JP2003047273A - Motor controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller wherein reduction in the output of a brushless motor is suppressed and yet the scale of a circuit can be reduced. SOLUTION: A speed control computing portion 46 outputs a PWM signal to a predriver circuit 48 to switch and alternately turn on and off the MOSFETs 70A to 70C and 72A to 72C of a three-phase inverter 50. However, the speed control computing portion 46 interrupts a cancel signal into a PWM signal corresponding to the energization time of the coils of a brushless motor 16, and thereby keeps on either of the MOSFETs 70A to 70C and the MOSFETs 72A to 72C and keeps off the other. During this period, the coils are kept energized without the occurrence of a dead time, and thus reduction in output is suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for controlling a brushless motor by control such as PWM control.

[0002]

2. Description of the Related Art A ventilation drive source in an air conditioner for a vehicle includes a permanent magnet, for example, by passing a current rectified by turning on and off a semiconductor element such as a power transistor provided in a drive circuit to a coil. A brushless motor that rotates a rotor configured as described above is used, and the rotational driving force of the brushless motor blows air from the main body of the air conditioner into the vehicle interior.

On the other hand, so-called PWM (Pulse Wi) is used for drive control of such a brushless motor, that is, for ON / OFF control of the semiconductor elements provided in the drive circuit described above.
dthModulation (pulse width modulation) control is used. Further, in this type of PWM control, a semiconductor element in the upper stage (upstream side of the coil with respect to the direction of the current flowing through the coil) of the winding (coil) of the brushless motor (hereinafter, referred to as “upper stage semiconductor element” for convenience) And a semiconductor element in the lower stage of the winding (downstream of the coil with respect to the direction of the current flowing through the coil) (hereinafter, referred to as “lower stage semiconductor element” for convenience),
To perform energization of an arbitrary waveform while performing full-wave rectification by complementary PWM control (hereinafter, referred to as “complementary PW for convenience”).
"M control").

Further, for this complementary PWM control,
A method of performing PWM control on only one of the upper semiconductor element and the lower semiconductor element (hereinafter, "one-sided PWM control" for convenience.
There is also).

[0005]

By the way, complementary PWM
In the control, the upper semiconductor element and the lower semiconductor element are alternately turned on and off. Ideally, the upper semiconductor element is turned on,
It is preferable that OFF and lower semiconductor elements are turned off and on at the same time (including upper semiconductor element OFF, ON and lower semiconductor elements ON and OFF), but in reality, semiconductor element ON, OFF and OFF, Since a time delay occurs in turning on, for example, when trying to turn on and off the upper semiconductor element and turn off and on the lower semiconductor element at the same time,
Although temporarily, both the upper semiconductor element and the lower semiconductor element are turned on, and as a result, there is a possibility that the circuit may malfunction.

In order to prevent both the upper semiconductor device and the lower semiconductor device from being turned on, normally,
A so-called dead time is provided in which the timing at which the lower semiconductor element is turned on is delayed with respect to the timing at which the upper semiconductor element is turned off, so that both semiconductor elements are temporarily turned off.

However, the power supply to the coil is stopped during the dead time. Considering that the output of the motor when the brushless motor is drive-controlled by the PWM control as described above becomes large according to the energization time to the coil, if the dead time is provided, energization to the coil is stopped. , The output is reduced by this stop time.

In the case of the above-mentioned one-sided PWM control, such a problem does not occur because the dead time is unnecessary due to its structure, but the one-sided PWM control is different from the drive circuit and the control circuit as compared with the complementary PWM control. Since the scale of the entire circuit configuration including the above is large and complicated, the one-sided PWM control is not suitable especially when miniaturization is required as in a motor actuator for an air conditioner mounted on a vehicle. .

In view of the above facts, an object of the present invention is to provide a motor control device capable of suppressing the output reduction of a brushless motor and reducing the circuit scale.

[0010]

According to a first aspect of the present invention, there is provided a motor control device, wherein an upper switching element and an upper stage switching element provided upstream of a winding of a plurality of phases constituting a brushless motor are provided. Rectifying means configured to include a lower switching element provided on the downstream side of the winding, and flowing a current of a specific waveform to any phase of the winding by switching of the upper switching element and the lower switching element, While switching the upper switching element and the lower switching element for a predetermined time based on the signal wave, the switching is stopped at a predetermined timing within the predetermined time, and the upper switching element and the lower step based on the signal wave. Longer than one energization time for one of the switching elements Continuously energize one of the switching elements to continuously energize the other switching element, and continuously deenergize the continuous energization state and the continuous energization stop state to the length of the winding. And a control means for intermittently changing each energization cycle.

According to the motor control device having the above-mentioned structure, when a predetermined signal wave such as a pulse signal is input to the control means, it is basically based on this signal wave (more specifically, the signal wave is a pulse signal). In the case of a signal, the control means can alternately switch the upper switching element and the lower switching element forming the rectifying means for a predetermined time based on the pulse width of the pulse signal or the like. Therefore, by actually switching the upper and lower switching elements, a current rectified into a specific waveform flows through the winding of the brushless motor, and the rotor of the brushless motor rotates.

Here, in the present motor control device, the control means normally stops switching at a predetermined timing within a predetermined time for switching each of the upper and lower switching elements, and instead of this, based on the signal wave. One energization time of either one of the upper switching element and the lower switching element (not the sum of energization times of one switching element within the above-mentioned predetermined time, but only one ON state time) The switching element is continuously energized for a longer period of time, and the other switching element is continuously deenergized.

Therefore, there is no dead time between the ON state in which one of the switching elements is continuous and the OFF state in which the other switching element is continuous. As a result, the number of occurrences of dead time during the energization time of the winding is reduced as compared with the case where the upper switching element and the lower switching element are switched. As a result, it is possible to suppress a decrease in output of the brushless motor due to dead time.

Moreover, since the lengths of the continuous energization time and the continuous energization stop time change stepwise for each energization cycle of the winding, the current flowing through the winding does not change abruptly.
As a result, it is possible to prevent a sudden change in the rotation speed of the brushless motor due to a sudden change in current, and it is possible to perform stable control of the brushless motor.

According to another aspect of the motor control device of the present invention, an upper stage switching element provided on the upstream side of the winding and a downstream side of the winding with respect to the currents flowing through the windings of a plurality of phases constituting the brushless motor. Rectification means configured to include a lower switching element provided, flowing a current of a specific waveform in any phase of the winding by switching of the upper switching element and the lower switching element, and a pulse of a pulse signal of a predetermined waveform While switching the upper switching element and the lower switching element for a predetermined time according to the width, the switching is stopped at each of a plurality of predetermined timings within the predetermined time, and the upper switching element according to the pulse width. And one of the switching elements of the lower-stage switching element is passed once. And control means for the continuous energization stopped any other switching device the one of the switching elements in the continuously energized continuously longer than the time,
Is equipped with.

According to the motor control device having the above structure, when a pulse signal is input to the control means, the control means basically constitutes the rectifying means in accordance with the pulse width of the pulse signal. It is possible to switch the elements alternately for a predetermined time. Therefore, by actually switching the upper and lower switching elements, a current rectified into a specific waveform flows through the winding of the brushless motor, and the rotor of the brushless motor rotates.

Here, in the present motor control device, the control means stops switching at each of a plurality of predetermined timings within a predetermined time for switching each of the upper and lower switching elements, and instead of this, ,
One energization time of either one of the upper-stage switching element and the lower-stage switching element based on the pulse width of the pulse signal (not the sum of the energization times of the one switching element within the above-mentioned predetermined time, but is 1 The current is continuously energized for a time longer than the ON time of one time), and the other switching element is continuously deenergized.

Therefore, there is no dead time between the continuous ON state of the one switching element and the continuous OFF state of the other switching element. As a result, the number of occurrences of dead time during the energization time of the winding is reduced as compared with the case where the upper switching element and the lower switching element are switched. As a result, it is possible to suppress a decrease in output of the brushless motor due to dead time.

Further, in this motor control device, the continuous energization and the continuous energization stop are performed alternately (that is, intermittently) with the energization based on the normal pulse signal. By adjusting it, it becomes possible to bias the cycle of sound and vibration generated when the brushless motor operates toward the higher order cycle side with respect to the commutation cycle of the brushless motor. Thereby, for example, it becomes possible to adjust the period of the sound and vibration to be deviated from the resonance point of the cushioning material for reducing the sound and vibration generated in the operating state of the brushless motor, and thereby the vibration isolation performance and Quiet performance is improved.

Further, in this motor control device, normal switching is performed for the upper-stage switching element and the lower-stage switching element in a state other than continuous energization and continuous energization stop even during the energization time of the winding. Therefore, it is possible to rectify the waveform of the current flowing through the winding into an arbitrary waveform.

According to a third aspect of the present invention, in the present invention according to the second aspect, the control means determines the temporal length of the continuous energization state and the continuous energization stop state by the energization cycle of the winding. The feature is that it is changed step by step.

In this motor control device, the time length of the continuous energization state for one switching element and the continuous energization stop state for the other switching element at a predetermined timing during energization of the winding is determined by the time length of the winding. It is changed step by step every energization cycle. For this reason, the current flowing through the winding does not change abruptly, which prevents a sudden change in the rotation speed of the brushless motor due to a rapid change in current and enables stable control of the brushless motor.

According to a fourth aspect of the present invention, in the motor control device according to the first aspect of the present invention, the control means sets the time length of the continuous energization state and the continuous energization stop state. Is gradually increased or decreased for each energization cycle of the winding.

In the motor control device having the above structure, the time length of the continuous energization state for one switching element and the continuous energization stop state for the other switching element at a predetermined timing when energizing the winding is determined by the winding length. It becomes longer or shorter step by step at every energization cycle. Therefore, the current flowing through the winding does not suddenly increase or decrease, which can prevent a sudden change in the rotation speed of the brushless motor due to a rapid increase or decrease in the current, and stable control of the brushless motor can be achieved. It will be possible.

According to a fifth aspect of the present invention, in the motor control device according to the first aspect of the present invention, there is provided a rotation speed detecting means for detecting the rotation speed of the rotor of the brushless motor, and the rotation speed detecting means is provided. Based on the deviation between the actual rotation speed of the rotor detected by the number detection means and the set value, the control means is at least any one of the predetermined timing and the temporal length of the continuous energization state and the continuous energization stop state. The feature is that one of them is determined.

In the motor control device having the above structure, the rotation speed of the rotor is detected by the rotation speed detection means, and the actual rotation speed of the rotor detected by the rotation speed detection means is fed back to the control means. The timing and the time length of the continuous energization state and the continuous energization stop state described above are determined based on the difference between the actual rotor speed fed back and the set value.

As a result, even if the set value is changed when it is desired to change the rotation speed, it is possible to prevent the number of occurrences of dead time during one cycle of the current flowing through the winding from increasing and decreasing rapidly, and to rotate the rotation speed of the brushless motor. Change can be stabilized.

A motor control device according to a sixth aspect of the present invention is the motor control device according to any one of the first to fifth aspects of the present invention.
Each of the plurality of phase windings includes storage means for storing a plurality of map data having different lengths of continuous energization and continuous energization stop for one phase winding, and the plurality of map data are stored. The map data are data for 360 electrical degrees each corresponding to the winding of one phase, and are conceptually arranged in a row in order from the shortest duration to the longest duration. , When setting the duration corresponding to windings of other phases other than the winding of one phase, the map data is shifted with a phase difference of the other phase with respect to the winding of the one phase. When the read map data is read, the shortage of the phase difference by the phase difference is supplemented by the next map data conceptually adjacent to the read map data.

In the motor control device having the above structure, the map data corresponding to the continuous energization of the upper switching element and the lower switching element and the continuation time of the continuous energization stop are stored in advance in the storage means, and the control means stores the data in the storage means. By reading the corresponding map data, the duration of continuous energization and continuous energization stop of the upper switching element and the lower switching element is set.

Therefore, it becomes unnecessary to determine continuous energization and continuous energization stop for each electrical angle within the entire energization cycle of the winding, so that the load on the control means is reduced. As a result, it becomes possible to use a control means having a relatively slow processing speed, and the cost can be reduced.

By the way, in the present invention, the map data corresponds to only one phase of the windings of a plurality of phases, and the individual map data is 360 in electrical angle.
There is only a degree.

Here, in the present invention, a plurality of map data stored in the storage means is also used for setting the duration of continuous energization and continuous energization stop for the windings of other phases. When setting the duration for the line, the control means reads the map data by shifting the electrical phase difference between the winding of one phase and the winding of the other phase for which the map data is prepared.

Further, as described above, since each map data has only an electrical angle of 360 degrees, the data is insufficient by the phase difference. However, in the present invention, as described above, a plurality of map data are continuously energized and The lines are conceptually arranged in one row from the one having a short continuation duration to the one having a long continuation duration, and the lack of data is supplemented conceptually by the next adjacent map data.

As described above, in the present invention, each electric angle is 3
Since the switching element is controlled only by the map data corresponding to the winding of one phase having the data for 60 degrees, the total amount of data stored in the storage means can be reduced and the cost can be reduced.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION <Structure of First Embodiment> (Outline of Structure of In-Vehicle Air Conditioner Motor Actuator 12) FIG. 3 shows a motor control device 10 according to a first embodiment of the present invention. A front cross-sectional view in which a motor actuator 12 for an in-vehicle air conditioner (hereinafter, simply referred to as “motor actuator 12”) equipped with is partially cut away is shown.

As shown in this figure, the present motor actuator 12 is provided with a housing 14, inside which a brushless motor 16 (hereinafter simply referred to as "motor 16") is provided.
Control board 18 of the motor control device 10 is housed.

As shown in FIG. 3, the housing 14 is formed in a shallow box shape with one end opened, and a substantially cylindrical tube portion 34 is formed at the open end of the housing 14 with respect to the housing 14. It is provided integrally.

Further, the housing 14 is provided with a substantially cylindrical support portion 36, and a stator 28 is integrally attached to the outer peripheral portion of the support portion 36. The stator 28 includes a core 26 formed by laminating a plurality of core pieces made of a thin silicon steel plate or the like. Further, the core 26 has three-phase coils 30A and 30A as windings.
A coil group 30 (see FIG. 2) including B and 30C is wound. These coils 30A to 30C are provided so that their electrical phases are shifted by 120 degrees, and by alternately energizing these coils 30A to 30C at a predetermined cycle, a predetermined rotation is performed around the stator 28. Create a magnetic field.

On the other hand, as shown in FIG.
A pair of bearings 38 is fixed to the inside of the shaft 38, and the shaft 20 is supported by these bearings 38 coaxially with the support portion 36 and the cylindrical portion 34 and rotatable about its own axis.

One end side of the shaft 20 in the axial direction is the cylindrical portion 3.
4 and is mechanically connected to a fan for blowing provided in an air conditioner main body (not shown) that rotates by receiving the rotational force of the shaft 20 at or near one end thereof.

The rotor 22 is integrally attached to the portion of the shaft 20 penetrating from the tubular portion 34.
The rotor 22 is formed in a bottomed tubular shape coaxial with the tubular portion 34 and the support portion 36 that are opened in a direction opposite to the opening direction of the housing 14, and the shaft 20 penetrates the upper bottom portion of the rotor 22. is doing.

A substantially cylindrical magnet 24 is coaxially fixed to the rotor 22 on the inner peripheral portion of the rotor 22. The magnet 24 is formed such that one side in the radial direction has an N pole and the other side has an S pole through the axis, and the magnet 24 has a predetermined angle (eg, 6 degrees) about its axis.
It is formed so that the polarity of the magnetic pole changes every 0 degree, and a predetermined magnetic field is formed around it.

As shown in FIG. 3, this magnet 2
4 is provided along the radial direction of the support portion 36 so as to face the stator 28 outside the stator 28. When the coil group 30 is energized and a rotating magnetic field is formed around the stator 28, Due to the interaction between the rotating magnetic field and the magnetic field formed by the magnet 24, a rotating force around the support portion 36 is generated in the magnet 24, and the shaft 20 is thereby rotated.

On the other hand, as shown in FIG.
A control board 18 is disposed closer to the bottom of the housing 14 than the housing 8. Printed wiring is provided on at least one of the front surface and the back surface of the control board 18, and a plurality of resistance elements, transistor elements, and further elements such as a microcomputer are appropriately connected through the printed wiring. There is.

(Outline of Configuration of Motor Control Device 10) Next, an outline configuration of the control board 18, that is, an outline configuration of the motor control device 10 will be described with reference to FIGS. 1 and 2.

The motor controller 10 (control board 18) is
A speed command circuit 42, a power supply standby circuit 44, a pulse signal generating means, and a pre-driver circuit that constitutes a control means together with a speed control calculation portion 46 that constitutes a control means as a canceling means and a speed control calculation portion 46 as a driver means. 48, three-phase inverter 50 as rectifying means,
It is configured to include the booster circuit 52.

The speed command circuit 42 is configured by including various circuits such as a filter circuit and an amplifier circuit, or by an IC having the same function as the configuration including these circuits. Operation signals are input from one or a plurality of operation switches 54 used for turning on / off an air conditioner provided in the instrument panel or the like and for switching the air volume.

The power supply standby circuit 44 is interposed between the speed command circuit 42 and a speed control calculation unit 46, which will be described later, and controls a weak current flowing from the power supply 56 to the air conditioner even when the air conditioner is stopped. It is a circuit that suppresses.

The speed control calculation section 46 is a microcomputer including a CPU 62, a ROM 64 as a storage means, a RAM 66, a timer 68, etc., and is structurally composed of one to a plurality of integrated circuits and functionally. Has various circuits such as a comparator circuit (comparison circuit), an amplification circuit, and a multiplication circuit, and a function of a reference wave signal generation circuit such as a triangular wave or a sawtooth wave or a PWM (pulse width modulation) circuit formed by combining these circuits. Finally, the power standby circuit 44
A PWM signal corresponding to the speed command signal input from the speed command circuit 42 is output.

A plurality of map data are stored in the ROM 64, and the CPU 62 reads any one of the plurality of map data from the ROM 64. The map data is used to generate a cancel signal described later.

Here, the cancel signal is the above-mentioned PWM.
This is a signal for canceling the signal and continuously energizing or stopping energizing MOSFETs 70A to 70C and 72A to 72C described later for a preset length.

The duration of continuous energization and stop of continuous energization is a deviation between the actual rotational speed of the rotor 22 obtained from the detection results of Hall IC elements 78A to 78C described later and the set rotational speed of the rotor 22. The map data is stored in the ROM 64 as at least a part of the map data prepared in order from the shortest to the longest continuous duration of the continuous energization state and the continuous energization stop state.

Here, FIG. 6 is a view conceptually showing the above map data. As shown in this figure, a plurality of map data are provided from map data 1 to map data N. In the map data 1, the time length of the continuous energization and the continuous energization stoppage described above is “0”, and the map data 2, the map data 3 ,.
In the order of ..., The temporal length of the continuous time gradually or stepwise increases, and the temporal length of the continuous time of continuous energization and continuous energization stop becomes maximum in the map data N.

Further, these map data are conceptually arranged in sequence in one column from map data 1 to map data N. Further, map data 2 to map data N
Up to -1, basically only one is prepared, but the map data 1 whose temporal length of the above duration is "0" and the map data which maximizes the temporal length of the above duration. Two Ns are prepared, and as shown in FIG. 6, the map data conceptually arranged in one column has two map data 1 arranged at the beginning and two map data N arranged at the end.

Further, the map data is prepared only in the ROM 64 for the phase corresponding to the coil 30A among the phases of the coils 30A to 30C. Moreover, each map data has only an electrical angle of 360 degrees.

The three-phase inverter 50 includes three N-channel power MOS field effect transistors 7 each serving as an upper switching element (or an upper semiconductor element).
0A, 70B, 70C, and three N-channel power MOS field effect transistors 72A, 72 each serving as a lower stage switching element (or a lower stage semiconductor element).
B and 72C (hereinafter, these N-channel field effect transistors 70A to 70C and 72A to 72C).
For convenience, C is "MOSFETs 70A to 70C, 72A to
72C ").

These MOSFETs 70A to 70C, 7
Of 2A to 72C, the source of the MOSFET 70A and the drain of the MOSFET 72A are connected to the terminal of the coil 30A. The source of the MOSFET 70B and the drain of the MOSFET 72B are connected to the terminal of the coil 30B, and the source of the MOSFET 70C and the M
The drain of the OSFET 72C is connected to the terminal of the coil 30C.

The pre-driver circuit 48 is a circuit interposed between the speed control calculation unit 46 and the three-phase inverter 50, and is connected to the gates of the above-described MOSFETs 70A to 70C and 72A to 72C, and the speed control calculation unit. Based on the PWM signal from 46, each MOSF of the three-phase inverter 50
ET70A-70C, 72A-72C to the switching signal of "HIGH" level or "LOW" level M
It outputs to each gate of OSFET70A-70C, 72A-72C. As is well known in the art, MOSFETs 70A-7
0C and 72A to 72C are in the OFF state when the "LOW" level switching signal is input to the gate, and basically the current from the power supply 56 does not flow from the drain to the source, but the "HIGH" level switching signal. Is turned on by inputting to the gate, and the current from the power supply 56 flows from the drain to the source.

The booster circuit 52 is a circuit connected to the pre-driver circuit 48, and is a circuit for making the voltage level of the switching signal output to the MOSFETs 70A to 70C higher than the voltage level of the power supply 56.

On the other hand, the motor control device 10 is provided with a rotation detecting device 74 as a rotation speed detecting means.

The rotation detecting device 74 includes a sensor magnet 76 and three Hall IC elements 78A, 78B and 78C.
It is configured to include and.

The sensor magnet 76 is coaxially and integrally fixed to the shaft 20 on the other end side in the axial direction of the shaft 20. This sensor magnet 76 is also a permanent magnet, and has a predetermined angle (for example, 60 degrees) around its axis.
It is a multi-pole magnet in which N-poles and S-poles are alternately positioned for each, and forms a specific magnetic field around it.

On the other hand, the Hall IC elements 78A to 78C are provided on the outer side in the radial direction of the sensor magnet 76 at every 120 degrees around the axis of the sensor magnet 76, and the magnetic force lines forming the magnetic field of the sensor magnet 76 at each position. To detect.

Each of these Hall IC elements 78A to 78C is connected to the above-mentioned speed control calculating section 46.

Further, the motor control device 10 is provided with various sensors such as a current sensor 82, a voltage sensor 84, a temperature sensor 86 and the like. The current sensor 82 is the three-phase inverter 50.
Detects the current value of the current flowing in the
Detects the voltage applied to the three-phase inverter 50. Further, the temperature sensor 86 detects the temperature of the three-phase inverter 50 and the like. These current sensor 82, voltage sensor 84,
Various sensors such as the temperature sensor 86 are used in the speed control calculation unit 4
6 is connected to the CPU 62, and a signal corresponding to the detected value is output to the CPU 62 to determine whether or not the current, voltage, and temperature are normal. CPU 6 when any of the temperatures is detected
2 stops the motor 16.

<Operations and Effects of First Embodiment> (Outline of Basic Operation) Next, operations and effects of this embodiment will be described.

The present motor control device 10 is a so-called "complementary PW".
The drive control of the motor 16 is performed by "M control". Since the complementary PWM control is a well-known technique basically, a detailed description thereof will be omitted and a brief description will be given below.

In this motor control device 10, the air conditioner O
When the operation switch 54 is operated for N / OFF or air volume switching, an operation signal of a predetermined voltage is output from the operation switch 54 and input to the speed command circuit 42.

The operation signal input to the speed command circuit 42 is converted by the speed command circuit 42 into a speed command signal as a set value that can be compared by the CPU 62 of the speed control calculation unit 46, and then the power standby circuit 44 is operated. It is output to the speed control calculation unit 46 via.

Each of the speed command signal input to the speed control calculation unit 46 and the reference wave signal such as a triangular wave or a sawtooth wave separately generated by the speed control calculation unit 46 is processed in the same manner as the comparator circuit. Further, a PWM signal as a pulse signal having a pulse width corresponding to the operation command signal level is generated based on the speed command signal and the original signal and output to the pre-driver circuit 48.

In the pre-driver circuit 48, the booster circuit 52
Together with each M based on the level and pulse width of the PWM signal
O of each of the OSFETs 70A to 70C and 72A to 72C
A pulse-shaped switching signal is generated as a drive signal that can be turned on / off, and this switching signal is used as each of the MOSFETs 70A to 70C, 72A to of the three-phase inverter 50.
It is output to the gate of 72C.

As described above, MOSFETs 70A-7
Each of 0C and 72A to 72C is in the OFF state when the input switching signal is at the “LOW” level, and basically cuts off the current from the power source 56 from the drain to the source, and is at the “HIGH” level. For example, it is turned on to allow the current from the power supply 56 to flow from the drain to the source. Here, the switching signal is the above PW.
The MOSFET 70 is generated by being generated based on the M signal.
Any of A to 70C and any of MOSFETs 72A to 72C are alternately turned on, whereby a rectangular wave current as shown in FIG.
It flows to 30C.

In this way, a predetermined magnetic field is formed around the coils 30A to 30C, and the interaction between the magnetic field formed by the coils 30A to 30C and the magnetic field formed by the magnet 24 causes the magnet 24 to rotate. The shaft 20 integral with 24 rotates. As described above, since the shaft 20 is connected to the fan of the air conditioner on the outside of the housing 14, the rotation of the shaft 20 causes the fan to rotate, thereby blowing air from the air conditioner.

On the other hand, when the shaft 20 rotates, the sensor magnet 76 also rotates. As described above, the sensor magnet 76 forms a multi-pole magnet and forms a specific magnetic field around it. However, when the sensor magnet 76 rotates, the magnetic field of the sensor magnet 76 with respect to the surroundings of the sensor magnet 76 is increased. Fluctuates.

The fluctuation of the magnetic field around the sensor magnet 76 causes a change in the strength of the magnetic force line at a specific position around the sensor magnet 76. Sensor magnet 76
The magnetic force lines of the magnetic field formed by are detected by the Hall IC elements 78A to 78C arranged around the sensor magnet 76, and a rotation signal corresponding to the intensity of the detected magnetic force lines is speed-controlled by the Hall IC elements 78A to 78C. Part 4
6 is output.

The speed control calculation unit 46 calculates the actual rotation direction and rotation speed of the rotor 22 (shaft 20) based on the rotation signals input from the Hall IC elements 78A to 78C. Further, in the speed control calculation unit 46, each of the actual rotation signal based on the calculation result and the above-described speed command signal is subjected to the same processing as that of the comparator circuit to obtain a deviation. The speed control calculation unit 46 generates a PWM signal based on this deviation, and the pre-driver circuit outputs the PWM signal.
MOSFETs 70A-70C, 72 based on the WM signal
By switching operation of A to 72C, the shaft 2
The rotational speed of 0 is corrected.

(Characteristic Actions and Effects of the Present Embodiment) Here, in the present motor control device 10, for example, based on the deviation between the actual rotation signal calculated by the speed control calculation unit 46 and the speed command signal. If the determined PWM signal does not exceed the predetermined range, first, of the plurality of map data stored in the ROM 64 of the speed control calculation unit 46, the temporal length of the continuous energization state and the continuous energization stop state duration time. The map data 1 having a value of “0” is read by the CPU 62.

In this state, basically, the cancel signal is generated by the speed control calculation unit 46 based on the map data 1, interrupts the PWM signal, and is output to the pre-driver circuit 48. However, as described above, in the map data 1, since the duration of the continuous energization state and the continuous energization stop state is “0”, the cancellation signal is input to the pre-driver circuit 48. Change does not occur, the pre-driver circuit 48 generates a switching signal based on the PWM signal, and the MOSFETs 70A ...
Output to 70C, 72A to 72C.

On the other hand, the PWM signal determined based on the deviation calculated by the speed control calculation unit 46 is
If it exceeds the predetermined range, the RO of the speed control calculation unit 46
Of the plurality of map data 1 to map data N stored in M64, the actual rotor 22 fed back
Map data corresponding to the PWM signal determined based on the deviation between the speed command signal and the rotation speed of the rotor IC (that is, the actual rotation speed of the rotor 22 based on the detection signals of the Hall IC elements 78A to 78C). Be done. As a result, based on the map data read by the CPU 62, as shown in FIG. 5, the speed control calculation unit 46 is sufficiently shorter than the total energization time of the coils 30A to 30C and less than one energization time. A long cancel signal interrupts the PWM signal and is generated corresponding to each phase of the coils 30A to 30C, and interrupts the PWM signal corresponding to a substantially intermediate portion from the start to the end of energization of the coils 30A to 30C. The cancel signal is sent to the pre-driver circuit 4
8 is output.

The pre-driver circuit 48, to which the cancel signal is input, receives the MOSFE signal corresponding to the cancel signal.
The signals immediately before the cancellation signal is input are continuously output to T70A to 70C and 72A to 72C. That is, the MOSFETs 70A to 70C, 72 corresponding to the cancel signal that was in the ON state immediately before the cancel signal was input.
A to 72C remains ON until the cancel signal ends
MOSFET 70A corresponding to the cancel signal that is in the OFF state immediately before the cancel signal is input
70C and 72A to 72C maintain the OFF state until the cancellation signal ends.

Furthermore, when the output of the cancel signal from the speed control calculation unit 46 is completed, immediately after that, the PWM signal is output again from the speed control calculation unit 46 to the pre-driver circuit 48, and again the MOSFETs 70A to 70C and 72A to.
72C is switched.

In this state, if the PWM signal determined based on the deviation calculated by the speed control calculation unit 46 exceeds the predetermined range, the map data having the long duration is based on the map data. A cancel signal is generated and output to the pre-driver circuit 48. However, the length of the cancel signal in this case is determined by the coils 30A to 30C.
The PWM signal determined based on the above-mentioned deviation calculated by the speed control calculation unit 46 continues for a time equal to or less than the energization time of No. Longer and finally coil 3
It is the same as the energization time of 0A to 30C.

Here, the cancel signal as described above is generated and output, and the switching operation is stopped based on this, but the coils 30A to 30C are still energized. Therefore, the shaft 2 of the motor 16 is basically the same as when the switching operation is performed.
0 rotates.

However, when the switching operation is stopped based on the cancel signal, the MOSFET 70A
The element corresponding to the cancel signal out of 70 C is continuously turned on or off, and the MOSFET 7
Of the 2A to 72C, the element corresponding to the cancel signal is continuously in the OFF state or the ON state, so that the current continuously flows through the corresponding coils 30A to 30C, and as a result, the dead time is different from that during the switching operation. Disappears.

During this dead time, the MOSFET 7
Both the elements of 2A to 72C and the MOSFETs 70A to 70C corresponding to these elements are turned off, and the current does not flow through the corresponding coils 30A to 30C, and as a result, the output of the motor 16 becomes the dead state. It decreases corresponding to the total time.

However, in the present motor control device 10, since the dead time is temporarily eliminated as described above, the output reduction of the motor 16 can be suppressed.

Moreover, P determined based on the above deviation
When the state in which the WM signal exceeds the predetermined range continues, the cancel signal gradually increases (stepwise), and finally becomes the same as the energization time of the coils 30A to 30C.
Therefore, if the PWM signal determined based on the above deviation continues to exceed the predetermined range, the dead time gradually decreases (stepwise), and finally the longest cancel signal (that is, map data). The cancellation signal based on N) eliminates or minimizes the dead time. Therefore, the output reduction of the motor 16 can be further suppressed.

Further, immediately after the normal PWM signal is output to the pre-driver circuit 48, the longest cancel signal can be output to the pre-driver circuit 48 to drastically reduce the number of dead times. However, considering that the energization current to the coils 30A to 30C increases corresponding to the decrease of the dead time, the rapid decrease in the dead time occurrence frequency results in a sharp increase in the energization current to the coils 30A to 30C. As a result, the rotation speed of the motor 16 suddenly changes and controllability deteriorates.

Here, in the motor control device 10, since the number of occurrences of dead time is reduced stepwise by lengthening the cancel signal stepwise, the coils 30A to 30A.
The energizing current of 30C is increased stepwise, and the rotation speed of the motor 16 can be controlled without sudden change.

Furthermore, the same effect as the present motor control device 10 can be obtained even if the configuration is other than the present motor control device 10. However, as compared with the configuration for obtaining the same effect, the present motor control device 10 that performs complementary PWM control can reduce the circuit scale, and as a result, the cost can be reduced and the size can be reduced.

The cancel signal described above is generated in accordance with each phase of the coils 30A to 30C. On the other hand, the map data used to generate the cancel signal is only the map data corresponding to the coil 30A in the ROM.
64, and each of the map data has only an electrical angle of 360 degrees.

Here, in this embodiment, the coil 30B is used.
Even when generating a cancel signal corresponding to
2 uses map data corresponding to the coil 30A. However, the coil 30A and the coil 30B have an electrical angle of 12
Since the phase is shifted by 0 degree, when generating the cancel signal corresponding to the coil 30B, the CPU 62 reads the map data in a state shifted by this phase difference (FIG. 6).
See the conceptual diagram).

However, as described above, since each map data has only an electrical angle of 360 degrees, when the cancel signal corresponding to the coil 30B is generated, the CPU
62 is short of data by this phase difference.

Here, in the present embodiment, as described above, each map data has the temporal length of the cancel signal (the temporal length of the duration of continuous energization and continuous energization stop).
Are conceptually arranged in a line from a short one to a long one, so that the CPU 62 reads from the ROM 64 across two adjacent map data so as to supplement the above shortage with the next adjacent map data. Read.

Similarly, when the cancel signal corresponding to the coil 30C is generated, the coil 30A and the coil 30C are
C with a phase difference of (240 electrical degrees)
The PU 62 reads the map data from the ROM 64 (see the conceptual diagram of FIG. 6).

Further, the shortage of data corresponding to the phase difference is read from the ROM 64 across two adjacent map data so that the CPU 62 supplements it with the next adjacent map data.

Further, the time length of the above continuation time is "0".
2 are prepared for each of the map data 1 and the map data N that maximizes the temporal length of the above-mentioned duration, and as shown in FIG. Are lined up conceptually. Therefore, when the temporal length of the continuation time is set to “0” and when the temporal length of the continuation time is maximized, based on the first (leading side) map data 1 or map data N. Even if the cancel signals corresponding to the coils 30B and 30C straddle the map data adjacent to the rear side by generating the cancel signal corresponding to the coil 30A, the map data adjacent to the rear side is the same map data 1 or It becomes the map data N. For this reason, in this state, the temporal length of the above-mentioned continuation time by all the cancellation signals corresponding to each of the coils 30A to 30C can be "0" or maximized.

Thus, in this embodiment, the coil 3
In generating a cancel signal corresponding to each of 0A to 30C (each phase), map data 1 to map data N corresponding to the continuous time of continuous energization and continuous energization stop included in the cancel signal are prepared in advance, Since the map data 1 to the map data N are conceptually stored in the ROM 64 sequentially in a row from one having a short temporal length of continuous energization and one having a long continuous energization stop to a long one, each coil 30
The CPU 62 does not need to determine continuous energization and continuous energization stop for the phase angles of the energization waveforms A to 30C. Therefore, the load on the CPU 62 can be reduced, and the CPU 62 having a relatively low processing speed can be sufficiently used, so that the cost can be reduced.

In the present embodiment, as described above,
Each of the map data stored in the ROM 64 has only the map data corresponding to the coil 30A. Moreover, since each map data has only an electrical angle of 360 degrees, the storage amount in the ROM 64 can be effectively reduced, so that the ROM 64 having a small storage capacity can be applied.
In this sense, the cost can be reduced.

<Second Embodiment> FIG. 7 is a block diagram showing the configuration of a motor control device 110 according to the present embodiment. As shown in this figure, the motor control device 110 is a speed control calculation unit 1 that constitutes a control means instead of the speed control calculation unit 46 in the first embodiment.
It has twelve. The structural structure of the speed control calculation unit 112 is basically the same as that of the speed control calculation unit 46,
The mode of the cancel signal generated by the speed control calculation unit 112 is different from that of the cancel signal generated by the speed control calculation unit 46.

That is, in the present motor control device 110,
If the PWM signal determined based on the deviation between the actual rotation signal calculated by the speed control calculation unit 112 and the speed command signal exceeds the predetermined range, the speed control calculation unit 112
A cancel signal that is sufficiently shorter than the energization time of the coils 30A to 30C is generated by interrupting the generation of the PWM signal. However, as shown in FIG.
The PWM signal corresponding to the energization time is generated so as to be interrupted stepwise by being divided into a plurality of times.

Therefore, in the present motor control device 110, the MOSFETs 70A to 70C and the MOSFET 72 are arranged.
A state in which one of A to 72C is kept ON and the other is kept OFF appears a plurality of times within the energization time of the coils 30A to 30C.

Further, in the present embodiment as well, as in the first embodiment, the cancellation signal is gradually lengthened by continuing the state in which the PWM signal determined based on the deviation exceeds the predetermined range.

As described above, also in the motor control device 110,
MOSFETs 70A to 70C based on the cancel signal
Since the dead time disappears in a state in which one of the MOSFETs 72A to 72C is kept ON and the other is kept OFF, basically the same effect as that of the first embodiment can be obtained. .

Further, in the present motor control device 110, the cancel signal is interrupted in plural times with respect to the PWM signal corresponding to the energization time of the coils 30A to 30C, so that the noise generated when the motor 16 is operated and The vibration cycle can be biased toward the higher-order cycle side with respect to the commutation cycle of the motor 16. Therefore, for example, in the case of adopting a rubber isolation structure using a rubber material in order to reduce the sound and vibration generated in the operating state of the motor 16,
It is also possible to adjust the period of sound and vibration to be deviated from the resonance point of the rubber material, which improves vibration damping performance and quietness performance.

Further, in the motor control device 110, the MOSFETs 70A to 70A are provided in the range where the cancel signal does not interrupt even during the energization time of the coils 30A to 30C.
A normal switching signal is output from the pre-driver circuit 48 to the 70C and the MOSFETs 72A to 72C. Therefore, the waveform of the current flowing through the coils 30A to 30C can be rectified into an arbitrary waveform, and for example, a pseudo sine wave or the like can be created.

In each of the above embodiments, the cancel signal is output to the pre-driver circuit 48 so as to interrupt the PWM signal, so that the MOSFETs 70A to 70C and the MOSFET 72A are based on the cancel signal.
-ON at either one of the 72C and O of the other
This is a configuration for maintaining the FF. However, from the viewpoint of the present invention, the present invention is not limited to the configuration in which the cancel signal for canceling such a PWM signal is interrupted. For example, by so-called sequence control, the MOSFETs 70A to 70C and A configuration may be used in which one of the MOSFETs 72A to 72C is kept on and the other is kept off.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a motor control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing an outline of the relationship between the configuration of rectifying means (three-phase inverter) and the surroundings.

FIG. 3 is a cross-sectional view schematically showing the configuration of a brushless motor actuator to which the motor control device according to the first embodiment of the present invention is applied.

FIG. 4 is a time chart showing a waveform of a current flowing through a coil.

FIG. 5 is a time chart showing a correspondence between a waveform of a current flowing through a coil and a cancel signal.

FIG. 6 is a diagram conceptually showing a relationship between map data stored in a ROM and a CPU that reads the map data as a storage unit.

FIG. 7 is a block diagram showing an outline of a configuration of a motor control device according to a second embodiment of the present invention.

FIG. 8 is a time chart showing a correspondence between a waveform of a current flowing through a coil and a cancel signal in the second embodiment.

[Explanation of symbols]

10 ... Motor control device, 16 ... Brushless motor, 22 ... Rotor, 30A, 30B, 30C ...
Coil (winding), 46 ... Speed control calculation section (control means), 64 ... ROM (storage means), 48 ... Pre-driver circuit (control means), 50 ... Three-phase inverter (rectification) Means), 70A, 70B, 70C ... MOSF
ET (upper switching element), 72A, 72B, 72
C ... MOSFET (lower switching element), 74
... Rotation detection device (rotation speed detection means), 110 ...
Motor control device, 112 ... Speed control calculation unit (control means)

Continued front page    F-term (reference) 5H560 AA01 AA08 BB04 BB08 BB12                       DA02 DA19 DB20 DC05 DC12                       DC13 EB01 EB05 EC01 EC10                       RR01 SS01 TT01 TT11 TT15                       TT18 UA05 XA02 XA11 XA12                       XB10

Claims (6)

[Claims] 1. A brushless motor including an upper stage switching element provided on the upstream side of the winding and a lower stage switching element provided on the downstream side of the winding with respect to a current flowing through the winding. Rectifying means configured to flow a current of a specific waveform in any phase of the winding by switching the upper switching element and the lower switching element, and the upper switching element and the lower switching based on a predetermined signal wave. The element is switched for a predetermined time, the switching is stopped at a predetermined timing within the predetermined time, and one energization is performed to one of the upper switching element and the lower switching element based on the signal wave. Continuously energize one of the switching elements for longer than the time Control means for switching the other switching element to the continuous energization stop state and intermittently changing the duration of the continuous energization state and the continuous energization stop state for each energization cycle of the winding. And a motor control device comprising. 2. An upper-stage switching element provided on the upstream side of the winding and a lower-stage switching element provided on the downstream side of the winding with respect to the currents flowing through the windings of a plurality of phases constituting the brushless motor. Rectifying means for flowing a current of a specific waveform to any phase of the winding by switching of the upper switching element and the lower switching element, and the upper switching element according to the pulse width of a pulse signal of a predetermined waveform. And switching the lower switching element for a predetermined time, stopping the switching at each of a plurality of predetermined timings within the predetermined time, and either the upper switching element or the lower switching element according to the pulse width. One of the switching elements is continuously turned on for a time longer than one energization time. A motor control device and a control means for continuous energization stop state, the one other switching element of the switching element in the continuously energized state. 3. The control means changes the temporal length of the continuous energization state and the continuous energization stop state stepwise for each energization cycle of the winding. Motor control device. 4. The control means gradually increases or decreases the temporal length of the continuous energization state and the continuous energization stop state for each energization cycle of the winding. The motor control device according to claim 3. 5. A rotation speed detection means for detecting the rotation speed of the rotor of the brushless motor is provided, and the control is performed based on a deviation between the actual rotation speed of the rotor detected by the rotation speed detection means and the set value. The means for determining at least one of the predetermined timing and the temporal length of the continuous energization state and the continuous energization stop state, according to any one of claims 1 to 4. Motor control device. 6. A storage means for storing a plurality of map data, each of which has different durations of the continuous energization and the continuous energization stop for one phase winding among the plurality of phase windings. At the same time, each of the plurality of map data is data for an electrical angle of 360 degrees corresponding to the winding of one phase, and is conceptually arranged in one row in order from the shortest duration to the longest duration. A state in which the control means shifts only the phase difference between the one phase winding and the other phase when setting the duration corresponding to the other phase windings other than the one phase winding. At the same time as reading the map data, and compensating for the shortage of the phase difference in the read map data with the next map data conceptually adjacent to the read map data. The motor control device according to any one of claims 1 to 5.