JPH0965678A - Sensorless brushless motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent asynchronization during ultra-high speed rotation of motor by outputting a feedback signal corresponding to the actual rotating speed of a rotor when a speed converter receives at least one of three induced voltage signals. SOLUTION: A speed converter 13 receives induced voltage signals S24, S25, S26 to calculate individual mean values. Therefore, it calculates the total mean value and detects the value multiplied by a coefficient to produce a feedback signal S2 corresponding to the actual speed of the rotor 1 to be sent to a velocity error amplifier 6. A speed command signal S1 is converted into an error correcting command signal S4, a current command controller 7 inputs the 180 degrees feeding sine wave phase signals S5a, S6a, S7a from the feeding phase commander 12 and then converts these signals into current command signals S8, S9, S10, a current error amplifier 8 converts the current detection signals S11, S12, S13 into the current error correction current command signals S17, S18, S19, and these signals are outputted to a PWM signal generator 9 to provide an output of 3-phase AC to rotate the rotor 1. As a result, asynchtonization during ultra-high speed rotation can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is capable of detecting an accurate induced voltage with almost no noise even under harsh operating conditions and an average voltage of motor terminal voltages, and is likely to lose synchronization even when rotated at an extremely high speed exceeding 10,000 rpm. There is no sensorless brushless motor.

[0002]

2. Description of the Related Art There are several methods for detecting an induced voltage in a brushless motor. For example, a method of detecting an induced voltage from a signal in which a filter is added to the terminal voltage of each motor phase, a method of detecting a motor terminal voltage when 120 ° energization is not applied, and a method of connecting three Y-connected wires There is a method of detecting the induced voltage of the stator winding by the potential difference between the neutral point where the resistor is connected in parallel with the stator winding and the neutral point of the stator winding.

However, due to the delay of the filter, is easily affected by load fluctuations, reverse energization braking is difficult, high speed operation of the motor is difficult, and a PWM noise is generated because a signal is input from the terminal voltage of each phase of the motor. There is a drawback that it is easily affected by. Has a drawback in that it cannot perform 180-degree energization operation because it detects the induced voltage when there is no energization. Since the motor requires a neutral point, the motor has four lines, and the magnetizing waveform is a trapezoidal wave, which increases the loss of the motor operating at high speed. .

As a brushless motor adopting an induced voltage detecting method in which these drawbacks have been solved, Japanese Patent Laid-Open No. 64-4
There is No. 3095. However, this technique has the following drawbacks. The motor terminal voltage contains switching noise of the inverter transistor, and since the motor terminal voltage fluctuates at high frequency especially in the case of PWM control, the switching noise is large. Therefore, when the motor terminal voltage is directly detected, it is accurate due to the effect of switching noise. It is difficult to detect various motor terminal voltages. Since [di / dt] of L · [di / dt] is the amount of change in current (differential detection), it is easily affected by noise, so an accurate calculation result of L · [di / dt] can be obtained. difficult. If the voltage between the collector and emitter of the switching transistor is neglected for the value of the motor terminal voltage for PWM control, the + voltage of the DC power supply will be either the-voltage. Therefore, if a large filter is not used for detection, the magnitude of the current or the motor The induced voltage cannot be obtained unless the amount of change [di / dt] of the current is accurately detected and L · [di / dt] is calculated regardless of the magnitude of the winding inductance. When an attempt was made to rotate at an ultra-high speed by the above items and, the step-out occurred, and the ultra-high speed rotation could not be performed.

[0005]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned points, and it is possible to detect an accurate induced voltage with almost no noise and an average voltage of the motor terminal voltage, and thus a harsh vibration occurs. The purpose of the present invention is to provide a sensorless brushless motor that does not get out of step even if it is rotated at an ultra-high speed exceeding 10,000 rpm under various usage conditions.

[0006]

According to the present invention, a permanent magnet rotor 1 and three stator windings 2a, 2b and 2c are Y-connected to each other to apply a magnetic field to the permanent magnet rotor 1 to generate a rotational force. Three-phase stator winding 2 to be given, and switching elements U +, of a required arrangement
V +, W +, U-, V-, W- are controlled on / off as required by a PWM signal to convert the direct current of the direct current power source 4 into an alternating current and output from three output lines 3a, 3b, 3c. A three-phase inverter 3 that feeds power to the three-phase stator winding 2 to control commutation
And three input current error correction current command signals S17, S
18, which is the switching element drive signal based on S19
In a sensorless brushless motor having a PWM signal generator 9 for outputting WM signals U1, U2, V1, V2, W1, W2 to the three-phase inverter 3, a speed error amplifier 6 outputs a speed command signal S1 to a speed error correction speed. The command signal S4 is converted and output, and the current command controller 7 converts the speed error correction speed command signal S4 into current command signals S8, S9, S10 for three phases, which are then output. Minute current command signal S8,
S9 and S10 are current error correction current command signals S17 and S, respectively.
The speed error amplifier 6 is configured to convert to 18, S19 and output to the PWM signal generator 9, and the speed error amplifier 6 corresponds to the actual rotation speed of the rotor 1 output from the actual speed converter 13. By inputting the speed feedback signal S2, the speed error correction speed command signal S4 is calculated and outputted to a magnitude necessary for matching the actual rotation speed of the rotor 1 with the speed command signal S1. The current command controller 7 inputs the three 180-degree conduction sine wave phase signals S5a, S6a, S7a or the 120-degree conduction switching signals S5b, S6b, S7b output from the conduction phase commander 12, The current command signals S8, S9, S10 for the three phases are
The actual phase of the electrical angle with respect to the stator windings 2a, 2b, 2c of the rotor 1 is included to form a waveform and output. The current error amplifier 8 is configured to output the three phases of the three-phase inverter 3. Detection signals S11, S1 of the output lines 3a, 3b, 3c of
2 and S13 are fed back, the three current error correction current command signals S17, S18, and S19 are sent to the three phase output lines 3a, 3b, and 3c to which the motor currents actually flowing correspond. Two current command signals S8, S9, S10
The induced voltage detector 11 directly inputs the three current error correction current command signals S17, S18, S19, or the voltage fluctuation component of the DC power supply 4 is output. The three current command feedback signals S21, S22, S23 corrected to eliminate the above are input as feedback, and the current detection signals S11, S12,
By inputting S13 as feedback, induced voltage signals S24, S25, S26 generated with the rotation of the rotor 1 are output, and the energization phase commander 12 is
By feedback-inputting the three induced voltage signals S24, S25, S26, the three induced voltage signals S24, S24,
Three 180-degree conduction sine wave phase signals S5a, S6a, S7a or 120-degree conduction switching signals S5b, S6b, S7b corresponding to the respective phases of S25 and S26 are applied to the multipliers 7a, 7b, 7c, and the actual speed converter 13 outputs the three induced voltage signals S24, S2.
5. A sensorless brushless motor, characterized in that the actual speed feedback signal S2 is output corresponding to the actual rotational speed of the rotor 1 by inputting at least one of the signals S5 and S26. Is provided.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION

<First Embodiment> As shown in the block diagram of FIG. 1, a sensorless brushless motor of this embodiment has a permanent magnet rotor 1, a three-phase stator winding 2, a three-phase inverter 3, and a three-phase inverter 3. Speed commander 5, speed error amplifier 6, current command controller 7, current error amplifier 8, and PWM signal generator 9
The voltage fluctuation compensator 10, the induced voltage detector 11, the energization phase commander 12, and the actual speed converter 13 are provided.

The three-phase stator winding 2 is composed of three stator windings 2.
The a, 2b and 2c are Y-connected and an alternating current is fed from the three-phase inverter 3 to apply a magnetic field to the permanent magnet rotor 1 to give a rotational force.

The three-phase inverter 3 is connected so that the switching elements U +, V +, W +, U-, V-, W- of a required arrangement are fed from the DC power source 4 and PW.
Switching signals U +, V +, W +, U-, V-, of the required arrangement are generated by the M signal (pulse width modulation commutation control signal).
W- is controlled to be turned on and off as necessary to convert direct current into alternating current, and the alternating current is connected to the non-neutral side terminals of the three stator windings 2a, 2b and 2c. Output from 3a, 3b, 3c and feed the three-phase stator winding 2 to control commutation.

The speed command device 5 outputs a speed command signal S1 which determines the rotational speed of the permanent magnet rotor 1.

The speed error amplifier 6 has a comparator 6a and a multiplier 6b and outputs the speed command signal S from the speed command circuit 5 to the plus side input terminal of the comparator 6a shown in FIG. 2 (r).
Input 1 and input the actual speed feedback signal S2 shown in Fig. 2 (q) to the minus input terminal, calculate the deviation between both signals, and input the deviation signal S3 output from the output terminal to the multiplier 6b. By multiplying by the required gain, the speed error correction speed command signal S4 shown in FIG. 2 (p) having the magnitude necessary for matching the actual rotation speed of the rotor 1 with the speed command signal S1 is output. The speed command signal S1, the actual speed feedback signal S2, and the speed error correction speed command signal S4 are voltage signals of required values, respectively.

The current command controller 7 includes three stator windings 2
The multipliers 7a, 7b and 7c corresponding to a, 2b and 2c are provided, and the velocity error correction speed command signal S4 shown in FIG. As a conduction phase information feedback signal corresponding to the three stator windings 2a, 2b, 2c, a 180 degree conduction sine wave phase signal S5a, which has three sine curves as shown in FIG. By distributing and inputting S6a and S7a and multiplying them respectively, waveforms are formed by incorporating the phase of the actual electrical angle with respect to the stator windings 2a, 2b and 2c of the rotor 1 based on the speed error correction speed command signal S4. The current command signals S8, S9, and S10 whose phases are different by 120 degrees are output from the three sinusoidal curves shown in FIG. 2 (n).

The current error amplifier 8 comprises three stator windings 2
Three comparators 8a, 8b, 8c corresponding to a, 2b, 2c and three multipliers 8d, 8 serially connected to each comparator 8a, 8b, 8c
e, 8f, and the three current command signals S8, S9, S10 at the positive side input terminals of the three comparators 8a, 8b, 8c.
2m in which the current is detected by the three-phase output lines 3a, 3b, 3c of the three-phase inverter 3 by the current detectors 14a, 14b, 14c at the respective negative side input terminals.
The current detection signals S11, S12, S13 as shown in FIG.
By inputting S15, S16 into each of the multipliers 8d, 8e, 8f and multiplying the required gain, the actual three motor currents match the corresponding three current command signals S8, S9, S10. In order to correct the current error, three current error correction current command signals S17, S18, S19 as shown in FIG.
Is output. The current detection signals S11, S12 and S13 are shown in Fig. 2 (c).
The signals have the same phase in proportion to the motor current shown in. The current error correction current command signals S17, S18, S19 are in-phase signals proportional to the averaged motor terminal voltage shown in FIG. 2 (b). Current error correction current command signal S17, S18, S19
Causes a fluctuation corresponding to the fluctuation of the DC power supply voltage shown in FIG.

The PWM signal generator 9 includes three signal generators 9a, 9b, 9c corresponding to the three stator windings 2a, 2b, 2c.
Each of the signal generators 9a, 9b, 9c, and the three current error correction current command signals S17, S18, S19.
By inputting these signals and the self-generated triangular wave signal as shown in FIG. 2 (h) and collating them as shown in FIG. 2 (g) respectively, and each current error correction current command signal S17, S18, S19 is a triangular wave signal. The rising and falling timings of the rectangular wave are determined on the basis of the intersection points to form a pair of rectangular waves, and the + side switching elements U +, V +, W + and the negative side switching element U of the three-phase inverter 3 are formed.
As shown in FIG. 2 (e) for driving −, V−, W−, + side switching element drive signals U1, V1, W1 and
-side switching element drive signal U2, V as shown in (f)
2 and W2 are output from the two output terminals of each of the signal generators 9a, 9b and 9c to the three-phase inverter 3. 2 (d) to 2 (h) show the principle of U-phase PWM signal generation. Corresponding to this, three-phase output terminals 3a, 3b,
The voltage between 3c and the negative side of the DC power supply 4, that is, the actual motor terminal voltage of the U-phase, V-phase, and W-phase is amplified to the same waveform as the + -side switching element drive signal of the corresponding phase. Although it is a value, it fluctuates corresponding to the voltage fluctuation of the DC power supply 4. FIG. 2D shows the voltage between the U-phase output terminal 3 a and the negative side of the DC power supply 4.

The voltage fluctuation compensator 10 comprises three multipliers 10a, 10b, 10 corresponding to the three stator windings 2a, 2b, 2c.
c and inputs the three current error correction current command signals S17, S18, S19 to each of the multipliers 10a, 10b, 10c and the DC voltage detection signal S20 shown in FIG. 2 (k). By multiplying both signals, it corresponds to the voltage fluctuation of the DC power source 4 as shown in FIG. 2 (a), and three current error correction current command signals S17, S18, S as shown in FIG. 2 (l) are provided.
The current command feedback signals S21, S22, S23 as shown in FIG.

The induced voltage detector 11 comprises three comparators 11a, 11b, 11 corresponding to the three stator windings 2a, 2b, 2c.
It has c and distributes and inputs three current command feedback signals S21, S22, S23 as shown in FIG. 2 (j) to the plus side input terminal of each comparator 11a, 11b, 11c and to the minus side input terminal. The current detection signals S11, S12, S13 as shown in FIG. 2 (m) are input and the deviation between both signals is calculated and output as the induced voltage signals S24, S25, S26 as shown in FIG. 2 (i).

The energization phase commander 12 includes three multipliers 12a, 12b, 12 corresponding to the three stator windings 2a, 2b, 2c.
2 (i) in each of the multipliers 12a, 12b, 12c
The three induced voltage signals S24, S25, S26 shown in (4) are distributed and input to the multipliers 7a, 7b, 7c of the current command controller 7 corresponding to the three stator windings 2a, 2b, 2c. 2 which correspond to the respective phases of the three induced voltage signals S24, S25, S26 as the energized phase information feedback signal.
Three 180 degree conduction sine wave phase signals S5a, S6 shown in (o)
Output a, S7a. The 180-degree conduction sine wave phase signal S5a,
S6a and S7a receive only phase information from the induced voltage signals S24, S25 and S26, and are three sinusoidal curves having a constant peak amplitude value and output as signals having different phases by 120 degrees.

The actual speed converter 13 inputs the three induced voltage signals S24, S25 and S26, calculates the individual average value of each induced voltage signal, and further calculates the total average value for the three individual average values. Then, a value obtained by multiplying the total average value by a constant coefficient is detected as the actual speed feedback signal S2 shown in FIG. 2 (q) which is input to the speed error amplifier 6, and thus the induced voltage signals S24, S25, S26. Outputs the actual speed feedback signal S2 corresponding to the actual rotation speed of the rotor 1 to the speed error amplifier 6.

According to the sensorless brushless motor having the above-mentioned configuration, the speed error, the phase error, the current error, and the voltage error due to the DC voltage fluctuation are all eliminated by the feedback control. That is, the speed error amplifier 6 inputs the actual speed feedback signal S2 to convert the speed command signal S1 into the speed error correction speed command signal S4, and the current command controller 7 uses the energization phase command unit 12 to energize the sine wave phase 180 degrees. The signals S5a, S6a, S7a are input to convert the speed error correction speed command signal S4 into current command signals S8, S9, S10, and the current error amplifier 8 detects the current detection signals S11, S12, S13.
To input the current error correction current command signal S
Converted to 17, S18, S19 and output to PWM signal generator 9,
The PWM signal is output to the three-phase inverter 3 to output a three-phase alternating current to excite the three-phase stator winding 2 to rotate the rotor 1.
The current error correction current command signals S17, S18, S19 output from the current error amplifier 8 are signals corresponding to the averaged motor terminal voltage shown in FIG. 2 (b). However, when the DC power supply voltage fluctuates as shown in Fig. 2 (a), the actual motor terminal voltage fluctuates in synchronization as shown in Fig. 2 (d).
In order to compensate for the tuning fluctuation of the actual motor terminal voltage, FIG.
As shown in (l), current error correction current command signals S17, S1
8, S19 changes. Then, as shown in FIG. 2 (g), the PWM signal generator 9 compares the current error correction current command signal with the triangular wave signal to reduce the energization stop time as shown in FIG. 2 (e) (d). Become. Regarding the detection of the induced voltage required for the feedback control of the speed error and the phase error, the current error correction current command signals S17, S18, S19 and the current detection signals S11, S12, S output from the current error amplifier 8 are detected.
The current error correction current command signals S17, S18, S19 are signals before PWM modulation, so that the current error amplifier 8 has an accurate motor terminal voltage with almost no switching noise. Can be detected extremely accurately, and the averaged motor terminal voltage as shown in FIG. 2 (b) can be detected very accurately. Therefore, in the current error amplifier 8, when the motor terminal voltage is small or L ×
When [di / dt] is at a level sufficiently smaller than the motor induced voltage, extremely accurate induced voltage can be detected without calculating L × [di / dt]. There is no fear of getting out of sync even if you do. The induced voltage signals S24, S25, S26 output from the induced voltage detection circuit 10
Is a signal of the same phase proportional to the induced voltage (dotted line part) shown in Fig. 2 (b). Even if the phase of the motor current shown in Fig. 2 (c) deviates from the phase of the induced voltage, Can be detected.

The time chart of FIG. 3 shows the state of signals during reverse energization braking. During reverse energization braking, the speed command signal S1 shown in Fig. 3 (r) becomes smaller than the actual speed feedback signal S2 shown in Fig. 3 (q), and the speed error correction speed command signal shown in Fig. 3 (p) This is the case when S4 becomes a negative value. Therefore, the current command signals S8, S9, S shown in FIG.
Since 10 has an inverted value, the current detection signals S11, S12, S13 shown in FIG. 3 (m) have inverted values and the motor current shown in FIG. 3 (c) is inverted. In addition, the current command signals S8, S9,
When S10 is reversed, the actual motor voltage becomes smaller as shown in FIG. 3 (d), so that the averaged motor terminal voltage shown in FIG. 3 (b) becomes smaller than the induced voltage.

<Second Embodiment> A second embodiment of the present invention will be described with reference to FIGS. 4, 5 and 6. As shown in the block diagram of FIG. 4, the sensorless brushless motor of this embodiment has a permanent magnet rotor 1, a three-phase stator winding 2, a three-phase inverter 3, a speed commander 5, and a speed error. Amplifier 6, current command controller 7, current error amplifier 8, PWM signal generator 9, and voltage fluctuation compensator 10
The induced voltage detector 11, the energization phase commander 12, and the actual speed converter 13 are provided.

The only difference from the sensorless brushless motor of FIG. 1 is the energization phase commander 12. The energization phase commander 12 has three comparators 12a, 12b, 12c corresponding to the three stator windings 2a, 2b, 2c, and each comparator 12a, 12b, 12c is shown in FIG. 5 (i). The induced voltage signals S24, S shown in Fig.
25 and S26 are distributed and inputted, and the three stator windings 2a, 2b, and 7b are connected to the multipliers 7a, 7b, 7c of the current command controller 7.
As the conduction phase information feedback signals corresponding to 2c, three 120 degree conduction switching signals S5b, S corresponding to the respective phases of the three induced voltage signals S24, S25, S26.
6b and S7b are output. The rising and falling timings of the three 120-degree conduction switching signals S5b, S6b, S7b, which are rectangular waves, are detected at the crossing points of the three induced voltage signals S24, S25, S26 as shown in FIG. Since it is executed by detecting the change direction between the signals, the accurate 120-degree energization switching signals S5b, S6b, S are generated even when the ultra-high speed rotation of about 12,000rp, m is performed.
7b is obtained and step out is avoided.

The current command signals S8, S9, S10 output from the current command controller 7 are three 120 degree energization switching signals S5b,
Since S6b and S7b are rectangular waves, they are rectangular waves. Further, the motor current shown in FIG. 5 (c) becomes a rectangular wave signal corresponding to the current command signals S8, S9, S10 shown in FIG. 5 (n), and therefore, the current detection signals S11, S12, S12, shown in FIG. 5 (m). Fig. 5 (c) for S13
The square wave signal corresponds to the motor current shown in. The current error amplifier 8 inputs the rectangular wave current command signals S8, S9, S10 and the rectangular wave current detection signals S11, S12, S13. The actual three motor currents correspond to the three current command signals. Since feedback control is performed to correct the current error so as to match the signals S8, S9, and S10, the rectangular wave is not output, and the phases are changed by 120 degrees corresponding to the three 120-degree conduction switching signals S5b, S6b, and S7b. A current error correction current command signal S having a waveform in which a rectangular wave signal is captured in each shifted sine curve
Outputs 17, S18 and S19. The averaged motor terminal voltage when energized at 120 ° shown in Fig. 5 (b) is such that L ・ [dt / di] is sufficiently smaller than the motor terminal voltage (small enough for a normal motor). In case of (induced voltage + current i ×
The winding resistance becomes R), and the averaged motor terminal voltage when there is no energization at 60 ° becomes equal to the induced voltage.

According to the sensorless brushless motor having the above-mentioned structure, the motor is operated by energizing 120 degrees. However, in the same manner as the sensorless brushless motor energizing 180 degrees shown in FIG. Any voltage error due to DC voltage fluctuation is eliminated by feedback control that performs the same signal processing. That is, the speed error amplifier 6 outputs the actual speed feedback signal S2.
Is input to convert the speed command signal S1 into a speed error correction speed command signal S4, and the current command controller 7 inputs the 120 ° energization switching signals S5b, S6b, S7b from the energization phase command device 12 to input the speed error correction speed. The command signal S4 is converted into current command signals S8, S9, S10, the current detection signals S11, S12, S13 are fed back by the current error amplifier 8 and converted into current error correction current command signals S17, S18, S19, and the PWM signal It outputs to the generator 9, outputs a PWM signal to the three-phase inverter 3, outputs three-phase alternating current, excites the three-phase stator winding 2, and rotates the rotor 1. Regarding the detection of the induced voltage,
Just like the sensorless brushless motor that conducts 180 degrees, the current error correction current command signals S17, S18, S19 and the current detection signals S11, S12, output from the current error amplifier 8 are output.
Since the current error correction current command signals S17, S18, S19 are signals before PWM modulation, the current error amplifier 8 has an accurate motor terminal voltage with almost no switching noise. Can be detected extremely accurately, and the averaged motor terminal voltage as shown in FIG. 5 (b) can be detected very accurately.

The time chart of FIG. 6 shows the state of signals during reverse energization braking. Current command signals S8 and S shown in Fig. 6 (n)
Since 9, S10 have inverted values, the current detection signals S11, S12, S13 shown in FIG. 6 (m) have inverted values, and FIG. 6 (c)
The motor current shown in is reversed. Also, as shown in Fig. 6 (d), the actual motor voltage energization time becomes shorter,
The averaged motor terminal voltage shown in is smaller than the induced voltage. In addition, when the averaged motor terminal voltage shown in Fig. 6 (b) is at a level where L · [dt / di] is sufficiently smaller than the motor terminal voltage (small enough for a normal motor), -Motor current i x winding resistance R), 6
The averaged motor terminal voltage when there is no energization at 0 ° is equal to the induced voltage.

<Third Embodiment> A third embodiment of the present invention will be described with reference to FIG. The sensorless brushless motor of this embodiment, as shown in the block diagram of FIG. 7, has a permanent magnet rotor 1, a three-phase stator winding 2,
Three-phase inverter 3, speed commander 5, speed error amplifier 6, current command controller 7, current error amplifier 8, PW
M signal generator 9, voltage fluctuation compensator 10, induced voltage detector 11, energization phase commander 12, and actual speed converter 13
And

The sensorless brushless motor of this embodiment is an example of the configuration in the case where the DC power supply 4 does not change in voltage. The difference from the sensorless brushless motor in FIG. 1 is that the DC power supply 4 does not change in voltage as shown in FIG. The voltage fluctuation compensator 10 shown is not provided, and the actual speed converter 1
3 the induced voltage signal S output from the induced voltage detector 11
Only 24 is entered.

In the sensorless brushless motor shown in FIGS. 1, 4 and 7, the signals of the two current detectors are added and inverted to obtain the signal of the phase without the current detector. The induced voltage can be detected as in the case where the individual current detectors are provided. Also, the functions of the induced voltage circuit, phase conversion, current command control, speed error amplifier, current error amplifier, actual speed converter, voltage fluctuation compensator, and PWM signal generation circuit are calculated and processed by a microcomputer or the like. -You may get the data. Also,
The actual speed converter may output the actual speed feedback signal from the cycle of the induced voltage signal.

[0029]

As described above, according to the sensorless brushless motor of the present invention, the speed error amplifier 6 inputs the actual speed feedback signal S2 to convert the speed command signal S1 into the speed error correction speed command signal S4. Further, the current command controller 7 inputs the 180 ° conduction sine wave phase signals S5a, S6a, S7a from the energization phase command unit 12 to convert the speed error correction speed command signal S4 into current command signals S8, S9, S10, The current error amplifier 8 outputs current detection signals S11, S12, S13.
To input the current error correction current command signal S
Converted to 17, S18, S19 and output to PWM signal generator 9,
The PWM signal is output to the three-phase inverter 3 to output a three-phase alternating current to excite the three-phase stator winding 2 to rotate the rotor 1.
The induced voltage detection signals S24, S25, S26 are the current error correction current command signals S17, S18, S19 and the current detection signals S11, S12,
Detected from S13, the actual speed feedback signal S2 and 180
Since it is configured to obtain the energized sine wave phase signals S5a, S6a, S7a, the induced voltage is detected by extracting the signal before input to the PWM signal generator so as not to be affected by PWM noise (switching noise). Since the noise that accompanies the detection of the induced voltage is very small and can be removed by a filter with a very small delay, an extremely accurate induced voltage proportional to the average voltage of the motor terminal voltage can be detected without causing a delay, and the motor current is When it is small or when L · [di / dt] is at a level sufficiently smaller than the motor terminal voltage, L · [d
It is possible to detect the motor terminal voltage accurately and without any delay even without performing the calculation of [i / dt]. Therefore, it is necessary to detect an extremely accurate induced voltage even if an ultrahigh speed operation exceeding 10,000 revolutions is given. It is possible to realize ultra high speed operation,
Without providing a rotor position detector such as a hall sensor or an encoder, the current phase of a permanent magnet synchronous motor is controlled to provide an extremely excellent electromechanical energy conversion characteristic equivalent to a DC motor. be able to. Further, since the induced voltage can be detected without being affected by the load fluctuation, there is no fear of step out even under severe operating conditions involving vibration. Since the PWM noise can be removed by a filter with a very small delay, accurate induced voltage detection without a delay becomes possible. Also, 180 degree energization and 12
The induced voltage can be detected at both 0-degree energizations. Furthermore, the induced voltage can be reliably detected even when reverse energization braking is performed, and there is no fear of step out. Furthermore, the three motor wirings enable the detection of signals in proportion to the induced voltage of the motor and of the same phase.

[Brief description of drawings]

FIG. 1 is a block diagram of a sensorless brushless motor according to a first embodiment of the present invention, which performs 180-degree energization control.

FIG. 2 is a time chart of the sensorless brushless motor according to the first embodiment of the invention.

FIG. 3 is a time chart during reverse energization control of the sensorless brushless motor according to the first embodiment of the present invention.

FIG. 4 is a block diagram of a sensorless brushless motor according to a second embodiment of the present invention, which carries out 120-degree energization control.

FIG. 5 is a time chart of the sensorless brushless motor according to the second embodiment of the present invention.

FIG. 6 is a time chart during reverse energization control of the sensorless brushless motor according to the second embodiment of the present invention.

FIG. 7 is a block diagram of a sensorless brushless motor that performs 180-degree energization control according to a third embodiment of the present invention.

[Explanation of symbols]

 1 ... Permanent magnet rotor, 2 ... Three-phase stator winding, 2a, 2b, 2c ... Stator winding, 3 ... Three-phase inverter, 3a, 3b, 3c ... Output Lines, 4 ... DC power supply, 6 ... Speed error amplifier, 7 ... Current command controller, 8 ... Current error amplifier, 9 ... PWM signal generator, 11 ... Induced voltage detection Device, 12 ... energization phase command device, 13 ... actual speed converter,

Claims (1)

[Claims] 1. A three-phase stator winding 2 in which a permanent magnet rotor 1 and three stator windings 2a, 2b, 2c are Y-connected to each other to apply a magnetic field to the permanent magnet rotor 1 to give a rotational force. And the required switching elements U +, V +, W +, U-, V-,
W- is controlled by a PWM signal as required to convert the direct current of the direct-current power source 4 into an alternating current to output three output lines 3a, 3b, 3
A three-phase inverter 3 which outputs from c to feed the three-phase stator winding 2 to control commutation, and a switching element drive signal based on three input current error correction current command signals S17, S18, S19 PWM signals U1, U2, V1, V2, W
In a sensorless brushless motor having a PWM signal generator 9 for outputting 1, W2 to the three-phase inverter 3, a speed error amplifier 6 converts the speed command signal S1 into a speed error correction speed command signal S4 and outputs the speed error correction speed command signal S4. The current command controller 7 converts the speed error correction speed command signal S4 into current command signals S8, S9, S10 for three phases and outputs the current command signal S8, S9, S10 for the three phases by the current error amplifier 8. Are converted into current error correction current command signals S17, S18, S19, respectively, and the PWM
It is configured to output to the signal generator 9, and the speed error amplifier 6 inputs the actual speed feedback signal S2 corresponding to the actual rotational speed of the rotor 1 output from the actual speed converter 13. , The speed error correction speed command signal S4 is calculated and outputted to a magnitude necessary to match the actual rotation speed of the rotor 1 with the speed command signal S1, and the current command controller 7 , Three 180 degree conduction sine wave phase signals S5a, S6a, S output from the conduction phase commander 12
By inputting 7a or 120 degree conduction switching signals S5b, S6b, S7b, the current command signals S8, S9, S for the three phases are input.
10 is designed to include the actual phase of the electrical angle with respect to the stator windings 2a, 2b, 2c of the rotor 1 to form a waveform and output the current error amplifier 8 to the three-phase inverter 3 Current detection signals S11, S12, S13 of the three-phase output lines 3a, 3b, 3c of
By inputting the three current error correction current command signals S17, S18, S19 to the three current commands corresponding to the motor current actually flowing through the three-phase output lines 3a, 3b, 3c. The induced voltage detector 11 directly outputs the three current error correction current command signals S17, S18, S19, or outputs the direct current signals S8, S9, S10. The three current command feedback signals S21, S22, S23 corrected to eliminate the voltage fluctuation of the power source 4 are fed back and the current detection signal S1
By inputting 1, S12, S13 as feedback,
Induced voltage signals S24, S2 generated by the rotation of the rotor 1
5, S26 is output, and the energization phase commander 12 outputs the three induced voltage signals S
By inputting 24, S25, S26 as feedback,
Three 180 degree conduction sine wave phase signals S5a, corresponding to the respective phases of the three induced voltage signals S24, S25, S26,
S6a, S7a or 120 degree conduction switching signals S5b, S6b, S
7b is output to the multipliers 7a, 7b, 7c of the current command controller 7, and the actual speed converter 13 outputs the three induced voltage signals S2.
A sensorless device characterized in that the actual speed feedback signal S2 is output in response to the actual rotational speed of the rotor 1 by inputting at least one signal of 4, S25 and S26. Brushless motor.