor The three-phase brushless motor is configured by sequentially switching the energization direction of the three-phase drive coil to a predetermined energization direction to be set for each predetermined electrical angle based on the six drive control signals. In the drive device of the three-phase brushless motor that is driven to rotate,
When the three-phase brushless motor is in a rotational drive state, the six drive control signals are received from the drive control circuit, and the received six drive control signals are in the predetermined energization direction for each predetermined electrical angle. A motor protection circuit that performs a motor protection control to stop the operation of the drive circuit when it is determined whether or not the logical pattern is displayed according to the normal rotation drive A drive device for a three-phase brushless motor.   When it is determined that the motor protection circuit does not indicate the logic pattern, the motor protection circuit simultaneously turns off one of the three-phase source transistors or the three-phase sink transistors in the drive circuit, thereby The three-phase brushless motor drive device according to claim 1, wherein protection control is performed. The motor protection circuit is
The operation state of the three-phase brushless motor is detected based on the received stop reset signal. When the reception interval of the stop reset signal exceeds a predetermined period, the operation of the drive circuit is stopped. An operation state detection circuit that generates a stop signal and supplies the stop signal to the drive circuit;
The six drive control signals are received from the drive control circuit, and it is determined whether or not the received six drive control signals indicate the logical pattern for each predetermined electrical angle, and the logical pattern is indicated. When it is determined that the stop reset signal is generated and transmitted to the operation state detection circuit within the predetermined period, and when it is determined that the logic pattern is not indicated, the generation of the stop reset signal and the operation are performed. A stop reset signal generation circuit for stopping transmission to the state detection circuit;
The drive device for a three-phase brushless motor according to claim 1, wherein: The stop reset signal generation circuit
A latch circuit that is set at the edge of the latch clock signal and is reset by a latch reset signal, and generates a pulse signal in accordance with switching from the set state to the reset state;
An edge detection circuit that receives the pulse signal from the latch circuit, detects an edge of the received pulse signal, and generates the stop reset signal indicating that the edge has been detected;
The six drive control signals are received from the drive control circuit, and it is determined whether or not the received six drive control signals indicate the logical pattern for each predetermined electrical angle, and the logical pattern is indicated. The latch clock signal and the latch reset signal corresponding to the logic pattern are supplied to the latch circuit. When it is determined that the logic pattern is not indicated, the latch clock whose level is fixed is determined. A latch control circuit that generates the latch reset signal with a fixed signal or level and supplies the latch reset signal to the latch circuit;
The drive device for a three-phase brushless motor according to claim 3, wherein: The six drive control signals are:
A first drive control signal (UL) for controlling conduction / non-conduction of the sink transistor of the first phase;
A second drive control signal (VL) for controlling conduction / non-conduction of the sink transistor of the second phase;
A third drive control signal (WL) for controlling conduction / non-conduction of the sink transistor of the third phase;
A fourth drive control signal (UH) for controlling conduction / non-conduction of the source transistor of the first phase;
A fifth drive control signal (VH) for controlling conduction / non-conduction of the source transistor of the second phase;
A sixth drive control signal (WH) for controlling conduction / non-conduction of the source transistor of the third phase;
The latch control circuit
Based on the received six first to sixth drive control signals,
A first logical product of the first drive control signal (UL) and the fifth drive control signal (VH);
A second logical product of the second drive control signal (VL) and the sixth drive control signal (WH);
A third logical product of the third drive control signal (WL) and the fourth drive control signal (UH);
A first inversion of the first logical product and the second logical product;
A second inverted logical sum of the first logical product and the third logical product;
Calculating the second logical product and a third inverted logical sum of the third logical product,
Selecting any one of the first to third logical products as the latch reset signal;
The latch clock signal is selected by selecting any one of the first to third inverted logical sums based on any two of the first to third logical products not selected as the latch reset signal. The three-phase brushless motor drive device according to claim 4, wherein: The operating state detection circuit includes:
A counter that starts counting when the three-phase brushless motor starts to drive, generates a notification signal indicating that the count value reaches a predetermined value, and resets the count value when the stop reset signal is received Circuit,
A latch circuit that receives the notification signal from the count circuit, sets the stop signal by an edge of the received notification signal, and sets the stop signal to a reset state when the stop reset signal is received;
The three-phase brushless motor driving device according to claim 3, wherein the three-phase brushless motor driving device is provided. The operating state detection circuit includes:
A capacitive element;
A charge / discharge circuit that starts charging the capacitive element as the driving of the three-phase brushless motor starts, and stops charging and starts discharging when the stop reset signal is received;
A comparator that compares the charge / discharge voltage of the capacitive element with a predetermined reference voltage and generates the stop signal indicating that when the charge / discharge voltage exceeds the reference voltage;
The three-phase brushless motor driving device according to claim 3, wherein the three-phase brushless motor driving device is provided.   The three-phase brushless motor is a motor with a sensor having a rotational position detecting element that detects a relative position of the rotor with respect to the stator, and the drive control circuit is configured to perform the six driving operations based on the detection result of the rotational position detecting element. The three-phase brushless motor drive device according to any one of claims 1 to 7, wherein a control signal is generated.   The three-phase brushless motor is a sensorless motor, and the drive control circuit detects a relative position of the rotor with respect to the stator based on a back electromotive voltage generated in the three-phase drive coil, and based on the detection result. The three-phase brushless motor driving device according to any one of claims 1 to 7, wherein the six driving control signals are generated.

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