JPS5899287A - Controlling method for synchronous motor - Google Patents

Abstract

PURPOSE:To control the speed of the synchronous motor readily and to perform fine, responsive control, by providing a pulse encoder, a reversible counting means, and a converting means, and generating the phase of induced electromotive voltage. CONSTITUTION:The pulse encoder 2 outputs both a position pulse train and rotary pulses. An up down counter 4 presets the position of the rotor of the synchronous motor 1 by the position pulse train and performs reversible counting by the rotary pulse. A DA converter 6 converts the value of costheta and the value of sintheta corresponding to the counted values of the counter 4 into analog voltages. In this way, the phase of the induced electromotive voltage is generated and the synchronous motor 1 can be controlled by the similar way as a DC motor. Therefore the speed control can be performed more readily, torque generation control can be facilitated, and the fine responsive control can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a synchronous motor control method that is applicable and suitable for 1% synchronous motors and rotating field type synchronous motors. A rotating field type synchronous motor has an armature as a stator, is configured as a field tube rotor, and has a stator winding (electrical pre-winding I).
Applying a three-phase current to s) generates a rotating magnetic field from V, and the field pole is pulled by the rotating field a, causing the field pole to rotate at the same speed as the rotating magnetic field @ ° Such synchronization The speed control of the electric motor is more complicated than that of @ashimamoki, and the control circuit configuration is also complicated.
t.

In summary, the present invention provides a synchronous motor control method f that enables easy control of a synchronous motor at a speed of 1 ft, enables control of torque generation equivalent to that of a DC motor, and enables fine-grained and responsive control. Another object of the present invention is to provide a synchronous motor control method that can achieve torque generation control equivalent to that of a DC motor by implementing a simple NLL configuration.

Embodiments of the present invention will be described in detail below with reference to the drawings.

Figure 1 is a diagram of the principle of torque generation in a shunt-wound DC machine.
The IfL aircraft is Amade Air AM as shown in Figure 1 (a) K.
The tIL bond winding 11AW is wound around the armature to form an armature, and this armature is provided between the pair of field poles FM. As shown in Section 19), this torque generation mechanism is based on the electric machine pre-winding 11 with respect to the main magnetic flux φ of the field pole FM, which is the stator.
The current switching operation is performed so that the armature current Ial of AW and the generated torque T is directed in the rotation direction, and the generated torque T is expressed by the following equation.

φI a (1
1. In other words, in a shunt-wound DC machine, if the main magnetic flux φ is constant, the generated torque T is proportional to the armature current Ia, making it extremely easy to control torque and speed. The type of synchronous motor has a field pole ratio M as shown in the configuration diagram in Figure 2.
One rotor and armature**sWt stator,
The king of the world apole KM 11 appears, and the serpentine torque is directed to the rotational force. The relationship between the generated torque and armature current of a rotating field type synchronous motor is expressed by the above-mentioned (1)
) Ni〇王-flux φ becomes the main magnetic flux vector φS of the field a & 几M,
The xg current knee is the current vector IsK of the electric machine prewinding @SW
Therefore, the generated torque T of synchronous electric shock can be expressed by the following equation.

T=ni'・φ张・X@・Makir (2) Here, r is the equivalent of the synchronous motor in the circuit diagram 5
2! According to the I diagram t#, the phase difference between the armature IE flow 3 and the vj induced voltage EO is 0, - In the diagram, the resistance of the taFi electron winding SW,
Considering the magnetic flux caused by the magnetic flux, the reactance is 9 synchronous reactance. Therefore, if the induced electromotive voltage EO and the electric motor 4 electric fils are made in phase, in other words, if the main magnetic flux φS and the armature 11 accent Is are controlled so that they are orthogonal, the The torque T given by equation (2) is:

T=ni' φeasy I s
(3), and the synchronous motor can be driven exactly as the DC motor generates torque.

Therefore, in the present invention, the position of the field 81i (that is, the phase of the main magnetic flux, which is 90 degrees out of phase with the #s induced voltage EO) is detected, and a current command having a phase corresponding to the detected position is generated. The basic concept is to drive and control the synchronous motor in the same way as the 11151 motor by applying this current command t to the electric motor pre-winding IK of the synchronous motor. In the present invention, the structure for detecting the position of the field pole is simple and it is possible to handle the position detection signal in the same way as the phase signal up to the speed control of the rotor.

Figure IIK-4 is a 92-dimensional diagram of an embodiment of the synchronous motor control method of the present invention.

In the figure, 1 is a rotating field type synchronous motor, 2 is a pulse encoder, which is connected to the shaft of the synchronous motor 1, and is generated as various position signals 1. Regarding the conopulse encoder 2, The 0-pulse encoder 2tiε will be explained in detail using the configuration and causes in FIGS. 5 and 6, the circuit diagram in FIG. 7, and the operation diagram in FIG. 8. It is provided and the code plate 25 position fl11
Signal t1! Light-emitting element 22 such as a light-emitting diode with a peeling surface
and the light receiving element 21 below the photodiode are connected to the code plate 2.
The 0 code board 23, which is provided across from the 51 and further provided with the output circuit 24, is connected to the A phase → track a, the B phase → track b, the z phase track C, and from the 4 tracks as shown in FIG. The code tracks d are formed on concentric circles.

A pattern is formed in the human-phase and B-phase tracks a and b so that a nine-turn pulse train with a phase difference of π/2 is generated when the code plate rotates.In the two-axis track C, a synchronous motor 4 makes one turn. A pattern is formed in which one pulse is generated every time. On the other hand, code track d consists of 4 tracks, and each track is designed so that a different 4-bit position code is retained for each rotation angle of the code plate. A turn is formed, and a gray code is used as a position code.As shown in FIG. 21
128% element a corresponds to the B-phase track, the first element 21C corresponds to the Z-phase track c, and the four elements 21d correspond to the code track d. As shown in the output circuit diagram of FIG. 7, each element 21g to 21c is connected to an amplifier 24m to 2
4c, while the four elements 21d are connected to a parallel-to-serial converter 24d (hereinafter referred to as a P8 converter). The P8 converter 24d is connected to the pulse generator 24eK, and converts the 4-bit position code of the code plate 25 read by the four elements 21d into the number of pulses at the pulse frequency of the pulse generator 24e and outputs it. , the above-mentioned 4-bit position code is set, the output pulse of the pulse generator 24e [up-down counter that performs a run count], and when the contents of the up-down counter become zero, a pulse pasted on the gate is generated. It can be considered that the P8 converter 24d is composed of a gate circuit that blocks the passage of the output pulses of the converter 24e, and a gate circuit that blocks the output pulses from passing through.
At the same time, the pulse train is outputted to the output terminal with a phase difference of 1/2 from this pulse train, and two pulse signals are generated which are coincident with the meandering period of the pulse train.

On the other hand, the control signal 2 and the control signal 2 inverted by the inverter 24f are input to the switching circuits 24g and 24hKF'i, which are composed of a pair of AND gate circuits and an OR gate circuit, and perform a switching operation.

The switching circuit 24g receives the human phase rotation pulse from the amplifier 241 and the position pulse train from the A' output terminal of the P8 converter 24d, and when the control signal 2 is on, it outputs the position pulse train and turns the 1181IIili signal 2 off. At this time, a human phase rotation pulse train is generated. Similarly, switching circuit 2
The B-phase rotation pulse from the amplifier 24b and the position pulse train from the B' output terminal of the P8 converter 24d are input to 4h, and when the control signal 2 is on, the position pulse train is output, and when the control signal 2 is off, the position pulse train is input. B@ 0 each switching 1gl path 24g, 24h that generates a rotating pulse train is line 5
24 i, 24 j KWltJe field, its output [give to outside] Also, the two-phase pulse generated by the output of main unit 21c is similarly output to the outside via amplifier 24c and line dryer/<24kt. The operation will be described with reference to the operation explanatory diagram of FIG. 8. When the power supply No. 1 PW is turned on, the clear signal CL is manually inputted to the P8 converter 24d. At this time, the synchronous motor 1 is not rotating, and the PS conoverter 24
d is the clear signal CLt-tri, and the four elements 21
4-bit code signal of d, i.e. read on the position of the field a pole;
A nine-rotation pulse train B' is generated with a phase difference of π/2 between the pulse train A' of the number corresponding to the code and the rotational pulse train, and a control signal zt- is also generated. By this control signal zVc, the switching circuits 24g and 24i are switched to the P8 converter 24d side, and each pulse train A is output from each switching circuit 24g and 24i.
/ , B/ are output, and the line driver 24i,
24j to the outside. This control signal 20 generation period includes a field pole position detection period L)T'''C, and the switching circuit 24g is activated by the fall of the control signal 2.

24h switches to the amplifiers 24m and 24b111, and becomes the servo control period SR of the synchronous motor 1.
In accordance with the rotation of the line drivers 24i and 24j, individual phase and B phase rotation pulses are outputted from the line drivers 24i and 24j. 0, that is, from the line drivers 24+ and 24j, the position detection period 1) T and t
In the following position pulse, the human phase and B-phase rotation pulses are outputted. Such an output circuit 24 is created using recent high-density direct product circuit technology. With less metal, it can be mounted on 21 pulse encoders.

Summary Returning to Figure 4, 5 is a rotation direction determination circuit.

When the output pulses of the line drivers 24i and 24j of the pulse encoder 2 are input, the rotation direction of the synchronous motor 1 is detected, and the synchronous motor 1 is rotating in the forward direction, VC is 11!4, and the pulse speed generated by the pulse encoder 2 is Outputs a positive pulse train P P @' at the same speed or four times the speed, and outputs a negative pulse NPt at the same speed or four times the speed of the pulses generated from the pulse encoder 2 on line 4 during negative rotation. 04 is 7
It is a drop-down counter, which counts up the positive pulse PP from the rotation direction discrimination circuit 5 and counts down the negative pulse NPi. ◎5 is a read-only memory.
The CeI# basket corresponding to the count value of 5Ijo is outputted by the jJA converter, and 6 is converted into an analog voltage to the output cmfj value of the read-only memory 5, sij#[1. 7 is F/V that converts the pulse speed [' of the positive pulse train PP or negative pulse train NP into voltage.
The output voltage is proportional to the rotational speed of the synchronous motor 1 and becomes the actual speed voltage TSA. 08 is the difference between the specific speed command voltage VCMD and the actual speed voltage TEA (hereinafter referred to as A calculation circuit that calculates the ER (referred to as speed error),! is an error amplifier that amplifies the speed error ER to produce the amplitude Is of the armature current, and 10 is a multiplier circuit that multiplies the output of the error amplifier 9, the output pot θ, l# of the DA converter 6, and the t power jl L 2 [(7) tfilim order 11a (=Is
−sinθ1, II b (=Is −csse
) Output each meeting. Reference numeral 11 denotes a 2-phase to 3-phase conversion circuit for converting a 2-phase electric signal to a t-5 phase, and has a circuit configuration as shown in FIG. That is, the 2-phase to 5-phase conversion circuit [11 is the two operating voltages 7'OA1°0 and 2, and 10 to Ω.
The resistance of Aya~R4 and! L78 has a resistance fL of Ω, and 5
It has a resistance fis1 of Ω. Now, each resistor R1-
The direct sound of R1 is determined as above, and as shown in the figure <M-
Then, the terminals Tu, Tv, '1'w; 5a 6 are output respectively〇And these Iu, Iv,
Lw has a phase difference of 2π15 with respect to each other, and is an island phase current command that is in phase with the main electromotive force Eo.

Reference numeral 12 denotes an arithmetic circuit that calculates the difference between the command currents Iu, Iv, Iw and the actual phase currents, and has the configuration shown in FIG.

Iw and actual sliding electricity @ Imu, IJl'V, III
Arithmetic circuits 12m, 12b, 12c that calculate the difference in W
and an arithmetic circuit 12d which adds IJIV and Iiw detected by the current transformer and outputs the U-phase sliding current 15tLau.
and a current amplifier 12e that is provided for each phase voltage and amplifies the current difference between the phases.

Consisting of 12f and 12g ◎ 15 is a pulse width modulation circuit, 14 is an inverter controlled by the output signal of the pulse wheel variable circuit, and the externally provided 5-phase alternating waterfall and this 5-phase father current t. A tI current voltage is applied by a rectifier 5 circuit (diode group and capacitor) that rectifies [fi].

The pulse width modulation circuit 13 generates a sawtooth signal 8T8 as shown in FIG.

Not Gate NOT, ~NOT,, Driver DV1
~DV.

The inverter 14 has six power transistors Q.
, -Q- and diodes D1 to D. Each comparator COMU, COMV of the pulse width modulation circuit w115.

C0Mw compares the amplitudes of the sawtooth wave signal 8T8 and the three-phase AC signals iu, iv, iw, respectively.
When iw is larger than the cage of 8T8, it outputs 1", and when it is smaller, it outputs "0". Therefore, for iu, the pulse width is changed and the current command tUC shown in FIG. is output. That is, 凰u.

The pulse width is modulated according to the amplitude of iv, iw, and three-phase current commands iuc, ivc, +wc are output. , ivc,
iwc is converted into drive signals 8Q+ to 8Q·, and each power transistor Qs to Qs constituting the inverter 14 is controlled on/off. 14' is a rectifier circuit for direct current power supply as described in Figure 4. When the power is turned on, the clear signal 2 is output in the pulse encoder 2 as described above. As a result, position pulse trains A/ and B/ indicating the position of the field pole are output, and the rotation direction discrimination circuit 3 receives the position pulse train A'.

This position pulse train A/ is outputted from B' as a positive pulse train PP having a speed four times faster than f31. In this case, sync! Motive 1 is stationary without rotating, but - pulse encoder 2
outputs a position pulse train B' having a phase shift of 1E/2 with respect to the position pulse train A', the rotation direction determining circuit 5 regards it as a positive rotation and outputs a positive pulse train PP. This positive pulse train PP is counted by the uptown counter 4. As a result, the initial rotational position of the field pole of the synchronous motor 1 at rest is preset in the counter 4.
The output of counter 4 is read-only memory 5 with width # cage,
It is converted to the siθ value, and the DA converter 6 converts the pot θ,■-
9 voltage will be output according to 0 and henceforth,
A speed command V CMD is given to the synchronous motor 1 and three-phase AC is supplied. When the synchronous motor 111J rotates, the rotation direction discrimination circuit 5 outputs a positive pulse PP or a negative pulse NP depending on the rotation direction. Or #'i4 occurs, and the V-down counter 4 counts up this positive pulse PPt or counts down this negative pulse NPt, and according to the contents of the counter 4, the read-only memory 5 and the LIA converter 6 rotate. A sine wave S'θ and a cosine wave harmonic 0 are output according to the position θ of the child.

On the other hand, a speed command voltage VCMD having a predetermined analog value is manually applied to the addition terminal of the arithmetic circuit 8 to the synchronous motor so as to rotate it at a desired rotational speed Vc. On the other hand, since the synchronous motor 11-1 is rotating at the actual speed Va ((Vc), the k'/V converter 7 outputs the actual speed Ill pressure T8A proportional to the actual speed Vi, and this actual speed voltage TSA
is input to the subtraction terminal of the arithmetic circuit 80.

Therefore, the arithmetic circuit 8 calculates the speed error ER((() which is the difference between the commanded speed Vc and the actual speed ■1, and inputs it to the error amplifier!.
Let's do it.

Note that the equation (5) corresponds to the amplitude of the armature current. That is, when the load fluctuates or the speed command changes, the speed error ER (=Vc-Va) increases, and the armature current amplitude Is also increases accordingly.

As Is becomes larger, a larger torque is generated, and this torque causes the actual speed of the motor to increase to the command speed. On the other hand, the position of the field pole of the synchronous motor 1 θ of all two phases A sine wave dia as # and a cosine wave ■θ are outputted from the L)A converter 6 as described above, or the 6th power 31 circuit 10.

11m==ISc&*#, 11b==Is Sc&
1s# operation jl is performed and two-phase current commands 11a, Ilb
Then, the 2-phase to 5-phase conversion circuit 11 performs the calculation Xt shown in equation 41 to obtain the 5-phase current commands Iu, Iv, I
@Tao outputs each wl, these Iu, Iv, I
It is a 5-phase current command that is in phase with the wrj synchronous motor-4 electromotive force Eo.

Thereafter, the one-phase current commands Iu, lv, and Iw are divided into the actual phase currents 1au, lav, and Law in the arithmetic circuit 12, and then the three-phase current commands 5e [signal i
u.

iv, sw are amplified and applied to the comparators COMU, COMV, COMW of the pulse width variable circuit 5315.
Each comparator COMU, COMV, COMW compares the amplitude of the sawtooth wave signal 8T8 and the three-phase AC signals iu, iv, iw.

Pulse width modulated 93-phase current command IUC, IVC,
iwct is output, and inverter drive signals 8Qt to 8Q@[ are outputted via )1 gates NOT, ~N0Ts and drivers L)V, -DV. These inverter drive signals 8Q1 to 8Q are respectively input to the bases of the power transistors Q1 to Q- constituting the inverter 14.
Each of these power transistors Q, to Qst is controlled on/off to supply all three-phase currents to the synchronous motor 1. Thereafter, similar control is performed, and finally the synchronous motor 1 rotates at the commanded speed.

As described above, according to the present invention, there is provided a pulse encoder that outputs both a position pulse train and a rotation pulse.

When the position of the rotor is preset by the position pulse train, several tens of stages are provided for reversible counting by the rotation pulses, and the phase of the induced electromotive force is generated, so the synchronous motor is It can be controlled in the same way as a current motor, speed control is easier, torque generation control is also easier, and fine-grained control with quick response is possible.
Because two pulse encoders can obtain the position pulse for setting the initial value of the rotor's rotational position and the rotation pulse during rotation.

Individual pulse generation parts can be shared, making it possible to reduce the size and simplify the configuration, and also facilitate adjustment.

Historically, the output lines of the pulse encoder are shared by position pulses and rotation pulses, which reduces the number of output lines, reduces the number of line drivers, and simplifies manufacturing.□
Moreover, since the position pulse is generated in the same format as the rotation pulse, the reversible stitch count means is not aware of these factors.
Since multiple signals can be treated as the same signal, no additional configuration is required.

Further simplification of the configuration can be obtained.Although the present invention has been described based on one embodiment, various modifications are possible within the scope of the gist of the present invention, and these are not excluded from the scope of the present invention. do not have.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram explaining the torque generation principle of the shunt-fi Iso, Fig. 2 is an explanatory diagram of a rotating field type synchronous motor, Fig. 5 is an equivalent circuit diagram of the synchronous motor, and Fig. 4 is an illustration of the present invention. FIG. 5 is a block diagram of an embodiment of the encoder shown in FIG. 4, and FIG.
The figure is a block diagram of the main parts of Figure 5, Figure 7 is an output circuit diagram of the encoder in Figure 5, Figure 8 is an explanatory diagram of the operation of the circuit in Figure 7, and Figure 9 is the 2-phase to 5-phase diagram in Figure 4. The circuit diagram of the conversion circuit, Figure WJ10 is the circuit diagram of the arithmetic circuit in Figure 4, Figure 11 is the circuit diagram of the pulse width modulation circuit, circuit and inverter in Figure 4, and Figure 12 is an explanation of the operation of the pulse width modulation circuit. 0 1...Synchronization 111 movement 11.2...Pulse encoder, 6...Rotation direction discrimination circuit, 4...About down counter, 5...Read only memory, 6... D.A.
Converter, 7...FV converter, 8... Arithmetic circuit,!・
...-difference amplifier, 10... multiplication circuit, 11... 2-phase to 6-phase conversion circuit, 1, -2... arithmetic circuit, 15...
Pulse width modulation circuit, 14... Inverter C Introduction/Mekhoki 2nd 3rd riJ. 1τ $7 Drawing rod 9 drawing broom 10 concave

Claims (1)

[Claims] The phase of the induced electromotive voltage of the synchronous motor is detected, a current command in phase with the detected phase is generated, and the pressure is controlled so that the armature current t- in phase with the induced electromotive voltage flows through the armature winding. In a synchronous motor control system, a pulse encoder detects the position of the rotor of the synchronous motor, outputs a position pulse train, and outputs a rotation pulse when the synchronous motor rotates. a reversible stitch number means for reversibly counting in a positive or negative direction depending on the rotational direction of the rotation pulse;
A conversion means is provided for converting into an analog voltage according to silθ and generating a phase of the casting induction pressure, and the pulse encoder switches and outputs the position pulse train and the iron phase pulse. Synchronous motor control method 0