SK284657B6 - Method for driving a single phase synchronous motor and device for thereof - Google Patents

Abstract

For reliable starting even when there is a relatively large load torque or inertia torque, the single phase synchronous motor (1) is connected to the supplying AC voltage power supply network (L1; L2) as a function of a rotor rotation position sensor (2), via an AC voltage switch, in particular a triac (7), when the rotor is positioned between a first indent position and the subsequent second indent position, only during the half cycles of one polarity, and subsequently between the second and the first indent position only during the half cycles of the other polarity. According to a preferred refinement of the invention, the reference signal for the supplying AC voltage which is to be linked to a signal from the rotation position sensor (2) is picked off directly via the switching path of the triac (7).

Description

Technical field

The invention relates to a method of operating a single-phase synchronous motor, in particular to operating a pump drive in a household appliance and to apparatus for carrying out the method.

BACKGROUND OF THE INVENTION

DE-A1-4 033 121 discloses a method for starting an electric single-phase synchronous motor in a preferred direction of rotation, in which the motor rotor with at least one isolated current pulse consisting of a single half-wave AC power supply having a predetermined polarity for one specific interval, it preliminarily positions and then, after a time that is sufficiently long to stabilize the rotor mechanically at this interval, it is fed with a full wave alternating current from an AC source whose first half has opposite polarity to the current pulse polarity to specifically pre-position the rotor. This procedure is only applicable to self-starting single-phase synchronous motors, conditional on design.

EP-B1-0 358 805 or EP-B1-0 358 806 disclose permanent magnet excited single-phase synchronous motors in which the starting torque for the actual start-up can be clearly increased by the fact that the rotor with its pole axis can be specially to form the air gap or sheet metal cut into the zero position of the stop, which is rotated opposite the longitudinal axis of the stator excitation up to the so-called position of the minor axis. Such single-phase, preferably double-pole, permanent-magnet-driven, synchronous motors with a secure start-up are particularly suitable for use at an output power of up to about 40 watts.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the invention to make it possible to use single-phase synchronous motors with low production and assembly costs for propulsion at loads greater than 40 watts in a safe and fast start-up.

This object is achieved by a method of operating a single-phase synchronous motor, in particular the operation of a pump drive in a household appliance, according to the invention, which consists in that the single-phase synchronous motor is connected to AC power via an AC switch. in this switched-on state, it maintains the alternating current flowing up to zero, the alternating voltage switch being switched on depending on the rotor power of the single-phase synchronous motor, always in the region of the first position by half-polarity; depending on the position sensor, the motor is fed by positive half-waves in the region of the first position and negative half-waves in the region of the second position, and the switching pulse for switching the AC voltage switch off depending on the voltage in the forward direction on its switching path.

The AC voltage switch is preferably switched on, depending on the combination circuit, at the input side H-signal caused by the positive half-wave supply voltage and the position sensor H-signal or at the input side H-signal caused by the negative half-AC supply voltage and H signal generated by inverting from the L-signal of the position sensor.

The AC voltage switch is preferably switched on depending on the combination circuit at each input side H-signal caused by the positive half-wave on the switching path of the alternating voltage switch and the position sensor H-signal or at the input side H-signal caused by the negative half-wave on the path of the AC voltage switch and the L-signal of the position sensor.

Preferably, the trigger pulse is preceded by the AC voltage of the AC power supply to achieve maximum torque, wherein the trigger pulse is preceded by a delay circuit for inputting the AC power supply signal, and then the sign of the positive or negative AC power supply alternates.

The switch pulse of the AC voltage switch is preferably switched off depending on the comparison circuit to compare the sequence of the two time-shifted rotor speed signals.

The time-shifted speed signals are preferably signals of two position sensors displaced in opposite directions in the direction of rotation.

The time-shifted speed signals are preferably the position sensor signals associated with one half-wave supply AC voltage, as well as the course of the other half-wave supply AC voltage shifted by an angle, in particular delayed.

Preferably, the AC voltage switch is then switched on again after being switched off by the comparator circuit, depending on the timing member downstream of the comparator circuit.

The switching on of the AC voltage switch is preferably dependent on the trigger timing member and the at least one delayed circuit so that after the trigger timing has elapsed in terms of phase cut-off control, the at least one half voltage is delayed against the position sensor signal and delayed.

The object of the present invention is to provide a method according to the invention for operating a single-phase synchronous motor, in particular for operating a pump drive in a household appliance, wherein the single-phase synchronous motor comprises a permanent magnet rotor. the AC power supply terminal being coupled to the combination circuit, the line voltage modulator and the driver via the power supply part, the terminal being connected directly to the line voltage signal modulator, and the line voltage modulator being connected to the line voltage modulator. a logic signal combining circuit that is subsequently coupled to an AC driver to control the AC voltage switch, and wherein the position sensor for position sensing is coupled to the combination circuit a single-phase synchronous motor rotor and a voltage sensor for detecting the forward voltage on the switching path of the AC voltage switch.

The position sensor is preferably a Hall element, in particular with a digital output.

The position sensor is preferably arranged in the air gap of a single-phase synchronous motor in the region between two adjacent poles.

The AC voltage switch is preferably a semiconductor switch, in particular a triac.

The rotor of a single-phase synchronous motor can be excitable by means of at least one two-pole permanent magnet and has zero positions corresponding to the number of its poles and the boundary area of the position. The position sensor can be excited by the magnetic pole of the rotor.

By means of the device according to the invention, depending on the drive load of the single-phase synchronous motor and thus the mechanical time constant determined by the rotating rotor mass and the actual drive load, it is possible to start the single-phase synchronous motor safely and in shortest time Rotation speed of the rotor with the frequency of the AC supply voltage.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention as well as further advantageous developments of the invention according to the features of the above claims are explained in more detail below on the basis of schematically illustrated exemplary embodiments or functional diagrams in the drawing; Fig. show:

Fig. 1 in a first block diagram, an excitation of a single-phase synchronous motor driven permanently in dependence on the current sensor and the mains voltage signal modulator;

Fig. 2, in the second block diagram, excitation of a single-phase synchronous motor as a function of the timing element and the mains voltage modulator;

Fig. 3 in the third block diagram, excitation of a single-phase synchronous motor depending on the voltage sensor and the mains voltage signal modulator;

Fig. 4 in a fourth block diagram, excitation of a single-phase synchronous motor in dependence on a line voltage signal modulator with one upstream delay voltage circuit;

Fig. 5 shows, in a fifth block diagram, the actuation of a single-phase synchronous motor as a function of the first control of the direction of rotation;

Fig. 6 shows, in a sixth block diagram, the construction of a single-phase synchronous motor as a function of the second direction of rotation control;

Fig. 7 in a seventh block diagram, excitation of a single-phase synchronous motor as a function of a time-shifted delay voltage circuit;

8 shows, in the eighth block diagram, the excitation of a single-phase synchronous motor as a function of the reference voltage for the AC supply taken through the switching path on the AC switch; FIG.

Fig. 9 shows the AC power supply as well as the individual signal waveforms and motor current waveforms of the single-phase synchronous motor drive device of FIG. 1-7.

DETAILED DESCRIPTION OF THE INVENTION

In the block diagrams, in order to clearly differentiate the serial stream flows of a single-phase synchronous motor 1, the lines of the signal are thin-line and the arrows and the wires and wires supplying the components are shown in dashed lines.

Fig. 1 shows a single-phase synchronous motor, which can be connected via a preferably triac-formed AC switch 7 and a motor current sensor 4 to a power supply with AC voltage sources L1, L2, with a permanently excited, two-pole N, S rotor. The AC switch 7 receives its pulse to be energized via the excitation arrangement 6 from the combination circuit 5, depending on the signal values given on the input side to the combination connection 5 of the rotor position sensor 2 on one side or the mains voltage signal modulator 3 on the other. The line voltage signal modulator 3 is upstream of the combination circuit 5 in such a way that in each case as positive logic signals for the AC power supply, positive half-wave AC power supplies L1, L2, converted to pulses, e.g. rectangular pulses, further guided from the first part 3.1 of the mains voltage modulator 3 to the first part 5.1 of the switching circuit 5 and the negative half-wave AC power supply L1, L2, converted to rectangular pulses and from the second part 3.2 to the second part 5.2 of the switching circuit.

In this case, the AC voltage switch 7 is in a preferred mode of switching on the combination circuit 5 at the input side H-signal caused by the positive half-wave supply voltage and the position sensor H-signal or the input side H-signal caused by the negative half-wave supply voltage. one H-signal generated from the L-signal of the position sensor by inverting. The rotor position sensor 2, the mains voltage modulator 3, the motor current sensor 4 as well as the combination circuit 5 and the exciter 6 are supplied via the mains part 8 from an AC voltage source L1, L2.

Principal methods of operation of the device according to the invention, in particular according to the block diagrams in FIG. 1 to 7, depending on the switching command for the triac control voltage and the first current recording through the current sensor 4, are first based on the diagrams of FIG. 9 explained in more detail; U1 = f / t /: signal at the output of first part 3.1 of the modulator 3 of the line voltage signal, u ₂ = f / t /: signal at the output of the second part of the modulator 3.2 3 mains voltage, u ₃ = f / t /: rotor output sensor 2 signal output, u ₄ = f / t /: rotor position sensor 2 output inverted signal, i = f7t /: motor current through single-phase synchronous motor 1, u ₅ = f / t /: signal at the output of the motor current sensor 4, u ₆ = f / t /: signal at the input of the AC switch 7.

Based on the assumption that the rotor taking its zero position at shutdown produces an H-signal at the output of the rotor position sensor 2 corresponding to the voltage u ₃ and based on the positive half-wave line voltage u = f / t / at the output of the first part the H-signal is also adjacent to u _t, and since no motor current is flowing there, the triggering signal 6 is sent to the triac via the excitation device 6 in the first part 5.1 of the combination circuit 5, thereby thereby a single-phase synchronous motor 1 to the L1 source. , L2 connects AC; the single-phase synchronous motor 1 is thus overflowed by the supply of the positive half-wave AC source L1, L2, so that its rotor starts to rotate and accelerate.

The control voltage for the triac is advantageously disconnected after the motor current sensor 4, through its output side signal u ₅ = f / t /, detects the stator winding current of the single-phase synchronous motor 1 in order to keep the current drawn from the mains as small as possible. 8. However, the triac remains switched on as long as the motor current, determined by the mains voltage, the inductance of the motor 1, the induced voltage by the permanently excited rotor in the motor winding and the ohmic voltage drop, continues to flow.

If not enough when you first connect the positive half-wave source Ll, L2 AC voltage - as previously indicated - created rotary motion of the rotor to bring the rotor to the next resting zero position, the sensor 2 position of the rotor according to the course of voltage at ₃ its signal level does not change, ie, continues to transmit the H-signal. Since during the following negative half-wave AC source L1, L2 of AC voltage is transmitted from the first part of circuit 3 of the line voltage modulator 3 of the L-signal to the first part 5.1 of the combination circuit 5, its condition "a" is not met. thus, the connection of the AC power supply L1, L2 to the single-phase synchronous motor 1 is interrupted.

Due to the now unsatisfied condition "a", no triac command is given from the first part 5.1 of the combination circuit 5, so that it is opened when the current is zero and thus does not flow by the single-phase synchronous motor 1 during negative half-current. During the next positive half-wave source Ll, L2 AC voltage and continues H-lasting signal of the voltage sensor ₃ at 2 position of the rotor is a single phase synchronous motor 1 at now during the positive half-wave again closed triac current to flow and further accelerated.

If the second rotor zero position is now reached, an L-signal corresponding to the voltage u ₄ in FIG. 3, which is inverted by the inverting part 5.3 in the second part 5.2 of the combination circuit 5 such that the H-signal from the rotor position sensor 2 of the second part 5.2 of the combination circuit 5 is presented. of the AC voltage source L1, L2, the H-signal according to Uj = f / t / is also connected and since there is no current flowing, the connection "a" in the second part 5.3 of the combination circuit 5 is satisfied so that the signal can be switched again The single-phase synchronous motor 1 can now be further accelerated in the region between the second zero position and the first zero position by supplying one or more negative half waves of the AC voltage source L1, L2. On the basis of this excitation, the motor current curve according to i = f / t / according to FIG. 9th

Fig. 2 shows a simplification of the device according to FIG. 1 in such a way that, by omitting the motor current sensor 4, the triac on command is not disturbed, depending on the detected motor current, but on a simple time element.

Fig. 3 shows, according to a further embodiment of the invention, an alternative for the embodiment according to FIG. 1 or FIG. 2; Here, the tripping of the switching pulse for the triac takes place as a function of recording the voltage in the forward direction through the triac switching path, for example by means of a voltage sensor 11 which compares the positive or negative voltage on the triac switching path according to the window comparator method. in the forward direction on the triac, it outputs a corresponding signal via an output to the first part 5.1 or the second part 5.2 of the combination circuit 5 and this, similar to FIG. 1 with respect to the current recording described, the switching pulse for the triac prevents or disrupts the switching pulse. In contrast to motor current detection, a reduced signal output results in a more clearly detectable signal, determined by the amplitude of the mains voltage.

Fig. 4 shows the preferred use of the device according to the invention for taking into account the phase shift between the motor current on the one hand and the motor voltage on the other hand, or the so-called supply angle between the rotor position in the power supply on the one hand and its unpowered position, for example at the stepped pole. However, in order to ensure the maximum torque of the motor, a start-up pulse, and thus a switching time of the triac, is provided provisionally; this occurs according to one embodiment of the invention, in particular in the preferred arrangement of the position sensor within the air gap and in the region between two adjacent poles of the rotor and in the advantageous excitation of the position sensor preferably formed as a Hall element by a particular magnetic field of the rotor driven by a permanent magnet only by: the signals from the AC power supply L1, L2 are transmitted via the delay circuit 10 to the combination circuit 5, and thus to control the AC voltage switch 7 formed as a triac, and are subsequently transmitted by varying the positive or negative voltage half-wave signals. In FIG. 4, the last one is achieved by crossing the connecting lines between the outputs of the first part 3.1 and the second part 3.2 of the mains voltage modulator 3 and the inputs of the first part 5.1 and the second part 5.2 of the combination circuit 5 as a whole.

In a preferred method, protection against an undesired direction of rotation is also possible with the use of a low-cost device as explained above, in particular for the operation of a liquor pump, for example in the case of unbalanced shaking of automatic washing machines or in the case of backflowing liquids. According to FIG. 5, in addition to the first position sensor 2, a further position sensor 2 is disposed on the periphery, both position signals being transmitted to the comparator 12.1, in particular in the form of a bistable flip-flop; upon detection of an incorrect rotation movement, for example based on the signal difference sign, the triac control via the combination circuit 5 is closed.

Fig. 6 shows a further simplification of using the circuit known from FIG. 4, in another manner, in that, when dropping another rotation position sensor, a time-shifted signal is obtained from one voltage signal delayed through the delay circuit 10 to be compared with the signal of the first position sensor 2 and which in the present case is connected The output signal of the position sensor 2 is connected to the input of the first part 5.1 of the combination circuit 5.

In both cases, according to a further embodiment, a time member 12.2, additionally connected to the comparator 12.1, is switched on depending on the detection of the wrong direction of rotation to block the triac switching option only for a predetermined time.

Fig. 7 shows in a further embodiment of the invention a simple connection of the device for driving the synchronous motor to a reduced power input after starting into synchronism by means of phase cut-out control. To this end, for example, in the simplest case, after a certain start time, which can be determined by the start time member T _s , by means of at least one delay circuit 10 or 14, one upstream voltage half or, as shown in FIG. 7 - by means of the delay circuits 10,14 upstream of the two voltage half-waves, the switching times of the triac are simply shifted to the later switching times.

In case the output signal of the current sensor 4 (Figs. 1, 4, 5, 6, 7) is also connected to the inputs of the combination circuit 5, for example according to U5 = f / t / in Fig. 1. 9 or the voltage sensor 11 (FIG. 3), the AC switch 7 is additionally dependent on the L-levels of this voltage signal.

Fig. 8 shows a further simplification of the apparatus of FIG. 3 so that in order to generate a switch-on command for the AC voltage switch 7, the reference signal for adjacent AC voltage is directly sensed at the supply voltage level through the switching path of the AC voltage switch 7, and thus the selected auxiliary logic signal level can be the AC power supply L1, L2 connected to the mains voltage modulator 3 of FIG. 1 to FIG. 7; The excitation signal for the AC voltage switch 7 is produced directly from the voltage drawn through its clamping of the main connection of its switching path and, when the present connection with the signal of the position sensor 2 is satisfied in terms of the desired torque generation. In this exemplary embodiment, the essential switching elements can be used together for both switching and voltage-dependent switching - as shown in FIG. 3, wherein the function of the parts of the voltage sensor 11 and the driver 6 of FIG. 3 from the connecting circuit 4 of FIG. 8 download; in this case, the first switching element 4.1 is responsible for processing the positive AC voltage half parallel to the connection of the AC voltage switch 7, and the second switching element 4.2 is responsible for processing the corresponding negative half wave.

In this case, the AC voltage switch 7 is in the switch-on dependence of the connection circuit 4 at the input side H-signal caused by the positive half-wave on the switching path of the AC voltage switch 7 and one H-position sensor. negative half-wave on the switching path of the AC voltage switch 7 and one L-signal of the position sensor 2.

When the AC switch 7 is switched on, the voltage drops through its switching path to the so-called forward voltage, this is no longer sufficient to maintain the switching pulse for the AC switch 7.

Of course, not only the signal connections described for the so-called positive logic circuit but also their corresponding inverted assignment in the negative logic circuit are included in the scope of protection.

Claims (13)

A method of operating a single-phase synchronous motor, in particular a pump in a household appliance, wherein the single-phase synchronous motor comprises a rotor built with permanent magnets, characterized in that: the single-phase synchronous motor (1) is connected to AC power via an AC switch (7) a voltage which is switched on by a pulse and which is automatically maintained in this switched on state until the current of the alternating current flow is zero, the AC switch (7) being switched on depending on the rotor power of the single-phase synchronous motor (1). half-waves of one polarity and in the next region of the second position by the half-waves of the opposite polarity of the AC source (L1, L2), the single-phase synchronous motor (1) being fed by positive halfwires in the first position and and wherein the switching pulse for switching on the AC switch (7) is switched off depending on the voltage in the forward direction on its switching path. Method according to claim 1, characterized in that the AC switch (7) is switched on, depending on the combination circuit (5), each time an H-signal on the input side caused by a positive half-wave AC supply voltage, and H- a position sensor signal (2) or an input-side H-signal caused by a negative half-wave AC power and an H-signal formed by inverting from the L-signal of the position sensor (2). Method according to claim 1, characterized in that the AC voltage switch (7) is switched on depending on the combination circuit (5) at each H-signal on the input side, caused by a positive half-wave on the switching path of the AC switch (7). voltage, and the H-signal of the position sensor (2) or the H-signal on the input side caused by a negative half-wave on the switching path of the AC switch (7), and the L-signal of the position sensor (2). Method according to one of the preceding claims, characterized in that the switching pulse is preceded by the alternating voltage of the AC power supply (L1, L2), the switching pulse being preceded by the delay circuit (10) for inputting the signal by the AC supply and then the sign of the positive or negative half-wave of the AC power supply (L1, L2) always changes. Method according to one of the preceding claims, characterized in that the switching pulse of the AC voltage switch (7) is switched off depending on the comparison circuit (12.1) for comparing the sequence of the two time-shifted rotor speed signals. Method according to claim 5, characterized in that the time-shifted speed signals are signals of two position sensors (2, 12) spatially opposed in the direction of rotation. Method according to claim 5, characterized in that the time-shifted speed signals are the position sensor signals (2) associated with one semi-AC supply voltage and the course of the other half-AC supply voltage offset by an angle, in particular delayed. Method according to one of Claims 5 to 7, characterized in that the AC switch (7) is switched on again after switching off the comparator circuit (12.1), depending on the time element (12.2) downstream of the comparator circuit (12.1). Method according to one of the preceding claims, characterized in that the switching-on of the AC voltage switch (7) is dependent on the trigger time member (Ts) and at least one delay circuit (10, 14) such that after the trigger time member (Ts) ) in the sense of phase cut-out control, at least one half-wave voltage is shifted against the signal of the position sensor (2) and the moment of switching on the AC switch (7) is delayed. Apparatus for carrying out the method according to one of claims 1 to 9, for operating a single-phase synchronous motor, in particular for operating a pump drive in a domestic appliance, the single-phase synchronous motor comprising a permanent magnet rotor, characterized in that the single-phase synchronous motor (1). ) is connected to the AC power supply (L1, L2) via the AC switch (7), the terminal (L1) of the AC power supply (L1, L2) being connected to the combination circuit (5) via the mains part (8), a mains voltage modulator (3) and an exciter (6), the terminal (L1) being connected directly to the mains voltage modulator (3), the mains voltage modulator (3) being coupled to the combining circuit (5) for coupling logic signals, which is subsequently connected to an exciter (6) for controlling the AC switch (7), and wherein A position sensor (2) for sensing the rotor position of a single-phase synchronous motor and a voltage sensor (11) for detecting a forward voltage on the switching path of the AC voltage switch (7) are connected to the circuit (5). Device according to claim 10, characterized in that the position sensor (2) is a Hall element, in particular with a digital output. Device according to one of claims 10 or 11, characterized in that the position sensor (2) is arranged in the air gap of the single-phase synchronous motor (1) in the region between two adjacent poles. Device according to one of Claims 10 to 12, characterized in that the AC voltage switch (7) is a semiconductor switch, in particular three.