JP4458863B2 - Motor drive device - Google Patents

Description

  The present invention relates to a brushless DC motor driving apparatus.

  In order to detect the position of the rotor of the brushless DC motor, a magnetic detection element such as a Hall IC is provided.

  When the position of the rotor is detected by such a magnetic detection element, it is necessary to adjust the phase angle with respect to the detected position detection signal.

As a method of controlling this phase angle, conventionally, a current flowing through a shunt resistor provided between the inverter circuit and the stator winding of the brushless DC motor is detected, and a change in the detected current is amplified with a filter circuit. One that is used as a phase angle adjusting voltage through a circuit has been proposed (Patent Document 1).
JP 2002-101683 A

However, since brushless DC motors use an inverter circuit to vary the rotational speed by a pulse width modulation method, when the phase angle is adjusted with the phase angle adjusting voltage as described above, the phase angle is accurately set. there is a problem that will not and can not be adjusted.

  Therefore, in view of the above problems, the present invention provides a motor drive device that can accurately adjust the phase angle when adjusting the phase angle.

The invention according to claim 1 is a magnetic detection element that detects a position of a rotor of a three-phase brushless DC motor, and a position estimation that estimates a rotation position of the rotor based on a position detection signal from the magnetic detection element. A circuit, a position estimation signal from the position estimation circuit, a control circuit that outputs a control signal based on a speed command signal input from the outside, a PWM circuit that outputs a PWM signal based on the control signal, and the PWM An inverter circuit that supplies a three-phase driving current to each of the three-phase stator windings based on the signal, based on the motor current flowing in the inverter circuit and the speed command signal , It has a lead angle circuit for generating an advance signal including both of the speed command signal and the motor current flowing through the inverter circuit, the advance circuit, the motor current An amplification circuit for amplifying, a PWM circuit for performing PWM modulation by comparing the speed command signal with a triangular wave, and a switching circuit for generating an advance angle signal by switching the amplified motor current based on the PWM modulated modulation signal The larger the motor current flowing through the inverter circuit, the larger the amplitude of the advance angle signal, and the greater the speed command signal, the longer the wavelength of the advance angle signal, the control circuit The phase of the control signal is adjusted based on the advance angle signal. The larger the amplitude of the advance angle signal , the larger the advance angle of the phase of the control signal, and the longer the wavelength of the advance angle signal. The motor driving apparatus is characterized in that the advance angle of the phase of the control signal is increased.

The invention according to claim 2, a motor current flowing in the pre-Symbol inverter circuit is a motor driving apparatus according to claim 1, wherein the detecting and outputting the detection resistor the motor current to the advance circuit .

The invention according to claim 3 is the motor drive device according to claim 1 or 2 , wherein the advance circuit determines a weight for the motor current based on an amplification factor of the amplifier circuit.

According to a fourth aspect of the present invention, in the motor drive device according to the first to third aspects, the advance angle circuit determines a weight for the speed command signal based on an amplitude of a triangular wave input to the PWM circuit.

According to a fifth aspect of the present invention, the control circuit stores in advance a relationship between information on the magnitude of the torque and a degree of advance of the phase of the control signal, and information on the speed of the rotation speed. Storage means for storing in advance the relationship between the phase angle of the control signal and the advance angle of the control signal, and the phase advance based on the information on the magnitude of the torque or the information on the speed of the rotation speed. the degree of angular a motor driving apparatus according to claim 1 to 4, wherein the calling from the storage unit.

  In the motor drive device according to the first aspect of the present invention, the advance circuit provides both information on the magnitude of the torque and information on the speed of the rotation speed based on the information on the torque of the brushless DC motor and the information on the rotation speed. An included advance angle signal is generated.

  The control circuit increases the advance angle of the control signal as the information on the magnitude of the torque included in the advance angle signal increases, and increases as the information on the speed of the rotation included in the advance angle signal increases. The advance angle of the control signal is increased.

  As a result, the motor drive device can accurately perform phase control. Therefore, the motor can be accurately controlled even during constant speed operation or constant torque operation.

Moreover , since the information regarding the rotational speed is the speed command signal, the information regarding the rotational speed can be easily obtained.

Further , information on the rotational speed is a speed command signal, and information on torque is a motor current flowing through the inverter circuit. The advance circuit amplifies the motor current by the amplifier circuit, and performs PWM modulation on the speed command signal by the PWM circuit to generate a modulation signal. In the switching circuit, the motor current amplified based on the generated modulation signal is switched to generate an advance angle signal. Thereby, the amplitude of the advance signal becomes information on the magnitude of the torque, and the modulation rate (wavelength length) becomes information on the speed of the rotation speed.

  The control circuit increases the advance angle of the control signal as the amplitude of the advance signal increases, and increases the advance angle of the control signal as the wavelength of the advance signal increases.

  In the motor drive device according to the second aspect of the present invention, the information on the torque is the motor current flowing through the inverter circuit, and the motor current is detected by a detection resistor and output to the advance circuit. Information about can be obtained.

In the motor driving device of the invention according to claim 3 , the advance circuit determines the weight for the motor current based on the amplification factor of the amplifier circuit. Thus, if it is desired to increase the weight for torque, it can be realized by increasing the amplification factor. For example, when the rotational speed is constant, such as constant speed rotation, the advance angle signal can be accurately generated by increasing the weight for this torque.

In the motor driving device of the invention according to claim 4 , the advance circuit determines the weight for the speed command signal based on the amplitude of the triangular wave input to the PWM circuit. That is, the weight for the speed command signal is determined by the modulation rate. Accordingly, when the torque is constant as in constant torque operation, the advance angle signal can be accurately generated by increasing the weight for the speed command signal (rotation speed).

In the motor drive device of the invention according to claim 5 , the control circuit calls the degree of phase advance from the storage means based on the information on the magnitude of the torque or the information on the speed of the rotational speed, and accurately It is possible to adjust the advance angle of the phase of the control signal.

  Hereinafter, a driving device 12 for a three-phase brushless DC motor (hereinafter referred to as a motor) according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

(1) Configuration of Drive Device 12 Hereinafter, the configuration of the drive device 12 will be described with reference to FIG.

  The driving device 12 includes a first control block 14 and a second control block 16, and each block is configured by an IC or a microcomputer.

(1-1) Configuration of First Control Block 14 First, the configuration of the first control block 14 will be described.

  The first control block 14 includes an inverter circuit 18, a logic circuit 20, an upper driver circuit 22, and a lower driver circuit 24.

  The inverter circuit 18 receives a motor voltage Vm and a control voltage Vcc for moving the entire first control block 14.

  The inverter circuit 18 is composed of six switching transistors and diodes, and supplies drive current to the three-phase stator windings 26u, 26v, and 26w from the connection point of the upper and lower transistors in the inverter circuit 18. To do.

  The logic circuit 20 controls the upper driver circuit 22 and the lower driver circuit 24 on the basis of the control signal input from the second control block 16, so that the upper transistor and the lower transistor 3 of the inverter circuit 18 are controlled. The rotation of the motor 10 is controlled by turning on / off the transistors.

  A shunt resistor 28 for detecting the motor current is connected to the minus side of the lower transistor of the inverter circuit 18.

  In order to detect the position of the rotor of the motor 10, a Hall IC 30 is provided, and a position detection signal is output from the Hall IC 30.

(1-2) Configuration of Second Control Block 16 Next, the configuration of the second control block 16 will be described.

  The second control block 16 includes a counter circuit 32, an output waveform generation circuit 34, a data selection circuit 36, a PWM circuit 38, a gate block circuit 40, a dead time circuit 42, a protection reset circuit 44, an advance circuit 46, and a position estimation circuit 48. And is made up of.

  The position estimation circuit 48 outputs a position signal that is the estimated rotor position to the counter circuit 32 based on the position detection signal input from the Hall IC 30.

  The counter circuit 32 counts the time from the up edge (or down edge) of the position signal from the position estimation circuit 48 to the next down edge (or up edge) and outputs it to the output waveform generation circuit 34. Further, phase control is performed based on the advance angle signal LA from the advance angle circuit 46. This phase control will be described later.

  The output waveform generation circuit 34 generates a modulation waveform based on the speed command signal Ve and the time counted by the counter circuit 32.

  The data select circuit 36 resets the modulation waveform in 60 ° reset or 360 ° reset based on a predetermined condition, and outputs a control signal of the modulation waveform to the PWM circuit 38.

  The PWM circuit 38 generates a PWM signal by comparing the control signal having the input modulation waveform with the triangular wave and outputs the PWM signal to the gate block circuit 40. This PWM signal is output to the logic circuit 20 through the dead time circuit 42.

  The gate block circuit 40 cuts off the PWM signal by a signal from the protection reset circuit 44, and the protection reset circuit 44 assumes that an overcurrent occurs when the detection current Idc detected by the shunt resistor 28 exceeds a predetermined value. Instructs the gate block circuit 40 to shut off.

  The dead time circuit 42 adjusts the output timing of the PWM signal.

  As described above, the control circuit including the counter circuit 32, the output waveform generation circuit 34, and the data selection circuit 36 sets the currently estimated rotational speed to the value of the speed command signal Ve based on the speed command signal Ve input from the outside. The control signal of the modulated waveform that is feedback-controlled so as to be output can be output to the PWM circuit 38, and the motor 10 can be rotated at the target rotational speed.

(2) Configuration of Advancement Circuit 46 (2-1) Description of Phase Control First, phase control will be described before the configuration of the advancement circuit 46 is described.

  When the position of the rotor of the motor 10 is detected by the Hall IC 30, the position of the Hall IC 30 is detected by the magnetic force from the S pole and N pole magnet portions provided on the rotor. However, in this position detection, the Hall IC 30 rotates under the influence of the field current as the drive current (field current) flowing through the stator winding 26 of the motor 10 increases, that is, as the torque increases. Since the exact position of the child cannot be detected, it is necessary to adjust the phase. Accordingly, since the phase to be detected is delayed as the torque increases, it is necessary to advance the phase for performing the control.

  The position detection of the Hall IC 30 is also affected by the rotation speed. In other words, the phase to be detected is delayed as the rotational speed is faster, so the phase to be controlled needs to be advanced.

  Therefore, in this embodiment, the control phase is advanced as the torque is increased, and the control phase is advanced as the rotation speed is increased. An advance angle circuit 46 is provided to perform this control.

(2-2) Configuration of Advancement Circuit 46 FIG.

  The advance angle circuit 46 includes an amplification circuit 50, a peak hold circuit 52, a switching circuit 54, a PWM circuit 56, a triangular wave generation circuit 58, and a filter circuit 60.

  The amplifier circuit 50 receives the detection current Idc detected by the shunt resistor 28. Then, the detection current Idc is amplified by the amplification factor A and output to the peak hold circuit 52.

  In the peak hold circuit 52, the amplified detection current Idc is peak-held for a predetermined time with the maximum value, and is output to the switching circuit 54.

  On the other hand, the speed command signal Ve and the triangular wave from the triangular wave generating circuit 58 are input to the PWM circuit 56, the speed command signal Ve is compared with the triangular wave, PWM modulation is performed, and the PWM circuit 56 outputs it to the switching circuit 54.

  The switching circuit 54 turns on / off based on the PWM signal output from the PWM circuit 56, turns on / off the detection current Idc output from the peak hold circuit 52, and outputs the detection current Idc to the filter circuit 60.

  The filter circuit 60 removes noise and the like and outputs the advance angle signal LA.

(2-3) Action of Advance Circuit 46 The action of the advance circuit 46 will be described.

  The detected current Idc detected by the shunt resistor 28 corresponds to the torque of the motor 10, and the detected current Idc increases as the torque increases. That is, the detection current Idc includes information on torque. Therefore, this detection current Idc is amplified by the amplifier circuit 50 and output through the peak hold circuit 52.

  On the other hand, the speed command signal Ve is information about the number of rotations, which is PWM-modulated to convert the information on the number of rotations into the length of the wavelength.

  In order to include the converted wavelength information of the PWM signal in the amplified detection current Idc, the switching circuit 54 turns on / off to generate the advance angle signal LA. In the advance angle signal LA, the magnitude of the torque is represented by the magnitude of the amplitude, and the magnitude of the rotational speed is represented by the length of the wavelength. If the amplitude is large, the torque is large, and if the wavelength is long, the rotation speed is fast.

(2-3) Role of Counter Circuit 32 The role of the counter circuit 32 to which the advance angle signal LA is input from the advance angle circuit 46 will be described again.

  As described above, the counter circuit 32 performs feedback control based on the speed command signal Ve and the currently estimated rotational speed, and sets the counter value so that the current rotational speed always becomes the rotational speed commanded by the speed command signal. In this case, the counter value is adjusted based on the advance signal LA to control the phase.

  That is, if the amplitude of the advance angle signal LA is large, it is determined that the torque is large, and the counter value is controlled so that the phase advances.

  Further, if the wavelength of the advance signal LA is long, the phase is controlled so that the rotation speed is fast.

  The relationship between the amplitude value and the phase advance value is stored in advance, and the wavelength value and the phase advance value are also stored in the memory in advance. Thus, the phase advance can be controlled based on the amplitude and wavelength of the input advance angle signal LA.

  When the progress of the phase is adjusted by the counter value, the PWM signal output from the PWM circuit 38 is also output to the logic circuit 20 with the phase adjusted. Therefore, unlike conventional systems, phase control is performed based on information on torque and information on the number of revolutions. Therefore, even if the speed of the pulse width modulation method is changed, the phase angle can be set normally and the motor 10 can be rotated accurately. Can be made.

(2-4) In the case of constant speed operation In the case of the constant speed operation in which the motor 10 is rotated at a constant rotational speed, it is necessary to control the phase with more emphasis on information about the torque than information on the rotational speed.

  Therefore, when the motor 10 is used for constant speed operation, the amplification factor A of the amplifier circuit 50 is increased in advance, the weight for the torque information (detection current Idc) is increased, and the torque information is obtained. It is made easy to be reflected in the phase control.

  Thereby, phase control which reacts sensitively to torque can be performed in constant speed operation.

(2-5) In the case of constant torque operation When making the torque constant and making the rotational speed variable, it is necessary to place more importance on the information on the rotational speed than on the information on the torque.

  Therefore, the amplitude of the triangular wave generated by the triangular wave generation circuit 58 is increased in order to increase the weight of the information regarding the rotational speed. Therefore, the weight can be reflected in the PWM signal generated by the PWM circuit 56.

  Thereby, phase control which reacts sensitively to rotation speed can be performed in constant torque operation.

  The motor driving device according to the present invention is suitable as a driving device for a fan motor or other motors.

It is a block diagram of a motor drive device showing one embodiment of the present invention. It is a block diagram of an advance angle circuit.

10 Motor 12 Drive device 18 Inverter circuit 28 Shunt resistor 30 Hall IC
32 Counter circuit 38 PWM circuit 46 Advance angle circuit 48 Position estimation circuit 50 Amplification circuit 52 Peak hold circuit 54 Switching circuit 56 PWM circuit 58 Triangular wave generation circuit

Claims (5)

A magnetic detection element for detecting the position of the rotor of the three-phase brushless DC motor;
A position estimation circuit that estimates a rotational position of the rotor based on a position detection signal from the magnetic detection element;
A control circuit that outputs a control signal based on a position estimation signal from the position estimation circuit and a speed command signal input from the outside;
A PWM circuit that outputs a PWM signal based on the control signal;
An inverter circuit for supplying a three-phase driving current to each of the three-phase stator windings based on the PWM signal;
In the motor drive device having
A motor current flowing through the inverter circuit, based on said speed command signal includes the advance circuit for generating an advance signal including both the motor current and the speed command signal flowing through said inverter circuit,
The advance circuit is
An amplifier circuit for amplifying the motor current;
A PWM circuit for performing PWM modulation by comparing the speed command signal with a triangular wave;
A switching circuit that switches the amplified motor current based on the PWM modulated modulation signal to generate an advance angle signal;
Increasing the amplitude of the advance signal as the motor current flowing through the inverter circuit increases, and increasing the wavelength of the advance signal as the speed command signal increases,
The control circuit adjusts the phase of the control signal based on the advance signal , and increases the advance angle of the phase of the control signal as the amplitude of the advance signal increases. The motor drive apparatus characterized by increasing the advance angle of the phase of the control signal as the wavelength of the angle signal is longer . The motor current flowing in the pre-Symbol inverter circuit,
The motor driving device according to claim 1, wherein the motor current is detected by a detection resistor and output to the advance angle circuit. The advance angle circuit, a motor driving apparatus according to claim 1 or 2, wherein the determining the weights for the motor current by the amplification factor of the amplifier circuit. The advance angle circuit, according to claim 1 to 3 motor drive apparatus, wherein the determining the weight for speed command signal by the amplitude of the triangular wave to be input to the PWM circuit. The control circuit stores in advance the relationship between the information on the magnitude of the torque and the degree of advance of the phase of the control signal, and the information on the speed of rotation and the advance of the phase of the control signal. Having storage means for storing the relationship with the degree of angle in advance;
Size information of the said torque or the rotational speed of the speed of information motor driving apparatus according to claim 1 to 4, wherein invoking the degree of advance of the phase from the storage means based on .

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