JPS623672B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a lead angle control method for an AC non-commutator motor using a cycloconverter as a power converter. Among self-controlled separately excited non-commutator motors that use a synchronous motor as the motor and commutate the power converter using the induced voltage, AC non-commutator motors that use a cycloconverter as the power converter are Commutation can be performed in synchronization with the motor frequency using the power supply voltage even at startup and at low speeds when induced voltage cannot be obtained, so there is no need for commutation auxiliary circuits for startup and low speeds. It is widely used because of its simple circuit configuration. However, the high-speed characteristics of an AC non-commutator motor are similar to those of other self-controlled separately excited non-commutator motors, and its commutation ability is determined by the magnitude of the motor's terminal voltage and the control progress of the armature current with respect to the terminal voltage. It is greatly influenced by the angle β. Figure 1 shows the control lead angle β in a non-commutated motor.
and the commutation overlap angle u of the current are shown with the motor output as the horizontal axis. A solid line in FIG. 1 shows a rotor position detector that detects the relative rotational position of the armature and rotor of the motor, and commutates the commutating element of the power converter based on the signal. In other words, it shows the commutation characteristics of the conventional system in which the mechanical control lead angle β _p , which is determined by the relative mechanical position of the motor's armature and the field, is fixed and controlled. As the child current increases, the phase of the motor voltage shifts due to armature reaction, the effective control advance angle β with respect to the terminal voltage gradually decreases, and the commutation overlap angle u of the armature current increases as the load increases. As a result, the initial commutation value of the current increases, and the reverse bias voltage that contributes to commutation decreases due to the phase shift of the motor voltage due to armature reaction, so it increases rapidly. The point where the effective control advance angle β and the commutation overlap angle u match is the commutation limit, but in reality, operation at that point is impossible, so the commutation overlap angle u is subtracted from the control advance angle β. The point at which the commutation margin angle γ (γ=β−u) reaches a certain value γ _s that takes into account stability and other various margins is the limit of the output that can be guaranteed. Therefore, in the conventional system in which the mechanical control advance angle β _p is fixed, if an overload capacity of 150% is required, as shown in Fig. 1, the commutation margin angle becomes γ at an output of 150%. It is necessary to set the mechanical control advance angle β _p large in advance so that _s is obtained, which inevitably leads to a low power factor at the rated point as well as at light loads, and has the disadvantage that torque pulsation is also large. In contrast, it is possible to arbitrarily control the control advance angle according to load conditions and other factors, without fixing the ignition point of the commutating element of the power converter by the relative mechanical position of the armature and the field. Therefore, these drawbacks can be improved. The curves indicated by broken lines β' and u' in Figure 1 are for the case where the control advance angle is controlled to make the commutation margin angle γ a constant value γ _s regardless of the load. As a result, the power factor can be improved and torque pulsation can be reduced, and the output limit can be significantly increased as shown in the figure. However, in this case, since the commutatorless motor is a variable speed motor, it can take any rotational speed, so it requires relatively difficult control to control the control advance angle at any frequency, and the circuit configuration is also complicated. It was apt to be the case. The present invention has been made with attention to this point,
In particular, as a method of control advance angle control in AC non-commutator motors that use a cycloconverter as a power converter, a voltage zero point detector that detects the zero point of the terminal voltage of the motor and an end point of the armature current of the motor are used. a commutation end point detector, a pulse generator that generates a pulse proportional to the rotational speed, a first pulse counter, a second pulse counter, and a cycloconverter firing timing signal synchronized with the power supply frequency. By combining the two, a relatively simple method of constant commutation margin angle control that takes into consideration the influence of power supply commutation peculiar to a cycloconverter is provided.The present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing an embodiment of a commutatorless motor device incorporating the control advance angle control method according to the present invention. In Figure 2, 1 is an AC power supply, 2
is a cycloconverter, 3 is a synchronous motor driven by the cycloconverter 2, 4 is a rotor position detector that detects the rotational position of the rotor of the synchronous motor 3, and 5 is a speed that detects the rotational speed of the synchronous motor 3. It is a detector. 6 is a voltage zero point detector that detects the zero point of the terminal voltage of the synchronous motor 3 (hereinafter referred to as motor voltage), and 7 is a commutation that detects the commutation end point of the armature current of the synchronous motor 3 (hereinafter referred to as motor current). It is an end point detector. 8 is a pulse oscillator, and the oscillation frequency of this pulse oscillator 8 is controlled by the output signal of the speed detector 5 to a frequency proportional to the rotational speed of the motor. This pulse generator is a pulse generator in which a rotating plate for pulse generation is provided on the rotor side of the synchronous motor 3, and a sensor provided on the stator side generates pulses according to the rotational position of the rotor. May be replaced. 9 is a control signal generator that generates a control advance angle control signal using a pulse counter from each output signal of the voltage zero point detector 6, commutation end point detector 7, and pulse oscillator 8;
The firing timing signal (power supply side firing timing signal) of the cycloconverter 2 synchronized with the power supply side frequency is inputted, and the power supply side firing timing signal is input during the commutation period on the motor side. The output signal of either the first pulse counter or the second pulse counter is selected depending on whether the arc signal). 10 is a signal switcher that selects either the output signal of the rotor position detector 4 or the output signal of the control signal generator 9 depending on startup, regeneration, and other operating conditions; 11 is a signal switch that adjusts the input power of the power source 1; This is an input control signal generator that generates an ignition signal synchronized with the power supply frequency (power supply ignition signal). 12 creates a firing signal for each commutating element of the cycloconverter 2 from the output signal of the signal switch 10 (motor side firing signal) and the output signal of the input control signal generator 11 (power supply side firing signal). It is a logic circuit. FIG. 3 is a configuration diagram of a cycloconverter 2 that outputs three-phase variable AC from a three-phase AC power supply. 1
is a three-phase AC power supply; 3 is a three-phase synchronous motor driven by the cycloconverter 2; 201 to 21;
8 is a commutating element, and a controlled rectifying element such as a thyristor is used. 220 is a smoothing reactor, and the windings of each phase are magnetically coupled. As shown in Figure 3, unlike a power converter that has a DC intermediate circuit between the forward converter and the inverse converter, the cycloconverter 2 does not have independent commutation on the power supply side and motor side. First, the commutation on the power supply side R, S, and T and the commutation on the motor side U, V, and W are performed in a mixed manner, so if the power supply side commutation and the motor side commutation are performed at the same time, they will not interact with each other. influence each other. FIG. 4 shows the waveforms of the power supply voltages e _R , e _S , e _T and the motor voltages e _u , e _v , e _W and their respective commutation timings. As shown in the figure, the commutation on the power source side is fired at the firing angle α, and the commutation ends at overlap _us .
Further, the commutation on the motor side is started at the control advance angle β, and the commutation ends at the overlap _un . As shown in Fig. 4, assuming that the positive commutation from the R phase to the S phase on the power supply side and the positive commutation from the U phase to the V phase on the motor side are performed at the same time, the operation mode is set to 5. As shown in the figure. In FIG. 5, 201, 204, 205, and 218 are commutating elements of the cycloconverter 2 shown in FIG. 3, respectively.
l _n is motor side commutation inductance, and l _s is power supply side commutation inductance. Now commutation element 201
The commutating element 218 becomes conductive, and the constant current source causes I _p
When the commutating element 204 is ignited as shown in the mode shown in FIG _. Due to the voltage difference between and e _v , commutated elementary current i ₁ flows, and commutation from the U phase to the V phase begins. Next, when the commutation element 205 is ignited by the ignition command from the R phase to the S phase of the power supply, the R phase and S phase are commutated with the commutation element 204 as shown in the mode of FIG. 5b. This is short-circuited by the flow element 205, and commutation current i ₂ flows due to the voltage difference between the power supply voltages e _R and e _s , and commutation from the R phase to the S phase begins. When the motor side commutation current i ₁ and the power supply side commutation current i ₂ become equal and the current flowing through the commutation element 204 becomes zero, the commutation element 204 turns OFF and the fifth
The mode shown in FIG.
While 4 is conducting, motor side commutation and power supply side commutation are performed independently. The commutation element 204
When turned OFF, as shown in the mode of Figure 5c,
The motor side commutation from the U phase to the V phase and the power source side commutation from the R phase to the S phase are performed in the same circuit. In other words, the difference voltage between motor voltages e _u and e _v and power supply voltages e _R and e _S
A common commutation current i ₃ flows due to the sum of the differential voltages, i ₃ becomes equal to the constant current I _p , and the commutation element 2
When the current of 01 becomes zero, commutation element 201 turns OFF.
However, the motor side commutation and the power supply side commutation end at the same time. Assuming that the overlap is sufficiently small, the commutation voltage on the motor side (e _u - e _v ) is E _n and the commutation voltage on the power supply side (e _R -
When approximating e _S ) by the DC voltage of E _S , each commutation current
i ₁ , i ₂ , i ₃ are as follows. i ₁ = E _n /l _n t + C ₁ , i ₂ = E _S /l _S t + C ₂ , i ₃ = E _n + E _S /l _n + l _S t + C ₃ where C ₁ , C ₂ , C ₃ are constants . Let the commutation voltage at the rated speed N _p be E _S =1 and E _n =1, and the commutation inductance is l _S =1 on the power supply side and l _n on the motor side.
= 3, at rated speed and 1/2 speed
The slopes of i ₁ , i ₂ , and i ₃ are as follows.

[Table] Figure 6 shows the commutation current in this case, and Figure 6a shows the commutation current at the rated speed N _p ,
FIG. 6b shows the commutation current at 1/2 speed 1/2N _p . From now on, in the cycloconverter 2, when power supply side commutation is performed during the motor side commutation period,
It can be seen that the commutation overlap period is shorter than when the motor side commutation is performed alone. That is, in the figure, the overlapping period when motor commutation is performed alone is _un , whereas when power commutation is added, commutation ends at un _' . This tendency becomes more pronounced as the rotational speed decreases, as can be seen from the comparison of FIGS. 6a and 6b. In this way, in a cycloconverter, commutation characteristics are improved due to the effect of commutation on the power supply side of commutation on the motor side, and it also has a self-recovery effect after commutation failure, and furthermore, as mentioned above, the induced Even during startup and at low speeds when voltage cannot be obtained, this power supply commutation allows commutation on the motor side, which is a great advantage. However, the influence of this power supply commutation becomes a hindrance when it is attempted to directly detect the commutation end point of the motor current and the zero point of the motor voltage and thereby control the commutation margin angle. That is, since the detected value differs depending on the ignition timing on the power source side and the motor side, determining the next ignition point based on the detected value will cause instant commutation failure. The present invention provides a simple method that solves this drawback when controlling the commutation margin angle of an AC non-commutator motor using a cycloconverter. Next, an embodiment of each block of the voltage zero point detector 6, commutation end point detector 7, and control signal generator 9 shown in FIG. 2 is shown in FIGS. 7, 10, and 11 and will be described in detail. 20, 2 in Figures 7, 10, and 12
0-1 to 20-2 are comparators for zero point detection, 21,
21-1 to 21-7 are mono-multi vibrators (stable multi-vibrators) that generate pulses with a constant time width corresponding to the falling edge of an input signal; 22, 22-1;
~22-8 is an R-S flip-flop whose output is turned ON, or "1", by the ON signal, and turned OFF, or "0" by the OFF signal, 23,
23-1 to 23-2 are pulse counters, and the others are generally used logic symbols and electrical symbols. Figure 8, Figure 9, Figure 11, Figure 13
Figure 14 is an explanatory diagram of the operation of Figures 7, 10, and 12, and the waveforms with each number in parentheses are the waveforms with the same numbers shown in Figures 7, 10, and 12. Waveforms at each stage are shown. FIG. 7 shows an embodiment of the voltage zero point detector 6 and the commutation end point detector 7 shown in FIG. In Fig. 7, 6, 6-1 to 6-3 are voltage zero point detectors, and 6-1, 6-2, and 6-3 are U phase and V phase detectors, respectively.
This is for the phase and W phase, and the circuit is 6-1, 6
-2 and 6-3 are exactly the same. 7, 7-1 to 7-3 are commutation end point detectors 7-
1, 7-2, 7-3 are for the U phase, V phase, and W phase, respectively, and in terms of circuit, 7-1, 7-2, 7-3
Both are exactly the same. FIG. 8 is an explanatory diagram of the operation of the commutation end point detector 7 of FIG. 7. Commutation end point detectors 7, 7- shown in FIG.
1 to 7-3 input terminals 103-1, 103-2,
The outputs of current transformers CT ₁ , CT ₂ , CT ₃ for detecting U-phase, V-phase, and W-phase motor currents are connected to 103-3. On the other hand, 101-1, 10 shown in FIG.
Each input terminal of 1-2, 101-3 has U phase,
The output signals of the signal switching device 10 shown in FIG. 2 corresponding to the V phase and W phase are connected. As shown in FIG. 13, this output signal is a signal with an electrical angle width of 180° that commands the firing point of the commutating element of each phase, and is
Each phase signal has a phase difference of 120°.
From these signals, as logically shown in FIG. 82, signals indicating the period from the commutation start point A of each phase current to the next ignition timing are created, and the signals are output to the input terminals 102-1 and 102 of each phase. -2, 102-3. The detection signal of the motor current i _u shown in FIG.
1 to obtain the signal shown in FIG. on the other hand,
In order to obtain an output even when the initial commutation value of the motor current is zero, the monomulti 21-1 generates a pulse shown in FIG. 8 3 indicating the rising edge of FIG. 8 2, that is, the commutation starting point A point. The output signal of the comparator 20-1 is logically summed with the output signal of FIG. Therefore, in this output (FIG. 8), the output signal of the comparator 20-1 is normally output as is, but even if the initial commutation value of the motor current is zero, the output does not become zero; A pulse indicating the commutation starting point A point is output as shown by the broken line. By the AND of FIG. 85 and FIG. 82, a signal indicating the overlapping period of the U-phase current shown in FIG. 86 is obtained. Figure 8 6
If a pulse is generated at the falling edge of , a signal indicating the commutation end point B of the U-phase motor current i _u is obtained as shown in FIG.
-1 is output. Similarly, the V phase and W phase created by the commutation end point detectors 7-2 and 7-2 in FIG.
Signals indicating the commutation end point of the phase motor current are output from the output terminals 104-2 and 104-3, respectively, and the logical sum of the phase output signals (FIG. 8) is output from the output terminal 1.
Output from 05. FIG. 9 is an explanatory diagram of the operation of the voltage zero point detector 6 of FIG. 7. Voltage zero point detectors 6, 6- shown in FIG.
1 to 6-3 input terminals 107-1, 107-2,
107-3, the motor voltage between UV and V-
The outputs of transformers T _r1 , T _r2 , and T _r3 that detect the motor voltage between W and the motor voltage between W and U are connected. The detection signal of the motor voltage e _u -v shown in FIG. 9, which is detected by the transformer T _r1 , is half-wave rectified and input to the zero point detection comparator 20-2.
Obtain the signal shown in The monomulti 21-3 generates a pulse at the falling edge of the output signal of the comparator 20-2 in Fig. 9, 10, and indicates the commutation start point A and _{the zero} point C of the motor voltage, as shown in Fig. 9 and 11. Output a signal. Furthermore, the monomulti 21-4 generates a pulse at the rising edge of FIG. 9, and outputs _a signal indicating the commutation end point B and the other motor voltage zero point C, as shown in FIG. 9 and 12. On the other hand, input terminal 106-
The output signals of the output terminals 104-1, 104-2, 104-3 of the commutation end point detector 7, which indicate the commutation end point of each phase motor current, are input to 1, 106-2, 106-3. . The input signal of this input terminal 106-1 (FIG. 8, 7) is turned on, and the output signal of the R-S flip-flop 22-1 (FIG. 9, 13) is ANDed with the output signal of the monomulti 21-3 (FIG. 9, 11). and the zero point of the motor voltage as shown in Figure 9-14.
A pulse signal indicating C ₁ is obtained. In addition, the input terminals 108-1, 108-2, 108-3 have second
A signal indicating the period from the commutation start point on the negative side of each phase motor current to the next ignition timing, as shown in FIG. 9 and FIG. The voltage zero point C ₂ is determined by the logical product of the output signal of the monomulti 21-4 in FIG. 9 and 12.
A pulse signal (FIG. 9, 16) indicating the point is obtained. R-
The S flip-flop 22-2 is shown in FIG.
According to Figure 16, voltage zero points C ₁ and C ₂ are “1” and “0”.
The signal shown in FIG. 9 is inverted and output from the output terminal 109-1. V phase and W made in the same way with voltage zero point detector 6-2.6-3
The phase signals are output from output terminals 109-2 and 109-, respectively.
Output from 3. The logical sum of FIG. 9 14 and FIG. 9 16 (FIG. 9 18) becomes a timing signal indicating the zero point of the motor voltage e _u -V, and this signal turns off the R-S flip-flop 22-1, and The logical sum (FIG. 9) of the voltage zero point timing signals of each phase is created and outputted from the output terminal 110. FIG. 10 shows a circuit for creating and selecting a power supply side ignition timing signal that may affect commutation on the motor side from the power supply side ignition signal generated by the input control signal generator 11 of FIG. FIG. 11 is an explanatory diagram of the operation. In other words, the effect of the power supply side commutation on the motor side commutation as explained in Figs. 4, 5, and 6 occurs simply when the power supply side ignition timing occurs during the motor side commutation period. Rather, among the commutating element group in Fig. 3, commutating elements 201 to 209 are in the positive group, and commutating elements 210 to 218 are in the negative group, but within this same group, commutation on the power supply side and the motor side This occurs only when the motor side commutation is carried out in the positive group, while the power supply side commutation is carried out in the negative group. They are carried out independently and there is no mutual influence. FIG. 10 is for selecting a power supply side ignition timing signal in which there is a possibility that power supply side commutation will occur within the same group during the motor side commutation period. Input terminal 120- in FIG.
1,120-2,120-3 have R phase and S phase, respectively.
Fig. 2 Input control signal generator 1 corresponding to phase and T phase
A 180° width power supply side ignition signal which is the output of 1 is input, and a 60° wide signal shown in _FIG . The monomulti 21-6 generates a pulse at the rising edge of 20 in FIG. 11, and outputs the positive firing timing signal 21 in FIG.
1. A pulse is generated at the falling edge of FIG. 20, and a negative firing timing signal (FIG. 11, 22) is output. On the other hand, the input terminals 121-1, 121-2, 121-3 have
180° width motor side ignition signals, which are the outputs of the signal switching device 10 in Fig. 2, corresponding to the U phase, V phase, and W phase, respectively, are input, and from these signals, the signals shown in Fig. 11 23 are input.
A signal with a width of 60° (ω _n in the figure is the motor side angular frequency) is created. A period of "1" in FIG. 11 is a range where there is a commutation period on the positive side, and a period of "0" is a range where there is a commutation period on the negative side. Therefore, the signals in FIG. 11 23 and the same group as shown in FIGS. 21 and 22 to FIG. 11 24 and 25, respectively,
Select the power supply side firing timing signal whose commutation may overlap with that of the motor side, and synthesize it to generate the 11th
An output signal shown in FIG. 26 is obtained and outputted from the output terminal 122. FIG. 12 shows an embodiment of the control signal generator 9 of FIG. 2, and FIGS. 13 and 14 are diagrams explaining its operation. 23-1 in Figure 12
23-2 is a first pulse counter, and 23-2 is a second pulse counter, both of which start counting input pulses in response to a reset signal, and output one pulse after counting a preset fixed number. The output signal of the pulse oscillator 8 shown in FIG. 2 is input to the input terminal 111 in FIG. 12. The frequency of the output pulses of this pulse oscillator 8 is adjusted to the output of the speed detector 5 shown in FIG. 2 so that a certain number of pulses fall within a certain electrical angle corresponding to the rotational frequency of the synchronous motor 3 shown in FIG. The frequency is controlled to be proportional to the rotation speed. The number of pulses to be oscillated within a certain electrical angle depends on how many steps the commutation margin angle γ is controlled. For example, when controlling γ in steps of 1°, the oscillation frequency is set so that 60 pulses occur during an electrical angle of 60°. FIG. 13 is an explanatory diagram of the operation of the first pulse counter 23-1 having the function of constant commutation margin angle control. The output signal 19 in FIG. 13 of the output terminal 110 of the voltage zero point detector 6 shown in FIG. 7 is input to the input terminal 112 in FIG. 12, and the output signal 19 in FIG. The output signal of the output terminal 105 of No. 7 in FIG. 13 is inputted. The input signals to the input terminals 112 and 113 in FIG. 13, 19 and 8, cause the R-S flip-flop 22-3 to turn on at the zero point of the motor voltage and at the end of commutation of the motor current.
The signal shown in FIG. 13 28 that turns OFF is output, and by ANDing this and the oscillator output pulse 27 inputted to the input terminal 111, the signal shown in FIG. 13 29 is output.
A signal shown in is created and is used as the input pulse signal of the first pulse counter 23-1. In other words, the output pulses of the oscillator are input to the first pulse counter 23-1 during the period from the motor current commutation end point to the next motor voltage zero point (commutation margin period corresponding to commutation margin angle γ). Therefore, the first
During this period, the pulse counter 23-1 stops counting pulses. In other words, the first pulse counter 23-1 starts counting the output pulses of the oscillator in response to the reset signal, stops counting the commutation margin period pulses, and once the commutation margin period has passed, counts the pulses again. When the total number of pulses matches the set number n, one pulse is output. The output signal of the first pulse counter 23-1 (FIG. 13) is logically summed with the output signal of the second pulse counter 23-2 under certain conditions, as will be explained later. Although the sum signal is used as a reset signal for the first pulse counter 23-1 and the second pulse counter 23-2,
While the output signal of the second pulse counter 23-2 is not input, the output signal of the first pulse counter 23-2 serves as the reset signal. Therefore, as shown in Fig. 13, the first pulse counter counts the set number n of pulses and generates an output pulse, and at the same time is reset by the output pulse and repeats the same operation again. Become. Number of settings n of the first pulse counter 23-1
is the commutation margin angle γ _s set from the firing return angle of 60°
The number of pulses is selected to be equivalent to (60° - γ _s ). For example, if the output frequency of the pulse oscillator 8 shown in FIG. Set to =60-15=45. Therefore, the inter-pulse electrical angle of the output pulses of the first pulse counter 23-1 is the sum of the angle (60° - γ _s ) corresponding to the set number n and the count pause period angle, that is, the commutation margin angle γ ( 60゜−γ _s + γ)
As shown by the solid line in Fig. 13, the commutation margin angle γ is
If γ matches the set value γ _s , the steady firing angle is 60°, and γ is γ as shown by the broken line in Figure 13.
If it is smaller than _s , it will be smaller than 60°, and conversely γ
is larger than γ _s , it is larger than 60°. Therefore, if the next firing point is determined one after another based on the output signal of the first pulse counter 23-1,
If the commutation margin angle γ is smaller than the set value γ _s , the next ignition point will be earlier, that is, the control advance angle β will advance, and if the commutation margin angle γ is larger than the set value γ _s , the next point The arc time is delayed, and the control advance angle β is delayed so that the commutation margin angle γ matches the set value γ _s . This ignition timing signal 30 in FIG. 13 (actually, the signal shown in FIG. 14 35 obtained by ORing with the output signal of the second pulse counter 23-2) is output from the output terminal 116, and is also input to the Terminal 1
A control advance angle control signal (motor side firing signal) is created by a logical operation with the output signal of the voltage zero point detector 7 in FIG. That is, the input terminal 115-1,
115-2, 115-3 are the output terminals 109-1, 109-2, respectively of the voltage zero point detector 7 in FIG.
109-3 is input, and as shown in FIG.
From the firing timing signals of FIG. 17 and FIG. 13, the ON signal 36 and OFF signal 37 of the R-S flip-flop 22-6 are created,
As a result, the U-phase control advance angle control signal (motor side ignition signal) shown in FIG. 13 is obtained. V
Phase and W phase are created in exactly the same way, and each phase has output terminals 117-1, 117-2, 117-.
Output from 3. FIG. 14 shows how γ is automatically adjusted and the operation and effects of the second pulse counter 23-2. As explained in FIG. 13, by using the output signal of the first pulse counter 23-1 as the motor-side ignition timing signal, a signal for automatically controlling the commutation margin angle γ to the set value γ _s is generated. However, as mentioned above, in an AC non-commutator motor that uses a cycloconverter as a power converter, if commutation on the power supply side overlaps during the commutation period on the motor side, this will cause the motor current to increase. Commutation overlap angle becomes smaller. Therefore, in this case, the commutation margin angle is observed to be larger than in the case where the power supply commutations do not overlap, and this determines the next ignition point.
That is, if the output signal of the first pulse counter is used as the next ignition signal, ignition will be delayed from the desired ignition time, which will cause commutation failure. The second pulse counter 23-2 determines the next firing point at the same control advance angle as the previous firing point when the power supply side firing timing signal is input during the commutation period on the motor side. This is what we are trying to do. That is, as the input pulse of the second pulse counter 23-2, the oscillator output shown in FIG. 14, FIG.
As shown in 3, the input pulse count is started by the reset signal, the set number m is counted, and 1 is reached.
Outputs output pulses. The set number m of the second pulse counter 23-2 is the steady commutation return angle.
If the number of pulses corresponding to 60 degrees is set to be oscillated, for example, 60 pulses at an electrical angle of 60 degrees of the output frequency of the pulse oscillator shown in FIG. 2, then m is set to 60. Therefore, the second pulse counter 2
3-2 always generates a reset signal, ie, an output pulse at a point in time when 60 electrical degrees have elapsed from the previous ignition point. On the other hand, the flip-flop 22-4 uses the motor side ignition timing signal 35 in FIG. 14 as an ON signal, and the output signal 8 of the commutation end point detector inputted to the input terminal 113 in FIG. The signal shown in FIG. 14, 31, is output. In addition, the input terminal 114 includes the output of the output terminal 122 shown in FIG.
26 is input, and this signal is logically summed with the commutation overlap period signal of FIG.
The output of the R-S flip-flop 22-5 turns ON only when the power supply side ignition timing signal is input during the motor side commutation overlap period, as shown in the period shown in Fig. 4, and turns OFF during other periods (Fig. 14 32). ). Output signal of second pulse counter 23-2 FIG. 14 33
is ANDed with the output signal 32 of this RS flip-flop 22-5 in FIG. 14, and this AND signal 34 in FIG.
Since the logical sum of the output signals in FIG. 14, 30, is used as the motor side ignition timing signal, the motor side ignition timing signal is a normal one in which commutation on the motor side is performed independently, as shown in FIG. 14, 35. In this case, the output signal of the first counter (FIG. 14, 30) is output as is, and the commutation margin angle γ is set to the set value γ _s as already explained in FIG. 13 and as shown in FIG.
However, if the power source side ignition timing signal is input during the motor side commutation overlap period, the second pulse counter 23 is set at the stage of FIG. 12 as shown in FIG. Since the pulse of output signal -2 in FIG. 14, 33, is input, the output pulse of the second pulse counter 23-2 is output as the motor side ignition timing signal, FIG. 14, 35. In other words, in the period shown in Fig. 14, the commutation overlap period of the motor current decreases from normal u _n to u _n ' due to the influence of power supply commutation, and as shown in Fig. 14 28, the apparent commutation margin decreases. Since the angle becomes large, if the output of the first pulse counter 23-1 is used for ignition, ignition will occur at a point later than the desired control advance angle, as shown by the chain line in FIG. 14, 30. ,
This will cause commutation failure. Therefore, the present invention
As shown in FIG. 4, ignition is performed by the output pulse of the second pulse counter 23-2 during the period in which the power commutations overlap. In other words, ignition is performed at the same control advance angle as in the previous period, and the influence of power supply commutation can be avoided. Of course, during a transient period, even though the power commutations overlap, the output pulse of the first pulse counter 23-1 may be output before the output pulse of the second pulse counter 23-2 is output. However, in this case, since the pulse output first becomes the ignition timing signal, ignition is performed using a safer signal. As described above, the present invention directly detects the commutation end point of the motor current and the zero point of the motor voltage in an AC non-commutator motor using a cycloconverter in which the motor side commutation is affected by the power supply side commutation. It provides a simple method to control commutation margin angle,
A fixed set number is counted and output from each firing point, regardless of the signal of the rotor position detector that detects the relative mechanical position of the armature and the field, and that output point is set as the next firing point. By doing so, the commutation margin angle is automatically controlled to a constant value, and errors caused by detected values affected by power supply side commutation are eliminated without using complex control techniques such as peak hold or control using time average values. Control is solved. Therefore, control inputs such as current, rotational speed, commutation margin angle, etc. are captured quantitatively, and the output signal of the rotor position detector or the phase from a reference signal such as the zero point of the motor voltage is determined based on the amount of control input. Compared to the conventional method that controls the commutation margin angle by controlling the amount, it does not require functions such as conversion, adjustment, and calculation of control inputs, and has a much simpler control mechanism. There are no problems with time delays due to
Since the next ignition point is commanded one after another from the current commutation state, it is characterized by extremely quick response. This also improves the response speed in the event of an accident such as commutation failure, and can significantly improve the accuracy of equipment protection. Furthermore, the control method according to the present invention does not require individual adjustment or changing circuit constants depending on the model.
It is also advantageous in terms of cost because the same product can be used for both small and large capacities.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the control lead angle and commutation overlap angle in a non-commutated motor with the motor output as the horizontal axis, and Fig. 2 is a diagram showing the control lead angle and commutation overlap angle in a non-commutated motor, and Fig. 2 shows a non-commutated motor device incorporating the control lead angle control method according to the present invention. A block diagram showing one embodiment. Fig. 3 is a configuration diagram of a cycloconverter that outputs 3-phase variable AC from a 3-phase AC power supply. Fig. 4 shows the waveforms of the power supply voltage and motor voltage and their commutation timings. Figure 5 is a diagram showing the operation mode in Figure 4, Figure 6 is a diagram showing commutation current at rated speed and 1/2 speed, and Figure 7 is a diagram showing the voltage zero point detector and commutation current in Figure 2. A configuration block diagram showing an embodiment of the commutation end point detector, FIG. 8 is an explanatory diagram of the operation of the commutation end point detector of FIG. 7, and FIG. 9 is an explanatory diagram of the operation of the voltage zero point detector of FIG. Figure 10 is a diagram showing a circuit for creating and selecting a power supply side ignition timing signal that may affect commutation on the motor side from the power supply side ignition signal generated by the input control signal generator shown in Figure 2; 12 is a block diagram showing an embodiment of the control signal generator shown in FIG. 2, and FIG.
14 are explanatory diagrams of the operation. 2...Cycloconverter, 3...Synchronous motor, 4...Rotor position detector, 5...Speed detector, 6, 6-1 to 6-3...Voltage zero point detector,
7, 7-1 to 7-3... Commutation end point detector, 8...
Pulse oscillator, 9... Control signal generator, 10...
Signal switcher, 11... Input control signal generator, 12
...Logic circuit, 20, 20-1 to 20-2... Comparator, 21, 21-1 to 21-7... Monomulti, 22, 22-1 to 22-8... R-S flip-flop, 23 , 23-1 to 23-2...Pulse counter.

Claims (1)

[Claims] 1. an AC power supply, a cycloconverter that receives the AC power supply as input and outputs variable AC power, a synchronous motor driven by the cycloconverter, means for detecting the voltage zero point of the terminal voltage of the synchronous motor; means for detecting a commutation end point of an armature current of a synchronous motor; a pulse generator for generating a pulse having a frequency proportional to the rotational speed of the synchronous motor; It is reset by a synchronized motor-side ignition timing signal, and using the reset signal as a counting start command, the output pulses of the pulse generator are counted except for the period from the commutation end point to the next voltage zero point, and the set number of pulses is counted. a first pulse counter that generates an output signal when counting n; and a first pulse counter that is reset by the motor-side ignition timing signal and uses the reset signal as a counting start command to count the output pulses of the pulse generator; and a second pulse counter that generates an output signal when counting the number of pulses m corresponding to an electrical angle of 60° corresponding to the frequency of When the power supply side ignition timing synchronized with the frequency of the AC power source of the commutating element of the cycloconverter occurs, the first pulse counter and the second
Outputs the signal that is output first among the output signals of the pulse counter, and if the power supply side ignition timing does not come in the period from the motor side ignition timing signal to the commutation end point, the first signal that comes next is outputted. 1. A control advance angle control method for a non-commutated motor, comprising a signal selection function for outputting an output signal of a pulse counter, and using the selected output signal as a motor-side ignition timing signal.