JP2008067600A - Drive system for drive electromotor system, air cooling apparatus, frozen air-conditioner system, and electromotor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem, wherein two detection systems that very much complicates the control with a microcomputer of very high performance and a large amount of memory necessary, because step out is conventionally detected to decide the step out, when the arithmetic value of the shaft displacement amount to the rotational speed command exceeds a reference value, further, to calculate the reactive power of the electromotor from its applied voltage and current detection value so as to provide a function of discriminating the presence of step out of the electromotor. <P>SOLUTION: Without the use of a position sensor for detecting a rotor position, when outputting the voltage vector, such that a d-axis current of excitation current component of a current flowing in the electromotor is a target value to drive an inverter, the d-axis current target value is periodically changed so as to detect the step out by a current response of a q-axis, at this time. By outputting a voltage vector that makes a three-phase short-circuit at the start time, brake torque is applied to a rotor during rotation, and decelerates it to fix the rotor position, when a current generated at this time reaches the demagnetization level of the motor, current carrying is stopped quickly. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drive device and a drive method for an electric motor drive device that drives without using a position sensor for detecting a rotor position of a rotor of an electric motor. Moreover, it is related with the air blower and refrigeration air conditioner which used it.

  Conventionally, in a motor drive system that drives a permanent magnet type synchronous motor without a speed / position sensor, a physical quantity that appears characteristic only at the time of step-out, that is, a correction amount to a rotational speed command that is used to stabilize motor control or A reference value is set for the calculated value of the axis error (axis deviation amount), and when these correction values or the axis error exceeds a preset reference value, a function is provided for determining a step-out, or an electric motor The reactive power of the motor is calculated from the applied voltage and the current detection value, and a function for determining whether or not the motor has stepped out based on the calculation result is provided. (For example, see Patent Document 1)

  Further, in a conventional fan drive device using a permanent magnet type synchronous motor, before starting the brushless motor, a detection means for detecting the rotation direction and the rotation speed of the brushless motor based on the output signal of the position detection means is detected. When the rotation speed before start-up is below a predetermined value and the rotation direction is reverse, energization is performed by matching the energization mode of the drive signal of the switching means with the combination mode of the detection signals from the position detection means, and the brushless motor Therefore, even if the wind direction at the time of start-up is reverse, it was stopped and started. (For example, see Patent Document 2)

  Further, in a drive device having a position detecting means based on a motor induced voltage of a blower using a conventional permanent magnet type synchronous motor, after starting the brushless motor, after short-circuiting the coil winding, It started after energizing a specific phase and positioning the rotor. (For example, see Patent Document 3)

JP 2003-79200 A (claim 2, column 0011) JP-A-9-89352 (Claim 1) JP-A-9-14184 (column 0015)

  The out-of-step detection in the conventional inverter device shown in Document 1 is the correction amount to the rotational speed command or the axis error (axis deviation) performed for stabilizing the motor control in order to perform reliable detection. A reference value is set for the calculated value, and when these correction values or axis errors exceed a preset reference value, a function is provided to determine step-out, and further from the applied voltage and current detection value of the motor. Since it is necessary to provide a function to calculate the reactive power of the motor and to determine whether or not the motor has stepped out based on the result of the calculation, two detection methods are required at the same time, and the control becomes very complicated. Needed a very high-performance microcomputer and a large amount of memory. Also, because the axis deviation is used to stabilize the motor control, the output voltage saturates, the target voltage and the output voltage do not match, and the axis deviation estimation formula does not hold in the high output region, resulting in poor operation. There was a problem that it was possible.

  In the field of ventilation fans that used induction motors in the past, it is effective to use a DC motor to meet the energy-saving demands of the market. Cost reduction is strongly required. Such a low-cost product has a problem that it cannot be stably controlled in an abnormal state.

  In the conventional inverter device start-up method shown in Document 2, position detection means is required at the time of start-up in the outside wind, and there are problems such as an increase in cost and size due to the addition of circuit components for the realization. It was.

  Also, in the field of ventilation fans that used induction motors in the past, it is effective in terms of investment to divert existing induction motor production equipment and produce DC motors in order to promote energy saving. . However, when a sensor is required, there is a problem that a new installation space is required in the motor, the housing size of the motor is changed, the existing production equipment cannot be used, and new production equipment investment is required. There was a problem that low-cost products required stable control even at startup.

  The conventional inverter device shown in Reference 3 improves the start-up performance during outside wind. However, since the induced voltage information is required, position detection means using the induced voltage is required during start-up during outside wind. There were problems such as cost and size increase due to the addition of circuit components for realization. Thus, there is a problem that depending on the load, stable control cannot be performed under special conditions such as at startup.

  Also, when operating using only the position detection means using this induced voltage during steady operation, it is necessary to stop the energization of the detection phase for position detection. Torque fluctuation due to the voltage fluctuation occurs. Therefore, there is also a problem that noise due to resonance is likely to be generated and silent performance is required, and that a countermeasure for resonance that requires cost and a long development evaluation period is required for a blower. Further, since the winding current is not monitored, there is a problem in that demagnetization of the motor occurs when a torque higher than normally assumed is applied to the motor due to an abnormal shutter for preventing backflow.

  The present invention solves the above-described problems. An electric motor capable of stable control without a speed / position sensor during special operation or steady operation that does not catch on overcurrent protection of an electric motor driven by an inverter. A driving device and a driving method are provided. Further, the present invention provides a blower and a refrigerating and air-conditioning apparatus with high energy saving performance by using such a motor drive device.

  The motor drive device of the present invention includes a current detection unit that detects a current flowing through the motor, a d-axis current that is an excitation current component, and a d-axis current that is a torque current component. A coordinate conversion means for converting to -q coordinate current, and a voltage vector such that the d-axis current as an excitation current component becomes a target value from the value of the dq coordinate current obtained by the coordinate conversion means to output an inverter A voltage vector generating means for driving and a current output signal for fixing the position of the rotor of the motor after supplying a signal for outputting a voltage vector for causing a short circuit of the inverter as a signal set value to be output to the inverter at the time of starting And a starting current setting means for generating a brake torque before a position fixing signal is generated to an inverter that drives an electric motor that operates without a speed / position sensor. It is intended to output a signal.

  The motor drive device of the present invention generates a short circuit between the current detection means for detecting the current flowing from the inverter that drives the motor that operates without the speed / position sensor, and the signal set value that is output to the inverter at start-up. First signal setting means for supplying a signal, and second signal setting means for generating a current output signal for fixing the position of the rotor of the electric motor after the signal from the first signal setting means, The signal from the first signal setting means is stopped when the current detected by the current detection means reaches a predetermined value that affects the motor.

  The motor driving method of the present invention includes a step of outputting a voltage vector signal from the voltage vector generating means so that the d-axis current as an exciting current component becomes a target value to the inverter, and the motor is driven by the inverter without a speed / position sensor. A step of driving and driving, and a step of applying a brake torque to the rotating rotor by outputting a voltage vector that generates a short circuit when the electric motor is started.

  The present invention provides a driving device and a driving method capable of realizing an operating state of an electric motor that is inexpensive and highly reliable. The present invention also enables stable control with a simple configuration. In addition, the present invention provides a blower or a refrigeration air conditioner with high reliability and high energy saving performance.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating the first embodiment, and is a diagram illustrating a configuration of an inverter device. In the figure, direct current from the direct current power supply unit 1 is converted into variable frequency alternating current by the inverter device 2 and supplied to the three-phase synchronous motor 6. In the switching element 3 forming the inverter of the inverter device 2, 3a is a U-phase upper switching element, 3b is a V-phase upper switching element, 3c is a W-phase upper switching element, 3d is a U-phase lower switching element, and 3e is a V-phase. Lower switching elements 3f are W-phase lower switching elements. The free-wheeling diodes 4 connected in parallel to each of the switching elements 3 are useful for the switching operation. An inverter main circuit 5 is formed from a switching diode 3 and a free wheel diode 4 connected in parallel to each of the switching elements 3.

  Next, the control device will be described. 7a is a current detection means for detecting one phase of the current flowing into the synchronous motor 6, 7b is a current detection means for detecting a current of a phase different from the current detection means 7a, and 8 is detected by the current detection means 7a and 7b. Inverter control means for controlling on / off of the switching element 3 in the inverter main circuit 5 based on the generated current.

  Reference numeral 9 denotes an electric motor control unit for controlling the driving of the synchronous motor 6 provided in the inverter control means 8. Reference numeral 10 denotes a phase current calculation for obtaining a three-phase current from two-phase currents detected by the current detection means 7a and 7b. Means 11 is a coordinate conversion means for converting the three-phase current obtained by the phase current calculation means 10 into a dq coordinate current, and 12 is synchronized based on the dq coordinate current obtained by the coordinate conversion means 11. Voltage command value calculation means for obtaining an output voltage command value in dq coordinates for driving the electric motor 6, and 13 is an output voltage based on the output voltage command value in dq coordinates obtained by the voltage command value calculation means 12. An output voltage vector calculation means 14 for obtaining a vector, and a PWM signal 14 for generating a PWM signal for on / off control of the switching element 3 based on an output voltage command value obtained in the inverter control means 8 Raw means 15 DC voltage detection means for detecting a DC voltage of the DC power supply unit 1, 17 is a target excitation current (Id *) generating means for generating a target excitation current command corresponding to the current frequency.

  Reference numeral 16 denotes a step-out detection means for detecting a step-out of the synchronous motor 6 provided in the inverter control means 8, and includes a frequency component extraction means 18, a current comparison means 19, and a frequency comparison means 20. Note that the synchronous motor described here is a DC brushless motor, and a motor driving apparatus having a highly reliable control content with a low-speed and simple configuration without a speed / position sensor will be described.

  The frequency component extraction means 18 extracts the F0 component of the torque current component (Iq) from the dq coordinate current obtained from the coordinate conversion means 11 and the modulation frequency F0 of the target excitation current command Id *. This is referred to as Iqω0. The current comparison means 19 compares the absolute value of the Iq current of the F0 frequency component obtained from 18 with the absolute value of the first predetermined value Ith serving as the reference current. The number comparison means 20 compares the number of times Si whose changing Iq current value is equal to or smaller than the first predetermined value and the second predetermined value NG-Level as a result of the current comparison, Judgment of step-out.

  The operation of the inverter device whose means is constituted by software in the microcomputer as described above will be described with reference to FIG. In the figure, the inverter device 2 detects currents for two phases among the phase currents flowing into the synchronous motor 6 by means of current detection means 7a, 7b. Using the detected two-phase currents, for example, the U-phase current Iu and the V-phase current Iv, the inverter control means 8 determines the voltage value and voltage phase output from the inverter main circuit 5 to drive the synchronous motor 6. An output voltage command value is obtained by calculation, and a PWM signal for on / off control of the switching element 3 in the inverter main circuit 5 is output.

  The motor control unit 9 in the inverter control means 8 processes the motor drive signal of the inverter device. Here, a PWM signal for driving the motor is output by the operation described below. The phase current calculation means 10 obtains the phase currents Iu, Iv, Iw for three phases from the phase currents Iu, Iv detected by the current detection means 7a, 7b, and the phase current Iu, Iv and Iw are converted into currents Id and Iq in dq coordinates. The target excitation current generating means 17 generates a target excitation current command value Id * corresponding to the current rotation frequency f. The voltage command value calculation means 12 calculates the output voltage command values Vd * and Vq * in the dq coordinates based on the currents Id, Iq and Id * in the dq coordinates and the rotation speed command value f *. That is, the current frequency f is determined by the voltage command value calculation means 12 so as to converge to the target frequency f * at a constant rate, for example, and sent to the Id * generation means 17. In the Id * generation means 17, f generated by the voltage command value calculation means 12 and the Id * generation means are preset in advance so as to be significantly lower than the operating frequency range of the motor so as to be set lower than the current frequency f. Based on the currents Id, Iq, Id * of the dq coordinates and the rotational speed command value f *, Id * is generated by the frequency F0 registered as fixed data in 17 microcomputers and sent to the voltage command value calculation means 12. The output voltage command values Vd * and Vq * in the dq coordinates are obtained by calculation.

  Here, the rotational speed command value f * is given from a host device of the inverter device, for example, a main microcomputer of the system in which the inverter device is mounted or another interface (man machine interface or the like). The output voltage vector calculating means 13 calculates the output voltage vector Vx * from the output voltage command values Vd * and Vq * of the dq coordinates. The PWM signal generator 14 obtains and outputs a PWM signal for on / off control of the switching element 3 from the DC voltage Vdc obtained from the DC voltage detector 15 and the output voltage vector Vx *.

  Based on the PWM signal output from the PWM signal generating means 14, the switching element 3 in the inverter main circuit 5 is turned on / off. Electric power is supplied from the inverter main circuit 5 to the synchronous motor 6 by the on / off operation of the switching element 3, and the synchronous motor 6 that is a brushless motor is driven.

  Next, an example of the step-out detection method according to the present invention will be described in detail with reference to FIGS. The waveform diagram shown in FIG. 2 shows an example of various waveforms when the synchronous motor 6 is normally synchronously operated. In FIG. 2, the waveform (a) is the phase angle (electrical angle phase) used in the inverter control means 8, and the waveform (b) is the target value Id * of the d-axis current obtained by the target excitation current generating means 17. The waveform (c) shows the q-axis current Iq of the dq coordinate current obtained by the coordinate conversion means 11, and the waveform (d) shows the state where the q-axis current Iq is compared with the reference current Ith by the current comparison means 17. Show. When the synchronous motor is operated synchronously, the q-axis current varies according to the variation period of the target value Id * of the d-axis current. The waveform Iqω0 including the frequency component periodically exceeds a preset reference current Ith. The comparison result signal Si, which is a result of comparison with the reference current Ith, has a periodic pulse shape indicated by the waveform (c). That is, the waveform (c) shows the comparison result signal Si which is a comparison result between the q-axis current Iq and the reference current Ith by the current comparison means 17.

  The waveform diagram shown in FIG. 3 shows an example of various waveforms when the synchronous motor 6 is out of step. In FIG. 3, the waveform (a) is the phase angle (electrical angle phase) used in the inverter control means 8, and the waveform (b) is the target value Id * of the d-axis current obtained by the target excitation current generating means 17. The waveform (c) shows the q-axis current Iq of the dq coordinate current obtained by the coordinate conversion means 11, and the waveform (d) shows the state where the q-axis current Iq is compared with the reference current Ith by the current comparison means 17. Show. When the synchronous motor is operated synchronously, the q-axis current varies according to the variation period of the target value Id * of the d-axis current. The waveform Iqω0 including the frequency component periodically exceeds a preset reference current Ith. However, at the time of step-out, the q-axis current is independent of the fluctuation period of the target value Id * of the d-axis current and does not exceed the reference current Ith. When the load is a fan, the waveform Iqω0 hardly changes like the waveform (d). When the load is a compressor, the number varies slightly, but varies at a frequency lower than the variation period of the target value Id *, so the number exceeding the reference current Ith decreases. The comparison result signal Si, which is the result of comparison with the reference current Ith, does not generate a periodic pulse as shown by the waveform (c). That is, the waveform (c) indicates that the comparison result signal Si, which is the comparison result between the q-axis current Iq and the reference current Ith, is not generated in the current comparison means 17.

  Here, the waveform diagrams shown in FIGS. 2 and 3 show waveforms in a motor having a four-pole rotor as an example of the surface magnet arrangement type synchronous motor 6.

  As shown in FIG. 2, when the synchronous motor is in synchronous operation, the q-axis current fluctuates according to the fluctuation period of the d-axis current Id *, and the F0 component IqF0 periodically exceeds Ith. For this reason, the comparison result signal Si, which is a result of comparison with the reference current Ith, becomes a periodic pulse according to the reference current Ith.

  As shown in FIG. 3, if the synchronous motor is in a step-out state, the q-axis current does not vary according to the variation period of the d-axis current Id *, and the F0 component IqF0 does not exceed Ith. For this reason, the comparison result signal Si that is the result of comparison with the reference current Ith is zero.

  As described above, the response of the q-axis current to the periodic fluctuation F0 of the target value Id * of the d-axis current in the dq coordinate current differs between the step-out time and the synchronization time, and the F0 component of the q-axis current and the reference A difference occurs in the number of crossings with the current Ith. Therefore, it is possible to detect step-out by detecting this difference.

  Specifically, the number of intersections Si between the q-axis current Iq and the reference current Ith within a predetermined time Tm is measured, and it is determined that the step-out is out only when the sum of Si is equal to or less than the number of step-out detection times NG_Level. To do.

  In an electric motor that drives a load such as a blower having a small fluctuation during one rotation, a fluctuation component (alternating current component) generated in a dq coordinate current during synchronous operation is large as shown in FIG. The fluctuation component (alternating current component) generated in the dq coordinate current is smaller than that at the time of synchronization. In the case of an electric motor that drives a load such as a blower with a small fluctuation during one rotation, the F0 component included in Iq in the dq coordinate current is detected, and is removed when the magnitude of the AC component is smaller than a predetermined value. By adjusting the key, step-out detection may be performed.

  In addition, in an electric motor that drives a load such as a compressor having a large variation during one rotation, a large variation occurs in the dq coordinate current even during synchronous operation. In this case, the S / N ratio can be increased by selecting a preset fluctuation cycle F0 of Id * different from the load fluctuation cycle, and even in the case of an electric motor that drives a large load, step-out can be detected with high accuracy. it can.

  Here, a phenomenon in which a difference appears in the q-axis current Iq at the time of synchronization and step-out according to the fluctuation of the d-axis current Id * as shown in FIGS. 2 to 3 will be described below with reference to FIGS.

  FIG. 5 shows the relationship between the rotor of the permanent magnet type synchronous motor and the coordinates on the inverter control means 8. In FIG. 5, the N pole side on the rotor is generally d-axis, and the phase advanced 90 degrees in the rotation direction is generally q-axis.

  When the position sensor for detecting the position of the rotor is not used for driving the synchronous motor, the inverter control means 8 cannot accurately capture the dq axis of the rotor. The γ-δ axis is defined as the −q axis. In addition, the phase angle is defined as the electrical angle phase θe with respect to the angle defined as the γ-δ axis of the inverter control means viewed from the U phase of the three-phase fixed coordinates.

  Here, as the synchronous motor, a non-salient pole type motor having substantially the same value of the d-axis and q-axis inductances as in the surface magnet arrangement type synchronous motor will be described. In the synchronous operation state, the motor rotor and the output voltage phase of the inverter are synchronized. For this reason, the relationship between the rotor phase (dq axis) and the inverter output voltage phase (γ-δ axis) maintains a constant phase difference Δθ, that is, the inverter output voltage phase γ-δ axis as a reference. In this case, as shown in FIG. 4, the inductances Lγ and Lδ viewed from the γ-δ axis are equal, and the d-axis current Id (Iγ) and the q-axis current Iq (Iδ) are substantially DC.

  However, when the target d-axis current command Id * is periodically changed, the electrical angle phase θe and the electrical angle phase difference Δθ vary according to the variation period of Id *. This is a state in which periodic unevenness has occurred in the rotor. Since the rotor and the load have inertia against this rotation unevenness, the q-axis current Iq (Iδ) that generates the rotation torque fluctuates. That is, the d-axis current fluctuates with time, and uneven rotation occurs according to the fluctuation. For this reason, since the output voltage phase γ-δ axis and the rotor phase dq axis of the inverter change during one rotation, the q-axis current Iq (Iδ), which is a non-control amount, changes.

  On the other hand, in the step-out state, since the rotor is stopped and no induced voltage is generated, the target d-axis current command Id * does not generate uneven rotation according to the fluctuation, and the q-axis current Iq (Iδ) which is the torque current is not generated. No fluctuations according to rotation unevenness.

  In this way, by changing the d-axis current command Id * of the dq coordinate current Id during one rotation of the rotor and detecting the number of fluctuations of Iq, the operating state of the rotor can be grasped. The step-out of the electric motor can be detected.

  A flow of step-out detection according to the present invention will be described with reference to FIG. In FIG. 5, STP 101 is a step-out detection start step for starting out-of-step detection processing, and STP 102 is a phase current detection step for detecting current flowing into the synchronous motor 6, which is performed by the phase current detection means 7a and 7b in FIG. Corresponds to the action. STP 103 is a phase current calculation step for calculating phase currents for three phases, and corresponds to an operation performed by the phase current calculation means 10 in FIG. STP 104 is a coordinate conversion step for converting a three-phase current into a dq coordinate current, and corresponds to an operation performed by the coordinate conversion means 11 in FIG.

  STEP 105 is a step of extracting the F0 frequency component from the q-axis current after the coordinate conversion, and corresponds to the frequency component extraction operation performed at 18 in FIG. STP 106 is a current comparison step of comparing the dq coordinate current with a reference current that is a first predetermined value and outputting a comparison result output signal, and corresponds to the operation performed by the current comparison means 19 of FIG.

  The STP 107 calculates the number of step-out detections Nerr that is a predetermined value per unit time and the number of intersections between the dq coordinate current and the reference current Ith that is the first predetermined value from the comparison result signal obtained in the current comparison step STP106. Is a comparison step for detecting the presence or absence of occurrence of step-out and corresponds to the processing in the number comparison means 20 of FIG.

  STP 108 is a PWM output stop step for stopping PWM output when the result of the step of comparing the number of coincidence is step out, and STP 109 is a stop step for stopping the inverter as a step out abnormality.

  The flow of step-out detection is as follows. In the step-out detection start step of STP 101, step-out detection processing is started together with the drive control of the electric motor. Step-out detection processing after STP102 is executed. In the phase current detection step of STP 102, current detection means 7a and 7b detect at least two phases of current flowing into synchronous motor 6, for example, U-phase current Iu and V-phase current Iv. In the phase current calculation step of STP103, phase currents Iu, Iv, Iw for three phases are calculated by the phase current calculation means 10 from the phase currents Iu, Iv obtained in the phase current detection step STP2. In the coordinate conversion step of the STP 104, the three-phase currents Iu, Iv, Iw obtained in the phase current calculation step STP104 are converted into dq coordinate currents Id, Iq by the coordinate conversion means 11. Here, the phase current calculation step STP103 can be omitted, for example, by directly calculating the dq-axis current from the two-phase current, and it is also possible to proceed from the current detection step STP102 to the coordinate conversion step STP104.

  In the current comparison step of STP 106, the current comparison means 19 compares the F0 frequency component of the dq coordinate current Iq obtained in the coordinate conversion step STP105 with a reference current Ith which is a predetermined value to obtain a comparison result signal Si. Specifically, in the current comparison determination step of the STP 106a, for example, the q-axis current IqF0 of the dq coordinate current is compared with the reference current Ith based on the first predetermined value. If | IqF0 |> Ith, the process proceeds to STP6b. Otherwise, the process proceeds to STP6c. In the comparison result signal output step 1 of the STP 6b, the comparison result signal Si is output as Si = 1, and in the comparison result signal output step 2 of the STP 6c, the comparison result signal Si is output as Si = 0.

  In the number comparison step of STP 107, the comparison means 20 compares the number of changes per unit time of the comparison result signal Si obtained in the current comparison step STP 106 with the predetermined number of step-out detection times NG_Level to determine whether the step is out of sync. Judging. Specifically, when the comparison result signal Si obtained at the current comparison step STP106 at the coincidence number comparison determination step STP107a is compared with the step-out detection number NG_Level which is a predetermined value of the number of changes per unit time, Si <= NG_Level. Step S8 is determined. In other cases, the process returns to the phase current detection step of STP2.

  In the PWM stop step of STP 108, in order to stop the voltage output of the inverter when the step-out is detected in the number comparison step STP107, the PWM signal output of the PWM signal generating means 14 is stopped.

  In the inverter stop step of STP 109, the operation of the inverter control means 8 is also stopped, and the operation of the inverter device is stopped by generating an abnormal display, an abnormal state notification sound, or the like.

  Also, by applying the synchronous motor step-out detection method according to the present invention to an inverter device, a highly reliable and inexpensive inverter device capable of detecting step-out with high accuracy can be realized. When used in a fan that performs ventilation without using a position sensor that detects the position of the rotor to drive such an inverter-driven synchronous motor, the inverter can change the number of revolutions and perform energy-saving operation and be stable. And reliable operation can be performed at low cost. Many fans, such as indoor ventilation fans for buildings, building ventilation fans, factory fans, etc., can use this system to significantly reduce electric power, which is also useful for protecting the global environment.

  Also, in the refrigeration air conditioner, if the blower motor continues to step out, the capacity of the refrigeration air conditioner, for example, the cooling capacity of the refrigerator will decrease and the food in the refrigerator will not cool, or the air conditioner will not be cooled will not be obtained. In addition, an overload in a state where the overcurrent detection function is not caught by a compressor, an electric motor, a refrigerant pipe, an inverter circuit, or the like may continue to cause damage to each device or part. By applying the synchronous motor step-out detection method according to the present invention to the fan drive inverter of the refrigeration air conditioner, it becomes possible to detect the step out of the fan with high accuracy and suppress the adverse effects on the refrigeration air conditioner as described above. It becomes possible to do. This can improve the reliability of the refrigeration air conditioner.

  As described above, in the present invention, the example of the surface magnet type synchronous motor (SPMSM) is shown as the synchronous motor. Any motor such as a synchronous reluctance motor (SyRM) or a switched reluctance motor (SRM) can detect step-out with the same configuration.

  FIG. 6 is a flowchart showing the control flow of the present invention, and is a flowchart for starting up the inverter device. In the figure, STEP1 is a brake output process, STEP2 is a rotor position fixing process, STEP3 is a starting voltage output process, and STEP4 is a normal control process.

  Next, the starting method of the synchronous motor of the present invention will be described. The configuration of the inverter device is the same as that shown in FIG. First, in STEP 1 of FIG. 6, the lower IGBTs 3a, 3e, and 3f are simultaneously turned on by the PWM output means of FIG. At this time, when the motor is rotated by an external wind or the like, a short circuit current is generated in the motor, the brake mode is set, and the rotational speed of the rotor is reduced.

  Next, in STEP 2, the upper and lower IGBTs 3a and 3f are turned on by the PWM output means of FIG. 1 to excite the stationary phase, and the rotor whose rotational speed is reduced and the inertia energy is reduced is fixed at a specific position. Next, in STEP 3, a rotating magnetic field is generated in a target rotation direction from a position where the maximum torque is generated with respect to the fixed position, acceleration is performed, and rotation of the rotor is increased. Next, in STEP 4, the normal control shown in the present invention is performed when the predetermined number of rotations is exceeded.

  The present invention will be described in more detail with reference to FIG. FIG. 7 is a detailed flowchart of STEP 1 in FIG. As shown in FIG. 7, after the brake is output in STEP 10, the current flowing through the motor is monitored as shown in STEP 11, and if it is smaller than the demagnetizing current, the brake time is judged to end as shown in STEP 12. Perform brake output for a specified time, and proceed to the next step.

  In FIG. 7, when a current increase occurs during braking and a demagnetizing current is likely to be reached with respect to the permanent magnet of the motor, the process proceeds to STEP 13 to stop the brake output and prevent the generation of the demagnetizing current. There is a problem that the generated voltage of the magnet is lowered when the current flowing through the phase winding of the motor becomes large and induces a coercive force higher than that of the permanent magnet. Further, in STEP 14, the startup abnormality information is recorded in a nonvolatile memory. In STEP 15, the user is notified of the start-up abnormality. If a single LED for displaying product operation blinks, or if a display device such as an 8-segment LED or liquid crystal is provided, it may be used for visual notification. Moreover, you may alert | report alert | report by a buzzer. After that, as shown in STEP16, it waits until a restart command is issued.

  When this embodiment is applied to a blower such as a ventilation fan, the start-up abnormality is an abnormality in the backflow prevention shutter of the blower, which can be notified to the user or serviceman, and the shutter is attached during construction. It is possible to detect a shutter failure due to a defect or a foreign object.

  Further, by recording the abnormality information, it becomes possible for the service person to check the situation such as the number of times of abnormality after a lapse of time, and it becomes easy to determine the cause of the abnormality.

  The present invention will be described in more detail with reference to FIG. FIG. 8 is a detailed flowchart of STEP2 in FIG. As shown in FIG. 8, after the rotor position is fixed and output in STEP 20, the current flowing through the motor is monitored as shown in STEP 21, and when the current is smaller than the demagnetizing current, the rotor position fixing time is shown in STEP 22. Performs end determination, outputs a fixed rotor position for a specified time, and proceeds to STEP3, which is the next step.

  In FIG. 8, when the current increase occurs while the rotor position is fixed and the motor demagnetizing current is likely to be reached, the process proceeds to STEP 23 to stop the rotor position fixing output and prevent the generation of the demagnetizing current. Further, in STEP 24, the abnormality information of the start is recorded in the nonvolatile memory. In STEP 25, the user is notified of the startup abnormality. If a single LED for displaying product operation blinks, or if a display device such as an 8-segment LED or liquid crystal is provided, it may be used for visual notification. Moreover, you may alert | report alert | report by a buzzer. After that, as shown in STEP26, it waits until a restart command is issued.

  When the configuration of the present invention is applied to a blower such as a ventilating fan, the start-up abnormality is an abnormality in the backflow prevention shutter of the blower, which can be notified to the user or serviceman, and the shutter is attached during construction It is possible to detect a shutter failure due to a defect or a foreign object. Further, by recording the abnormality information, it becomes possible for the service person to check the situation such as the number of times of abnormality after a lapse of time, and it becomes easy to determine the cause of the abnormality.

  The control method shown in the present invention is capable of operation in a high output region in which the target voltage and the output voltage do not coincide with each other without using the axis deviation amount for stabilizing the motor control by adopting the starting method as described above. When starting in the case of outside wind, which was a problem in products that use the sensor, there is no need to add a rotor magnetic pole position detection sensor in the motor, and by reducing the energy of inertia caused by the outside wind and fixing the position, Torque can be generated in the direction and reliable start-up can be performed. In addition, even when a torque higher than normally assumed in a state such as an abnormal shutter for preventing backflow is applied to the motor, it is possible to prevent the demagnetization of the motor and to ensure the occurrence of the abnormality to the user or service person. Can be notified. In addition, the starting system demonstrated in FIG.6, FIG.7, FIG.8 of this invention is applicable also to various uses other than a ventilation fan, and the effect that a reliable starting is obtained is acquired.

  The synchronous motor step-out detection method according to the present invention uses a current detection means for detecting a current flowing through the synchronous motor without using a position sensor for detecting the rotor position, and a current obtained by the current detection means. Based on the d-axis current that is the excitation current component, the coordinate conversion means for converting the d-q coordinate current of the q-axis current that is the torque current component, and the value of the dq coordinate current obtained by the coordinate conversion means, the excitation current In an inverter apparatus for driving a synchronous motor having a voltage vector generating means for outputting a voltage vector that makes the component d-axis current a target value and driving the inverter, the d-axis current target value is periodically varied, The step-out is detected by the current response of the q-axis.

  Further, the synchronous motor step-out detection method according to the present invention includes an extraction means for extracting a fluctuation period component of the d-axis current target value in the q-axis current obtained from the current detection means, and the q obtained above. Comparing means for comparing the fluctuation period component of the shaft current with a predetermined value of the period is provided, and the number of times comparing means for detecting the step-out by comparing the number of times when it becomes equal to or less than the predetermined value is provided.

  Further, the synchronous motor starter according to the present invention includes a current detection means for detecting a current flowing through the synchronous motor without using a position sensor for detecting the rotor position, and a current obtained by the current detection means. Based on the d-axis current that is the excitation current component, the coordinate conversion means for converting the d-q coordinate current of the q-axis current that is the torque current component, and the value of the dq coordinate current obtained by the coordinate conversion means, the excitation current Output a voltage vector that causes a three-phase short circuit at start-up in an inverter device that drives a synchronous motor having a voltage vector generation means that outputs a voltage vector whose component d-axis current becomes a target value and drives the inverter Then, a brake torque is applied to the rotating rotor to decelerate, and then the voltage is output to fix the position of the rotor to start. Further, when the current generated at the start reaches the demagnetization level of the motor, the energization is immediately stopped. In addition, a stop history is recorded at the time of stop. In addition, when stopping, it is notified that it has stopped. If this activation device is used for a blower, it is possible to safely and reliably start even a blower device in which a decrease in reverse rotation occurs. Whether the blower is used alone as a ventilation fan such as indoor ventilation, an outdoor fan used in an outdoor unit of a separate air conditioner, or a large blower used in a factory or tunnel As described above, the highly efficient activation is performed.

It is a block diagram of the inverter apparatus of the synchronous motor which shows Embodiment 1 of this invention. It is a figure explaining the various waveforms at the time of the synchronous operation which shows Embodiment 1 of this invention. It is a figure explaining the various waveforms at the time of a step-out which shows Embodiment 1 of this invention. It is a figure which shows the relationship of the electrical angle phase used by the rotor of an electric motor and inverter control means which show Embodiment 1 of this invention, and a coordinate. It is a flowchart of the step-out detection process which shows Embodiment 1 of this invention. It is a flowchart of the starting process which shows Embodiment 1 of this invention. It is a flowchart of starting process STEP1 which shows Embodiment 1 of this invention. It is a flowchart of starting process STEP2 which shows Embodiment 1 of this invention.

Explanation of symbols

  1 DC power supply unit, 2 inverter device, 3 switching element, 3a U-phase upper switching element, 3b V-phase upper switching element, 3c W-phase upper switching element, 3d U-phase lower switching element, 3e V-phase lower switching element, 3f W-phase lower switching element, 4 freewheeling diode, 5 inverter main circuit, 6 embedded magnet type synchronous motor, 7a, 7b current detection means, 8 inverter control means, 9 motor drive means, 10 phase current calculation means, 11 coordinates Coordinate conversion means, 12 voltage command value calculation means, 13 output voltage vector calculation means, 14 PWM signal generation means, 15 DC voltage detection means, 16 step-out detection means, 17 Id * generation means, 18 current comparison means, 20 number comparison Means, 21 reference current calculation means, 22 noise elimination means, 30 overcurrent detection Stage.

Claims (6)

Current detection means for detecting the current flowing through the motor, and coordinate conversion for converting the current obtained by the current detection means into a d-q coordinate current of a d-axis current that is an excitation current component and a q-axis current that is a torque current component And a voltage vector generating means for driving the inverter by outputting a voltage vector from which the d-axis current as an exciting current component becomes a target value from the value of the dq coordinate current obtained by the coordinate conversion means, A current setting signal for generating a current output signal for fixing the position of the rotor of the motor after supplying a signal for outputting a voltage vector for generating a short circuit in the inverter as a signal set value to be output to the inverter at the time And a signal for generating a brake torque before the position fixing signal is output to the inverter that drives an electric motor that operates without a speed / position sensor. Motor driving device, characterized in that. A current detecting means for detecting a current flowing to the motor from an inverter that drives an electric motor that operates without a speed / position sensor, and a first signal that supplies a signal for generating a short circuit for the signal set value to be output to the inverter at start-up Signal setting means, and second signal setting means for generating a current output signal for fixing the position of the rotor of the electric motor after the signal from the first signal setting means, The motor drive device according to claim 1, wherein the signal from the signal setting means is stopped when the current detected by the current detection means reaches a predetermined value that affects the motor. An air blower characterized in that the motor driving device according to claim 1 or 2 is controlled and operates without a speed / position sensor. A refrigerating and air-conditioning apparatus characterized in that a load driven by the electric motor controlled by the electric motor driving apparatus according to claim 1 and operated without a speed / position sensor is a blower or a compressor. A step of outputting a voltage vector signal from the voltage vector generating means so that the d-axis current as an exciting current component becomes a target value to the inverter; a step of driving and driving the motor without a speed / position sensor with the inverter; Applying a braking torque to a rotating rotor by outputting a voltage vector that causes a short circuit when the motor is started, and a method for driving the motor. 6. The method of driving an electric motor according to claim 5, wherein the operation of applying the brake torque includes a step of stopping when the current flowing through the electric motor reaches a predetermined value.

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