JP2020043758A - Motor driver, vacuum cleaner and hand dryer - Google Patents

Abstract

To obtain a motor driver capable of realizing air volume control corresponding to single-phase instantaneous power pulsation, when realizing air volume control for a single-phase PM motor.SOLUTION: A motor driver 100 for driving a motor blower including a single-phase PM motor 3 includes a single-phase inverter 2 for rotating the rotor of the single-phase PM motor 3 by applying an AC voltage to the single-phase PM motor 3, a motor current detector 5 outputting a signal according to a motor current flowing through the single-phase PM motor 3, a DC power supply voltage detector 6 for detecting the voltage of a DC power supply 1 supplying power to the single-phase inverter 2 and an inverter control section 4 receiving the motor current and outputting a drive signal to switching elements 211-214 of the single-phase inverter 2, where the single-phase inverter 2 increases and decreases effective power or wattless power supplied to the single-phase PM motor 3, and changes the number of revolution of the single-phase PM motor 3 by increasing and decreasing effective power or wattless power.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor drive device for driving a single-phase permanent magnet synchronous motor (hereinafter, appropriately referred to as a single-phase PM (Permanent Magnet) motor), and a vacuum cleaner and a hand dryer using the single-phase PM motor.

  There are various types of motors such as brushed DC motors, induction motors, PM motors, and the like. The number of motor phases also includes single-phase and three-phase. Among these various motors, the single-phase PM motor has a brush-less structure that does not use a brush, which is a mechanical structure, as compared with a DC motor with a brush, so that brush wear does not occur. With this feature, the single-phase PM motor can easily obtain a long life and high reliability.

  Further, the single-phase PM motor is a highly efficient motor because no secondary current flows through the rotor as compared with the induction motor.

  Further, in the case of a single-phase PM motor, there are the following advantages as compared with a three-phase PM motor having a different number of phases. In the case of a three-phase PM motor, a three-phase inverter is required, whereas a single-phase PM motor may be a single-phase inverter. When a full-bridge inverter generally used as a three-phase inverter is used, six switching elements are required. On the other hand, a single-phase PM motor can be configured with four switching elements even if a full-bridge inverter is used. . Therefore, the single-phase PM motor can be downsized compared to the three-phase PM motor.

  As prior documents relating to the driving method of a single-phase PM motor, for example, Patent Document 1 and Non-Patent Document 1 described below are disclosed.

JP 2012-130378 A

IEEJ Joint Research Group on Rotating Machines and Linear Drives "Airflow Sensorless Airflow Constant Control for SPMSM by DC Shunt Detection"

  According to Patent Literature 1, "control means for controlling the amount of current supplied to the electric blower is provided, and the air volume is estimated and estimated from the" current-current-air volume "relationship obtained in advance through experiments and the like. When the air volume is within a first predetermined range, as the estimated air volume decreases, the amount of power to the electric blower is controlled to be reduced, and the amount of power is the first predetermined amount. In such a range, the degree of vacuum in the dust collection chamber is controlled to be substantially constant and to a value set in advance by experiments or the like. " That is, in Patent Literature 1, the air volume of the electric blower is determined by the work amount of the electric blower.

  As described above, in Patent Literature 1, the amount of energization is controlled according to the estimated airflow. However, although apparent power is controlled only by the amount of energization, control is not performed in terms of active power and reactive power. That is, in the control of Patent Document 1, the required active power cannot be individually controlled. For this reason, the technique of Patent Literature 1 has a problem that the current flowing through the electric motor becomes larger than the maximum efficiency point, and the efficiency is deteriorated.

  In addition, Non-Patent Document 1 describes a technique for performing control based on an estimated air volume, but describes only a three-phase PM motor and does not describe a single-phase PM motor. In particular, since the single-phase instantaneous power, which is the instantaneous power when supplied to the single-phase PM motor, pulsates in a sine wave or cosine wave at twice the electrical angular frequency, the method described in Non-Patent Document 1 There is a concern that noise may be generated due to the pulsation of the rotation speed or the pulsation of the load torque due to the pulsation of the single-phase instantaneous power.

  The present invention has been made in view of the above, and when realizing the air flow control for a single-phase PM motor, a motor driving device capable of realizing the air flow control corresponding to the pulsation of the single-phase instantaneous electric power, an electric cleaner The purpose is to provide machines and hand dryers.

  In order to solve the above-described problems and achieve the object, the present invention is a motor driving device for driving an electric blower including a single-phase permanent magnet synchronous motor, comprising: a plurality of switching elements; A single-phase inverter that applies an AC voltage to the permanent magnet synchronous motor, a current detection unit that outputs a signal corresponding to a motor current flowing through the single-phase permanent magnet synchronous motor, and a DC power supply that supplies power to the single-phase inverter. A DC power supply voltage detection unit that detects a voltage, and an inverter control unit that receives the motor current and outputs a drive signal to the switching element of the single-phase inverter, wherein the single-phase inverter includes the single-phase inverter. Increase or decrease the active power or reactive power supplied to the permanent magnet synchronous motor, and change the rotation speed of the motor by increasing or decreasing the active power or the reactive power. .

  According to the present invention, when realizing the air volume control for the single-phase PM motor, there is an effect that the air volume control corresponding to the pulsation of the single-phase instantaneous electric power can be realized.

FIG. 3 shows a configuration of a motor drive device according to the first embodiment. FIG. 4 is a diagram illustrating a relationship between a rotor rotation position and a position detection signal according to the first embodiment. Block diagram showing a configuration of an inverter control unit according to the first embodiment. FIG. 4 is a diagram illustrating a relationship between a position detection signal and a motor rotation speed estimated value according to the first embodiment. FIG. 4 is a diagram illustrating a relationship between a motor rotation speed estimated value and a rotor rotation position estimated value according to the first embodiment. FIG. 5 is a diagram showing a relationship between a motor current and a pq-axis current according to the first embodiment. FIG. 6 shows a relationship between a motor current and an inverter output voltage in the first embodiment. Time chart for explaining the operation of the switching element drive signal generation unit according to the first embodiment FIG. 4 illustrates an example of a configuration of a vacuum cleaner as an application example of the motor drive device in Embodiment 1. The figure which shows an example of a structure of a hand dryer as another application example of the motor drive device in Embodiment 1. The figure which shows the relationship between the air volume Q and active power P in the control of Embodiment 1. FIG. 4 is a diagram showing an example of a case where the q-axis current command value is controlled to a value other than 0 in the control of the first embodiment Block diagram showing a configuration of an inverter control unit according to the second embodiment. FIG. 10 is a diagram for explaining a relationship between a p-axis current and a p-axis current correction amount according to the second embodiment. Block diagram showing a configuration of an inverter control unit according to the third embodiment. Illustrates an example of the instantaneous active power P _a and the air volume command value correcting amount Delta] Q * of the waveform

  Hereinafter, a motor drive device, a vacuum cleaner, and a hand dryer according to an embodiment of the present invention will be described in detail with reference to the drawings. The present invention is not limited by the following embodiments.

Embodiment 1 FIG.
FIG. 1 is a diagram illustrating a configuration of a motor drive device according to the first embodiment. The motor driving device 100 according to the first embodiment is a motor driving device that drives a load including the single-phase PM motor 3, and includes a DC power supply 1, a single-phase inverter 2, an inverter control unit 4, a motor current detection unit 5, a DC current A power supply voltage detector 6 and a rotor position detector 7 are provided. Examples of the load including the single-phase PM motor 3 include a vacuum cleaner equipped with an electric blower and a hand dryer.

DC power supply 1 supplies DC power to single-phase inverter 2. The single-phase inverter 2 includes switching elements 211 to 214 and diodes 221 to 224 connected in anti-parallel to the switching elements 211 to 214, respectively, and applies an AC voltage to the single-phase PM motor 3. The inverter control unit 4 outputs drive signals S1 to S4 to the switching elements 211 to 214 of the single-phase inverter 2. Rotor position detector 7 outputs the position detection signal S_ _rotation is a signal corresponding to the rotor rotational position theta _m is the rotational position of the single-phase PM motor 3 of the rotor 3a to the inverter control unit 4. Motor current detector 5 outputs a signal corresponding to the motor current I _m flowing through the single-phase PM motor 3 to the inverter control unit 4. The DC power supply voltage detector 6 detects a DC voltage _Vdc , which is a voltage of the DC power supply 1. Drive signals S1~S4 the rotor rotational position θm and the motor current pulse width modulation that is generated based on the _{I m:} is (Pulse Width Modulation hereinafter referred to as "PWM") signal. By driving the switching elements 211 to 214 of the single-phase inverter 2 with the drive signals S1 to S4, which are PWM signals, an arbitrary voltage can be applied to the single-phase PM motor 3.

  The DC power supply 1 may be a DC power supply that rectifies and smoothes an AC voltage from an AC power supply with a diode bridge or the like and generates a DC voltage without any problem. no problem. The switching element of the single-phase inverter 2 is a transistor, an IGBT (Insulated Gate Bipolar Transistor), a MOS-FET (Metal Oxide Semiconductor-Field Effect Transistor), a thyristor, or a GTO (Gate Turn-Off element). There is no problem even if there is. Further, there is no problem in using any semiconductor material such as SiC and GaN, which are called wide band gap semiconductors, as well as the mainstream Si as the semiconductor material of the switching element as described above.

Rotor position detector 7 outputs for example, generates a position detection signal S_ _rotation corresponding to the rotor rotational position theta _m of the motor shown in FIG. 2 to the inverter control unit 4. In the case of Figure 2 assumes the case of outputting a position detection signal S_ _rotation the pulse-like voltage signal corresponding to the rotor rotational position theta _m using a magnetic sensor such as a Hall sensor, 0 ≦ theta _m <in π, S_ _rotation = "High level", the π ≦ θ _m <2π, is described as an example S_ _rotation = "Low level". However, there is no problem in using a position detection sensor such as an encoder or a resolver without being limited to the Hall sensor.

FIG. 3 is a block diagram illustrating a configuration of the inverter control unit 4 according to the first embodiment. The inverter control unit 4 includes a first current control unit 411 for controlling the p-axis current _Ip , a second current control unit 412 for controlling the q-axis current _Iq, and an airflow control unit 42 for controlling the estimated airflow value Q ^. , A first coordinate conversion unit 431 that performs coordinate conversion from a notation in a single-phase AC to a p-axis and a q-axis (hereinafter, referred to as “pq-axis”), from a notation in the pq-axis to a notation in a single-phase AC second coordinate conversion unit 432, a position detection signal S_ motor position and rotation speed detector 44 that detects a rotor rotational position estimate theta _{m ^} and the motor rotation speed estimation value omega _{m ^} in response to _rotation for conversion, air volume estimation air amount estimating unit 45 for the value Q ^ of the estimated switching element drive signal generating unit 46 from the inverter output voltage command value V _{m *} generates switching element driving signals S1 to S4, air amount command value for generating the air amount command value Q * Generation unit 47, and Are configured with a q-axis current command value generating unit 48 that generates a q-axis current command value I _{q *,} each part will be described in detail below. Note that the notation of “^” in “θ _m ^”, “Q ^”, etc. should be attached to the upper part of the character of “θ” or “Q”. , The notation can not be. For this reason, in this specification, except for the mathematical expression part to be inserted in the image, the character or character string is indicated by adding a character of “^”.

First, the detailed operation of the motor position / rotational speed detector 44 will be described. As described above, the rotor position detecting unit 7, and outputs to the motor position and rotation speed detector 44 generates a position detection signal S_ _rotation as shown in FIG. Figure 4 is a diagram showing a position detection signal S_ _rotation and the motor rotation speed estimation value omega _m ^ and the relationship in the first embodiment. Motor position and speed detecting section 44 can detect the motor rotation speed estimation value omega _m ^ by a calculation formula shown in the position detection signal S_ period T_ following (1) equation using the _rotation of the _rotation. Although describing the pole pairs P _m of the motor in the first embodiment as P _{m =} 1, may be a course P _m ≠ 1. However, in the case of P _m ≠ 1, there is a relation of ω _e = P _m × ω _m between the electric angular rotational speed ω _e and the motor rotational speed ω _m which is a mechanical angular rotational speed.

FIG. 5 is a diagram showing the relationship between the estimated motor rotation speed ω _m ^ and the estimated rotor rotation position θ _m ^ in the first embodiment. As shown in FIG. 5 and the following equation (2), the rotor rotational position estimated value θ _m ^ can be calculated by integrating the motor rotational speed estimated value ω _m ^. However, in the example of FIG. 5, the description assumes a discrete control system in the control cycle _Tcnt , and the rotor rotational position estimation value at the control timing n is described as θ _m ^ [n].

Thus, (1) by using the formula and (2), it is possible to calculate the motor speed estimated value omega _m ^ and the rotor rotational position estimate theta _m ^ from the position detection signal S_ _rotation. The above-described method of calculating the motor rotation speed estimation value omega _m ^ and the rotor rotational position estimate theta _m ^ than the period T_ _rotation position detection signal S_ _rotation is only an example, it is employed other methodological issues Needless to say, there is nothing.

Next, a description will be given of the first coordinate conversion unit 431 that performs coordinate conversion from the representation in single-phase AC to the pq axis. FIG. 6 is a diagram illustrating a relationship between the motor current _Im , the p-axis current _Ip, and the q-axis current _Iq in the first embodiment. In p-axis and q-axis are two axes that are orthogonal to the motor current I _m which represents the single-phase AC, when regarded as a vector quantity in a polar coordinate system, p-axis component and q-axis component the following equation (3-1) And (3-2).

Here, the instantaneous value of the motor current I _m is defined by the following (4-1) equation, it defines the instantaneous value of the inverter output voltage command value V _{m *} in the following (4-2) equation. In (4-1) equation, _{I m} _ _rms is the effective value of the motor current _{I m,} in (4-2) equation, _{V m} _ _rms *, the inverter output voltage command value _{V m} * rms It is. The relationship between the motor current I _m and the inverter output voltage command value V _{m *} is as shown in FIG. 7, represents the phase difference between the inverter output voltage command value V _{m *} and the motor current I _m by Φ I have. Note that, in the expressions (4-1) and (4-2) and FIG. 7, the case where the motor current _Im is in the leading phase with respect to the inverter output voltage command value _Vm * is defined as positive.

Using the expressions (4-1) and (4-2), the single-phase instantaneous power _Pm is expressed by the following expression (5).

  Also, when formula (5) is expanded into a formula by the addition theorem, it is expressed by the following formula (6).

Further, when the equation (6) is transformed using the equations (3-1) and (3-2), the following equation (7) can be transformed. Here, θ _m = θ _m ^.

(7) is an equation representing the instantaneous power, in particular the first term indicates the active power instantaneous value, represented by p-axis current I _p as shown in equation (3-1). The (7) The second term of the shows the reactive power instantaneous value, represented by q-axis current I _q as shown in (3-2) below. Therefore, the control using the equation (7), specifically, the motor current _Im is coordinate-transformed and separated into the p-axis current _Ip and the q-axis current _Iq, and the separated p-axis currents _Ip and q are separated. By individually controlling the shaft currents _Iq , it is possible to control the active power and the reactive power.

  In the description of the first coordinate transformation unit 431 so far, as shown in the expressions (3-1), (3-2), (4-1) and (4-2), and FIG. Although the description of the formula expansion was made after making the above definitions, these definitions and illustrations are set for the sake of convenience of the description, and the definitions themselves are not essential matters of the invention.

Next, the second coordinate conversion unit 432 that performs conversion from the notation on the pq axis to the notation on the single-phase AC will be described. The second coordinate conversion unit 432 uses the p-axis voltage command value _Vp * and the q-axis voltage command value _Vq * to _generate an inverter output voltage command value _Vm * that is an AC voltage based on the following equation (8). Convert to The expression (8) is an example of a coordinate conversion expression to the inverter output voltage command value V _m *, and the expression expressed by the expression (8) also changes according to the definition in the first coordinate conversion unit 431 described above. Needless to say.

Next, the first current controller 411 and the second current controller 412 will be described. The first current control unit 411 is a feedback controller that controls the above-described p-axis current I _p to match the p-axis current command value I _p *, and the second current control unit 412 performs the above-described q axis current I _q is a feedback controller for controlling so as to coincide with the q-axis current command value I _{q *.} Each of the first current control unit 411 and the second current control unit 412 can employ, for example, a PID control system having a transfer function as shown in the following equation (9). (9) In the equation, _{K p} is a proportional gain, _{K I} is an integral gain, _{K d} is the differential gain, s represents the Laplace operator. Needless to say, PID control, feedback control, and the like are examples of the control method described as an example in this specification.

  Next, the air volume control unit 42 will be described. The air volume control unit 42 is a feedback controller that controls the air volume estimated value Q ^ to match the air volume command value Q *, and performs PID control similar to the first current control unit 411 or the second current control unit 412. Etc. can be adopted. Needless to say, PID control, feedback control, and the like are examples of a control method similar to the current control units 411 and 412.

  Next, the air volume estimating unit 45 will be described. Equation (9) on page 2/6 of Non-Patent Document 1 listed in the prior art document describes the following relational expression.

  In the above equation (10), N is the number of revolutions, and I is the current. When the above equation (10) is replaced with the present embodiment, the estimated airflow value Q ^ in the present embodiment can be expressed by the following equation (11).

  However, as described in the prior art document, the function f representing the air volume Q is a function that also depends on the fan diameter, the pressure loss condition, and the like. May be adopted. That is, any method may be used to determine the estimated airflow value Q ^.

Next, the switching element drive signal generator 46 will be described. FIG. 8 is a time chart for explaining the operation of switching element drive signal generation section 46 according to the first embodiment. In the upper part of FIG. 8, a thin line shows a carrier waveform, and a thick line shows a waveform of an inverter output voltage command value. In the example of FIG. 8, with respect to the carrier period _{T c,} and setting the control period _{T cnt} to 1/2 of carrier period _{T c.} The lower part of FIG. 8 shows the waveforms of the drive signals S1 to S4 for driving the switching elements 211 to 214.

Assuming a discrete control system based on the control cycle _Tcnt described above, the inverter output voltage command value _Vm * has discretely changed values. For example, when focusing on the control timing n, the high level and the low level of the switching element drive signals S1 to S4 are determined based on the magnitude relationship between the inverter output voltage command value _Vm * [n] and the carrier at the control timing n. At this time, S1 and S4 are the same signal, S2 and S3 are the same signal, and S2 and S3 are waveforms inverted with respect to S1 and S4. Here, since a switching element has a delay time such as a rise time and a fall time inherent to the switching element, a short circuit prevention time (dead time) is generally provided in many cases. In FIG. 8, the dead time is described as 0, but there is no problem even if dead time ≠ 0. Note that the generation method of the switching element drive signals S1 to S4 in FIG. 8 is merely an example, and any method may be used as long as it generates a PWM signal.

  Next, the air volume command value generation unit 47 will be described. FIG. 9 is a diagram illustrating an example of a configuration of a vacuum cleaner as an application example of the motor driving device according to the first embodiment. 9, the vacuum cleaner 8 includes a DC power supply 1 such as a battery, an electric blower 81 driven by the above-described single-phase PM motor 3, and further includes a dust collection chamber 82, a sensor 83, a suction port 84, an extension pipe. 85 and an operation unit 86.

  The vacuum cleaner 8 drives the single-phase PM motor 3 using the DC power supply 1 as a power supply, performs suction from the suction port body 84, and sucks dust into the dust collection chamber 82 via the extension pipe 85. In use, the user holds the operation unit 86 and operates the vacuum cleaner 8.

  The operation unit 86 is provided with an operation switch 86 a for adjusting the suction amount of the vacuum cleaner 8. The user of the vacuum cleaner 8 operates the operation switch 86a to arbitrarily adjust the suction amount of the vacuum cleaner 8. The suction amount set by the operation unit 86 is the air volume setting value Q ** to be given to the air volume command value generation unit 47 (see FIG. 3). The air volume setting value Q ** is input to the air volume command value generation unit 47, and the air volume command value generation unit 47 outputs the air volume command value Q *. Note that the method of setting the air volume setting value Q ** by the operation unit 86 is an example in the present embodiment, and another method may be used. For example, a method of automatically setting the air volume setting value Q ** according to the sensor 83 may be used, and any method may be used.

  FIG. 10 is a diagram illustrating an example of a configuration of a hand dryer as another application example of the motor driving device according to the first embodiment. 10, the hand dryer 90 includes a casing 91, a hand detection sensor 92, a water receiving section 93, a drain container 94, a cover 96, a sensor 97, and an air inlet 98. An electric blower (not shown) driven by the motor driving device of the first embodiment is provided in the casing 91. The hand dryer 90 has a structure in which water is blown off by blowing with an electric blower by inserting a hand into a hand insertion portion 99 above the water receiving portion 93, and water is stored from the water receiving portion 93 to the drain container 94. ing. The sensor 97 is either a gyro sensor or a human sensor, and the control system of the inverter control unit 4 may be configured to automatically set the air volume setting value Q ** according to the sensor 97.

As described above, the air volume command value Q * is set by the air volume set value Q **, the air volume estimated value Q ^ is controlled according to the air volume command value Q *, and the p-axis current I _{Since p} is controlled, the effective power P is finally controlled according to the air volume Q. Here, the relationship between the air volume Q and the active power P is shown in FIG. As shown in the upper part of FIG. 11, the air volume in the first period is Q1, the air volume in the second period is Q2, and the air volume in the third period is Q3. Further, as shown in the lower part of FIG. 11, the active power in the first period is P1, the active power in the second period is P2, and the active power in the third period is P3. In each of these periods, when it is assumed that the air volume Q matches the air volume set value Q **, the air volume Q2 is larger than the air volume Q1 in FIG. Control is performed so that the active power P2 increases. Further, since the air volume Q3 is smaller than the air volume Q1, the control is performed such that the active power P3 is smaller than the active power P1. As described above, the control system operates so as to control the active power P according to the air volume Q.

Next, the q-axis current command value generator 48 will be described. The q-axis current command value generation unit 48 receives the motor rotation speed estimation value ω _m ^ generated by the motor position / rotation speed detection unit 44, and the q-axis current command value generation unit 48 supplies the q-axis current command value I _q * Is output. The q-axis current _Iq is an operation amount for controlling the reactive power as described above. Reactive power is power that does not contribute to the actual work load. However, when the reactive power increases, the motor current _Im increases, so that the efficiency deteriorates. For this reason, usually, it is set so that the q-axis current command value I _q * = 0. However, when a control method such as a field weakening is also used, the reactive power may be controlled to a value other than zero in accordance with an increase in the rotation speed.

FIG. 12 is a diagram illustrating an example of a case where the q-axis current command value I _q * is controlled to a value other than 0 in the control according to the first embodiment. As shown in FIG. 12, the q-axis current command value _Iq * may be changed at a specific rotation speed ω1 or more. Such control can be realized by holding the table data corresponding to the curve in FIG. 12 in the q-axis current command value generation unit 48. In FIG. 12, the q-axis current command value I _q * is changed according to the rotation speed. However, when the q-axis current command value I _q * is determined according to the driving state of the single-phase PM motor, There is no problem if the airflow command value Q *, the p-axis current _Ip , the p-axis current command value _Ip *, the motor current _{Im, and the} like are set as the determination indexes without being limited to the rotation speed. When a determination index other than the rotation speed is used as a determination index, a control system using the determination index as an input signal of the q-axis current command value generator 48 is, of course, configured.

With the above structure, it is possible that the air volume estimate Q ^ controls the active power in the p-axis current I _p to match the air flow rate command value Q *. At the same time, the reactive power can be controlled by the q-axis current _Iq , and the power factor at the time of driving the motor can be controlled. By performing such control, for example, by controlling the reactive power to be zero, the motor current can be suppressed only to the extent related to the active power. As a result, the motor current is controlled to a minimum, and the copper loss of the motor (loss in winding resistance, etc.), the conduction loss of the inverter (loss due to on-resistance and on-voltage in the switching element), and the switching loss (when the switching element turns on and off) Loss) can be suppressed, so that the efficiency of applied products to which the motor drive device is applied can be improved.

  As described above, according to the motor drive device according to the first embodiment, the airflow of the electric blower driven by the motor drive device is changed by increasing or decreasing the active power supplied to the single-phase PM motor by the single-phase inverter. Therefore, it is possible to perform the air volume control corresponding to the pulsation of the single-phase instantaneous power.

Embodiment 2 FIG.
FIG. 13 is a block diagram illustrating a configuration of the inverter control unit 4 according to the second embodiment. The inverter control unit 4 according to the second embodiment is different from the configuration shown in FIG. 3 in that a pq-axis current correction unit 49 is added as shown in FIG. The pq-axis current correction unit 49 includes a p-axis current I _p and a q-axis current I _q output from the first coordinate conversion unit 431, and a rotor rotation position estimated value output from the motor position / rotation speed detection unit 44. θ _m ^ are input, and a p-axis current correction amount ΔI _p and a q-axis current correction amount which are correction values for suppressing current pulsation in the p-axis current I _p and the q-axis current I _q based on these inputs. Generate ΔI _q . The p-axis current correction amount ΔI _p and the q-axis current correction amount ΔI _q are added to the p-axis current I _p and the q-axis current I _q respectively, and the first current control unit 411 and the second current control unit Is input to the current control unit 412. The other configuration is the same as or equivalent to the configuration shown in FIG. 3, and the same or equivalent components are denoted by the same reference numerals and overlapping description will be omitted.

Next, the operation of the pq-axis current correction unit 49 will be described. First, the conversion equation (Equation (3-1)) in the first coordinate conversion unit 431 that performs the coordinate conversion from the motor current _Im to the p-axis current _Ip will be described again.

Here, the motor current _Im is defined as the equation (4-1) as described above. By substituting the equation (4-1) into the equation (3-1) and transforming the equation, the following equation is obtained. 13) Equation is obtained.

Similarly, the conversion equation (Equation (3-2)) in the second coordinate conversion unit 432 that performs the coordinate conversion from the motor current _Im to the q-axis current _Iq is shown again.

Similarly to the p-axis current _Ip , the following equation (15) is obtained by substituting equation (4-1) into equation (3-2) and deforming the equation.

The above (13) and (15), p-axis current _{I p} and the q-axis current _{I q} is seen to vary at twice the frequency for the motor rotational speed omega _m. Here, the first term of the expression (13) in the p-axis current _Ip is a DC component, and determines the active power in time average. On the other hand, since the second term becomes 0 when time averaged, it does not contribute to the time average active power.

As described above, the p-axis current _Ip and the q-axis current _Iq fluctuate according to the equation (13) or (15). Due to this fluctuation, the p-axis voltage command value _Vp * and the q-axis voltage command value _Vq * also fluctuate with the same components, so that the motor current _Im also fluctuates, that is, current pulsation occurs. Further, the output torque of the motor is proportional to the motor current I _m, for pulsation motor rotational speed omega _m by the motor current I _m pulsates, noise is generated in the single-phase PM motor 3.

Figure 14 is a diagram for explaining a relationship between a p-axis current I _p and p-axis current correction amount [Delta] I _p in the second embodiment. 14, the solid line is (13) waveform shown in formula (However, in FIG. 14, is set to _{√ (2) I m _ rms} = 1 is a coefficient). The correction component for broken lines to cancel the pulsating component contained in the solid line waveform, that is, shows the p-axis current correction amount [Delta] I _p of the waveform, p-axis current correction amount [Delta] I _p the following (16) (However, in FIG. 14 is a coefficient √ (2) is set to _{I m} _ _rms = 1) is set to be.

By adding the pre-correction represents a p-axis current _{I p} (13) indicating the type and p-axis current correction amount [Delta] I _p (16) equation, the value after the _{addition, "√ (2) I m} _ rms / 2 ", and the instantaneous value of the active power component of the motor current I _m is controlled to be constant, pulsating component of p-axis current I _p is removed. That is, current pulsation can be suppressed by controlling using the corrected p-axis current I _p ′, so that the voltage pulsation of the p-axis voltage command V _p * can be suppressed and the p-axis voltage command V _p * distortion can be suppressed. Incidentally, the same control system by applying also the q-axis, it is possible to set the [Delta] I _q with respect to the pulsation of the q-axis current I _q, a constant instantaneous value of the reactive power component of the motor current I _m By performing the control, the pulsation component of the q-axis current _Iq can be removed, and the pulsation and distortion of the q-axis voltage command _Vq * can be suppressed.

  Note that the same function can be implemented using a low-pass filter, but the low-pass filter has a delay time, and the delay time limits the response speed of the current controller. On the other hand, according to the method according to the second embodiment, the pulsating component of the current can be successively removed each time the control is performed. Therefore, the delay time is shorter than the case where the low-pass filter is used, and the current controller is higher. A response can be obtained, and improvement in controllability can be expected.

Embodiment 3 FIG.
FIG. 15 is a block diagram showing a configuration of the inverter control unit 4 according to the third embodiment. The inverter control unit 4 of the third embodiment differs from the configuration shown in FIG. 3 in that an air flow command value correction unit 50 is added as shown in FIG. The wind amount command value correcting unit 50 includes a motor current I _m, the inverter output voltage command value V _{m *} is the output of the second coordinate conversion unit 432, the rotor rotation, which is the output of the motor position and rotation speed detector 44 a position estimate theta _{m ^,} and the air volume estimate Q ^ is the output of the air flow estimation unit 45 is input, air amount command is a correction quantity for suppressing the pulsation in instantaneous active power P _m based on these inputs A value correction amount ΔQ * is generated. The airflow command value correction amount ΔQ * is first added to the airflow command value Q *, then a difference is obtained from the estimated airflow value Q ^, and the difference value is input to the airflow control unit 42. . The other configuration is the same as or equivalent to the configuration shown in FIG. 3, and the same or equivalent components are denoted by the same reference numerals and overlapping description will be omitted.

Next, the operation of the airflow command value correction unit 50 will be described. First, reconsider respect (7) in a single-phase instantaneous power _{P m.} By substituting the equations (13) and (15) into the terms of the p-axis current I _p and the q-axis current I _{q in} the equation (7), the following equation (17) is obtained.

As described above, the first term of the equation (17) represents instantaneous active power, and the second term represents instantaneous reactive power. Hereinafter, the instantaneous active power of the first term is denoted by P _a, the instantaneous reactive power of the second term is expressed as Pn. (17) As is clear from the equation, the instantaneous active power _{P a} is pulsating with _{"cos (2θ m ^)"} .

Further, the mechanical output _{P M} of the single-phase PM motor 3 is expressed by the following equation (18).

In the above equation (18), “τ _m ” is a motor torque. Instantaneous active power Pa are the component that contributes to the rotation of the single-phase PM motor 3, the pulsation of the instantaneous active power P _a is a pulsation of torque tau _m or rotational speed omega _m.

Therefore, air amount command value correcting unit 50 performs compensation control corresponding to the pulsation of the instantaneous active power P _a. Figure 16 is a diagram showing an example of the instantaneous active power P _a and the air volume command value correcting amount Delta] Q * of the waveform. As described above, the air amount command value correcting unit 50, the motor current I _m, * the inverter output voltage command value V _m, the air volume estimate Q ^ and the rotor rotational position estimate theta _{m ^} is input. Air amount command value correcting unit 50, the motor current I _m, the inverter output voltage command value V _{m *} and the rotor rotational position estimate theta _{m ^,} calculates the instantaneous active power P _a with the above equation (17). An example of the instantaneous active power P _a of the waveform is as shown in the upper portion of FIG. 16.

  Further, the air volume command value correction unit 50 generates the air volume command value correction amount ΔQ * using the following equation (19).

In the above equation (19), Q * _ave represents a time average value of the airflow command value Q *. An example of the waveform of the airflow command value correction amount ΔQ * is as shown in the lower part of FIG.

(19) In equation and FIG. 16, the instantaneous active and generates an air flow command value correction amount Delta] Q * such that the phase opposite to the pulsation of the power P _a, air amount command value Q * air volume command value correcting amount Delta] Q The air volume Q and the p-axis current _Ip are controlled based on the corrected air volume command value Q * 'corrected by *. This control instantaneous active power P _a real air quantity Q so as to cancel the pulsation of the control, pulsation of the instantaneous active power P _a can be suppressed. As a result, the pulsation of the rotational speed of the motor and the pulsation of the torque are suppressed at the same time, so that it is possible to reduce the noise of the applied product to which the motor driving device is applied.

  It should be noted that the configuration shown in the above-described embodiment is an example of the content of the present invention, and can be combined with another known technology, and the configuration is not deviated from the gist of the present invention. Can be omitted or changed.

  Reference Signs List 1 DC power supply, 2 single-phase inverter, 3 single-phase PM motor, 3a rotor, 4 inverter control section, 5 motor current detection section, 6 DC power supply voltage detection section, 7 rotor position detection section, 8 vacuum cleaner, 42 air volume control Unit, 44 motor position / rotation speed detection unit, 45 air volume estimation unit, 46 switching element drive signal generation unit, 47 air volume command value generation unit, 48 q-axis current command value generation unit, 49 pq axis current correction unit, 50 air volume command Value correction unit, 81 electric blower, 82 dust collection chamber, 83 sensor, 84 suction port body, 85 extension tube, 86 operation unit, 86a operation switch, 90 hand dryer, 91 casing, 92 hand detection sensor, 93 water receiving unit, 94 drain container, 96 cover, 97 sensor, 98 air inlet, 99 hand insertion part, 100 motor drive device, 211-214 switch Switching element, 221-224 diode, 411 first current controller, 412 second current controller, 431 first coordinate converter, 432 second coordinate converter.

Claims (12)

A motor drive device for driving an electric blower including a single-phase permanent magnet synchronous motor,
A single-phase inverter that includes a plurality of switching elements and applies an AC voltage to the single-phase permanent magnet synchronous motor;
A current detection unit that outputs a signal corresponding to a motor current flowing through the single-phase permanent magnet synchronous motor,
A DC power supply voltage detection unit that detects a voltage of a DC power supply that supplies power to the single-phase inverter;
An inverter control unit that receives the motor current and outputs a drive signal to the switching element of the single-phase inverter,
With
The motor drive device, wherein the single-phase inverter increases / decreases active power or reactive power supplied to the single-phase permanent magnet synchronous motor, and changes the rotation speed of the motor by increasing / decreasing the active power or the reactive power. A motor drive device for driving an electric blower including a single-phase permanent magnet synchronous motor,
A single-phase inverter that includes a plurality of switching elements and rotates a rotor of the single-phase permanent magnet synchronous motor by applying an AC voltage to the single-phase permanent magnet synchronous motor,
A current detection unit that outputs a signal corresponding to a motor current flowing through the single-phase permanent magnet synchronous motor,
An inverter control unit that receives the motor current and outputs a drive signal to the switching element of the single-phase inverter,
With
The motor drive device, wherein the inverter control unit increases or decreases the active power component or the reactive power component of the motor current, and changes the rotation speed of the motor by increasing or decreasing the active power component or the reactive power component. The motor drive device according to claim 1, wherein the inverter includes a DC power supply voltage detection unit. The inverter control unit includes:
A coordinate conversion unit that performs coordinate conversion of the motor current into an active power component and a reactive power component,
A first current control unit that controls an active power component of the motor current;
With
The motor drive device according to any one of claims 1 to 3, wherein an active power component of the motor current is controlled according to an air volume. The inverter control unit includes:
A coordinate conversion unit that performs coordinate conversion of the motor current into an active power component and a reactive power component,
A second current control unit that controls a reactive power component of the motor current;
With
The motor drive device according to any one of claims 1 to 3, wherein a reactive power component of the motor current is controlled according to a drive state of the single-phase permanent magnet synchronous motor.   The motor drive device according to claim 5, wherein the driving state of the single-phase permanent magnet synchronous motor is a motor current flowing through the single-phase permanent magnet synchronous motor.   The motor drive device according to claim 5, wherein the driving state of the single-phase permanent magnet synchronous motor is a rotation speed of the single-phase permanent magnet synchronous motor. The inverter control unit includes a current correction unit that corrects the active power component of the motor current and the reactive power component of the motor current,
The current correction unit corrects at least one of the active power component and the reactive power component according to the motor current and a rotor rotation position of the single-phase permanent magnet synchronous motor. 2. The motor drive device according to claim 1. The motor drive device according to claim 8, wherein the inverter control unit controls at least one of an instantaneous value of an active power component of the motor current and an instantaneous value of a reactive power component of the motor current to be constant. The inverter control unit includes an air volume command value generation unit that generates an air volume command value,
The motor drive device according to any one of claims 1 to 7, wherein the air volume command value generation unit generates an air volume command value according to an instantaneous value of active power supplied to the single-phase permanent magnet synchronous motor.   An electric vacuum cleaner equipped with the motor drive device according to claim 1.   A hand dryer equipped with the motor drive device according to claim 1.

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