JP4083354B2 - Motor control device with soft start function for brushless motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a motor control device for a brushless motor, and more particularly, to a motor control device with a soft start function that can easily change a soft start slope and time in accordance with the speed of a soft start operation at the start and motor characteristics.
[0002]
[Prior art]
As a motor for driving a blower fan in an automobile air conditioner, a brushless motor in which a permanent magnet is a rotor, an armature winding is a stator, and a rectifying mechanism is replaced with a magnetic pole sensor and a switching element has come to be used. ing.
[0003]
FIG. 7 is a schematic configuration diagram of a conventional automobile air conditioner. As shown in FIG. 7, the brushless motor 1 includes a FAN provided in the vicinity of an air intake door 4 provided between an inside air introduction duct 2 for taking in the inside air of an automobile and an outside air duct 3 for taking in outside air. Attached to the motor main body unit 5, a drive circuit unit 6 that supplies electric power of different phases to the motor main unit 5, a FAN rotation instruction signal from an air conditioning control circuit 8 to be described later, and the motor main unit 5. The motor control circuit unit 7 generates a control signal having a predetermined duty ratio to the drive circuit unit 6 based on a detection signal from a magnetic pole sensor (not shown). An evaporator E is provided in the vicinity of the motor body 5.
[0004]
The air conditioning control circuit 8 (also referred to as an AC amplifier) receives a detection signal from a water temperature sensor, a temperature sensor, an outside air sensor, etc. (not shown) and an instruction signal from the operation panel 9 assembled on the instrument panel of the vehicle, The FAN instruction signal as shown in FIG. 8 for obtaining the target rotational speed of the motor from this instruction signal and the detection signals from the various sensors and reaching the target rotational speed after a predetermined time is sent to the motor control circuit unit 7. Send it out.
[0005]
The motor control circuit unit 7 is specifically a microcomputer or a custom IC. When the motor control circuit unit is a microcomputer, this microcomputer gradually increases the duty ratio of the control signal (also referred to as output PWM signal) to the drive circuit unit 6 from 0 with the input of the FAN instruction signal. (This period is called the soft start time), and soft start control is performed to send the output PWM signal of the duty ratio that becomes the target rotation speed, or rapid start control that rapidly rotates at high speed (in terms of motor characteristics) At the same time, the duty ratio may be rapidly increased.
[0006]
On the other hand, when the motor control circuit unit 7 is a custom IC instead of a microcomputer, a custom IC having a circuit for soft start control and a custom IC having a circuit for quick start control It was divided and mounted on the board.
[0007]
[Problems to be solved by the invention]
However, conventionally, the motor control unit is composed of a microcomputer having a soft start control function and a quick start control function, or a custom IC with a built-in soft start control circuit and a custom built-in quick start control circuit. It is divided into ICs.
[0008]
In other words, if the motor characteristics are changed by controlling soft start and rapid start with a microcomputer, the control program for soft start and rapid start must be rewritten. There was a problem that it took.
[0009]
On the other hand, when a custom IC is used instead of the microcomputer, the processing speed is increased, but the soft start custom IC and the quick start custom IC are used. For this reason, when the characteristics of the motor change, the circuit for controlling the soft start and the quick start has to be changed, so that there has been a problem that each custom IC has to be remade. That is, if the characteristics of the motor are changed, costs increase.
[0010]
The present invention has been made to solve the above-described problems. Even if the characteristics of the motor change, the soft start or quick start control can be easily changed without replacing the custom IC. An object is to obtain a motor control device for a custom IC type brushless motor that can efficiently perform a soft start and a rapid start by integrating a rapid start function.
[0011]
[Means for Solving the Problems]
The present invention is provided with a plurality of terminals (30a, 30b...) For connecting the outside and the inside, and detection from a target rotation signal and a plurality of Hall elements (IC1, IC2, IC3) provided in the motor main body. In a motor control device for a brushless motor that obtains a duty ratio control signal for each of a plurality of drive pulses from a signal and rotates a rotor of a motor body, a first resistor externally attached to a first terminal (30b) (RS1), a second resistor (RS2) externally attached to the second terminal (30c), a third resistor (Rsa) externally attached to the third terminal (30d), and a third resistor A first capacitor (C3) connected in series to the resistor (Rsa), the connection point of which is connected to the fourth terminal (30e), and a second capacitor (C4) connected to the fifth terminal (30g) ) And the value of the first resistance (RS1) Either the first constant current (IS1) or the addition current obtained by adding the second constant current (IS2) based on the second resistor (RS2) to the first constant current (IS1) is the third terminal. When the first capacitor (C3) is charged via (30d) and the soft start circuit (22) using the potential of the first capacitor (C3) as a target rotation signal and the quick start signal are input, The first constant current (IS1) and the third constant current (IS3) equal to or greater than the second constant current (IS2) are forcibly charged to the first capacitor (C3) via the fourth terminal (30e). The quick start circuit (23) is provided.
[0012]
Therefore, when the rapid start signal is not input, the first constant current (IS1) based on the value of the first resistor (RS1) externally attached to the soft start circuit (22) is supplied to the third terminal ( 30d) to charge the first capacitor (C3) through the third resistor (Rsa).
[0013]
Alternatively, an additional current obtained by adding the second constant current (IS2) based on the second resistor (RS2) externally attached to the first constant current (IS1) is added via the third terminal (30d). 1 capacitor (C3) is charged.
[0014]
Since the potential of the first capacitor (C3) at this time is set as the target rotation signal, the target rotation signal gradually rises with the first constant current (IS1), and the first constant current is charged when the addition current is charged. It is possible to obtain a soft start waveform having a larger slope than the current (IS1).
[0015]
When the rapid start signal is input, the rapid constant circuit (23) forcibly applies the third constant current (IS3) equal to or higher than the first constant current (IS1) and the second constant current (IS2). Since the first capacitor (C3) is charged through the terminal (30e) of the first capacitor (C3), the potential of the first capacitor (C3) does not become a soft start waveform but rapidly rises with the input of the quick start signal. Start waveform.
[0016]
【The invention's effect】
As described above, according to the present invention, all the capacitors and resistors for determining the waveform slope and the time during soft start or rapid start are externally attached.
[0017]
When a rapid start signal is not input, an external first capacitor is connected with a constant current (IS1, IS2) based on the first external resistor RS1 and the second resistor RS2 at the initial detection of the rotation instruction signal. C3 is charged, and a rotation instruction signal having a soft start waveform with an inclination based on the values of these resistors and capacitors is sent out.
[0018]
When a quick start signal is input, the third constant current (IS3) is immediately added to the constant currents (IS1, IS2) and the first capacitor (C3) is charged to obtain a soft start waveform. Instead, a sudden start waveform that rises rapidly is used as a rotation instruction signal.
[0019]
In other words, since a soft start waveform or a sudden start waveform can be obtained based on the values of resistors and capacitors externally attached by a hard circuit, soft start or rapid start can be performed by following the motor rotation at high speed. The effect is obtained.
[0020]
In addition, since it is possible to change the slope of the soft start waveform or the slope of the sudden start waveform by changing the external resistor or capacitor, when the motor characteristics are changed, An effect is obtained in that it is possible to easily obtain a soft start waveform or a sudden start waveform having a slope that matches the characteristics of the motor by simply replacing the capacitor.
[0021]
Therefore, it is not necessary to recreate the IC or the program as in the conventional case, so that the manufacturing cost can be reduced even if the motor characteristics are changed.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic configuration diagram of a motor control device for a brushless motor according to the present embodiment. A motor control device 10 shown in FIG. 1 is a custom IC, which has a plurality of input / output terminals, a drive circuit 6 for supplying power having different phases to the motor main body, and a hall IC (IC1, IC2, IC3) of the motor main body. ), And a control signal for setting a predetermined rotation speed is generated based on each detection signal from the Hall IC and the FAN rotation instruction signal, and is sent to the drive circuit unit 6.
[0023]
At this time, with the input of the FAN rotation instruction signal, a soft start waveform is obtained in which the FAN instruction signal is gradually raised using a resistor, a comparator (comparator) transistor, or the like. The inclination of the soft start waveform or the rapid start time can be varied by an external resistor, a capacitor, or the like. In other words, the slope of the soft start waveform and the quick start time can be easily changed by changing the external resistor and capacitor according to the motor characteristics, etc., and the soft start or quick start can be switched. ing.
[0024]
Next, a schematic configuration of the motor main body will be described first. As shown in FIG. 2, the motor body is provided with a magnet 13 for detecting rotation (hereinafter referred to as a sensor magnet 13) around one end of the shaft 12, and six salient poles 14 a around the sensor magnet 13. , 14b,... Are attached. The above-described sensor magnet 13 is provided around one end of the shaft 12 such that the N pole and the N pole, and the S pole and the S pole face each other.
[0025]
.. Are wound around the six salient poles 14a, 14b,... Of the stator 14, and two opposing coils form one phase. That is, a six-phase drive system is configured with six coils.
[0026]
As shown in FIG. 2, main magnets 17a, 17b,... Are provided around the rotor 16 outside the stator 14 at intervals of 90 degrees. The rotor 16 is rotatably connected to the other end (not shown) of the shaft 12 integrally with the shaft 12.
[0027]
Furthermore, Hall elements 18a (IC1), 18b (IC2), and 18c (IC3) for detecting the magnetic field direction of the magnetic poles (S pole and N pole) of the sensor magnet 13 are equally arranged on the stator 14 at 120 intervals. ing.
[0028]
On the other hand, the drive circuit unit 6 includes six resistors R1, R2,... Connected to the motor control device 10 and six power elements Q1, Q2,. Drive signals based on the signals are generated, and these drive signals are sent to the corresponding power elements Q1, Q2,.
[0029]
Next, the configuration of the motor control device 10 will be described. As shown in FIG. 1, the motor control device 10 includes an input detection circuit 20 that inputs a FAN rotation instruction signal (hereinafter simply referred to as a rotation instruction signal), a quick charging circuit 21, a soft start circuit 22, and a quick start circuit 23. And a soft start time setting circuit 25, a sudden start time setting circuit 26, and a constant current value setting circuit 27. However, the drive circuit unit 6 and the motor control device 10 made into a custom IC are provided in different regions of the same substrate.
[0030]
The input detection circuit 20 inputs a rotation instruction signal to the terminal 30a, compares the rotation instruction signal with a reference value by a comparator (open collector type), and the level of the rotation instruction signal is within a range of 10% or more (for example, 10%). % -90%), the current IS1 is caused to flow from the soft start circuit 22 to the soft start time changing circuit 25.
[0031]
The soft start circuit 22 includes a constant current source 36 for supplying a current IS1, a constant current source 37 for supplying a current IS2, a diode D, and a comparator 38. The constant current source 36 is connected to a terminal 30b, and an external resistor RS2 for changing the constant current value setting is connected to the terminal 30b. The constant current source 37 is connected to a terminal 30c, and an external resistor RS2 for changing a constant current value setting is connected to the terminal 30c.
[0032]
The external resistor RS1 and resistor RS2 are collectively referred to as a constant current value setting circuit 27 in the present embodiment.
[0033]
The diode D has the anode side connected to the constant current source 37 and the cathode connected to the constant current source 36 and the output terminal of the input detection circuit 20 and the terminal 30d.
[0034]
Further, the comparator 38 has one input terminal connected to the terminal 30e, the constant current source 39 (IS3) of the quick start circuit 23, and the voltage follower 24.
[0035]
The quick start circuit 23 includes a constant current source 39 (IS3) and an AND 40, and one input terminal of the AND is a terminal 30f of the custom IC (a terminal to which an H level or L level quick start control signal is input). The other input terminal is connected to the output of the quick charging circuit 21. The output of the AND 40 is an output signal for turning the constant current source 39 (IS3) off and off. That is, the AND 40 can be switched between soft start and sudden start.
[0036]
The quick charging circuit 21 includes a transistor TR, a constant current source 42, a comparator 43, a resistor, and the like, and connects the base side of the transistor TR to the input detection circuit 20 via a terminal 30f and a NOT 44. The collector of the transistor TR is connected to the constant current source 42 (IS4), one input terminal of the comparator 43, and the terminal 30g of the custom IC. In the above-described NOT 44, when the level of the rotation instruction signal is 10% or less or 90% or more, the input detection circuit 20 sets the output to L level and discharges the capacitor C4.
[0037]
The comparator 43 has the other input terminal connected to the voltage dividing resistor and the output connected to one input terminal of the AND 40 of the quick start circuit 23.
[0038]
Further, a capacitor C4 is externally attached to the terminal 30g of the custom IC. In the present embodiment, the capacitor C4 is referred to as the rapid start time setting circuit 26.
[0039]
Further, a series circuit including a resistor RSa and a capacitor C3 is connected to the terminal 30d of the custom IC. The connection point between the resistor RS and the capacitor C3 is connected to the terminal 30e of the custom IC.
[0040]
The resistor RS and the capacitor C3 are collectively referred to as a soft start setting circuit 25 in the present embodiment.
[0041]
The operation of the motor controller 10 configured as a custom IC configured as described above will be described below with reference to the waveform diagram of FIG.
[0042]
(Soft start operation)
For example, when the rotation instruction signal shown in FIG. 3 (a) is input to the terminal 30a of the motor control device 10 that has been made into a custom IC, the input detection circuit 20 is compared with a reference power supply (for example, a voltage corresponding to 4V, 10%). When the power is below the reference power supply, the output is set to a high impedance state. As a result, the soft start circuit 22 causes the current IS1 based on the resistor RS2 of the external constant current value setting circuit 27 to flow to the soft start setting circuit 25 via the terminal 30d. That is, when the level of the rotation instruction signal becomes 10% or more, the capacitor C3 is charged with the current IS1 based on the resistor RS1 via the external resistor Rsa.
[0043]
At this time, the voltage of the capacitor C3 of the soft start time setting circuit 25 is amplified by the voltage follower 24 of the soft start circuit 22. That is, at the initial stage of input of the rotation instruction signal, as shown in FIG. 3B, the soft start waveform is transmitted within the range of the broken line 1 because the voltage when the current IS1 is accumulated in the capacitor C3 is transmitted. The waveform has a slope.
[0044]
Further, the voltage of the capacitor C3 is input to one input terminal of the comparator 38 of the soft start circuit 22, and the comparator 38 compares with a reference power source (e.g., equivalent to 6V, 10%), and the voltage of the capacitor C3 is the reference. The output is set to a high impedance state while it is above the power source.
[0045]
As a result, a current obtained by adding the constant current IS1 and the current IS2 based on the external resistor RS2 flows through the soft start setting circuit 25 and charges the capacitor C3.
[0046]
That is, when the capacitor C3 is about 0.6 V (corresponding to 10% of the rotation instruction signal), the soft start waveform is an addition current of the constant current IS1 and the constant current IS2, as shown in FIG. Therefore, the output waveform is a polygonal line 2 having a steeper slope than the polygonal line 1.
[0047]
That is, by changing the capacitor C3 and the resistor Rsa of the constant current value setting circuit 27, it is possible to change the inclination of the range of the broken line 1 in the initial stage at the time of soft start as shown in FIG.
[0048]
The reason why the slope of the soft start waveform IS1 at the time of the soft start is preferably set so that the output duty is in the range of 3.75% / sec to 15% / sec will be described. In general, in the soft start of a blower brushless motor for vehicle air conditioning, there is no clear standard for the slope of the initial drive voltage, and it is simply determined so that there is no sense of incongruity in the amount of air blown from the fan.
[0049]
However, depending on the slope of the initial voltage (the slope of the soft start waveform IS1), the blower may turn around and generate noise from the motor.
[0050]
In general, when the slope of the initial drive voltage of the blower brushless motor is 8.333% / sec or less, it is difficult to hear the noise caused by the motor at the start of hearing. That is, it decreases as the inclination becomes smaller. However, as the slope of the initial drive voltage is reduced, the motor starts to run slower.
[0051]
For this reason, the slower the change in the air volume, the more uncomfortable the passenger feels, so about 5% is the limit.
[0052]
That is, it can be said that it is desirable for the vehicle air-conditioning system to determine the slope of the initial drive voltage within the range of 3.75% / sec to 15% / sec including the variation of the motor. Here, “%” indicates the ratio of the driving voltage when the air volume is fully opened.
[0053]
For example, when the FAN instruction voltage is a voltage value indicating stop, soft start is set, and when the FAN instruction voltage is a voltage indicating FAN activation, soft start control is started. At this time, the slope constant (slope) is changed every set time. That is, FAN is activated by variable slope control.
[0054]
When the target is reached (equivalent to FAN instruction voltage), soft start is canceled and control is performed with the FAN instruction voltage even during soft start activation.
[0055]
As shown in FIG. 4, this soft start eliminates the initial stop time (0 start) and changes the FAN output voltage from 0 to 7.5% / sec (T2 in FIG. 4).
[0056]
When the soft start setting is completed as described above, the soft start is not performed unless the FAN is stopped.
[0057]
That is, as shown in FIG. 5, with the start of FAN starting, the idle time of the motor (which varies depending on the motor characteristics) is taken into account for 3.0 seconds, 6.7%, Change to 7.5%.
[0058]
In addition, if the resistance Rsa and the capacitor C3 are changed, the inclination of the broken line 2 can be changed. However, since the inclination of the broken line 1 is an inclination set in accordance with the characteristics of the motor, the resistance Rsa and the capacitor C3 are changed. If it changes, the inclination of the broken line 1 will also change.
[0059]
Therefore, in this example, by changing the resistance RS2 connected to the terminal 30c, the low current (IS2) is changed and the inclination of the broken line 2 is changed.
[0060]
(Sudden start)
For example, it is assumed that a rotation instruction signal is input to the terminal 30a of the motor control device 10 that has been made into a custom IC, and the input detection circuit 20 detects a level corresponding to 10% and puts the output in a high impedance state.
[0061]
At this time, when the sudden start signal input from the outside is set to H level (becomes L level after a predetermined time), the transistor TR of the quick charging circuit 21 is turned off and is connected from the constant current source IS4 via the terminal 30d. An external capacitor C4, which is a quick start time setting circuit, is charged. When the voltage of the capacitor C4 increases and reaches VDD, the comparator 43 of the quick charging circuit 21 sets the output to the H level.
[0062]
That is, the H level sudden start signal and the H level output signal from the comparator 43 are input to the AND 40 of the rapid start circuit 23 to operate the constant current source IS3.
[0063]
Therefore, an additional current of the current IS1 of the soft start circuit 22 and the current IS3 of the quick start circuit 23 flows through the resistor RS and the capacitor C3, which are the soft start time setting circuit 25, and the potential of the capacitor C3 is rapidly increased. Thus, the output of the comparator 38 is brought into a high impedance state. For this reason, when the sudden start control signal is set to the H level, an added current of the current IS1, the current IS2, and the current IS3 flows through the resistor Rsa and the capacitor C3, and the potential of the capacitor C3 is rapidly increased. As shown in (c) of FIG. 3, a sudden start waveform that rises rapidly is obtained. For example, the FAN can be rotated at 1000 revolutions simultaneously with the start.
[0064]
When the rapid start control waveform becomes H level or L level, the transistor TR of the quick charging circuit 21 is turned on, and a discharge current is supplied from the external capacitor C4.
[0065]
For this reason, the output of the comparator 43 of the quick charging circuit 21 becomes L level, the current IS3 from the constant current source 39 is stopped, and the addition current of the current IS1 and the current IS2 is caused to flow through the capacitor C3. Therefore, as shown in FIG. 3 (c), the waveform in the output circuit 24 drops rapidly and returns to the soft start waveform.
[0066]
That is, by changing the capacitor C4, it is possible to change the operating time at the time of sudden start according to the characteristics of the motor as shown in FIG. 6 (dotted line).
[0067]
Note that all of the external resistors RS1 and RS2, the resistor Rsa, the capacitor C3, and the capacitor C4 may be changed to obtain a start operation that matches the characteristics of the motor.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a motor control device of a brushless motor according to an embodiment.
FIG. 2 is a configuration diagram of a main body portion of a brushless motor.
FIG. 3 is a waveform diagram for explaining the operation of the embodiment;
FIG. 4 is an explanatory diagram for explaining a ratio of a variable slope of a soft start waveform.
FIG. 5 is an explanatory diagram for explaining a ratio of a variable slope slope according to motor characteristics;
FIG. 6 is a waveform diagram when the capacitor used at the time of sudden start is changed.
FIG. 7 is a schematic configuration diagram of a conventional air conditioning control device.
FIG. 8 is an explanatory diagram illustrating a FAN instruction signal.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Motor control apparatus 20 Rotation detection circuit 21 Quick charge circuit 22 Soft start circuit 23 Rapid start circuit 25 Soft start time setting circuit 26 Start time setting circuit 27 Constant current value setting circuit

Claims (6)

A plurality of terminals (30a, 30b...) For connecting the outside and the inside are provided, and a plurality of phases are obtained from the target rotation signal and the detection signals of the plurality of Hall elements (IC1, IC2, IC3) provided in the motor main body. In a motor control device of a brushless motor that obtains a duty ratio control signal for each drive pulse and rotates the rotor of the motor body,
A first resistor (RS1) externally attached to the first terminal (30b);
A second resistor (RS2) externally attached to the second terminal (30c);
A third resistor (Rsa) externally attached to the third terminal (30d);
A first capacitor (C3) connected in series to the third resistor (Rsa), the connection point being connected to a fourth terminal (30e);
A second capacitor (C4) connected to the fifth terminal (30g);
The first constant current (IS1) based on the value of the first resistor (RS1) or the second constant current (IS2) based on the second resistor (RS2) is added to the first constant current (IS1). One of the added currents is charged to the first capacitor (C3) via the third terminal (30d), and the potential of the first capacitor (C3) is used as the target rotation signal. A soft start circuit (22);
When a quick start signal is input, the fourth constant terminal (30e) is forced to apply a third constant current (IS3) equal to or higher than the first constant current (IS1) and the second constant current (IS2). And a quick start circuit (23) for charging the first capacitor (C3) through a motor control device with a soft start function of a brushless motor. The input terminal is connected to the sixth terminal (30a) to which the rotation instruction signal is input, and the output terminal is connected to the first constant current (IS1) of the soft start circuit, and the rotation instruction signal exceeds the reference value. When the output terminal is in a high impedance state, the first constant current (IS1) or the addition current is charged to the first capacitor (C3) via the third terminal (30d). The motor control device with a soft start function of the brushless motor according to claim 1, further comprising a circuit. When the sudden start signal is input, or when the input detection circuit (20) puts the output terminal in a high impedance state, the fourth constant current (IS4) is passed through the fifth terminal (30g). A quick charge circuit (21) for charging the second capacitor (C4) and sending an output signal to the quick start circuit (23) when the potential of the second capacitor (C4) reaches a predetermined level. The motor control device with a soft start function for a brushless motor according to claim 1 or 2. The rapid start circuit includes:
When both the rapid start signal and the output signal from the rapid charging circuit are input, the third constant current (IS3) is supplied to the first capacitor (C3) via the fourth terminal (30e). The brushless motor according to claim 1, 2 or 3, wherein charging is performed and charging of the third constant current (IS3) is stopped when neither the quick start signal nor the output signal is input. Motor control device with soft start function. The soft start circuit
One is connected to the fourth terminal (30e), the other is connected to a reference power source, an output is connected to the second constant current source (IS2), and when the potential of the fourth terminal (30e) is below the reference, When the first constant current (IS1) is charged to the first capacitor (C3) via the third resistor (Rsa) and exceeds the reference, the output is set to a high impedance state and the second constant current (IS3) is set. 2. A motor control device with a soft start function for a brushless motor according to claim 1, wherein a current (IS2) is forcibly added to the first constant current (IS1). 5. The motor control apparatus with a soft start function for a brushless motor according to claim 1, wherein the input detection circuit, the soft start circuit, the quick charge circuit, and the quick start circuit are integrated.

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