JP4083352B2 - Brushless motor control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention supplies power to the armature coil while sequentially switching the conduction states of a plurality of switching elements, and makes the switching of the conduction state precede the change of the rotor magnetic pole detected by the magnetic sensor. The present invention relates to a control device, and more particularly, to a brushless motor control device that can switch a conduction state without using software.
[0002]
[Prior art]
Generally, in a brushless motor, the conduction state of a plurality of switching elements is sequentially switched by a microcomputer, and current supply to the armature coil is controlled. Then, for the purpose of preventing the generation of noise or improving the torque efficiency, advance angle control is performed in which the switching state of each switching element is preceded by the change of the rotor magnetic pole detected by the magnetic sensor. .
[0003]
FIG. 9A shows the configuration of a conventional brushless motor control device. In this figure, when a rotation command is input, the microcomputer a sequentially supplies a gate signal to each field effect transistor configured in the switching circuit b. The switching circuit b drives each field effect transistor with the supplied gate signal to energize and rotate the three-phase brushless motor body c. When the brushless motor main body c rotates, the magnetic sensor d disposed on the stator detects the rotor magnetic pole and feeds back the detection signal to the microcomputer a. The microcomputer a obtains the delay time data ta from the returned detection signal. The delay time data ta is calculated as data obtained by subtracting a desired advance time from the switching period of the rotor magnetic poles.
[0004]
Then, the internal timer is operated from the time when the rotor magnetic pole is switched in the detection signal, and when the time corresponding to the delay time data ta has elapsed, the timer is stopped and the next switching is performed. Therefore, as shown in FIG. 9B, the gate signal can be switched by the advance time from the time of switching of the rotor magnetic poles.
[0005]
Therefore, the advance angle control by this software makes it possible to control a brushless motor that balances low noise and high efficiency.
[0006]
[Problems to be solved by the invention]
However, in the above conventional brushless motor control device, the calculation of the switching period and delay time of the rotor magnetic poles and the setting of the advance time based on these calculation results are performed by software. Whenever it changes, software development must be redone according to the characteristics. This development work includes the creation of a source program, the work of compiling the created source program and translating it into a machine language, the verification (debugging) work, and the like, leading to a prolonged development period. As a result, it has become difficult to answer the desire to shorten the development period.
[0007]
Therefore, the present invention has been made in view of the above-described conventional circumstances, and as its purpose, advance angle control that precedes the switching of the conduction state of the switching element before the change of the rotor magnetic pole detected by the magnetic sensor, It is an object of the present invention to provide a brushless motor control device that can be executed in accordance with the characteristics of the brushless motor without depending on software.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problem, the brushless motor control device according to the first aspect of the present invention supplies power to the armature coil while sequentially switching the conduction states of the plurality of switching elements, and at the time of switching the conduction state. In the brushless motor control device that precedes the change of the rotor magnetic pole detected by the magnetic sensor, the frequency voltage conversion for converting the change frequency of the rotor magnetic pole detected by the magnetic sensor into a voltage corresponding to the change frequency A circuit, a first capacitor, a charging circuit that charges the first capacitor in a predetermined time when the rotor magnetic pole detected by the magnetic sensor changes, and a second capacitor, After the charging of the first capacitor is completed, charging of the second capacitor is started, and the voltage of the second capacitor is changed to the frequency voltage. Upon reaching the converted voltage conversion circuit, characterized by comprising a lead angle circuit for switching the conduction state of the switching subject to switching elements of the plurality of switching elements.
[0009]
In the brushless motor control device according to the first aspect of the present invention, the change frequency of the rotor magnetic pole detected by the magnetic sensor is converted into a voltage corresponding to the change frequency by the frequency voltage conversion circuit, while the first capacitor In the charging circuit including the first capacitor, the first capacitor is charged in a certain time when the rotor magnetic pole detected by the magnetic sensor changes. In the lead angle circuit including the second capacitor, charging of the second capacitor is started after the charging of the first capacitor is completed, and the voltage of the second capacitor reaches the voltage converted by the frequency voltage conversion circuit. When this is done, the conduction state of the switching element to be switched among the plurality of switching elements is switched.
[0010]
A brushless motor control device according to a second aspect of the present invention is the brushless motor control device according to the first aspect, wherein the frequency-voltage conversion circuit includes an adjustment circuit for adjusting a conversion rate. .
[0011]
In the brushless motor control device according to the second aspect of the present invention, the conversion rate is varied by the adjustment circuit, and the magnitude of the voltage output from the frequency voltage conversion circuit is adjusted.
[0012]
A brushless motor control device according to a third aspect of the present invention is the brushless motor control device according to the first or second aspect, wherein the advance circuit charges the second capacitor with a constant current. It is characterized by performing using a source or resistance.
[0013]
In the brushless motor control device according to the third aspect of the present invention, the second capacitor is reliably charged using a constant current source or a resistor, and particularly when the constant current source is used, the voltage of the second capacitor is The rise is linear.
[0014]
A brushless motor control device according to a fourth aspect of the present invention is the brushless motor control device according to the third aspect, wherein the constant current source has a current value for setting a current value of the constant current source. A setting circuit is added.
[0015]
In the brushless motor control device according to the fourth aspect of the present invention, the voltage increase rate of the capacitor during charging is adjusted by the current value setting circuit.
[0016]
【The invention's effect】
As described above, according to the brushless motor control device of the first aspect of the present invention, when the change frequency of the rotor magnetic pole is converted into voltage by the frequency voltage conversion circuit, and the rotor magnetic pole is changed by the charging circuit. The first capacitor is charged from a certain time to secure a certain time, and the second capacitor started after the completion of charging the first capacitor reaches the voltage converted by the frequency voltage conversion circuit by the advance circuit. In this case, since the conduction state of the switching element to be switched is switched, the advance angle control can be performed without using software. In addition, by changing the capacity of the second capacitor, the advance time can be adjusted in accordance with the characteristics of the brushless motor.
[0017]
According to the brushless motor control apparatus of the second aspect of the present invention, the advance time is adjusted by adjusting the conversion rate by the adjustment circuit and adjusting the magnitude of the voltage output from the frequency voltage conversion circuit. Is possible.
[0018]
According to the brushless motor control device of the present invention according to claim 3, since the capacitor is charged by the constant current source and the voltage rise becomes linear, linear advance angle control that is easy to adjust is possible. Become.
[0019]
Further, according to the brushless motor control device of the present invention according to claim 4, the voltage increase rate at the time of charging the second capacitor can be set by the current value setting circuit, so that the advance time can be adjusted. The effect is obtained.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of a control apparatus for a brushless motor according to the present invention will be described in detail with reference to FIGS.
[0021]
FIG. 1 is a diagram showing a first embodiment of a brushless motor control apparatus according to the present invention. In this figure, a brushless motor 200 is used as a blower motor for an air conditioner of an automobile, and includes a motor body 10, a switching circuit 20 for energizing armature coils 4a to 4f disposed in the motor body 10, and a custom IC 150. And a peripheral circuit of the custom IC 150 and the like, and the rotor 1 (not shown) of the motor body 10 is rotated at the indicated rotation speed indicated by the rotation instruction signal Vin from the auto amplifier. Here, the custom IC 150 is a circuit in which circuits shared by various motors are integrated and housed in a dedicated package, and the dedicated package is provided with terminals for connecting peripheral circuits.
[0022]
The switching circuit 20 includes field effect transistors (hereinafter simply referred to as transistors) Q1 to Q6 and resistors R1 to R6 connected in series to the gates of the transistors. Transistors Q1, Q2 and Q3 have their drain terminals connected to a power supply (DC power supply), while transistors Q4, Q5 and Q6 have their source terminals grounded. The source of the transistor Q1 and the drain of Q4, the source of Q2 and the drain of Q5, the source of Q3 and the drain of Q6 are connected as a U point, a V point, and a W point, respectively.
[0023]
The switching circuit 20 receives the gate signal generated by the drive control circuit 140 based on the rotation instruction signal Vin via the terminals T141 to T146, and switches the current from the power source, thereby causing the U point, the V point, Current is supplied to the armature coils 4a to 4f of the motor body 10 through the point W.
[0024]
The magnetic sensors IC1 to IC3 detect magnetic poles of a sensor magnet (rotor magnetic pole) 5 formed in the motor body 10, and pulse-shaped non-inverted magnetic sensor signals S1L, S2L, and S3L corresponding to the polarities of the magnetic poles Inverted magnetic sensor signals S1H, S2H, and S3H in which the on / off periods of these signals are inverted are generated and sent to a sensor input circuit 30 to be described later via terminals T31 to T36.
[0025]
The custom IC 150 and its peripheral circuits shown in the figure include a sensor input circuit 30, a first timer circuit 40, a second timer circuit 50, an advance angle switching circuit 60, an F / V conversion circuit 70, an F / V gain setting circuit 80, The advance angle Max control circuit 90, the clock generation circuit 100, the latch circuit 110, the select circuit 120, the three-phase control circuit 130, and the drive control circuit 140 are configured, and advance angle control is performed by these circuits.
[0026]
The sensor input circuit 30 includes comparators 30a to 30c (not shown) having hysteresis characteristics, and non-inverting magnetic sensor signals S1L and S2L are connected to the non-inverting input terminals of these comparators via terminals T31, T32, and T33. , S3L are input, and inverted magnetic sensor signals S1H, S2H, S3H are input to the inverting input terminals via terminals T34, T35, T36, respectively. The outputs of the comparators 30a to 30c are sent to the clock generation circuit 100, the latch circuit 110, and the select circuit 120 as signals S1, S2, and S3, respectively. In the sensor input circuit 30, since the comparators 30a to 30c have hysteresis characteristics, the influence of noise superimposed on the magnetic sensor signal and chattering can be prevented.
[0027]
The first timer circuit 40 outputs a sawtooth signal TM2 for converting the number of revolutions to a voltage to an F / V conversion circuit 70, which will be described later, and sets an advance time for the second timer circuit 50. It is a circuit that sends out a signal TM1. The second timer circuit 50 is a circuit that generates an advance time setting signal MS for setting the advance time by a charging operation of the capacitor C2 connected to the terminal T52, and sends it to the latch circuit 110.
[0028]
The advance angle switching circuit 60 receives a rotation speed signal FV1 from an F / V gain setting circuit 80 described later and a voltage (advance start start rotation speed setting FV / MG) set at the terminal T61, and receives the rotation speed signal. When FV1 exceeds the voltage of the advance angle start rotation speed setting FV / MG, the switching signal MGSEL is set to a high voltage level to perform advance angle control. Conversely, when the voltage is less than the voltage of the advance angle start rotation speed setting FV / MG, The advance angle control is prohibited as a low voltage level.
[0029]
Here, the circuit configurations of the first timer circuit 40, the second timer circuit 50, and the advance angle switching circuit 60 will be described in detail with reference to FIG. As shown in the figure, the first timer circuit 40 includes a comparator 40a having a constant current source IS1 and an open collector type output transistor inside a custom IC 150 (hereinafter simply referred to as an inside). A capacitor C1 having a positive electrode connected to T41 and a negative electrode grounded outside the custom IC 150 (hereinafter simply referred to as “external”) and a constant current setting resistor R41 having one end connected to the terminal T43 and the other end grounded externally are provided.
[0030]
The constant current source IS1 is for charging the capacitor C1, and the current value can be set by a constant current setting resistor R41. The terminal T41 to which the capacitor C1 is connected is connected to the non-inverting input terminal of the comparator 40a. Furthermore, the first timer circuit 40 uses the positive voltage of the capacitor C1 as the sawtooth signal TM2 to be described later. Also output to the V conversion circuit 70.
[0031]
On the other hand, the second timer charging start level (voltage) RST is input to the inverting input terminal of the comparator 40a via the terminal T42. Then, the first timer circuit 40 sends the output of the comparator 40a to the second timer circuit 50 as the signal TM1.
[0032]
The second timer circuit 50 includes a constant current source IS2 and a comparator 50a configured inside the custom IC. In addition, a constant current setting resistor R51 having one end connected to the terminal T51 and the other end grounded externally. And a capacitor C2 having a positive electrode connected to the terminal T52 and a negative electrode externally grounded. A resistor R52 is connected between the positive electrode of the capacitor C2 and the DC power source.
[0033]
The output (signal TM1) of the comparator 40a configured in the first timer circuit 40 described above is connected to the positive electrode of the capacitor C2 and the non-inverting input terminal of the comparator 50a. A constant current source IS2 that can set a value is connected. A rotation speed signal FV1, which will be described later, is input to the inverting input terminal of the comparator 50a. Then, the comparator 50 a sends an advance time setting signal MS to the latch circuit 110.
[0034]
The advance angle switching circuit 60 shown in the figure includes a comparator 60a, and the advance angle start rotation speed setting FV / MG is input from the outside as a voltage to the inverting input terminal via the terminal T61. The rotation speed signal FV1 is input to the inverting input terminal. With such a configuration, it is possible to inhibit the advance angle control in a predetermined rotation speed region by comparing the rotation speed signal FV1 with the externally set voltage FV / MG and outputting the switching signal MGSEL. ing.
[0035]
In FIG. 1, an F / V conversion circuit 70 is a circuit that converts the sawtooth signal TM2 from the first timer circuit 40 into a voltage signal FV0. An F / V gain setting circuit 80 is an arbitrary F / V This is an inverting amplifier circuit that converts this signal FV0 so as to have characteristics. The advance angle limit circuit 90 is a circuit that limits the voltage signal FVO to be less than or equal to the advance angle limit VM set by a voltage from the outside.
[0036]
Here, the F / V conversion circuit 70, the F / V gain setting circuit 80, and the advance angle limit circuit 90 will be described in detail with reference to FIG. In this figure, the F / V conversion circuit 70 includes a comparator 70a, an operational amplifier 70b, and a resistor R71. The comparator 70a inputs the sawtooth signal TM2 from the first timer circuit 40 to its inverting input terminal, compares this signal with the DC reference voltage ref input to the non-inverting input terminal, and produces a constant pulse width. This is for outputting a square wave signal. The output terminal of the comparator 70a is connected to a terminal T71 via a resistor R71. The positive terminal of a capacitor C71 whose negative electrode is grounded externally is connected to the terminal T71. The resistor R71 and the capacitor C71 are provided to smooth the output signal of the comparator 70a.
[0037]
Then, the advance angle limit circuit 90 restricts the smoothed voltage to the advance angle MAX limit voltage VM set at the terminal T91 and inputs it to the non-inverting input terminal of the operational amplifier 70b. The operational amplifier 70b constitutes a buffer circuit by connecting its output terminal and inverting input terminal.
[0038]
The F / V gain setting circuit 80 shown in the figure includes an operational amplifier 80a inside, and an output terminal of the operational amplifier 70b of the F / V conversion circuit 70 is connected to the terminal T81, and between the terminals T81 and T82. The resistor R81 is connected, and the terminal T82 is connected to the inverting input terminal of the operational amplifier 80a, whereby the voltage signal FV0 is input to the inverting input terminal of the operational amplifier 80a.
[0039]
On the other hand, the bias voltage Vb is applied to the non-inverting input terminal of the operational amplifier 80a via the terminal T84. The output terminal of the operational amplifier 80a is connected to the terminal T83, and the feedback resistor R82 is connected between the terminal T83 and the terminal T82. With this configuration, the operational amplifier 80a functions as an inverting amplifier, thereby generating a DC rotational speed signal FV1 that becomes a lower voltage as the actual motor rotational speed becomes higher.
[0040]
The gain of the operational amplifier 80a can be varied by adjusting the resistance value of the resistor R81 or the resistor R82. Moreover, the minimum voltage of the rotation speed signal FV1 is defined by setting the advance angle MAX limit voltage VM.
[0041]
Returning to FIG. 1, the clock generation circuit 100 generates the control clock signal CKM at a repetition period corresponding to an electrical angle of 30 degrees (1/12 rotation) based on the signals S1, S2, and S3 output from the sensor input circuit 30. It outputs continuously. Hereinafter, the signals S1, S2, and S3 are referred to as pre-advance signals S1, S2, and S3 for convenience of explanation.
[0042]
The latch circuit 110 inputs the pre-advance signals S1, S2, S3, the control clock signal CKM, and the advance time setting signal MS, and performs an advance process on the pre-advance signals S1, S2, S3. That is, it is normalized by the advance time setting signal MS, and is delayed by a time obtained by subtracting the advance time from the time corresponding to 30 electrical degrees. Then, signals S1B, S2B, and S3B after the advance angle processing (hereinafter referred to as after-advance signals S1B, S2B, and S3B) are sent to the select circuit 120.
[0043]
The select circuit 120 inputs both the pre-advance signal and the post-advance signal and also receives the switching signal MGSEL, and switches between the pre-advance signal and the post-advance signal according to the state of the switching signal MGSEL. , One of them is sent to the three-phase control circuit 130.
[0044]
The three-phase control circuit 130 generates signals G1, G2, G3, G4, G5, and G6 using an internal logic circuit for the pre-advance signal or the post-advance signal. These signals are signals having an ON time corresponding to an electrical angle of 60 degrees, and correspond to the transistors Q1, Q2, Q3, Q4, Q5, and Q6, respectively. Then, the three-phase control circuit 130 supplies the signals G1 to G6 to the drive control circuit 140.
[0045]
The drive control circuit 140 switches the signals G1 to G6 as a gate signal by controlling the pulse width of the signals G1 to G6 at a high frequency in the ON period of these signals based on the rotation instruction signal Vin given from the auto amplifier via the terminal T147. This is supplied to each transistor of the circuit 20.
[0046]
Here, before describing the specific operation, the configuration of the brushless motor 200 main body will be described with reference to FIG.
[0047]
FIG. 4 is a cross-sectional view of the motor body 10 with respect to the rotation axis direction. The motor main body 10 has an outer rotor type structure having three-phase armature coils, and the inner peripheral side stator 3 shown in the figure has six protrusions 3a to 3f radially at an angle of 60 degrees. Are formed, and the armature coils 4a to 4f are arranged with the respective protruding portions as cores. A cylindrical rotor 1 provided with main magnets 2 (field permanent magnets) is arranged outside the stator 3 at intervals of 90 degrees in the circumferential direction.
[0048]
Also, the sensor magnet 5 shown in this figure is formed with two N poles and two S poles alternately magnetized at equal angles, and is attached to a shaft 6 that rotates integrally with the rotor 1, so that the rotor magnetic poles Is configured. Magnetic sensors IC <b> 1 to IC <b> 3 that detect the magnetic poles of the sensor magnet 5 are evenly arranged on the inner periphery of the stator 3 with an angle of 120 degrees.
[0049]
When the conduction of the transistor is switched when the magnetic pole boundary of the sensor magnet 5 is detected, the torque generated by the brushless motor is a mechanical mounting angle (hereinafter referred to as “the center of the main magnet with respect to the center of each magnetic pole of the sensor magnet”). Delay angle D "). For example, as shown in FIG. 5A, when the delay angle is 30 degrees, the generated torque is the largest and the efficiency is improved. On the other hand, as shown in FIG. 5B, when the delay angle is D42 degrees, the beat sound due to resonance between the vibration frequency of the motor and the natural vibration frequency of the motor storage case is minimized.
[0050]
In this embodiment, the delay angle D is set to 44 degrees, and the same effect as the adjustment for reducing the mechanical delay angle by leading the transistor conduction switching to the detection of the magnetic pole boundary of the sensor magnet 5 is obtained. It is about to try. Hereinafter, an angle obtained by subtracting an electrical angle corresponding to the advanced advance time from the delay angle D44 degrees is referred to as a sensor angle. Therefore, for example, when the advance angle is equivalent to 8 electrical degrees, the sensor angle is 36 degrees.
[0051]
In FIG. 4, (1) indicates a coil having a short current path and a current flowing twice that of other armature coils. (2) is a position for generating forward rotation torque due to the repulsive force between the armature coil 3c (3f) and the main magnet 2, and (3) is a position for generating reverse torque due to the repulsive force between the armature coil 3a (3d) and the main magnet 2. Indicates.
[0052]
Next, the operation of the brushless motor control apparatus according to the first embodiment of the present invention will be described.
[0053]
First, the F / V conversion circuit 70 shown in FIG. 3 generates the rotation speed signal FV1 as follows. That is, the comparator 70a compares the sawtooth signal TM2 with the reference voltage ref and outputs a square wave pulse signal having a constant pulse width every 30 degrees of electrical angle, which is smoothed by the resistor R71 and the capacitor C71. It is smoothed by a circuit, and a DC voltage that becomes higher as the rotation speed is higher is obtained.
[0054]
Then, this DC voltage is limited to the advance angle limit VM or less by the advance angle limit circuit 90, and is inverted and amplified by the operational amplifier 80a of the F / V gain setting circuit 80 via the operational amplifier 70b as a buffer. Therefore, the amplified rotation speed signal FV1 (DC signal) is lower when the rotation speed is higher and is higher when the rotation speed is lower.
[0055]
FIG. 5 shows the control clock signal CKM, the charging waveform of the capacitor C1 and the capacitor C2, and the waveform of the advance time setting signal TM. As shown in the figure, the control clock signal CKM continuously outputs a pulse having a very short width at a repetition period corresponding to an electrical angle of 30 degrees.
[0056]
In response to this pulse, the first timer circuit 40 starts discharging the capacitor C1 by a discharge circuit (not shown). When the voltage of the capacitor C1 becomes lower than the second timer charging start level RST set at the terminal T42, the output transistor of the comparator 40a draws current from the capacitor C2 and discharges the capacitor C2.
[0057]
When the charge voltage of the capacitor C2 falls below the voltage level of the rotation speed signal FV1 output from the F / V gain setting circuit 80, the second timer circuit 50 reduces the output (advance time setting signal MS) of the comparator 50a to a low voltage. Invert to level.
[0058]
When the voltage of the capacitor C1 drops below a predetermined voltage, the first timer circuit 40 charges the capacitor C1 from the constant current source IS1. When the voltage of the capacitor C1 rises due to this charging and exceeds the second timer charging start level RST, the first timer circuit 40 inverts the output of the comparator 40a to high impedance.
[0059]
In response to the inversion of the output, the second timer circuit 50 starts charging the capacitor C2 with the constant current source IS2. In this charging, a time constant determined by the current value setting resistor R51 of the constant current source IS2 and the capacitance of the capacitor C2 can be adjusted to freely determine the voltage increase rate of the capacitor C2. Further, the capacitor C2 can be charged via the resistor R52. In that case, the voltage rise rate of the capacitor C2 can be changed by adjusting the value of the resistor R52.
[0060]
When the voltage of the capacitor C2 exceeds the voltage level of the rotation speed signal FV1 output from the F / V gain setting circuit 80, the second timer circuit 50 outputs the output of the comparator 50a (advance time setting signal MS). ) To high voltage level.
[0061]
Then, in response to the next rise of the control clock signal CKM, the first timer circuit 40 discharges the capacitor C1 again, and the second timer circuit 50 determines that the voltage of the capacitor C2 becomes lower than the voltage of the rotation speed signal FV1. The advance time setting signal MS is inverted to the low voltage level.
[0062]
Therefore, the rising of the advance time setting signal MS can be preceded by the advance time with respect to the next rise of the control clock signal CKM, as shown in FIG. As described above, since it is lower at higher speeds and higher at lower speeds, the advance time can be longer at higher speeds and shorter at lower speeds.
[0063]
Further, since the rotation speed signal FV1 is obtained from the voltage signal FV0 limited to the advance angle MAX limit voltage VM or less by the advance angle max limit circuit 90, it does not become less than the minimum value as shown in FIG. In the high rotation range, the advance time can be gradually approached to zero (zero) as the rotational speed increases.
[0064]
Further, the advance time can be adjusted by the time constant of the second timer circuit 50 and the voltage (conversion rate) of the rotation speed signal FV1 with respect to the rotation speed.
[0065]
In this embodiment, the first timer circuit 40 is a circuit for generating the rotation speed signal FV1, but the time constant is adjusted by changing the capacitance of the capacitor C1 and the resistance value of the resistor R41, or The advance time can also be varied by adjusting the second timer charging start level RST. At this time, by using the capacitor C1 or the capacitor C2 as a temperature-compensated ceramic capacitor having good capacitance stability, an effect of improving the stability of the advance time with respect to the temperature can be obtained.
[0066]
FIG. 6 is a timing chart of signals during one rotation of the rotor in the present embodiment. The rotation speed signal FV1 exceeds the advance angle start rotation speed setting FV / MG, and advance angle control is possible. It shows the waveform when
[0067]
Signals S1L, S2L, and S3L shown in the figure are non-inverted magnetic sensor signals, while signals S1H, S2H, and S3H are inverted magnetic sensor signals. With these 6 signals, the timing can be finely controlled every 30 degrees of rotation of the rotor, and control with high responsiveness to changes in the rotational speed is possible. The inversion timing of the pre-advance signals S1, S2, S3 is the same as that of the non-inversion magnetic sensor signals S1L, S2L, S3L.
[0068]
The control clock signal CKM outputs a pulse every 30 degree rotation of the rotor in response to the state inversion of the magnetic sensor signal. The advance time setting signal MS rises when the voltage level of the rotation speed signal FV1 is exceeded while the positive voltage Vc2 of the capacitor C2 changes in a sawtooth shape.
[0069]
The latch circuit 110 switches the states of the post-advance signals S1B, S2B, and S3B in synchronization with the rising timing of the advance angle setting signal MS. Therefore, the switching timing can be preceded by the advance time with respect to the rising timing of the control clock signal CKM. Then, the latch circuit 110 sends the post-advance signal to the three-phase control circuit 130.
[0070]
FIG. 7 is a diagram for explaining a signal processing process in the three-phase control circuit 130 and the drive control circuit 140.
[0071]
The three-phase control circuit 130 generates signals G1 to G6 whose ON time corresponds to an electrical angle of 60 degrees in synchronization with the switching timing of the post-advance signals S1B, S2B, and S3B shown in the figure. The three-phase control circuit 130 sends signals G1 to G6 to the drive control circuit 140, and the drive control circuit 140 performs pulse width control on the signals G1 to G6 based on the rotation instruction signal Vin, as shown in this figure. As described above, the gate signal is supplied to the transistors Q1 to Q6 of the switching circuit 20 (the waveform of the pulse width control is not shown). The transistors Q1 to Q6 of the switching circuit 20 supply current to the armature coil 4 to rotate the rotor 1. Therefore, the rotor 1 can be rotationally driven based on the post-advance signal.
[0072]
FIG. 8 shows a change in the advance time with respect to the rotational speed. As shown in this figure, the advance time is 0 (zero) in the low rotation speed region (D angle operation region) below the rotation speed A set by the advance start rotation speed setting FV / MG, and the sensor angle is mechanical. Delay angle D (44 degrees). By performing such control, it is possible to avoid the inconvenience that the rotational torque fluctuates and rotational unevenness occurs while the rotational speed is not stable, such as when the motor is started.
[0073]
On the other hand, in the region exceeding the rotational speed A (sensor Mg control region), advance angle control is possible, and the sensor angle is changed from the delay angle D (degrees) to C (degrees) by the charging operation in the second timer circuit 50. Make a continuous change (decrease) smoothly in a straight line. By continuously varying the sensor angle in this manner, a change in rotational torque due to a sudden change in the sensor angle can be prevented, and the occurrence of uneven rotation can be avoided.
[0074]
As described above, in the first embodiment, a certain time is secured from the time when the state of the pre-advance signal changes due to the charging operation of the capacitor C1 in the first timer circuit 40 (charging circuit). After the charging of C1 is finished (after a fixed time has elapsed), the second timer circuit 50 starts charging the capacitor C2, and when the voltage of the capacitor C2 reaches the voltage of the rotation speed signal FV1, the latch circuit 110 advances. Since the state of the rear angle signal is reversed, it is possible to control the advance angle of the brushless motor without software control. As a result, the sensor angle of the brushless motor is adjusted to the same as the delay angle adjustment. Since the effect can be obtained, it is possible to control with a balance between low noise and high efficiency.
[0075]
Further, by changing the capacitance of the capacitor C2, the advance time can be adjusted. Since the capacitor C2 is externally attached to the custom IC 150, the adjustment is easy.
[0076]
The lead time can be adjusted by changing the resistance R81 or R82, changing the gain (amplification degree) of the operational amplifier 80a, and adjusting the variable range of the rotation speed signal FV1 in the operating rotation range. It becomes.
[0077]
In addition, since the capacitor C2 is charged using the constant current source IS2, the voltage rise is linear, and there is an effect that linear advance angle control that is easy to adjust is possible. It is also possible to adjust the advance time by adjusting the resistance value of the resistor R51 and changing the current value of the constant current source IS2, and this resistor R51 is externally attached to the terminal of the custom IC 150. Therefore, the setting change is extremely easy.
[0078]
The brushless motor control device according to the present invention is not limited to use in the blower motor described in the above embodiment, and can be applied to various brushless motors such as a radiator motor.
[Brief description of the drawings]
FIG. 1 is a diagram showing a first embodiment of a brushless motor control device according to the present invention;
FIG. 2 is a detailed view of a first timer circuit, a second timer circuit, and an advance angle switching circuit shown in FIG.
FIG. 3 is a detailed diagram of the F / V conversion circuit, the F / V gain setting circuit, and the advance angle limit circuit shown in FIG. 1;
4 is a configuration diagram of a motor body in the form shown in FIG. 1. FIG. 4A shows a configuration with high efficiency, and FIG. 4B shows a configuration with low noise.
FIG. 5 is a diagram for explaining a method for setting an advance time in the embodiment shown in FIG. 1;
6 is a timing chart of signals during one rotation in the embodiment shown in FIG.
7 is a diagram illustrating signal processing steps of a three-phase control circuit and a drive control circuit in the embodiment shown in FIG.
8 is a diagram showing a change in advance time with respect to the rotation speed in the embodiment shown in FIG.
FIG. 9 is a diagram illustrating the configuration of a conventional brushless motor control device and the principle of advance control.
[Explanation of symbols]
1 Rotor 2 Main magnet (field permanent magnet)
3 stator 4 armature coil 5 sensor magnet 10 motor body 20 switching circuit 30 sensor input circuit 40 first timer circuit 50 second timer circuit 60 advance angle switching circuit 70 F / V conversion circuit 80 F / V gain setting circuit 90 advance angle Max limit circuit 100 Clock generation circuit 110 Latch circuit 120 Select circuit 130 Three-phase control circuit 140 Drive control circuit 150 Custom IC
200 Brushless motor IC1 to IC3 Magnetic sensor

Claims (4)

In the brushless motor control device that feeds power to the armature coil while sequentially switching the conduction state of the plurality of switching elements, and precedes the change of the conduction state of the rotor magnetic pole detected by the magnetic sensor,
A frequency voltage conversion circuit (70) for converting the change frequency of the rotor magnetic pole (5) detected by the magnetic sensors (IC1 to IC3) into a voltage corresponding to the change frequency;
A charging circuit that includes a first capacitor (C1) and charges the first capacitor (C1) in a predetermined time when the rotor magnetic pole (5) detected by the magnetic sensors (IC1 to IC3) changes. 40)
The second capacitor (C2) is provided, and after the charging of the first capacitor (C1) is completed, charging of the second capacitor (C2) is started, and the voltage of the second capacitor (C2) is A lead angle circuit (50, 110) for switching a conduction state of a switching element to be switched among the plurality of switching elements when the voltage converted by the frequency voltage conversion circuit (70) is reached. A control device for a brushless motor characterized by the above. The brushless motor control device according to claim 1, wherein the frequency-voltage conversion circuit (70) includes an adjustment circuit (80) for adjusting a conversion rate. The lead angle circuit (50, 110) charges the second capacitor (C2) using a constant current source (IS2) or a resistor (R52). The brushless motor control device according to 2. The brushless motor according to claim 3, wherein a current value setting circuit (R51) for setting a current value of the constant current source (IS2) is added to the constant current source (IS2). Control device.

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