JP3672876B2 - Vector control inverter device and rotary drive device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sensorless vector control inverter device for a three-phase permanent magnet motor having a permanent magnet as a rotor and an armature winding as a stator, and in particular, the rotational speed of a permanent magnet motor in a free-run state before starting. The present invention relates to a vector control inverter device that can detect and appropriately select and execute a starting method based on the detection result, and a rotary drive device including the inverter device.
[0002]
[Prior art]
In recent years, there has been an increasing demand for compressor motors and fan motors for air conditioners, and drive motors for electric vehicles, such as a wide range of variable speed control, reduced power consumption, and improved maintainability. In many cases, sensorless vector control of a permanent magnet motor using a permanent magnet as a rotor by an inverter device has been adopted.
[0003]
However, for example, in a fan motor used in an outdoor unit of an air conditioner or the like, the motor may be free-running (self-running) by receiving external force such as natural wind before being started by the inverter device. When a motor in such a free-run state is suddenly started with an inverter device, depending on the rotation direction and rotation speed of the motor, the motor may be forced to change suddenly, resulting in erratic operation. In the worst case, the motor may be damaged.
[0004]
When a sensor for detecting the rotor position of the motor is attached, as disclosed in JP-A-11-332283 and JP-A-11-187690, the rotor is subjected to direct current excitation or winding short-circuiting. Has been developed in which the motor is stopped after being stopped at a predetermined position, or a proper starting method is selected by detecting the position of the rotor. However, in the case of a sensorless system that does not have a sensor for detecting the rotor position, the speed and position of the rotor cannot be known. Therefore, in order to prevent the occurrence of the above-mentioned problems, it is only possible to start after waiting for the natural stop of the motor, or to start after the rotor is stopped at a predetermined position by DC excitation or winding short circuit. is there. However, it is inefficient to wait for a natural stop, and in the case of DC excitation or winding short-circuit, when the external force acting on the motor is strong, the brake torque is insufficient and the rotor cannot be stopped. .
[0005]
[Problems to be solved by the invention]
The present invention has been devised to solve such inconveniences, and an object of the present invention is to detect the rotation speed and the rotor angle of a permanent magnet motor in a free-run state, and to determine an appropriate value based on the detection result. It is an object of the present invention to provide a vector control inverter device for a permanent magnet motor capable of selecting and executing a starting method.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the vector controlled inverter device according to claim 1 is configured to obtain an instantaneous value of current supplied to a three-phase permanent magnet motor having a permanent magnet as a rotor and an armature winding as a stator. , Converted into a d-axis current parallel to the magnetic flux on the rotating coordinate system rotating at the same speed as the magnetic flux generated by the permanent magnet, and a q-axis current advanced by π / 2 phase therefrom, and each is controlled independently In a vector control inverter device of a permanent magnet motor, a d-axis current and a q-axis current calculated from a measured motor current value and a rotor angle estimated value, a d-axis voltage command value, a rotor angular frequency estimated value, and a motor circuit An induced voltage estimating means for calculating an estimated d-axis induced voltage value using a constant, a proportional-integral calculator having the d-axis induced voltage estimated value as an input, and an output of the proportional-integral calculator to the angle of the rotor Subtract from frequency command value A subtractor for calculating the rotor angular frequency estimate value each, an integrator for calculating the rotor angle estimate by integrating the rotor angular frequency estimate, A first switch for switching the d-axis current command value between an external d-axis current command value and a zero value, and a q-axis current command value are obtained by further proportional-integral calculating the output signal of the proportional-integral calculator. A second switch for switching between the command value and the zero value, a delay circuit for delaying the signal of the rotor angular frequency estimation value, the rotor angular frequency command value, the command value from the outside, and the delay circuit A third switch for switching to the output signal; It is characterized by comprising.
[0007]
With this configuration, the inverter device can independently control the excitation current and the rotation speed of the permanent magnet motor without using a sensor for detecting the position or speed of the rotor.
[0008]
Furthermore, Claim 1 The inverter apparatus described includes a first switch for switching a d-axis current command value between an external d-axis current command value and a zero value, a q-axis current command value, and an output signal of the proportional-plus-integral calculator. A second switch for switching between a command value obtained by proportional integral calculation and a zero value, a delay circuit for delaying the signal of the rotor angular frequency estimation value, and the rotor angular frequency command value from an external command And a third switch for switching between the value and the output signal of the delay circuit, Claim 2 As described, by switching both the first and second switches to the zero value side and switching the third switch to the output side of the delay circuit, the rotor angle of the permanent magnet motor in the free-run state The frequency (rotation speed) and the rotor angle can be detected.
[0009]
By adopting such a configuration, this inverter device uses a sensor for the angular frequency and the rotor angle of a rotor of a fan motor or the like that is in a free-run state under external force such as natural wind before starting. It is possible to detect without. Since an appropriate starting method can be selected and executed based on the detected angular frequency and rotation direction, the motor can be started smoothly without forcing a sudden change in the motor.
[0010]
Claim 6 The rotary drive device described is a rotary drive device including the permanent magnet motor and an inverter device that drives the motor, and the vector control inverter device according to any one of claims 1 to 5 is used as the inverter device. It is the rotational drive device used. Such a rotary drive device is sensorless and brushless, and therefore has an advantage that maintenance is easy and there are few failures, and an appropriate start corresponding to the load can be performed.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a functional block diagram showing the configuration of an inverter device used for sensorless vector control of a permanent magnet motor according to the present invention. The motor 1 as a load is a rotating field type three-phase motor in which a permanent magnet is used as a rotor and an armature winding is provided in a stator. Current is supplied from the inverter device to the stator winding according to the rotor position. By supplying, it is driven brushlessly.
[0012]
This inverter device includes a current control means 2 for controlling the current of the motor 1, and a rotor speed / angle estimation means (rotational coordinate system defined on the rotor) for estimating the angular frequency (rotation speed) and angle of the rotor. Hereinafter, the means for estimating the angular frequency and the phase angle of the dq coordinate system) with respect to the fixed coordinate system (hereinafter referred to as the αβ coordinate system) will be called in this manner. The current of the motor 1 is detected by the current detector 4, and the detected three-phase currents Ia, Ib, Ic are converted by the abc / αβ converter 5 into the two-phase currents Iα, Iβ expressed in the equivalent αβ coordinate system. Is converted to Next, the two-phase currents Iα and Iβ are converted by the αβ / dq converter 6 into currents Id and Iq expressed in the dq coordinate system. In this conversion calculation, the rotor angle estimated value estimated by the rotor speed / angle estimating means 3 described later (the estimated value of the phase angle between the d-axis and the α-axis is referred to in this way). θ ₀ Is used.
[0013]
Here, the dq coordinate system is a coordinate system in which the direction of magnetic flux created by the permanent magnet on the rotor is defined as the d axis and the direction advanced by π / 2 is defined as the q axis, and the current Id is in the d axis direction, The current Iq means a current component in the q-axis direction. Since the dq coordinate system rotates together with the rotor, and the motor current is supplied from the inverter device in accordance with the rotor position, Id and Iq are direct current amounts.
[0014]
Id and Iq calculated by such coordinate conversion are subtracted from the command values Id-com and Iq-com in the subtractors 7 and 8 to calculate deviations ΔId and ΔIq. The first switch S1 (9) and the second switch S2 (10) are switches for selecting command values Id-com and Iq-com, and the figure shows a case where the motor 1 is driven by vector control. The selected state is shown. Deviations ΔId and ΔIq obtained by the above calculation are calculated by proportional-integral calculators 11 and 12, respectively, and generate d-axis command voltage Vd and q-axis command voltage Vq, respectively, at the outputs. That is, the subtractors 7 and 8 and the proportional-plus-integral calculators 11 and 12 serve as regulators for matching the motor currents Id and Iq with the corresponding command values Id-com and Iq-com. The outputs Vd and Vq are command voltages to be applied to the motor 1 in order to bring the motor current close to the command values Id-com and Iq-com.
[0015]
The command voltages Vd and Vq are converted by the dq / αβ converter 13 into values Vα and Vβ on the αβ coordinate system. The rotor angle estimation value θ described later also in this conversion calculation ₀ Is used. The PWM former 14 generates a signal for driving the switching element in the PWM inverter 15 based on the command voltages Vα and Vβ. When the PWM inverter 15 performs a switching operation according to the signal, a voltage proportional to Vd and Vq is applied to the stator winding of the motor 1 to drive the motor 1. Thus, the currents Id and Iq of the motor 1 are made to coincide with the command values Id-com and Iq-com by the control operation of the regulator described above.
[0016]
Here, Id-com is a command value of a component that generates magnetic flux (excitation current component), and this value is given as a command value from the outside. On the other hand, Iq-com is a command value of a component that generates rotational torque (torque current component), and is an amount directly related to the rotational speed of the motor 1. The value of Iq-com is given as an output of the proportional-plus-integral calculator 16 in a normal operation state.
[0017]
The proportional-plus-integral calculator 16 functions to adjust the rotational speed of the motor 1 together with the subtractor 17, and the angular frequency command value ω-com of the rotor is connected to the + input terminal of the subtractor 17 and the −input terminal. Is the estimated angular frequency value ω of the motor 1 estimated by the rotor speed / angle estimation means 3. ₀ Is entered. The deviation is calculated by the proportional-plus-integral calculator 16 to generate the q-axis current command value Iq-com as an output. The third switch S3 (18) selects the value of the angular frequency command value ω-com, and the figure shows a selection state when the motor 1 is normally operated.
[0018]
In this way, in order to apply the excitation current component command value Id-com and the torque current component command value Iq-com independently and to cause the motor 1 to flow a current according to the command value, the αβ / dq converter 6 and the dq / It is necessary to accurately grasp the rotor angle θ necessary for the conversion calculation in the αβ converter 13. In this inverter device, the rotor speed / angle estimation means 3 is obtained by using an electric motor model in the rotating coordinate system based on the measured motor current value and the voltage command value to the motor 1 without using a sensor. Estimated in.
[0019]
In other words, the induced voltage estimating means 19 calculates the d-axis component Ed of the induced voltage generated in the stator winding by the following equation as the magnetic flux generated by the permanent magnet attached to the rotor rotates.
Ed = Vd− (R + P · L) Id + ω ₀ ・ Iq (1) Formula
Where R is the winding resistance of the motor 1, L is the inductance of the winding, and ω ₀ Is an estimated angular frequency value of the rotor, and P is a differential operator. Id and Iq include measured current values and estimated rotor angle θ ₀ The command value is used for Vd instead of the actual measurement value because the responsiveness of the PWM inverter 15 is good. However, it goes without saying that measured values may be used.
[0020]
Angular frequency estimate ω ₀ Is obtained by the following equation obtained by subtracting the output ωerror obtained by calculating the Ed calculated by the equation (1) by the proportional-plus-integral calculator 20 from the angular frequency command value ω-com by the subtractor 21. (However, both equations (1) and (2) ₀ (1) ω ₀ Is ω before a minute time calculated by equation (2) ₀ Value, for example, using a DSP, the ω calculated one calculation cycle before ₀ The value of is used. )
ω ₀ = Ω-com −ωerror Equation (2)
Estimated rotor angle θ ₀ Is the estimated angular frequency ω ₀ Is integrated by the integrator 22.
[0021]
In the induced voltage, there is a q-axis component Eq in addition to Ed calculated by the equation (1), and ωerror is a numerical value obtained by calculating Ed by the proportional-plus-integral calculator 20, so that it is not always the actual rotor angle. It does not represent the exact error for frequency ω. However, the angular frequency estimated value ω calculated by equation (2) ₀ , And an estimated rotor angle θ obtained by integrating this ₀ Is used in the calculation, and the d-axis component estimated value Ed of the induced voltage can be converged to zero with the help of the regulator, at that time, the induced voltage estimated value is only the q-axis component. Become. In this state, the magnetic flux generated by the permanent magnet of the rotor can be considered to be parallel to the d-axis, and therefore the estimated rotor angle θ at this time ₀ Can be considered to coincide with the actual rotor angle θ.
[0022]
In this inverter device, the proportional-plus-integral computing unit 20 performs the most important adjustment function for converging this Ed to zero. When the block diagram of FIG. 1 is modified, it is rewritten into an equivalent block diagram as shown in FIG. The proportional-integral calculator 20 is assisted by the proportional-integral calculator 16 and the integrator 22 so that Ed converges to its target zero value. ₀ , And θ ₀ And adjust the value of Iq-com.
[0023]
On the other hand, with respect to the angular frequency of the rotor, the proportional-plus-integral computing unit 16 calculates the angular frequency command value ω-com and the angular frequency estimated value ω. ₀ An adjustment operation is performed so that ωerror, which is the deviation from, converges to zero. As a result of the adjusting operation of the proportional-integral calculators 20 and 16, both Ed and ωerror converge to zero. When this ωerror converges to zero, the angular frequency estimated value ω ₀ Coincides with the angular frequency command value ω-com, and the motor 1 is driven with the angular frequency command value ω-com.
[0024]
In parallel with the operation of estimating the rotor angle θ of the motor 1 in this way, the rotor angular frequency ω is adjusted to coincide with the angular frequency command value ω-com given from the outside. The exciting current component Id is also adjusted by the proportional-plus-integral computing unit 11 so as to coincide with the exciting current component command value Id-com given from the outside. In other words, vector control is performed in which the angular frequency (rotational speed) and the excitation current component are controlled independently so that they coincide with arbitrary numerical values given from the outside.
[0025]
The above description is an operation description for a normal operation state in which the motor 1 is driven by the inverter device. Next, an operation for detecting the angular frequency ω and the rotor angle θ of the rotor in a state where the motor 1 is free-running by an external force before starting will be described.
In this case, the first switch S1 (9), the second switch S2 (10), and the third switch S3 (18) are switched as shown in FIG. That is, “zero” is given as the command values of Id and Iq. Also, the angular frequency command value ω-com includes the angular frequency estimated value ω ₀ Is delayed through the delay circuit 23. It is desirable from the viewpoint of responsiveness that the delay time of the delay circuit 23 should be a value smaller than a period corresponding to the maximum response frequency of the motor 1.
[0026]
In FIG. 3, the estimated rotor angle θ ₀ Is estimated to be equal to the actual rotor angle θ, the currents Id and Iq of the motor 1 are adjusted to “zero” by the proportional-plus-integral calculators 11 and 12, respectively. Id and Iq are both “zero” when Iα, Iβ and Ia, Ib and Ic are all “zero”.
[0027]
Estimated rotor angle θ ₀ To converge to the actual rotor angle θ free-running, the angular frequency estimate ω ₀ Is delayed by the delay circuit 23 as an angular frequency command value ω-com. By doing so, as in the case of the normal operation state described above, the proportional-plus-integral calculator 20 estimates the rotor angular frequency value ω so that the induced voltage estimated value Ed converges to “zero”. ₀ And estimated rotor angle θ ₀ Adjust. Estimated rotor angle θ when Ed becomes “zero” ₀ Corresponds to the actual rotor angle θ of the motor 1. Also, the estimated rotor angle at that time θ ₀ That is, the estimated angular frequency ω ₀ Corresponds to the actual angular frequency ω of the motor 1 at that time.
With such an operation, according to the inverter device of the present invention, it is possible to detect the values of the rotor angle θ and the angular frequency ω of the motor 1 in the free-run state.
[0028]
Note that when the control of this inverter device is realized by a method in which it is periodically calculated and executed by a high-speed processor such as a DSP (Digital Signal Processor), the delay time of the delay circuit 23 is one of the DSP calculation cycles. It is good for the period. Further, when the DSP calculation speed is sufficiently high, the angular frequency estimated value ω obtained in the most recent calculation cycles instead of the signal delayed by the delay circuit 23. ₀ May be used as the command value. In this way, the estimated rotor angle θ ₀ Converges to the actual rotor angle θ of the motor 1.
[0029]
Furthermore, in the case of a DSP, the programming may be performed based on the block diagram of FIG. In FIG. 1, the value of the angular frequency command value ω-com is used in the subtractor 21, and the calculation result ω ₀ Is subtracted from ω-com in the subtractor 17. In this case, the block diagram of FIG. 2 equivalent to FIG. 1 may not be executed depending on the process of reading ω-com, the calculation in the subtractor 21, and the execution order of the calculation in the subtractor 17. It is.
[0030]
Further, as the proportional-plus-integral calculators 11, 12, 16, and 20 in FIG. 1, depending on the characteristics of the motor 1 and the load that the motor 1 drives, a proportional value obtained by adding a differential operation in order to improve control responsiveness. An integral / differential calculator may be used.
[0031]
As is apparent from the above description, the inverter device of the present invention can perform vector control of the permanent magnet motor 1 without using a sensor for detecting the position or speed of the rotor. Furthermore, there is an advantage that the rotational speed and the rotor angle of the motor 1 in a free-run state before starting can be detected without using a sensor.
[0032]
(Second Embodiment)
The present embodiment relates to an embodiment in which, for example, a permanent magnet motor for driving a fan attached to an outdoor unit of an air conditioner is appropriately started using the above-described vector control inverter device. In many cases, fan motors installed outdoors are free-running before starting due to an external force such as natural wind. In this case, starting the inverter drive regardless of the free-run state is not preferable because it causes a sudden change in the motor.
[0033]
FIG. 4 shows a flow of processing according to the present invention for reasonably starting properly according to the free-run state of the motor.
When power is supplied to the inverter device, the inverter device executes Step S1. In step S1, the angular frequency ω of the rotor in the free-run state is detected by the means described in the first embodiment. In this case, it is preferable to take an average value of a plurality of detection values for the sake of accuracy.
[0034]
Next, the process proceeds to step S2. Steps S2 and after are a sequence for performing appropriate starting in accordance with the detected angular frequency ω of the rotor. Here, the symbols A, B, C, and D used in FIG. 4 are positive constants representing the angular frequency, and A> B, D> C, and their values are determined in advance before starting. It is. In step S2, it is determined whether or not the detected angular frequency ω is D or more. The value of D is determined so as to correspond to a state where the fan motor is free-running at a considerably high speed in the forward rotation direction when ω ≧ D is satisfied. Therefore, if ω ≧ D is satisfied, the motor is rotating at a considerable speed in the forward rotation direction even if the fan motor is not driven. Return to step S1 without doing anything. If ω ≧ D is not satisfied, the process proceeds to step S3.
[0035]
In step S3, the inverter apparatus determines whether or not the condition of ω ≦ −A is satisfied. Here, the value of A is determined so as to correspond to a state in which the fan motor is rotating at a considerably high speed in the reverse direction when the condition of ω ≦ −A is satisfied. The fact that it is rotating at a considerable speed in the reverse direction means that it is rotating under a sufficient wind, for example, in the case of an outdoor unit. Therefore, in this case as well, driving by the inverter is unnecessary, so that the state is continued as it is and the processing returns to step S1 without doing anything. When the condition of ω ≦ −A is not satisfied, this is a case where −A <ω <D is satisfied. In this case, the process proceeds to step S4.
[0036]
In step S4, the inverter apparatus determines whether or not the condition of ω ≧ C is satisfied. This condition is satisfied when C ≦ ω <D. The value of C is determined so as to correspond to the state in which the fan motor rotates in the forward rotation direction at a moderate speed when this condition is satisfied. In this state, even if the inverter is driven based on the detected angular frequency ω and rotor angle θ, the fan motor is not forced so much. If the condition in step S4 is satisfied, the process proceeds to step S13.
[0037]
In step S13, the detected angular frequency ω is used as the angular frequency command value ω-com, and θ detected as the rotor angle is used as the rotor angle estimated value θ. ₀ Inverter drive by vector control is started. Then, the angular frequency command value ω-com is gradually increased (or gradually decreased), and a forward drive operation for shifting to the command value from the outside is executed. The starting operation ends when the angular frequency command value ω-com matches the command value from the outside. Thereafter, the process proceeds to step S14, and a steady operation is started in which the inverter drive is continued at an angular frequency according to an external command value.
[0038]
If the condition is not satisfied in step S4, the process proceeds to step S5. In step S5, the inverter apparatus determines whether or not the condition of ω ≧ −B is satisfied. This condition is satisfied when -B ≦ ω <C. This state corresponds to a state where the fan motor is stopped or is free running at a low speed close to the stop. If this condition is satisfied, the process proceeds to step S6. In step S6, a direct current is passed through the stator winding to temporarily stop the rotation of the fan motor. The time for which the DC excitation is continued is a predetermined time that is determined in advance, and is sufficient for stopping the fan motor. The determination of the elapse of the predetermined time is performed in step S7. After the DC excitation for a predetermined time is finished in step S7, the process proceeds to step S8 to perform commutation. Regardless of the position of the rotor, commutation generates a rotating magnetic field by passing a three-phase alternating current through the stator windings, and the interaction between the generated rotating magnetic field and the magnetic field created by the permanent magnet of the rotor An operation for forcibly rotating the motor in the forward direction. Such a rotating magnetic field gives constant Vd and Vq determined in advance as inputs of the dq / αβ converter 13 in FIG. 3, and the rotor angle θ used for calculation in the dq / αβ converter 13. ₀ Can be generated by giving a rotor angle that changes to a constant angular frequency greater than the angular frequency C. By driving in this way, the fan motor is accelerated toward the angular frequency C from the stopped state.
[0039]
During this commutation, the inverter device continues to detect the angular frequency ω of the rotor. Then, when the angular frequency ω exceeds C, that is, when the condition of step S10 is satisfied, the process proceeds to step S13. In this step S10, the end of commutation is determined by the value of the angular frequency ω, but instead the end may be determined by time as in step S7, or may be determined by a combination of both. .
[0040]
In step S13, the angular frequency ω detected as described above is used as the angular frequency command value ω-com, and θ determined as the rotor angle is the rotor angle estimated value θ. ₀ Inverter drive by vector control is started. Then, when the angular frequency command value ω-com matches the command value from the outside, the starting operation is finished, and thereafter, the process proceeds to step S14 to enter the steady operation.
[0041]
In addition, when the condition of step S5 is satisfied as described above, the direct current excitation and commutation are performed because the rotational speed of the rotor is low in the angular frequency range where the condition of step S5 is satisfied. This is because the detected value of the rotor angular frequency ω may not always have sufficient accuracy, and if the inverter driving is suddenly started in such a case, the fan motor may be forced.
[0042]
If the condition in step S5 is not satisfied, the process proceeds to step S11. The condition of step S5 is not satisfied when the angular frequency ω is in the range of −A <ω <−B. This state corresponds to a state where the fan motor is free-running in the reverse direction at a moderate speed. In such a state, the detected angular frequency ω is used as the angular frequency command value ω-com, and θ determined as the rotor angle is the estimated rotor angle θ ₀ Inverter drive by vector control is started. That is, the fan motor is inverter-driven in the reverse direction at the detected angular frequency ω. After starting the driving in this way, the inverter device gradually increases the angular frequency command value ω-com. That is, ω-com is changed in the forward direction. After ω-com reaches zero, it continues to increase gradually until it matches the external angular frequency command value. The fan motor rotating in the reverse direction is decelerated and the rotational speed becomes zero, and then it is driven in the forward direction. The operation of reversing the rotation direction is the return operation of step 12.
[0043]
After returning in step S12, the process proceeds to step S13. In step S13, the angular frequency command value ω-com is further increased gradually, the fan motor is also accelerated accordingly, and is eventually increased to the external angular frequency command value. The starting operation ends when the angular frequency command value ω-com matches the command value from the outside. Thereafter, as in the case described above, the process proceeds to step S14, and a steady operation in which driving is continued at an angular frequency according to an external command value is entered.
[0044]
As is apparent from the above description, the inverter device of the present invention can detect the rotational speed of the fan motor in a free-run state before starting without a sensor, and an appropriate starting method that matches the detected rotational speed. Can be selected. As a result, there is an effect that it is possible to smoothly enter the steady operation without forcing the fan motor.
[0045]
In the second embodiment, in order to facilitate understanding, the constants A, B, C, and D have been described as being set to values suitable for the case where the present invention is applied to an outdoor unit of an air conditioner. The application of the present invention is not limited to the outdoor unit of an air conditioner. For example, when applied to a ventilation fan that discharges indoor air to the outside, when the ventilation fan is reversely rotated at high speed by the wind blown from the outside, the inverter is not driven as in the second embodiment. It is not preferable to continue. In this case, as in the case of −A <ω <−B described above, it is necessary to shift to an operation of driving in the order of reverse rotation drive, return, normal rotation drive, and steady operation to discharge indoor air to the outside. is there. Such an operation can be realized in the sequence flow of FIG. 4 by setting a minus infinity numerical value as the value of -A in the second embodiment.
[0046]
As described above, the inverter device of the present invention can smoothly change the values of the constants A, B, C, and D, including the case where they take negative values, so that the smooth start that is most suitable for the motor drive target is achieved. Is possible.
[0047]
(Third embodiment)
The present embodiment relates to a rotary drive device including the vector control device of the present invention and a permanent magnet motor, and is an embodiment in which the vector control inverter device of the present invention is used as an inverter device. When performing inverter control of a permanent magnet motor, it is necessary to grasp various motor constants of the permanent magnet motor and reflect them in inverter control in order to optimize the control. Therefore, today, a permanent magnet motor and an inverter device for driving the permanent magnet motor are often integrated and sold as a rotary drive device. In this case, if the vector control inverter device of the present invention is employed as the inverter device, the permanent magnet motor can be driven sensorlessly and brushlessly, so that maintenance is easy, there is little failure, and appropriate start corresponding to the load can be performed. A rotational drive device can be provided.
[0048]
【The invention's effect】
As can be understood from the above description, the vector control inverter device of the present invention independently controls the excitation current and rotation speed of the permanent magnet motor without using a sensor for detecting the position or speed of the rotor. Therefore, it is possible to avoid an increase in cost and an increase in maintenance work amount due to sensor attachment. Furthermore, it is possible to detect the rotational speed of the motor in a free-running state before starting, and to select and execute an appropriate starting method based on the detection result, so that the motor can be smoothly changed without forcing a sudden change. This has the effect of starting the motor.
[0049]
In addition, the rotary drive device provided with the vector control device and the permanent magnet motor of the present invention is sensorless and brushless, so that maintenance is easy and there are few failures, and an appropriate start corresponding to the load can be performed. Have.
[Brief description of the drawings]
FIG. 1 is a functional block diagram showing an electrical configuration of a vector control inverter device according to a first embodiment of the present invention.
FIG. 2 is a functional block diagram according to another expression equivalent to the functional block diagram of FIG.
FIG. 3 is a functional block diagram for detecting the rotor angle and angular frequency of a motor in a free-run state.
FIG. 4 is a flowchart showing the start sequence of a motor in a free-run state
[Explanation of symbols]
In the figure, 1 is a permanent magnet motor, 2 is current control means, 3 is rotor speed / angle estimation means, 9 is a first switch, 10 is a second switch, 18 is a third switch, 11, 12, 16 and 20 are proportional-plus-integral calculators, 19 is an induced voltage estimating means, and 23 is a delay circuit.

Claims (6)

The instantaneous value of the current supplied to the three-phase permanent magnet motor with the permanent magnet as the rotor and the armature winding as the stator is changed to the magnetic flux on the rotating coordinate system that rotates at the same speed as the magnetic flux generated by the permanent magnet. In a vector control inverter device of a permanent magnet motor that converts a parallel d-axis current into a q-axis current that is advanced by π / 2 phase and controls each independently,
Estimating d-axis induced voltage using d-axis current and q-axis current, d-axis voltage command value, rotor angular frequency estimated value, and motor circuit constant calculated from actual measured motor current value and estimated rotor angle value An induced voltage estimating means for calculating a value;
A proportional-plus-integral calculator with the d-axis induced voltage estimated value as an input;
A subtractor for subtracting the output of the proportional-plus-integral calculator from the angular frequency command value of the rotor to calculate the rotor angular frequency estimate;
An integrator that integrates the rotor angular frequency estimate to calculate a rotor angle estimate;
a first switch for switching a d-axis current command value between an external d-axis current command value and a zero value;
a second switch for switching a q-axis current command value between a command value and a zero value obtained by further performing a proportional-integral operation on the output signal of the proportional-integral calculator;
A delay circuit for delaying the signal of the rotor angular frequency estimation value;
And a third switch for switching the rotor angular frequency command value between an external command value and an output signal of the delay circuit . Both the first and second switches are switched to the zero value side,
2. The vector control according to claim 1, wherein a rotor angular frequency and a rotor angle of the permanent magnet motor in a free-run state are detected by switching the third switch to the output side of the delay circuit. Inverter device. The vector control inverter device according to claim 2, wherein a starting method of the permanent magnet motor is selected based on a detected rotor angular frequency and a detected value of the rotor angle of the permanent magnet motor in a free-running state . When the detected value of the rotor angular frequency of the permanent magnet motor in the free-run state is ω, A, B, C, D as positive constants,
( a ). When ω ≧ D or ω ≦ −A, the free-run state is continued,
( b ). In the case of C ≦ ω <D, the rotor angular frequency command value is gradually increased or decreased from ω, and the inverter is driven to shift to match the command value from the outside,
( c ). When −B ≦ ω <C, the motor is temporarily stopped by direct current excitation, then forced commutation to accelerate forward rotation, and after acceleration to ω ≧ C, the angular frequency command value of the rotor is set to C Drive the inverter while gradually increasing and accelerate until it matches the command value from the outside,
( d ). In the case of -A <ω <B, the rotor angular frequency command value is gradually increased from -A and the inverter is driven to accelerate until it matches the command value from the outside.
3. The vector control inverter device according to claim 2, wherein the permanent magnet motor is started by this . 5. The vector control inverter device according to claim 1, wherein the permanent magnet motor is a fan driving motor . A rotation drive device comprising the permanent magnet motor and an inverter device for driving the motor, wherein the inverter device comprises the vector control inverter device according to any one of claims 1 to 4. Drive device.

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