Motor drive device, outdoor unit of air conditioner using the same, and motor drive control method

Abstract

Provided are a motor drive device and an outdoor unit of an air conditioner using the same, and a motor drive control method. The motor drive device comprises: a power conversion circuit that supplies power to a motor; a control unit that controls the power conversion circuit; and a current sensor that detects a three-phase current that energizes the motor, wherein the control unit comprises: a command voltage calculation unit that calculates a command voltage that contributes to the drive of the motor; a pulsating current detection unit that generates a first component and a second component based on components obtained by separating the three-phase detection current into mutually orthogonal components; a torque pulsation compensation unit that outputs a first compensation command voltage that compensates for torque pulsation caused by the structure of the motor based on the first component; and a failure time compensation unit that outputs a second compensation command voltage that compensates for output voltage distortion caused by failure time of the power conversion circuit based on the second component, wherein the torque pulsation and output voltage distortion are reduced by correcting the command voltage using the first compensation command voltage and the second compensation command voltage.

Description

Technical Field

[0001] The present invention relates to a motor drive device for driving a motor (electric motor) and control thereof, and in particular, to a technology effectively applicable to drive control of a motor (electric motor) used in applications requiring quietness. Background Art

[0002] The induced voltage of a permanent magnet synchronous motor ideally contains only the fundamental component, but in reality, there are spatial harmonic components such as the fifth and seventh components on the three-phase stationary coordinates. The distortion component of the induced voltage becomes a cause of pulsation of the motor torque, and the fluctuating torque becomes an excitation source of mechanical resonance, thereby generating noise and vibration.

[0003] For example, by installing vibration-proof rubber on the motor fixing part and the rotating bearing part, the noise and vibration caused by mechanical resonance can be reduced. However, in this method, the problem is that the structure becomes complicated and the cost increases with the increase in the number of parts.

[0004] Therefore, development of a technology for suppressing torque ripple, which is an excitation source of mechanical resonance, by a control method of a permanent magnet synchronous motor without using a component such as a vibration-proof rubber (hereinafter referred to as torque ripple suppression control) has been promoted.

[0005] When suppressing torque pulsation through control, it is necessary to know in advance what degree of distortion component of the induced voltage is included when generating control instructions. As a means, a method of measuring the motor characteristics including the induced voltage waveform in advance is considered, but it is not easy to measure individually for unspecified motors. In addition, it is difficult to measure the motor characteristics of existing products.

[0006] As background technology in this technical field, there is a technology such as Patent Document 1. Patent Document 1 discloses "a drive control device for a synchronous motor, characterized in that it comprises: a current control unit that obtains the stator current as a vector signal on a dq synchronous coordinate system of two orthogonal axes with the rotor N-pole phase as the d-axis phase, and controls in a manner of tracking the final current command value; a compensation signal generation unit that generates a compensation signal for compensating an initial torque command value or an initial current command value; and a final current command value generation unit that uses the generated compensation signal to compensate the initial torque command value or the initial current command value to generate a final current command value, wherein the compensation signal generation unit is constructed in a manner of extracting a part or all of the higher harmonic components contained in the induced voltage in real time, and generating the compensation signal using at least the higher harmonic components of the induced voltage extracted in real time, the stator current equivalent value, and the rotor speed equivalent value".

[0007] By estimating desired parameters on-line from control commands and sensor information in the motor drive device as in Patent Document 1, high versatility can be achieved even for applications such as fans and pumps equipped with unspecified motors.

[0008] In addition, Patent Document 2 discloses "a power conversion device that uses a current value supplied from a power conversion unit to a load when a switching element performs a connection and disconnection action according to a switching instruction based on a length instruction of a failure time, or a voltage instruction value used to generate a switching instruction, to calculate a compensation amount for the voltage instruction value, wherein the length instruction of the failure time determines the length of the failure time as a protection period for causing the switching element to be in an off state."

[0009] In addition, Patent Document 3 discloses "a motor drive device comprising: a power conversion circuit for driving a permanent magnet motor; and a control unit for controlling the power conversion circuit, the control unit including a voltage command generating unit and a torque pulsation compensation unit, the torque pulsation compensation unit including an amplitude generating unit, a correction voltage generating unit and an adding unit, the voltage command generating unit outputs a voltage command, the amplitude generating unit outputs a correction voltage amplitude, the correction voltage generating unit outputs a correction voltage command based on the correction voltage amplitude and the rotor position, the adding unit outputs a corrected voltage command based on the voltage command and the correction voltage command, and the power conversion circuit is operated according to the corrected voltage command."

[0010] Prior art literature

[0011] Patent Document 1: Japanese Patent Application Publication No. 2012-100510

[0012] Patent Document 2: Japanese Patent Application Publication No. 2018-182901

[0013] Patent Document 3: Japanese Patent Application Publication No. 2017-229126 Summary of the invention

[0014] However, as described above, the distortion components of the induced voltage in the permanent magnet synchronous motor include 5th and 7th order components on the three-phase stationary coordinates. These order components appear as 6th order components on the two-axis orthogonal coordinates (hereinafter referred to as dq coordinates) synchronized with the electrical rotation of the motor. Therefore, by constructing an observer (Observer) as disclosed in the above-mentioned patent document 1 on the dq coordinates, the distortion components of the induced voltage equivalent to the disturbance can be estimated based on the 6th order components included in the control instructions and sensor information.

[0015] However, when a sixth-order component is included in a control command or sensor information due to multiple factors, the method disclosed in Patent Document 1 does not distinguish the influence of each factor, so there is a problem that the distortion component of the induced voltage cannot be estimated with high accuracy.

[0016] As another factor that contains the sixth-order component in the control command and sensor information, there is an output voltage error caused by the inverter. The inverter supplies power to the motor by operating the switching element, and in order to prevent a short circuit between the upper and lower branches, a period (hereinafter also referred to as dead time) during which the switching elements are simultaneously disconnected is set. As a result, the output voltage of the inverter deviates from the command voltage, and a sixth-order interference voltage is generated on the dq coordinate.

[0017] Based on the above, when implementing torque pulsation suppression control when the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter exist at the same time, the following measures need to be taken: distinguish these influences from the control instructions and sensor information, and individually infer the related parameters and compensate them.

[0018] Patent Document 2 discloses an effective means of separating the above two effects from the detection current. In this method, the length of the dead time, which is usually set to be constant, is changed in a cycle other than six times, thereby avoiding interference with the distortion component of the induced voltage that changes in a six-time cycle.

[0019] In Patent Document 2, the output voltage distortion caused by the inverter is compensated, but it is considered that more effective torque pulsation suppression control can be achieved by combining the existing means for compensating the induced voltage distortion caused by the motor. However, when the length of the dead time is changed, it is necessary to make the lower end value of the setting with a width not less than the disconnection period required to prevent the short circuit between the upper and lower branches, which makes the control design complicated.

[0020] In addition, when using an inexpensive drive device for fans and pumps, it is sometimes difficult to periodically change the dead time as in Patent Document 2.

[0021] Therefore, an object of the present invention is to provide a motor drive device that can effectively suppress torque pulsation caused by induced voltage distortion caused by a motor and output voltage distortion caused by an inverter, and an outdoor unit and motor drive control method of an air conditioner using the same.

[0022] In order to solve the above-mentioned problems, the present invention is characterized in that it comprises: a power conversion circuit for supplying power to a motor; a control unit for controlling the power conversion circuit; and a current sensor for detecting a three-phase current supplied to the motor, wherein the control unit comprises: a command voltage calculation unit for calculating a command voltage contributing to the driving of the motor; a pulsating current detection unit for generating a first component and a second component obtained by extracting a pulsation amount of each component based on each component obtained by separating the three-phase detection current detected by the current sensor into mutually orthogonal components; a torque pulsation compensation unit for outputting a first compensation command voltage for compensating for a torque pulsation caused by the structure of the motor based on the first component; and a failure time compensation unit for outputting a second compensation command voltage for compensating for an output voltage distortion caused by a failure time of the power conversion circuit based on the second component, wherein the torque pulsation and the output voltage distortion are reduced by correcting the command voltage using the first compensation command voltage and the second compensation command voltage.

[0023] In addition, the present invention is an outdoor unit of an air conditioner, comprising: a permanent magnet synchronous motor; a motor drive device that drives the permanent magnet synchronous motor; a fan connected to the permanent magnet synchronous motor; a frame that mounts the permanent magnet synchronous motor; and a compressor device system, wherein the outdoor unit of the air conditioner is characterized in that the motor drive device is a motor drive device having the above-mentioned characteristics.

[0024] In addition, the present invention is characterized in that a three-phase current supplied to a motor is detected, the detected three-phase detection current is separated into mutually orthogonal components, a first component and a second component are generated by extracting the pulsation amount of each component, a first compensation command voltage is generated based on the first component to compensate for the torque pulsation caused by the structure of the motor, and a second compensation command voltage is generated based on the second component to compensate for the output voltage distortion caused by the failure time of the power conversion circuit, and the torque pulsation and the output voltage distortion are reduced by using the first compensation command voltage and the second compensation command voltage to correct the command voltage contributing to the drive of the motor.

[0025] According to the present invention, it is possible to provide a motor drive device that can effectively suppress torque pulsation caused by induced voltage distortion caused by a motor and output voltage distortion caused by an inverter, an outdoor unit of an air conditioner using the same, and a motor drive control method.

[0026] This makes it possible to reduce noise and vibration of the motor without prior adjustment through preliminary tests, thereby realizing a highly versatile motor drive device that can handle various motors, an outdoor unit of an air conditioner using the same, and a motor drive control method.

[0027] Other problems, structures, and effects than those described above will become apparent from the following description of the embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a diagram showing the structure of the motor drive device according to the first embodiment of the present invention.

[0029] Figure 2 It is expressed in dq coordinates Figure 1 Diagram of a portion of a structure.

[0030] Figure 3 This is a diagram showing an example of a voltage distortion waveform for each factor.

[0031] Figure 4 1 is a diagram showing the loci of the current vector and the voltage distortion component when only the q-axis current is passed.

[0032] Figure 5 It is shown Figure 1 FIG. 1 is a diagram showing a structure of a pulsating current detection unit 116 .

[0033] Figure 6 It is shown Figure 1 FIG. 1 is a diagram showing the structure of the torque ripple compensation unit 109.

[0034] Figure 7 It is shown Figure 1 FIG. 1 is a diagram showing a structure of the failure time compensation unit 112 .

[0035] Figure 8 This is a diagram showing an example of an operation waveform of the motor drive device according to the first embodiment of the present invention.

[0036] Fig. 9 It is a diagram showing the structure of a motor drive device according to a second embodiment of the present invention.

[0037] Fig.10 It is shown Fig. 9 FIG. 1 is a diagram showing the structure of a torque ripple compensation unit 109 ′.

[0038] Fig.11 This is a diagram showing an example of an operation waveform of the motor drive device according to the second embodiment of the present invention.

[0039] Fig.12 1 is a diagram showing the loci of the current vector and the voltage distortion component when the d-axis and q-axis currents are passed.

[0040] Fig.13 It is a diagram showing the structure of a motor drive device according to a third embodiment of the present invention.

[0041] Fig.14It is shown Fig.13 FIG. 1 is a diagram showing a structure of a pulsating current detection unit 116 ′.

[0042] Fig.15 This is a diagram showing an outdoor unit of an air conditioner according to Embodiment 4 of the present invention.

[0043] (Explanation of symbols)

[0044] 100: Motor drive device; 101: Permanent magnet synchronous motor (motor); 102: Command speed generating unit; 103: Control unit; 104: Power conversion circuit; 105: Current sensor; 106: Gain multiplication unit; 107: Command voltage calculation unit; 108: LPF (low pass filter); 109, 109': Torque pulsation compensation unit; 110, 110a, 110b: Addition unit; 111: dq / 3 phase conversion unit; 112: Dead time compensation unit; 113, 113a, 113b, 113c: Addition unit; 114: Rotor position detection unit; 115: 3 phase / dq conversion unit; 116, 116': Pulsating current detection unit; 200: Permanent magnet synchronous motor (dq coordinate model Type); 201a, 201b: Adder; 202a, 202b: Adder; 203, 204: Multiplier; 500: cos6θdc signal generator; 503: sin6θdc signal generator; 501, 504: Multiplier; 502, 505: LPF (low pass filter); 600: Integral control; 601: Adder; 602: Initial value setting; 603: sin6θdc signal generator; 604, 606, 607, 608: Multiplier; 605: cos6θdc signal generator; 700: Integral control; 701: Initial value setting; 702: Adder; 703, 705, 707: Sign function; 704, 706 , 708: multiplication unit; 1000: compensation voltage operation unit; 1002: LPF (low pass filter); 1003, 1004, 1006, 1007: multiplication unit; 1005, 1008: addition unit; 1400: current phase operation unit; 1401: dq / γδ conversion unit; 1402: addition unit; 1403: cos6θdc' signal generation unit; 1404: sin6θdc' signal generation unit; 1405, 1406: multiplication unit; 1500: outdoor unit (unit); 1501: drive device for fan motor; 1502: drive device for compressor motor; 1503: fan motor; 1504: fan; 1505: frame; 1506: compressor device; 1507: AC power supply; ωr: motor speed; ωr*: command speed (motor speed command); ω1c: electrical angular velocity obtained by PLL; Vu*, Vv*, Vw*: three-phase command voltage; Vdc*, Vqc*: d-axis and q-axis command voltage; ΔVd*, ΔVq*: d-axis and q-axis compensation command voltage; Vdc**, Vqc**: compensated d-axis and q-axis command voltage; ΔVu*, ΔVv*, ΔVw*: three-phase compensation command voltage; Vu**, Vv**, Vw**: compensated three-phase command voltage; Iu, Iv, Iw: three-phase detection current; Id, Iq: d-axis and q-axis current; Idc, Iqc: d-axis and q-axis detection current; Ih1 - ,Ih2- : The first and second components of the current pulsation; θd: rotor position; θdc: estimated value of the rotor position; Δθc: axis error; τm: motor torque; P: number of motor poles; R: winding resistance; Ld, Lq: d-axis and q-axis inductance; Ke: induced voltage coefficient; Kehd, Kehq: pulsation components (distortion components) of the induced voltage coefficient on the d-axis and q-axis; Keh - : Amplitude values ​​of Kehd and Kehq; Keh* - : Amplitude value Keh - Setting value; ΔKeh - : Keh* - The adjustment value in the calculation of Keh0 - : Keh* - The initial value in the calculation; Vtd: the three-phase stationary coordinate component of the output voltage distortion caused by the inverter; Vtdd, Vtdq: the d-axis and q-axis components of the output voltage distortion caused by the inverter; Vtd - : Amplitude value of Vtd; Vtd* - : Amplitude value Vtd - Setting value; ΔVtd - : Amplitude value Vtd* - The adjustment value in the calculation; Vtd0 - : Amplitude value Vtd* - Initial value in the calculation; ΔVd1* - , ΔVd2* - : The first amplitude and the second amplitude of the d-axis compensation voltage (the first d-axis compensation command voltage, the second d-axis compensation command voltage); ΔVq1* - , ΔVq2* - : The first amplitude and the second amplitude of the q-axis compensation voltage (the first q-axis compensation command voltage, the second q-axis compensation command voltage); Iγc, Iδc: γ-axis and δ-axis detection current; β: current phase; VAC: AC voltage; VDC: DC voltage. DETAILED DESCRIPTION

[0045] Hereinafter, the embodiment of the present invention will be described using the drawings. In addition, the same reference numerals are attached to the same structures in each drawing, and the detailed description of the repeated parts will be omitted.

[0046] Example 1

[0047] Reference Figures 1 to 8 , describing the motor drive device and control method thereof according to embodiment 1 of the present invention.

[0048] Figure 1 is a structural diagram of the motor drive device of this embodiment. Figure 1As shown, the motor drive device 100 of this embodiment includes a command speed generating unit 102, a control unit 103, a power conversion circuit 104 (hereinafter also referred to as an "inverter") that supplies power to a permanent magnet synchronous motor 101 (hereinafter also referred to as a "motor"), and a current sensor 105. In this embodiment, the motor drive device 100 includes the command speed generating unit 102, but it may also be a structure provided in the control unit 103 or outside the motor drive device 100.

[0049] The control unit 103 outputs three-phase command voltages Vu*, Vv*, and Vw* based on the command speed ωr* provided by the command speed generating unit 102 and the three-phase detection currents Iu, Iv, and Iw detected by the current sensor 105, and controls the rotation speed of the motor 101. In the present embodiment, the current sensor 105 detects all three-phase currents, but the current sensor 105 may detect any two-phase portion, and the control unit 103 may calculate the remaining one phase.

[0050] The power conversion circuit 104 performs PWM (Pulse Width Modulation) control based on the three-phase command voltages Vu*, Vv*, and Vw* output from the control unit 103 to generate a pulsed output voltage, thereby driving the motor 101 .

[0051] The control unit 103 is basically configured with vector control. The command speed ωr* input from the command speed generating unit 102 to the control unit 103 is multiplied by the gain "number of motor poles P / 2" in the gain multiplying unit 106 to calculate the electrical angular velocity (P / 2)·ωr*.

[0052] In the command voltage calculation unit 107, the d-axis and q-axis command voltages Vdc* and Vqc* are calculated based on the preset d-axis command current Id*, the q-axis command current Iq* calculated from the q-axis detection current Iqc via the LPF (Low Pass Filter) 108, the electrical angular velocity (P / 2)·ωr*, and the set value of the motor constant. The d-axis and q-axis command voltages Vdc* and Vqc* are command voltages of direct current that contribute to the rotation of the motor 101.

[0053] The torque ripple compensation unit 109 calculates the d-axis and q-axis compensation command voltages ΔVd* and ΔVq* for compensating the influence of the induced voltage distortion caused by the motor. The d-axis and q-axis compensation command voltages ΔVd* and ΔVq* are added to the d-axis and q-axis command voltages Vdc* and Vqc* in the adding unit 110 to generate the compensated d-axis and q-axis command voltages Vdc** and Vqc**. In addition, the adding unit 110 is composed of adding units 110a and 110b.

[0054] The dq / 3-phase conversion unit 111 converts the compensated d-axis and q-axis command voltages Vdc** and Vqc** into three-phase command voltages Vu*, Vv*, and Vw* according to the rotor position θdc.

[0055] The dead time compensating unit 112 generates three-phase compensation command voltages ΔVu*, ΔVv*, ΔVw* for compensating the influence of output voltage distortion caused by the inverter. The three-phase compensation command voltages ΔVu*, ΔVv*, ΔVw* are added to the three-phase command voltages Vu*, Vv*, Vw* in the adding unit 113 to generate compensated three-phase command voltages Vu**, Vv**, Vw**, and input them to the power conversion circuit 104. In addition, the adding unit 113 is composed of adding units 113a, 113b, and 113c.

[0056] In the rotor position detection unit 114, the phase deviation between the control axis (dc axis) and the magnetic flux axis (d axis) of the motor, i.e., the axis error Δθc, is calculated based on the d-axis and q-axis command voltages Vdc*, Vqc*, the d-axis and q-axis detection currents Idc, Iqc, the electrical angular velocity (P / 2)·ωr*, and the set value of the motor constant. In addition, the electrical angular velocity is controlled by PLL (Phase Locked Loop) so that Δθc becomes zero, and the obtained value is integrated to calculate the rotor position θdc. That is, in this embodiment, a sensorless vector control that does not require a position sensor is configured.

[0057] In the three-phase / dq conversion unit 115, the three-phase detection currents Iu, Iv, and Iw are converted into d-axis and q-axis detection currents Idc and Iqc according to the rotor position θdc.

[0058] In the pulsating current detection unit 116, the first component Ih1 which is the pulsating amount of the d-axis and q-axis detection currents Idc and Iqc is extracted based on the rotor position θdc and the d-axis and q-axis detection currents Idc and Iqc. - and the second component Ih2 - The first component Ih1 - is input to the torque ripple compensation unit 109, the second component Ih2 - The data are input to the dead time compensating unit 112 and are used for estimating the parameters related to the compensation control.

[0059] That is, in this embodiment, the influence of the induced voltage distortion caused by the motor and the influence of the output voltage distortion caused by the inverter are expressed as the pulsation amounts of the d-axis and q-axis detection currents Idc and Iqc, and control is performed by appropriately extracting the information thereof by the pulsating current detection unit 116.

[0060] The above is the basic structure of this embodiment.

[0061] In the command voltage calculation unit 107, the d-axis and q-axis command voltages Vdc* and Vqc* are calculated according to the following formula (1) based on the d-axis command current Id*, the q-axis command current Iq*, the electrical angular velocity (P / 2)·ωr*, and the set value of the motor constant.

[0062] [Mathematical formula 1]

[0063]

[0064] In the formula (1), R represents the winding resistance, Ld represents the d-axis inductance, Lq represents the q-axis inductance, Ke represents the inductive voltage coefficient, and the superscript character * represents the set value of each motor constant.

[0065] The command voltage calculation unit 107 calculates the equation (1) using a preset constant value as the d-axis command current Id* and a value obtained by low-pass filtering the q-axis detection current Iqc by the LPF 108 as the q-axis command current Iq*.

[0066] Thus, in a stable state where the motor 101 is driven at a constant speed, the d-axis command current Id* and the q-axis command current Iq* become constant, and the d-axis and q-axis command voltages Vdc* and Vqc* also become constant.

[0067] In the rotor position detection unit 114, according to the following formula (2), the axis error Δθc is calculated based on the d-axis and q-axis command voltages Vdc*, Vqc*, the d-axis and q-axis detection currents Idc, Iqc, the electrical angular velocity ω1c, and the set value of the motor constant.

[0068] [Mathematical formula 2]

[0069]

[0070] In the equation (2), the electrical angular velocity ω1c is a signal obtained by adjusting the electrical angular velocity using PLL so that the axial error Δθc becomes zero. The rotor position detection unit 114 integrates the electrical angular velocity ω1c to calculate the rotor position θdc.

[0071] When the motor 101 is driven by the above structure, the influence of the induced voltage distortion caused by the motor and the influence of the output voltage distortion caused by the inverter are expressed as the pulsation of the d-axis and q-axis detection currents Idc and Iqc. Figure 2 To illustrate this principle.

[0072] Figure 2 The diagram shows Figure 1The figure of the elements required for the explanation of the structure shown does not show the torque ripple compensation unit 109 and the dead time compensation unit 112. In addition, the permanent magnet synchronous motor 200 is shown by an equivalent model on the dq coordinate. In the subtraction units 201a and 201b, the distortion components Kehd and Kehq of the induced voltage coefficient on the d-axis and q-axis are multiplied by the electrical angular velocity (P / 2)·ωr to obtain (P / 2)·ωr·Kehd and (P / 2)·ωr·Kehq.

[0073] That is, the subtraction units 201a and 201b equivalently express the influence of the induced voltage distortion caused by the motor on the dq coordinates.

[0074] In the subtraction units 202 a and 202 b , the output voltage distortions Vtdd and Vtdq caused by the dead time on the d-axis and the q-axis are subtracted.

[0075] That is, the subtraction units 202a and 202b equivalently express the influence of the output voltage distortion caused by the inverter on the dq coordinates.

[0076] In addition, Figure 2 In the figure, the solid arrow indicates that it contains "DC quantity + AC quantity", and the dotted arrow indicates that it contains only "DC quantity".

[0077] like Figure 2 As shown, in the presence of induced voltage distortion caused by the motor and output voltage distortion caused by the inverter, the d-axis and q-axis command voltages Vdc* and Vqc* generated by the command voltage calculation unit 107 are respectively subtracted by "(P / 2)·ωr·Kehd+Vtdd" and "(P / 2)·ωr·Kehq+Vtdq" which are AC quantities.

[0078] As a result, in the permanent magnet synchronous motor 200, a DC amount Id is added to each of the d-axis and the q-axis. - , Iq - In addition, the pulsating current Idh and Iqh are also passed. Among these currents, the q-axis current "Iq - +Iqh" is converted into the q-axis command current Iq* via LPF 108 and fed back to the command voltage calculation unit 107. At this time, the cutoff frequency of LPF 108 is set to be sufficiently smaller than the frequency of change of the pulsation amount Iqh of the q-axis current, so that Iq*=Iq - .

[0079] As a result, the d-axis and q-axis command voltages Vdc* and Vqc* generated by the command voltage calculation unit 107 become DC quantities, and only the DC quantities Id of the d-axis and q-axis currents are controlled. - , Iq - .

[0080] On the other hand, the pulsation amounts Idh and Iqh remain intact regardless of the command voltage calculation unit 107, so by detecting these current pulsation amounts, the influence of the induced voltage distortion "(P / 2)·ωr·Kehd, (P / 2)·ωr·Kehq" caused by the motor and the output voltage distortion "Vtdd, Vtdq" caused by the inverter can be observed.

[0081] Here, it is assumed that the distortion components of the inductive voltage coefficients of the d-axis and the q-axis are equal to each other (Kehd=Kehq). In addition, on the stationary coordinate, the output voltage distortion caused by the dead time is expressed by the following equation (3).

[0082] [Mathematical formula 3]

[0083] ΔV td =T d ·f c ·V DC ·sign(i) ···(3)

[0084] In equation (3), Td is the length of the failure time, fc is the carrier frequency, VDC is the DC voltage applied to the inverter, and sign (i) represents the polarity of the detection current of each phase.

[0085] exist Figure 3 , the figure shows the induced voltage distortion "(P / 2)·ωr·Kehd, (P / 2)·ωr·Kehq" caused by the motor and the output voltage distortion "Vtdd, Vtdq" caused by the inverter when current is only passed through the q-axis side of the motor (the d-axis current is zero).

[0086] like Figure 3 As shown in FIG. 1 , the induced voltage distortion "(P / 2)·ωr·Kehd, (P / 2)·ωr·Kehq" caused by the motor becomes a pulsating voltage with the same amplitude on the d-axis and the q-axis and a phase shift of 90°. On the other hand, the output voltage distortion "Vtdd, Vtdq" caused by the inverter becomes a pulsating voltage with a sawtooth wave shape on the d-axis and a half wave shape on the q-axis, and the shapes are greatly different from each other.

[0087] From the viewpoint of ripple amplitude, Vtdd on the d-axis side is larger than Vtdq on the q-axis side, so it is known that output voltage distortion caused by the inverter appears significantly on the d-axis side, that is, the non-energized axis side.

[0088] When this characteristic is plotted on the dq coordinate, it can be expressed as follows Figure 4 As shown. Figure 4In the figure, I is the current vector (only the q-axis current is energized), X is the trajectory of the induced voltage distortion caused by the motor, and Y is the trajectory of the output voltage distortion caused by the inverter. X is a circular trajectory, while Y is a half-moon trajectory.

[0089] When expressing the distortion by formulas focusing only on the sixth-order component, the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter are respectively expressed by the following equations (4) and (5).

[0090] [Formula 4]

[0091]

[0092] [Mathematical formula 5]

[0093]

[0094] Among them, in formula (4), Keh - is the amplitude of Kehd and Kehq. In addition, in equation (5), Vtdd - and Vtdq - is the amplitude of Vtdd and Vtdq.

[0095] In this embodiment, the pulsating current detection unit 116 for extracting the pulsating amount of the d-axis and q-axis detection currents Idc and Iqc from the characteristics of the output voltage distortion caused by the inverter is set as Figure 5 The structure shown.

[0096] As described above, the output voltage distortion caused by the inverter mainly appears on the d-axis side as the non-energized axis, so the second component Ih2 used by the dead time compensation unit 112 is extracted from the d-axis detection current Idc. - .

[0097] More specifically, assuming that the frequency of change of Vtdd is sufficiently fast (i.e., assuming that the motor speed is sufficiently fast), the current phase is delayed by 90° relative to the voltage phase, and Vtdd as the main component is a function of sinθd according to equation (5), so the influence of output voltage distortion caused by the inverter is detected by multiplying the d-axis detection current Idc by cos6θdc in the multiplication unit 501. In LPF502, the DC amount of Idc·cos6θdc, which is the calculation result of the multiplication unit 501, is extracted and the second component Ih2 is output. - .

[0098] On the other hand, the first component Ih1 used in the torque ripple compensation unit 109 is extracted from the q-axis detection current Iqc as the influence of the induced voltage distortion caused by the motor. - .

[0099] More specifically, according to equation (4), (P / 2)·ωr·Kehq is a function of cos6θd, so the q-axis detection current Iqc is multiplied by sin6θdc in the multiplication unit 504. In LPF 505, the DC value of Iqc·sin6θdc, which is the calculation result of the multiplication unit 504, is extracted and the first component Ih1 is output. - .

[0100] In this embodiment, the pulsating current detection unit 116 includes LPF502 and LPF505, but it may be a structure without these LPFs. This is because the torque pulsation compensation unit 109 and the dead time compensation unit 112 have a first component Ih1 - and the second component Ih2 - The integral control will eliminate the alternating currents of Idc·cos6θdc and Iqc·sin6θdc as a result. The details will be described later.

[0101] Figure 6 1 is a diagram showing the structure of the torque ripple compensation unit 109. The torque ripple compensation unit 109 generates a torque ripple compensation signal based on the first component Ih1 extracted by the ripple current detection unit 116. - The d-axis and q-axis compensation command voltages ΔVd* and ΔVq* are generated by using the electrical angular velocity (P / 2)·ωr* to compensate for the torque ripple generated by the induced voltage distortion caused by the motor.

[0102] First, in the integral control unit 600, according to the first component Ih1 of the current pulsation - , generating the adjustment signal ΔKeh - Adjust the signal ΔKeh - In the adding unit 601, the initial value Keh0 set by the initial value setting unit 602 is added. - Add together to generate the set value Keh* - .

[0103] Then, the sin6θdc generated by the sin6θdc signal generating unit 603 and the electrical angular velocity (P / 2)·ωr* are respectively multiplied by Keh* in the multiplication units 604 and 607. - Similarly, the cos6θdc generated by the cos6θdc signal generating unit 605 and the electrical angular velocity (P / 2)·ωr* are multiplied by Keh* in the multiplication units 606 and 608, respectively. - Multiplying them generates the q-axis compensation command voltage ΔVq*.

[0104] In this embodiment, the value set by the initial value setting unit 602 is set as the initial value Keh. - , but it can be set to any value in control, and can also be set to zero.

[0105] like Figure 1 As shown, the d-axis and q-axis compensation command voltages ΔVd* and ΔVq* are added to the d-axis and q-axis command voltages Vdc* and Vqc* in the adding unit 110 to generate compensated d-axis and q-axis command voltages Vdc** and Vqc**.

[0106] exist Figure 2 In the embodiment, when the compensated d-axis and q-axis command voltages Vdc** and Vqc** are applied instead of the d-axis and q-axis command voltages Vdc* and Vqc*, (P / 2)·ωr·Kehd and (P / 2)·ωr·Kehq added in the addition units 201a and 201b in the permanent magnet synchronous motor 200 are offset by the d-axis compensation command voltage ΔVd* in the compensated d-axis command voltage Vdc** and the q-axis compensation command voltage ΔVq* in the compensated q-axis command voltage Vqc**, respectively, thereby compensating for the influence of the induced voltage distortion caused by the motor.

[0107] Figure 7 1 is a block diagram of the dead time compensation unit 112. The dead time compensation unit 112 generates a second component Ih2 extracted by the pulsating current detection unit 116. - The three-phase compensation command voltages ΔVu*, ΔVv*, ΔVw* for compensating for the influence of output voltage distortion caused by the inverter are generated by combining the three-phase detection currents Iu, Iv, and Iw.

[0108] First, in the integral control unit 700, according to the second component Ih2 of the current pulsation - The adjustment signal ΔVtd is generated - Adjustment signal ΔVtd - The addition unit 702 adds the initial value Vtd0 set by the initial value setting unit 701. - Add together to generate the set value Vtd* - .

[0109] Then, the signal of 1 or -1 corresponding to the polarity of the U-phase detection current Iu generated by the sign function unit 703 is multiplied by Vtd* in the multiplication unit 704. - The U-phase compensation command voltage ΔVu* is generated by multiplying the signal generated by the sign function unit 705 with Vtd* in the multiplication unit 706. - The V-phase compensation command voltage ΔVv* is generated by multiplying the signal generated by the sign function unit 707 with Vtd* in the multiplication unit 708. - Multiplying them generates the W-phase compensation command voltage ΔVw*.

[0110] In this embodiment, the value set by the initial value setting unit 701 is set as the initial value Vtd. -, but it can be set to any value in terms of control and can also be set to zero.

[0111] As Figure 1 shown, the three-phase compensation command voltages ΔVu*, ΔVv*, and ΔVw* are added to the three-phase command voltages Vu*, Vv*, and Vw* in the adder 113 to generate the compensated three-phase command voltages Vu**, Vv**, and Vw**.

[0112] Here, the results obtained by transforming the three-phase compensation command voltages ΔVu*, ΔVv*, and ΔVw* into dq-axis components are set as ΔVd** and ΔVq**, and the results obtained by adding these command voltages to the d-axis and q-axis command voltages Vdc* and Vqc* are set as Vd*** and Vq***.

[0113] In Figure 2 , when applying Vdc*** and Vqc*** instead of Vdc* and Vqc*, the Vtdd and Vtdq added in the adders 202a and 202b are respectively canceled by ΔVd** in Vdc*** and ΔVq** in Vqc***, compensating for the influence of the output voltage distortion caused by the inverter.

[0114] Figure 8 is a diagram showing the operation waveforms of this embodiment. Among them, the d-axis command current Id* is set to zero, and the initial value Keh0 - of the torque ripple compensation unit 109 - and the initial value Vtd0 Figure 8 of the dead time compensation unit 112 are set to zero. In

[0115] , at time T1 < t < T2, it can be seen that the pulsation amount of the q-axis detected current Iqc decreases when the torque ripple compensation unit 109 operates, and the set ratio of the set value Keh* - relative to the actual value Keh - increases. This is because, according to the first component Ih1 - of the current pulsation, that is, the pulsation amount of the q-axis detected current Iqc, the set value Keh* - is adjusted by the integral control unit 600.

[0116] However, the ratio Keh* - / Keh - is less than 1 and does not become "set value Keh* - = actual value Keh - ". This is because, as Figure 3As shown, there is an output voltage distortion Vtdq caused by the inverter on the q-axis side, and there is an error in the adjustment signal ΔKeh generated by the integral control unit 600. - There is an error in it.

[0117] At time T2 < t, it can be seen that when the failure time compensation unit 112 operates, the pulsation amount of the d-axis detected current Idc decreases, and the set value Vtd* - relative to the actual value Vtd - has an increased set ratio. This is because, according to the second component Ih2 of the current pulsation - , that is, the pulsation amount of the d-axis detected current, the integral control unit 700 adjusts the set value Vtd* - .

[0118] In addition, the set ratio of the set value Keh* - relative to the actual value Keh - also changes simultaneously. This is because the failure time compensation unit 112 compensates for the influence of the output voltage distortion Vtdq caused by the inverter in the torque pulsation compensation unit 109, removing the error contained in the adjustment signal ΔKeh generated by the integral control unit 600. - There is an error in it.

[0119] As a result, the ratio Vtd* - / Vtd - and the ratio Keh* - / Keh - both converge near 1, so as to become "set value Vtd* - = actual value Vtd - " and "set value Keh* - = actual value Keh - " for control.

[0120] In this way, when the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter exist simultaneously, the present invention can distinguish the effects of the two from the detected current, and separately estimate the related parameters and perform compensation (correction).

[0121] In Figure 8 , the start times of the operations of the torque pulsation compensation unit 109 and the failure time compensation unit 112 are staggered (T1 ≠ T2), but the operations of these compensation units can also start simultaneously (T1 = T2).

[0122] Embodiment 2

[0123] Refer to Figures 9 to 11 to describe the motor drive device and its control method according to Embodiment 2 of the present invention.

[0124] In the first embodiment, the torque ripple compensation unit 109 and the dead time compensation unit 112 operate to compensate Figure 2 The influence of the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter (the terms added in the adder 201a, 201b and the adder 202a, 202b are eliminated), and the constant d-axis and q-axis currents Id that do not include the pulsation amounts Idh, Iqh are energized. - , Iq - That is, by making the current waveform distorted by various factors close to an ideal sine wave, the torque ripple reduction effect is obtained.

[0125] However, even in Figure 2 A constant d-axis and q-axis current Id is passed through the - , Iq - , the influence of the induced voltage distortion caused by the motor in the multiplication units 203 and 204 will still remain, so the torque ripple reduction effect obtained is limited (refer to Figure 8 torque waveform).

[0126] Therefore, in order to compensate for the torque ripple, for example, it is possible to use the method disclosed in the above-mentioned Patent Document 3. That is, in order to cancel the torque ripple, it is also possible to intentionally control so that the q-axis current pulsates.

[0127] Fig. 9 1 is a structural diagram of the motor drive device of this embodiment. In this structure, the motor drive device of embodiment 1 ( Figure 1 ) is replaced by a torque ripple compensator 109'.

[0128] Fig.10 The structure of the torque ripple compensation unit 109' is shown. Figure 1 )'s torque pulsation compensator 109 is different in that it is input with the q-axis detection current Iqc, and is supplemented with a compensation voltage calculation unit 1000, an LPF (low-pass filter) 1002, multiplication units 1003, 1004, 1006, 1007 and addition units 1005, 1008.

[0129] LPF (low pass filter) 1002 extracts the DC value of the q-axis detection current Iqc and generates Iqc - .

[0130] The set value Keh* of the distortion component of the inductive voltage coefficient is input to the compensation voltage calculation unit 1000. - , Iqc generated by LPF1002 - , and electrical angular velocity (P / 2)·ωr*, the first d-axis compensation command voltage ΔVd1* is generated according to the following equation (6): -, the second d-axis compensation command voltage ΔVd2* - , the first q-axis compensation command voltage ΔVq1* - , the second q-axis compensation command voltage ΔVq2* - .

[0131] [Mathematical formula 6]

[0132]

[0133] ΔVd1*, which is the calculation result of the compensation voltage calculation unit 1000 - , ΔVd2* - , multiplied by sin6θdc and cos6θdc in multiplication unit 1003 and multiplication unit 1004, respectively, to generate ΔVd1* - sin6θdc and ΔVd2* - ·cos6θdc. Then, these calculation results are added in the adding unit 1005 to generate the d-axis compensation command voltage ΔVd*.

[0134] Similarly, for ΔVq1* - , ΔVq2* - , multiplied by sin6θdc and cos6θdc in multiplication unit 1006 and multiplication unit 1007, respectively, to generate ΔVq1* - ·sin6θdc and ΔVq2* - ·cos6θdc. Then, these calculation results are added in the adding unit 1008 to generate the q-axis compensation command voltage ΔVq*.

[0135] When the d-axis and q-axis compensation command voltages ΔVd* and ΔVq* generated by the configuration of this embodiment are applied, the q-axis current represented by equation (7) flows in a steady state.

[0136] [Mathematical formula 7]

[0137]

[0138] By supplying a q-axis current including the pulsation amount shown in equation (7), the ratio "ΔKeh - / Ke” reduces torque ripple.

[0139] Fig.11 is a diagram showing the operation waveform of this embodiment. Figure 8 The same as the case of the first embodiment shown in FIG. 1 is different only in that the torque ripple compensation unit 109 is replaced by a torque ripple compensation unit 109'. Figure 8When comparing, the torque and current waveforms are different. In this embodiment, when t > T1, a q-axis current Iq containing a pulsation component is deliberately energized, and it can be seen that a higher torque pulsation reduction effect is obtained.

[0140] Thus, in this embodiment, even under the condition where output voltage distortion is caused by the inverter, the distortion component Keh of the induced voltage coefficient can be estimated based on the detected current. - , based on the obtained Keh - a pulsating current is deliberately energized, so that torque pulsation can be more effectively canceled.

[0141] Embodiment 3

[0142] Refer to Figure 12 to Figure 14 to describe the motor drive device and its control method according to Embodiment 3 of the present invention.

[0143] As described above, output voltage distortion caused by the inverter significantly appears on the non-energized axis side. Therefore, if the directions of the energized axis and the non-energized axis can be grasped by observing the direction of the current vector, the same control actions as in Embodiments 1 and 2 can be achieved even under other energization conditions.

[0144] Here, the angle formed by the d-axis current Id and the q-axis current Iq is defined as the current phase β (= tan−1(−Id / Iq)). Fig.12 Shows the current vector I' when the current phase β is set to 45°, the locus X' of the induced voltage distortion caused by the motor, and the locus Y' of the output voltage distortion caused by the inverter.

[0145] If compared with the example of Figure 4 only energizing the q-axis current, it can be seen that the loci X and X' are the same, and the influence of the induced voltage distortion caused by the motor does not depend on the current. On the other hand, the loci Y and Y' are different from each other, and the influence of the output voltage distortion caused by the inverter changes with the direction of the current vector. When the direction of the current vector, that is, the energization direction, is set as the δ axis and the non-energized direction obtained by shifting the phase by 90° clockwise is set as the γ axis, the influence of the output voltage distortion caused by the inverter significantly appears on the γ axis.

[0146] Fig.13 is the structural diagram of the motor drive device according to this embodiment. In this structure, considering the relationship between the direction of the current vector and the influence of the output voltage distortion caused by the inverter, the pulsating current detection unit 116 in the structure of Embodiment 1 ( Figure 1 ) is replaced with a pulsating current detection unit 116'. In this embodiment ( Fig.13 ), it becomes a structure including a torque pulsation compensation unit 109, but it can also become a structure in which the torque pulsation compensation unit 109' shown in Embodiment 2 is replaced.

[0147] Fig.14 The structure of the pulsating current detection unit 116' is shown. Figure 5 ) is different from the pulsating current detection unit 116 in that a current phase calculation unit 1400, a dq / γδ conversion unit 1401 and an addition unit 1402 are additionally provided.

[0148] The current phase calculation unit 1400 calculates the current phase β "tan-1(-Idc / Iqc)" based on the d-axis and q-axis detection currents Idc and Iqc. The dq / γδ conversion unit 1401 calculates the following equation (8) based on the current phase β.

[0149] [Mathematical formula 8]

[0150]

[0151] By calculating the equation (8), the current vector is separated into the γ-axis component in the non-conductive direction and the δ-axis component in the conductive direction. The γ-axis detection current Iγc is multiplied by cos6θdc' in the multiplication unit 1405, and the second component Ih2 of the current pulsation is generated through the LPF 502. - Similarly, the δ-axis detection current Iδc is multiplied by sin6θdc′ in the multiplication unit 1406, and the first component Ih1 of the current pulsation is generated via the LPF 505. - .

[0152] The pulsating current detection unit 116' generates a first component Ih1 of the current pulsation. - and the second component Ih2 - The subsequent actions are the same as those in Embodiment 1 and Embodiment 2.

[0153] Example 4

[0154] Reference Fig.15 , an outdoor unit of an air conditioner according to a fourth embodiment of the present invention will be described. Fig.15 An example is shown in which the motor drive device according to any one of the embodiments 1 to 3 described above is applied to a fan motor system mounted in an outdoor unit of an air conditioner.

[0155] The outdoor unit 1500 includes a fan motor driver 1501, a compressor motor driver 1502, a fan motor 1503, a fan 1504, a frame 1505, and a compressor device 1506. The fan motor driver 1501 is a motor driver according to any of the first to third embodiments.

[0156] The operation of the fan motor system in the outdoor unit 1500 will be described. The AC power supply 1507 is connected to the compressor motor drive device 1502. The compressor motor drive device 1502 rectifies the supplied AC voltage VAC into a DC voltage VDC, and drives the compressor device 1506.

[0157] At the same time, the compressor motor driving device 1502 also supplies a DC voltage VDC to the fan motor driving device 1501 and outputs a motor speed command ωr*.

[0158] The fan motor driving device 1501 operates according to the input motor speed command ωr*, and supplies a three-phase voltage to the fan motor 1503. As a result, the fan motor 1503 is driven, and the connected fan 1504 is rotated. The above is the operation of the fan motor system.

[0159] In the outdoor unit of the air conditioner, in order to reduce costs, a cheap computing device is generally installed in the fan motor drive device 1501. In addition, in many cases, a position sensor is not attached to the fan motor 1503. Even in such an application, by using the motor drive device involved in the present invention as a fan motor drive device, torque pulsation suppression control can be achieved. As a result, the vibration caused by the fan motor 1503 to the frame 1505 is reduced, and the noise released from the outdoor unit 1500 can be reduced.

[0160] The motor drive device according to the present invention does not require preliminary tests, adjustment work, etc., and is therefore very easy to use. In addition, since it is an autonomous torque pulsation suppression control, the present invention can also be applied to existing equipment whose motor characteristics are difficult to measure.

[0161] Furthermore, the motor drive devices according to the embodiments 1 to 3 can also be used as compressor motor drive devices. In short, the present invention can be applied to any motor drive device as long as it is a vector control-based structure.

[0162] In the embodiments 1 to 3, the motor drive device based on the position sensorless method is used as an example for explanation, but the present invention can also be applied to a motor drive device equipped with a position sensor such as an encoder, a resolver, or a magnetic pole position sensor. Figure 1 , Fig. 9 , Fig.13 The present invention can also be applied to the configuration in which a position sensor is added to the motor 101 shown, and speed feedback control based on information from the position sensor is added to the control unit 103 .

[0163] In addition, even if you replace Figure 1 , Fig. 9 , Fig.13The present invention can also be applied to a configuration in which each command voltage calculation unit 107 includes current feedback control based on a deviation between the d-axis command current Id* and the d-axis detection current Idc and a deviation between the q-axis command current Iq* and the q-axis detection current Iqc.

[0164] In this case, the response frequency band of the constructed current feedback control is designed to be sufficiently lower than the variation frequency of the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter. As a result, the information contained in the d-axis and q-axis detection currents Idc and Iqc is the same as that in the implementation of Examples 1 to 3, and the appropriate operation involved in the present invention can be achieved.

[0165] In the first to third embodiments, the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter are described as changing in a 6-fold cycle. However, the present invention can be similarly applied even when the changing cycle is other than 6 (12 times, 24 times, etc.).

[0166] In addition, according to each embodiment of the present invention, the following control is performed: based on the d-axis and q-axis detection currents as one of the detection signals, the influence of the induced voltage distortion caused by the motor and the output voltage distortion caused by the inverter is detected and compensated. By using the detection signal instead of the command signal, the influence of the modeling error, the calculation error, etc. can be eliminated as much as possible, and the above control can be performed with high accuracy.

[0167] When using the detection signal, the cost may increase due to the addition of sensors, etc., but the motor drive device is equipped with a current sensor in most cases. That is, the present invention realizes the torque pulsation suppression control that operates autonomously using only the existing sensor.

[0168] In addition, the present invention is not limited to the above-mentioned embodiments, but includes various modified examples. For example, the above-mentioned embodiments are examples described in detail to help understand the present invention, and are not limited to having all the structures described. In addition, a part of the structure of a certain embodiment can be replaced with the structure of other embodiments, and the structure of other embodiments can also be added to the structure of a certain embodiment. In addition, for a part of the structure of each embodiment, other structures can be added, removed, or replaced.

Claims

1. A motor drive device, characterized in that: have: A power conversion circuit supplies power to the motor; a control unit that controls the power conversion circuit; and a current sensor for detecting a three-phase current supplied to the motor, The control unit has: a command voltage calculation unit that calculates a command voltage that contributes to driving the motor; a pulsating current detection unit that generates a first component and a second component obtained by extracting pulsation amounts of the components from the components obtained by separating the three-phase detection current detected by the current sensor into mutually orthogonal components; a torque ripple compensating unit that outputs a first compensation command voltage for compensating for torque ripple caused by the structure of the motor based on the first component; as well as a dead time compensating unit that outputs a second compensation instruction voltage for compensating for output voltage distortion caused by dead time of the power conversion circuit based on the second component; By correcting the command voltage using the first compensation command voltage and the second compensation command voltage, the torque ripple and the output voltage distortion are reduced.

2. The motor drive device according to claim 1, characterized in that: The control unit includes a three-phase / dq conversion unit that converts the three-phase detection current into a d-axis current and a q-axis current. The mutually orthogonal components are the d-axis component and the q-axis component, The first component is a pulsation amount of one of a d-axis component and a q-axis component. The second component is the pulsation amount of the other of the d-axis component and the q-axis component.

3. The motor drive device according to claim 2, characterized in that: The control unit includes a rotor position detection unit for detecting a rotor position of the motor. In the pulsating current detection unit, A signal including information of the first component is generated by multiplying the q-axis current by a sine wave signal or a cosine wave signal that varies 6n times according to the rotor position of the motor, wherein n is an integer greater than or equal to 1. The signal including the information of the second component is generated by multiplying the d-axis current by a sine wave signal or a cosine wave signal that varies 6n times according to the rotor position of the motor.

4. The motor drive device according to claim 1, characterized in that: The control unit has: A three-phase / dq conversion unit converts the three-phase detection current into a d-axis current and a q-axis current; and a rotor position detection unit for detecting a rotor position of the motor; The pulsating current detection unit comprises: a current phase calculation unit that calculates a current phase corresponding to an angle formed by a current vector formed by these currents and the q-axis based on the d-axis current and the q-axis current; an adding unit, which adds the rotor position of the motor and the current phase to generate a corrected rotor position; as well as a dq / γδ conversion unit that converts the d-axis current and the q-axis current into a component on a δ-axis opposite to the direction of the current vector and a component on a γ-axis whose phase is shifted by 90° with respect to the δ-axis, according to the current phase; A signal including information of the first component is generated by multiplying the current on the delta axis by a sine wave signal or a cosine wave signal that varies 6n times according to the corrected rotor position, wherein n is an integer greater than 1, The signal including the information of the second component is generated by multiplying the current on the γ-axis by a sine wave signal or a cosine wave signal that varies 6n times according to the corrected rotor position.

5. The motor drive device according to claim 4, characterized in that: In the torque ripple compensation unit, Based on the first component, a first parameter related to the induced voltage distortion caused by the structure of the motor is calculated by integral control, A d-axis compensation command voltage and a q-axis compensation command voltage are generated based on the first parameter, the electrical angular velocity of the motor, and a sine wave signal or a cosine wave signal that varies 6n times according to the rotor position or the corrected rotor position.

6. The motor drive device according to claim 4, characterized in that: In the torque ripple compensation unit, Based on the first component, a first parameter related to the induced voltage distortion caused by the structure of the motor is calculated by integral control, A d-axis compensation command voltage and a q-axis compensation command voltage are generated based on the first parameter, the q-axis current, the electrical angular velocity of the motor, and a sine wave signal or a cosine wave signal that varies 6n times according to the rotor position or the corrected rotor position.

7. The motor drive device according to claim 1, characterized in that: In the dead time compensation unit, Based on the second component, a second parameter related to output voltage distortion caused by the dead time of the power conversion circuit is calculated by integral control, A three-phase compensation command voltage is generated according to the second parameter and the information of the three-phase detection current.

8. An outdoor unit of an air conditioner, comprising: Permanent magnet synchronous motor; A motor driving device, driving the permanent magnet synchronous motor; A fan connected to the permanent magnet synchronous motor; A frame for mounting the permanent magnet synchronous motor; and Compressor installation system, The outdoor unit of the air conditioner is characterized in that: The motor drive device is the motor drive device according to any one of claims 1 to 7.

9. A motor drive control method, characterized in that: The three-phase current supplied to the motor is detected, the detected three-phase current is separated into mutually orthogonal components, and a first component and a second component are generated by extracting the pulsation amount of each component. generating a first compensation command voltage for compensating for torque ripple caused by the structure of the motor based on the first component, generating a second compensation command voltage for compensating for output voltage distortion caused by a failure time of the power conversion circuit based on the second component, The torque ripple and the output voltage distortion are reduced by correcting the command voltage contributing to driving the motor using the first compensation command voltage and the second compensation command voltage.

10. The motor drive control method according to claim 9, characterized in that: The mutually orthogonal components are the d-axis component and the q-axis component, The first component is a pulsation amount of one of a d-axis component and a q-axis component. The second component is the pulsation amount of the other of the d-axis component and the q-axis component.

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