JP5902781B1 - Permanent magnet synchronous motor drive device - Google Patents

Abstract

A permanent magnet synchronous motor drive device capable of accurately measuring an inductance value at a heavy load and / or detecting an open phase without rotating a rotor and suppressing a DC voltage fluctuation. A first energization period in which a switching element of one phase of an upper arm constituting a voltage source inverter and an element of at least one other phase of a lower arm are turned on before driving of the electric motor And the third energization period in which the element of the arm that is paired with the arm of the element that is in the on state during the same period is executed, and the element that is in the on state at least in the first and third energization periods. The second energization period in which the element on either one of the upper and lower arms is turned on is executed in all of the phases. In addition, after the execution of the third energization period, a fourth energization period in which the element on either the upper or lower arm is turned on in all phases having elements that are turned on in at least the first and third energization periods. Run to detect inductance values and / or phase loss. [Selection] Figure 1

Description

  Embodiments described herein relate generally to a sensorless drive permanent magnet synchronous motor drive device.

  2. Description of the Related Art A variable speed motor driving device that drives an electric motor at a variable speed using an inverter is applied to various fields. Among the electric motors, the permanent magnet synchronous motor has been widely adopted because it has a permanent magnet in the rotor and is more efficient than the induction motor. Further, position / speed sensorless control without using a speed sensor or position sensor is useful in terms of improving reliability and improving constraints on the installation environment.

  In a device that drives a permanent magnet synchronous motor without a position sensor, from the viewpoint of improving control performance and safety, an auto-tuning function that measures the inductance of the motor, and whether the wiring is not phased before driving the motor. The phase loss detection function to check may be implemented. If a current is passed through the motor when performing this function, the rotor may move due to the torque generated by the magnetic flux and current of the magnet. Therefore, using an alternating current that makes it difficult for the rotor to rotate, a method for measuring the inductance from the voltage value being applied and the amount of change in the current value at a predetermined time, or the current detection value is a current value for phase loss determination A method has been proposed in which the phase is determined to be missing when the phase is smaller.

  Specifically, voltage vectors (V1, V3, V5) in the positive direction and voltage vectors (V4, V6, V2) in the negative direction are applied in the direction of each phase (U, V, W) over a predetermined period. Means have been proposed (see Patent Documents 1 and 2). In addition, an inverter device in which the capacity of the smoothing capacitor is reduced has been proposed for the purpose of suppressing an increase in harmonic components in the power supply current, a deterioration in power factor, and an increase in effective value current and peak current (Patent Document). 3).

Japanese Patent No. 5431465 Japanese Patent No. 5314103 Japanese Patent No. 5,175,452

  Assuming a permanent magnet motor drive device that combines the above means, for example, if an alternating current with a large current amplitude is passed to measure the winding inductance value of the motor under heavy load, fluctuations in the DC voltage in the inverter device will occur. There is a possibility that the overvoltage protection function is activated and the inductance value cannot be measured.

  Therefore, even if the capacity of the smoothing capacitor is reduced, the permanent magnet synchronization can accurately measure the inductance value at heavy load and / or detect the open phase without rotating the rotor and suppressing the fluctuation of DC voltage An electric motor drive device is provided.

According to the permanent magnet synchronous motor driving apparatus of the embodiment, before starting the rotational drive of the permanent magnet synchronous motor, the inductance of the permanent magnet synchronous motor is calculated based on the change of the current detected by the current detecting means. Inductance calculation means and / or phase loss detection means for executing phase loss detection processing based on the magnitude of the current,
A first energization period in which the switching element of one phase of the upper arm constituting the voltage source inverter and the switching element of at least one other phase of the lower arm are turned on;
During the execution of the third energization period for turning on the switching element of the arm having the switching element that is turned on in the first energization period,
In all phases having switching elements that are turned on in at least the first energization period and the third energization period, a second energization period in which the switching element on either the upper arm or the lower arm is turned on is executed.

  In addition, after the execution of the third energization period, the switching element on either the upper arm or the lower arm is turned on in all phases having the switching elements that are turned on at least in the first energization period and the third energization period. The amount of change in each phase current can be determined by repeatedly executing the energization process of flowing an alternating current through the windings of the permanent magnet synchronous motor while sequentially changing the energized phases for all phases. The size is obtained, and inductance calculation and phase loss detection are performed, respectively.

Configuration diagram of the electric motor drive device according to the first embodiment Diagram showing voltage vector The figure which shows the relationship between a voltage vector and the on-off state of IGBT. Waveform diagram showing an energization sequence when the U phase is a detection phase in the prior art The figure which shows the electric current path corresponding to the area A-the area C shown in FIG. Voltage and current waveform diagram corresponding to the energization sequence shown in FIG. The wave form diagram which shows the electricity supply sequence at the time of making a U phase into a detection phase in 1st Embodiment The figure which shows the electric current path corresponding to the area A-the area C shown in FIG. In the energization sequence shown in FIG. 4, voltage and current waveform diagrams when the peak value of the U-phase current is gradually increased In the energization sequence shown in FIG. 7, voltage and current waveform diagrams when the peak value of the U-phase current is gradually increased Voltage and current waveform diagram corresponding to voltage vector output pattern 1 Voltage and current waveform diagram corresponding to voltage vector output pattern 2 Voltage and current waveform diagram corresponding to voltage vector output pattern 3 Voltage and current waveform diagram corresponding to voltage vector output pattern 4 Voltage and current waveform diagram corresponding to voltage vector output pattern 5 The figure which is 2nd Embodiment and shows typically the spatial distribution of the reciprocal number of an electric motor reactance Adjustment sequence flowchart Flowchart of processing A related to U phase energization sequence Flowchart of process B related to V phase energization sequence Flowchart of process C related to W phase energization sequence Waveform diagram of phase current during execution of adjustment sequence (1) Waveform diagram of phase current during execution of adjustment sequence (part 2) Waveform diagram of phase current during execution of adjustment sequence (part 3) Waveform diagram of phase current during execution of adjustment sequence (Part 4) The figure which is 3rd Embodiment and shows a current path at the time of switching a voltage vector using only the two-phase arm of an inverter

(First embodiment)
Hereinafter, a first embodiment will be described with reference to FIGS. FIG. 1 shows the configuration of an electric motor drive device that drives a permanent magnet synchronous motor. This electric motor drive device 1 drives the electric motor 2 without so-called sensorless without providing a sensor for detecting the magnetic pole position of the permanent magnet synchronous electric motor 2 (hereinafter referred to as the electric motor 2). In the electric motor 2, three-phase windings 2u, 2v, and 2w are wound around a stator 2s, and a rotor 2r is provided with a permanent magnet.

  The main circuit of the motor drive device 1 includes a converter 5, a smoothing capacitor 6, a voltage source inverter 7, current sensors 8, 9 and the like that rectify an AC voltage input from the commercial power supply PS and output the rectified voltage between the DC power supply lines 3, 4. It is configured. The voltage source inverter 7 includes a bridge circuit 12u including a pair of an upper arm 11up having an IGBT 10up and a lower arm 11un having an IGBT 10un, a bridge circuit 12v having a pair of an upper arm 11vp having an IGBT 10vp and a lower arm 11vn having an IGBT 10vn, and an IGBT 10wp. A three-phase bridge comprising a bridge circuit 12w comprising a pair of an upper arm 11wp having an IGBT and a lower arm 11wn having an IGBT 10wn is provided. These IGBTs 10 up to 10 wn (switching elements) are driven by a drive circuit 13. Although not shown in the drawing, free-wheeling diodes are respectively connected in reverse parallel to the IGBTs 10up to 10wn.

  Each phase winding terminal of the electric motor 2 as a load is connected to the output terminal of each bridge circuit 12u, 12v, 12w. Phase loss occurs due to unconnected or incomplete connection between the output terminal and the winding terminal. The current sensors 8 and 9 are current detection means composed of Hall elements and the like. The phase sensors Iu flowing from the output terminal of the bridge circuit 12u to the winding 2u and the phases flowing from the output terminal of the bridge circuit 12w to the winding 2w, respectively. The current Iw is detected.

  The control means 14 is mainly composed of a microcomputer having a CPU, RAM, ROM, EEPROM 15, input / output port, A / D converter 16, timer, PWM signal forming circuit, communication means, and the like. In the ROM, in addition to the hardware inspection program including IGBT 10up to 10wn, the auto tuning program for estimating the motor constant, etc., the rotational drive program for the motor 2 by vector control and V / F constant control, the phase loss is detected. The phase loss detection program is stored. The EEPROM 15 stores the value of time Δt used in the phase loss detection process described later, in addition to various parameters such as acceleration time, deceleration time, upper limit frequency, lower limit frequency, multistage speed operation frequency, and input / output terminal selection. .

  The control means 14 functions as an open phase detection means and an inductance calculation means. In FIG. 1, each block (excluding the EEPROM 15 and the A / D converter 16) in the control means 14 is executed by a microcomputer CPU according to a phase loss detection program and an auto tuning program stored in the ROM. And a processing function related to inductance calculation processing. Processing functions executed in accordance with other processing programs such as a rotation driving program are not shown. In addition, the electric motor driving device 1 includes an operation panel 17 having an operation key, a stop key, an up key, a down key, a mode key, an enter key, and the like, and a display unit 18 having a segment display, an LED, and the like. 19 is provided.

  The A / D converter 16 converts the signal voltage output from the current sensors 8 and 9 into U-phase and W-phase detection currents Iu and Iw, which are digital values. The voltage supply control means 20 causes the alternating current necessary for phase loss detection and auto-tuning to flow through the windings 2u, 2v, and 2w of the electric motor 2, so that the voltage source inverter 7 is controlled according to the detection phase that is the target of phase loss detection. A voltage vector to be output is determined, and an energization period corresponding to the voltage vector is provided. The phase loss detection process is performed for all three phases with the U phase, V phase, and W phase as detection phases in order. In parallel with phase loss detection, current information of each phase necessary for inductance calculation is also acquired.

  In order to select and output the voltage vector determined by the voltage supply control means 20, the voltage vector selection means 21 turns on the IGBT corresponding to the voltage vector among the IGBTs 10up to 10wn during each energization period.

  Based on the phase currents Iu and Iw detected by the current sensors 8 and 9, the comparison unit 22 obtains a detection current value for phase loss determination corresponding to the magnitude of the current flowing in the detection phase. When the V phase is set as the detection phase, the V phase current Iv is obtained by-(Iu + Iw). Then, the phase loss determination detection current value is compared with a preset phase loss determination reference current value. The phase loss determination means 23 determines a phase loss when the phase loss detection current value is smaller than the phase loss determination reference current value based on the comparison result. If it is determined that the phase is missing, the fact that the phase is missing is displayed on the display unit 18 of the operation panel 19.

  The detection current setting means 24 obtains the time Δt of the energization period for outputting the voltage vector and stores it in the EEPROM 15 which is a nonvolatile memory. The voltage supply control means 20 reads the time Δt from the EEPROM 15 and switches the voltage vector every time the energization period having the time Δt elapses.

  The auto-tuning execution means 25 corresponds to the above-described auto-tuning program, and performs a process of calculating inductance (motor constant). That is, the amount of change in each phase current is detected based on the phase currents Iu, Iv (similar to the current of the other two phases as in the comparison means 22) and Iw, and the inductance is calculated based on the amount of change. To do. Note that details of the phase loss determination processing by the phase loss determination means 23 are disclosed in Patent Document 2, and details of inductance calculation processing by the auto-tuning execution means 25 are disclosed in Patent Literature 1.

Next, the operation of this embodiment will be described. The control means 14 is set in advance, for example, every time the motor 2 is started for the first time after the power is supplied to the motor driving device 1 or when a request is received from a host system or every time the motor 2 is started. If the conditions are met, auto-tuning and phase loss detection processing are executed.
In this case, a hardware inspection program is executed first, then auto-tuning and phase loss detection processing are executed to set initial values, and then a rotation drive program is executed to start and accelerate the electric motor 2.

  Note that the auto-tuning and the phase loss detection process do not necessarily need to be executed independently of each other, and both processes may be performed in parallel. In these processes, a voltage is applied from the motor drive device 1 to the motor 2 by a predetermined energization process (energization sequence), and the flowing current is observed. As will be described later, since no torque is generated during these processes, it is not necessary to fix the rotor 2r with a brake or the like.

In the above energization sequence, in Patent Document 1 or 2, the energization time Δt [s] at which the current peak value matches the desired current level is determined in advance. Then, when detecting the U-phase current, for example, using the output voltage basic vectors V1 to V6 shown in FIG. 2 with the energization time Δt [s] as the output time unit, as shown in FIG. V4 → V4 → V1 (+ U → −U → −U → + U) are output in this order. This operation is similarly performed in the V and W phases (see Patent Document 1; FIG. 4, Patent Document 2; FIG. 5).
V-phase current detection: V3 → V6 → V6 → V3 (+ V → −V → −V → + V)
W-phase current detection: V5 → V2 → V2 → V5 (+ W → −W → −W → + W)
The current flowing in each phase with such an energization pattern does not cause the electric motor 2 to generate a rotational force in a certain direction, so that the rotation of the rotor 2r can be avoided.

  Here, when the polarity of the applied voltage is switched in order to give an alternating current, a current having a polarity opposite to the applied voltage flows temporarily, and the current is regenerated to the power supply side through each of the return diodes of IGBT 10up to 10wn. The As a result, when the capacity of the smoothing capacitor 6 is small, the DC voltage increases greatly.

  More specifically, in order to pass an alternating current as shown in FIG. 4 to the U phase, if the voltage vector is output in the order of V1 → V4 → V4 → V1 (+ U → −U → −U → + U), the first voltage vector In section A of V1, as shown in the path of FIG. 5A when voltage vector V1 (100) is output (section A), DC section current Idc flows with a positive polarity (Idc = Iu> 0). Therefore, the energy stored in the smoothing capacitor 6 in the DC part is transferred from the smoothing capacitor 6 to the electric motor 2, and the DC voltage Vdc drops.

  In the next step, section B in FIG. 4 where voltage vector V4 is applied, the polarity of current Iu remains positive immediately after the voltage vector is switched. The current path becomes Iu> 0 (section B) when the voltage vector V4 (011) is output in FIG. 5B, and the direct current portion Idc flows with negative polarity (Idc = −Iu <0). Since this path does not change while Iu is positive (during section B), the DC voltage Vdc rises.

  When the current value Iu falls below “0” and the polarity becomes negative, the current path becomes like Iu <0 (section C) when the voltage vector V4 (011) is output in FIG. At this time, since the direct current portion current Idc flows with a positive polarity (Idc = −Iu> 0), the direct current voltage Vdc drops.

  Next, in order to return the current level to “0”, a section D in which the voltage vector V1 is output again is provided. The current at this time remains negative immediately after the voltage vector is switched, and takes a current path indicated by Iu <0 (section D) when the voltage vector V4 (100) is output in FIG. Since the direct current portion current Idc flows in a negative polarity (Idc = Iu <0), during the section D, the direct current voltage Vdc rises.

  FIG. 6 shows a waveform example of each part when an alternating current is passed through the U phase. The DC voltage Vdc rises in the sections B and D in which the DC section current Idc has a negative polarity and is in a regenerative state, and the DC voltage decreases in the sections A and C in which the DC section current Idc has a positive polarity. Can be confirmed. The range of increase / decrease in the DC voltage Vdc is large when the smoothing capacitor 6 has a small capacity. In the figure, Vuref is the U-phase voltage command value (where 1.0 is the upper arm on, -1.0 is the lower arm on), and Vuv is the UV phase voltage.

  Further, when measuring the inductance by flowing a large current under heavy load, since the inductance is unknown at first, the applied voltage pulse width is initially reduced and gradually increased. Each voltage / current waveform in this case is shown in FIG. This figure is an example when connected to a three-phase 200V commercial power supply PS. As a sequence, alternating voltages are applied in order between U-VW, V-WU, and W-UV, A triangular wave current is passed through the phase. The current value is observed, and when the current value is smaller than the target current value, the pulse width is gradually increased and adjusted to match the target current value. As the current amplitude increases, the fluctuation of the DC voltage Vdc increases, and when the peak value exceeds the overvoltage limit value, the electric motor drive device 1 may be brought to an emergency stop for overvoltage protection.

  Here, the method of the present embodiment for avoiding the increase of the DC voltage Vdc will be described by taking the case of observing the U-phase current as an example. As shown in FIGS. 5B and 5D, it is necessary to prevent the negative current Idc, that is, the current in the direction of charging the DC power source, from flowing into the DC smoothing section via the freewheeling diode. Therefore, after increasing the current in the section A shown in FIG. 4, the voltage vector in the reverse direction is not immediately applied in the section B, and a zero vector (V0 or V7) in which no current flows once is output. Then, after the current value is sufficiently attenuated, a reverse voltage vector is applied.

  FIG. 7 shows a corresponding output voltage pattern. In the section A (first energization period), the current is increased, and in the section B (second energization period), the current is circulated inside the voltage source inverter 7 without passing through the DC smoothing section, thereby increasing the DC voltage. Without damaging the current. The reflux path is as shown in FIG. After the current is sufficiently attenuated, a negative current is supplied in section C (third energization period), and the current is attenuated again in section D (third energization period). The reflux path at this time is as shown in FIG. Since the amount of change in current and the peak value are measured in section A and section C, it is possible to measure (calculate) inductance or perform phase loss determination as in the conventional case.

  Similar to the conditions of FIG. 9, FIG. 10 shows changes in the DC voltage Vdc when the current value is gradually increased by the output voltage pattern shown in FIG. 7 when connected to the commercial power supply PS of three-phase 200 V. In the conventional system shown in FIG. 9, when the pulse width is increased so that the current peak value is about 40 A, the maximum value of the DC voltage Vdc increases to nearly 500V. On the other hand, in FIG. 10, no increase in the DC voltage Vdc is observed even when the current peak value is similarly increased to about 40A. Therefore, even if the smoothing capacitor 6 has a small capacity, the inductance value can be measured by flowing a large current.

As shown in FIG. 7, in order to attenuate the current in the section B and the section D by the return loop not via the DC power supply unit, it is conceivable to use the zero voltage vector V0 or V7 or both. Operation confirmation was performed for each of the following patterns (section A → section B → section C → section D).
<Pattern 1>
V1 → V0 → V4 → V7 (+ U → 0 → −U → 0)
V3 → V0 → V6 → V7 (+ V → 0 → −V → 0)
V5 → V0 → V2 → V7 (+ W → 0 → −W → 0)
<Pattern 2>
V1 → V0 → V4 → V0 (+ U → 0 → −U → 0)
V3 → V0 → V6 → V0 (+ V → 0 → −V → 0)
V5 → V0 → V2 → V0 (+ W → 0 → −W → 0)
<Pattern 3>
V1 → V7 → V4 → V7 (+ U → 0 → −U → 0)
V3 → V7 → V6 → V7 (+ V → 0 → −V → 0)
V5 → V7 → V2 → V7 (+ W → 0 → −W → 0)
<Pattern 4, SW switches V0 / V7 with PWM duty 50%>
V1 → SW → V4 → SW (+ U → 0 → −U → 0)
V3 → SW → V6 → SW (+ V → 0 → −V → 0)
V5 → SW → V2 → SW (+ W → 0 → −W → 0)
<Reference: Inappropriate when pattern 5, GB is executed as a gate block>
V1 → GB → V4 → GB (+ U → 0 → −U → 0)
V3 → GB → V6 → GB (+ V → 0 → −V → 0)
V5 → GB → V2 → GB (+ W → 0 → −W → 0)

  11 to 15 show the results of confirming the operation for the above five patterns. In each figure, (b) shows the time on the horizontal axis of (a) compressed. With respect to the reference pattern 5 shown in FIG. 15, since it can be in a regenerative state via the free wheeling diode during the gate block, an increase in the DC voltage Vdc is observed. Therefore, there is a possibility that the operation becomes difficult as in the conventional method. In the figure, Vvref is a V-phase voltage command value, Vwref is a W-phase voltage command value, and Vu_n is a U-phase potential with reference to the low potential side of the DC section.

  As described above, according to the present embodiment, the control unit 14 performs one phase of one of the upper arms constituting the voltage source inverter 7 when executing auto-tuning and phase loss detection processing for calculating the inductance of the electric motor 2. An IGBT having a pair of the first energizing period in which the IGBT of the other arm and the IGBT of the other at least one phase among the lower arms are turned on and the arm having the IGBT being turned on in the first energizing period are turned on. During the execution of the third energization period to be in the state, the IGBT on either the upper arm or the lower arm is turned on in all phases having the IGBT that is turned on in at least the first energization period and the third energization period. The second energization period for turning on is executed.

  In addition, after the execution of the third energization period, the IGBT on either the upper arm or the lower arm is turned on in all phases having IGBTs that are turned on at least in the first energization period and the third energization period. The amount of change or magnitude of each phase current is obtained by repeatedly executing the energization process in which the alternating current is passed through the windings of the electric motor 2 while changing the energized phase in order for all phases. , Inductance calculation, and phase loss detection. Specifically, any one of the patterns 1 to 4 described above is executed. As a result, even when the capacitance of the smoothing capacitor 6 is set to a small value, the current in the direction of charging the DC power supply is prevented from flowing into the DC smoothing section via the freewheeling diode, and the DC voltage Vdc is prevented from rising. Inductance calculation and phase loss detection can be performed.

  Further, the control means 14 gradually increases the time for outputting the voltage vector in the sections A and C so that the current peak value becomes a desired value, so that the current is excessively passed in the state where the inductance is unknown. Can be avoided.

(Second Embodiment)
FIGS. 16 to 24 show the second embodiment. The same parts as those in the first embodiment are denoted by the same reference numerals, description thereof is omitted, and different parts will be described below. FIG. 16 schematically shows a spatial distribution of the reciprocal 1 / (ωL) of the reactance of the electric motor 2. In a permanent magnet synchronous motor designed to actively use reluctance torque, the difference between the Q-axis inductance and the D-axis inductance is large, and the Q-axis inductance is larger than the D-axis inductance where the magnetic flux exists. Is common. Accordingly, the spatial distribution curve of the reciprocal of the reactance has the long axis in the D-axis direction.

  Intersection points 1 / Xu (= 1 / ωLu), 1 / Xv (= 1 / ωLv), 1 / Xw (= 1 / ωLw) and the origin O of each axis (U, V, W) in this distribution curve The distance is proportional to the reciprocal of the reactance in each phase. This distance changes according to the stop position of the rotor 2r. The longer the distance from the origin, the smaller the reactance, and the current reaches the specified current value Iamp in a shorter energization time. Therefore, when the electric motor 2 having saliency is used, if the lengths of the first and third energization periods are equal in each phase, the magnitude of the current is different for each phase.

  Thus, in the second embodiment, prior to the measurement of each phase current, the voltage supply control means 20 sets the time (positive or negative peak value) of each phase current to be equal to the specified current value Iamp. An adjustment sequence for adjusting Δtu, Δtv, Δtw is executed. FIG. 17 is a flowchart of the entire adjustment sequence, and FIGS. 18 to 20 show processing A, B, and C (energization sequence for each phase) for switching the voltage vector of each phase and detecting the positive and negative peak values of the phase current. It is a flowchart which shows. FIGS. 21 to 24 continuously show the waveforms of the phase currents Iu, Iv, and Iw during the adjustment sequence.

  The voltage supply control unit 20 repeatedly executes the above-described processes A to C sequentially. Since the inductance value at the start of the adjustment sequence is unknown, the short energization time Δt1 at which the peak current value is sufficiently small is set as the initial times Δtu, Δtv, Δtw. In the process A of step S1, the timer time t is initialized to 0 (step S21), and the output of the voltage vector V1 and the timer time t are added every control cycle Tc until the timer time t becomes Δtu or more (step S21). Steps S22 and S23). When the timer time t becomes equal to or greater than Δtu, the U-phase current Iu at that time is set to the peak current value Iu2 + (step S24).

  Next, the zero voltage vector V0 or V7 is output until the absolute value of the U-phase current Iu falls below the absolute value of the threshold value Iu_thre set near zero level (steps S25 and S26). When the timer time t is initialized again to 0 (step S27), the output of the voltage vector V4 and the timer time t are added every control cycle Tc until the timer time t becomes equal to or greater than Δtu (steps S28 and S29). . When the timer time t becomes equal to or greater than Δtu, the U-phase current Iu at that time is set to the peak current value Iu2- (step S30). Thereafter, processing similar to that in steps S25 and S26 is performed (steps S31 and S32). Finally, the timer time t is cleared to 0 and the process ends (step S33).

  In step S2, the voltage supply control means 20 determines whether or not at least one of the absolute values | Iu2 + | and | Iu2- | of the peak current value exceeds the specified current value Iamp (condition A). If it is determined that the value has been exceeded, 1 (adjustment completion) is set in FlagU (step S3). If it is determined that it does not exceed, FlagU is set to 0 (unadjusted), and the time Δtu is increased by the adjustment width Δtadj (step S4).

  Subsequently, the voltage supply control means 20 executes process B in step S5, and whether or not at least one of the absolute values | Iv2 + | and | Iv2- | of the peak current value exceeds the specified current value Iamp in step S6 ( Condition B) is determined. If it exceeds, FlagV is set to 1 (step S7), and if not exceeded, FlagV is set to 0 to increase the time Δtv by the adjustment width Δtadj (step S8).

  Further, the voltage supply control means 20 executes process C in step S9, and whether or not at least one of the absolute values | Iw2 + | and | Iw2- | of the peak current value exceeds the specified current value Iamp in step S10 (condition) C) is determined. If it exceeds, FlagW is set to 1 (step S11), and if not exceeded, FlagW is set to 0 to increase the time Δtw by the adjustment width Δtadj (step S12).

  In step S13, the voltage supply control unit 20 determines whether or not FlagU, FlagV, and FlagW are all 1 (adjustment complete) (condition D). Here, if it is determined that the adjustment of the time Δtu, Δtv, Δtw of any phase is incomplete (NO), the process proceeds to step S1 and the above-described processing is repeated. If it is determined that the adjustment of the times Δtu, Δtv, Δtw of all phases is completed (YES), the process proceeds to step S14, and the times Δtu, Δtv, Δtw are stored in the RAM. The voltage supply control means 20 executes the energization sequence using the energization times Δtu, Δtv, Δtw stored for each phase.

  As shown in FIGS. 21 to 24, the initial values of the times Δtu, Δtv, and Δtw are set to Δt1, Δtadj is added every time the energization sequence of each phase is completed, and the U-phase of the U-phase is increased in the energization sequence after increasing to Δt3. Since the peak current values | Iu2 + | and | Iu2- | exceed the specified current value Iamp, the time Δtu is fixed to Δt3. Thereafter, the energization sequence of each phase is executed while increasing the times Δtv and Δtw.

  Since the W-phase peak current values | Iw2 + | and | Iw2- | exceed the specified current value Iamp in the energization sequence after increasing to Δt5, the time Δtw is fixed to Δt5, and thereafter, only the time Δtv is increased. Execute the phase energization sequence. Since the V-phase peak current values | Iv2 + | and | Iv2- | exceed the specified current value Iamp in the energization sequence after increasing to Δt7, the time Δtv is fixed at Δt7 and the adjustment sequence is completed.

  As described above, according to the second embodiment, the voltage supply control unit 20 sets the time for outputting the voltage vector in the sections A and C so that the current peak value in each phase becomes a desired value. Adjust to different lengths for each phase. Thereby, for example, even if the electric motor 2 is an IPM (Interior Permanent Magnet) type in which the difference between the Q-axis inductance and the D-axis inductance is large, the peak value of each phase current can be adjusted to be equal. Therefore, it contributes to improvement of inductance calculation accuracy and prevention of erroneous detection of phase loss.

  Further, the voltage supply control means 20 maintains the time for outputting the zero voltage vector V0 or V7 in the sections B and D until the detected current value becomes smaller than the predetermined current value. Therefore, since the current value can be sufficiently lowered and then the section C or the section A of the next cycle can be shifted, it is possible to reliably prevent the regenerative current from flowing to the DC power source side.

(Third embodiment)
FIG. 25 shows a third embodiment. In the third embodiment, the voltage vectors in the sections A to D are switched using only the U-phase arm and the V-phase arm of the voltage source inverter 7. The W-phase arm is in a gate block state (GB) where both the upper and lower sides are off. In section A, a voltage vector (10 GB) is output as shown in FIG. At this time, the direct current portion current Idc flows in a positive polarity (Idc = Iu> 0). Therefore, the energy stored in the smoothing capacitor 6 in the DC part is transferred from the smoothing capacitor 6 to the electric motor 2, and the DC voltage Vdc drops.

  In the next section B, a voltage vector (00 GB) is output as shown in FIG. At this time, the direct current portion current Idc does not flow and becomes “0”, and the smoothing capacitor 6 is charged. In the next section C, a voltage vector (01 GB) is output as shown in FIG. At this time, since the direct current portion current Idc flows with a positive polarity (Idc = −Iu> 0), the direct current voltage Vdc drops. In the next section D, a voltage vector (11 GB) is output as shown in FIG. Also at this time, the direct current portion Idc does not flow and becomes “0”, and the smoothing capacitor 6 is not charged.

  As described above, according to the third embodiment, even when the voltage vectors in the sections A to D are switched using only the U-phase arm and the V-phase arm of the voltage source inverter 7, the DC voltage of the smoothing capacitor 6 is changed. An increase in Vdc can be suppressed.

(Other embodiments)
Only one of the auto tuning execution means 25 and the phase loss detection means 23 may be provided.
The third embodiment may be similarly implemented by replacing the V-phase and W-phase arms or the U-phase and W-phase arms.
Although several embodiments of the present invention have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

  In the drawings, 1 is a motor drive device (permanent magnet synchronous motor drive device), 2 is a permanent magnet synchronous motor, 2u, 2v and 2w are windings, 7 is a voltage source inverter, and 8 and 9 are current sensors (current detection means). 10up to 10wn are IGBTs (switching elements), 11up to 11wp are upper arms, 11un to 11wn are lower arms, 12u, 12v and 12w are bridge circuits, 14 is control means (phase loss detection means, inductance calculation means), 15 Is an EEPROM (memory), 20 is a voltage supply control means, 22 is a comparison means, 23 is an open phase determination means, and 25 is an inductance calculation means.

Claims (5)

A voltage-type inverter that includes a bridge circuit composed of a pair of an upper arm and a lower arm having a switching element for three phases, and supplies a voltage to the winding of each phase of the permanent magnet synchronous motor;
Current detecting means for detecting a phase current of the permanent magnet synchronous motor;
Before starting rotation of the permanent magnet synchronous motor, inductance calculation means for calculating the inductance of the permanent magnet synchronous motor based on a change in current detected by the current detection means, and / or the current A phase loss detection means for performing phase loss detection processing based on the size;
The inductance calculating means and / or the phase loss detecting means are
A first energization period for turning on a switching element of one phase of the upper arm and a switching element of at least one other phase of the lower arm;
During the execution of the third energization period for turning on the switching element of the arm having the switching element that is turned on in the first energization period,
A second energization period in which the switching element on either the upper arm or the lower arm is in the on state in all phases having the switching element in the on state in at least the first energization period and the third energization period. Run,
After the execution of the third energization period, in all phases having switching elements that are turned on at least in the first energization period and the third energization period, the switching element on either the upper arm or the lower arm is Execute the fourth energization period to turn on,
The amount of change or magnitude of each phase current is obtained by repeatedly executing the energization process of passing an alternating current through the windings of the permanent magnet synchronous motor while sequentially changing the energized phases for all phases, and calculating the inductance of each. A permanent magnet synchronous motor drive device characterized by performing phase loss detection. When the switching element of the upper arm of the bridge circuit is on, it is 1 when the switching element of the lower arm is on, and it is expressed by combining them in the order of (U phase V phase W phase), and the voltage source inverter outputs The possible voltage vectors are defined as V0 (000), V1 (100), V2 (110), V3 (010), V4 (011), V5 (001), V6 (101), V7 (111),
When the inductance calculation means and / or the phase loss detection means targets the U phase, the voltage vector is set in the first to fourth energization periods as the first energization period: V1 or V4.
Second energization period: V0 or V7
Third energization period: V1 or V4, the voltage vector that is not output in the first energization period. Fourth energization period : V0 or V7
In the order of
When the V phase is targeted, the voltage vector in the first to fourth energization periods is the first energization period: V3 or V6.
Second energization period: V0 or V7
Third energization period: V3 and V6, the voltage vector that is not output in the first energization period. Fourth energization period: V0 or V7
In the order of
When targeting the W phase, the voltage vector in the first to fourth energization periods is the first energization period: V5 or V2.
Second energization period: V0 or V7
Third energization period: voltage vector of V5 and V2 which is not output in the first energization period Fourth energization period: V0 or V7
The permanent magnet synchronous motor drive device according to claim 1, wherein the permanent magnet synchronous motor drive device outputs the same in order.
  The inductance calculating means and / or the phase loss detecting means gradually increase the time during which the voltage vector is output during the first and third energization periods so that the current peak value becomes a desired value. The permanent magnet synchronous motor drive device according to claim 2.   The inductance calculating means and / or the phase loss detecting means have a time for outputting a voltage vector in the first and third energization periods for each phase so that the current peak value in each phase becomes a desired value. The permanent magnet synchronous motor drive device according to claim 3, wherein the permanent magnet synchronous motor drive device is adjusted to a different length.   The inductance calculation means and / or the phase loss detection means maintain a time for outputting a voltage vector during the second and fourth energization periods until the detected current value becomes smaller than a predetermined current value. The permanent magnet synchronous motor drive device according to any one of claims 2 to 4, wherein the permanent magnet synchronous motor drive device is provided.

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