JP5116620B2 - Electric motor drive device and refrigeration air conditioner - Google Patents

Description

  The present invention relates to an electric motor drive device and a refrigeration air conditioner including the drive device.

Conventionally, as a method for obtaining electric power of a motor drive device, “in a motor control method, a voltage command is Vref, a d-axis component is vd *, a q-axis component is vq *, and a d-axis component of a voltage detection value is vd, q Inverter output using the inner product (vd ** id + vq ** iq) or (vd * id + vq * iq) where the axis component is vq, the d-axis component of the current detection value is id, and the q-axis component is iq. "Calculate the power Pinv" (Patent Document 1).
In addition, “motor rotation angular frequency, torque command, d-axis voltage and q-axis voltage expressed in dq-axis orthogonal coordinates rotating in synchronization with the motor rotor, and d-axis current and q-axis current are input. The inverter output active power command and the inverter output active power are calculated, and the current phase correction value such that the calculated active power follows the active power command is calculated as a correction value for the d-axis current command and the q-axis current command calculation. In other words, there is an active power control means for outputting the output (Patent Document 2).
Furthermore, “a power calculation device that obtains power consumption of an electric motor based on an inverter voltage command obtained from the speed information of the electric vehicle and an electric current command supplied to the electric motor and an electric current command supplied to the electric motor and an electric current command supplied to the electric motor, and a filter capacitor voltage There is also a detection device and a voltage control device that controls the filter capacitor voltage by using the electric power consumption of the electric motor, the target value of the filter capacitor voltage, and the detected value of the filter capacitor voltage obtained by the power calculation device (patent) Reference 3).

  Patent Document 4 below discloses a technique related to sensorless control.

Japanese Patent Laid-Open No. 11-235100 (page 4, FIGS. 1 to 4) JP 2000-116198 A (pages 18-19, FIG. 5, FIG. 8) Japanese Patent Laying-Open No. 2005-218186 (Pages 5-7, FIGS. 1-2) JP 2002-191197 A

When the power calculation method disclosed in Patent Document 1 is used, the power can be accurately calculated when the voltage detection values vd and vq are used, but a circuit for detecting the voltage is required separately. This increases the cost and is not practical. In addition, when vd * and vq * are used instead of vd and vq, in the overmodulation region where the modulation factor, which is the ratio of the voltage command value to the DC voltage value supplied to the inverter, exceeds 1, the voltage A large error occurs between the command value and the actually output voltage, and accurate power cannot be calculated.
Further, the conventional technique disclosed in Patent Document 2 also has a problem that, as in Patent Document 1, accurate power cannot be obtained in the overmodulation region, and effective power control cannot be performed with high accuracy.
Further, the prior art disclosed in Patent Document 3 also has a problem that, as in Patent Document 1 and Patent Document 2, an error occurs in power consumption obtained in the overmodulation region, and voltage control cannot be performed with high accuracy. .
Further, in the conventional technique disclosed in Patent Document 4, the overmodulation region can be operated. In this overmodulation region, the voltage command value and the voltage applied to the motor do not match, and the voltage command value and There is a problem that it is difficult to accurately estimate the power consumption from the current.

The present invention has been made to solve the above-described problems, and a first object is to accurately calculate the power consumption of the motor drive device even when the motor is operating in the overmodulation region. The second purpose is to achieve energy savings, reduce CO ₂ emissions, and reduce the aging caused by the heat generated by the equipment. The object is to obtain a high electric motor drive device and a refrigeration air conditioner.

An electric motor driving apparatus according to the present invention includes an inverter that converts a DC voltage into an AC voltage and applies the AC voltage to the motor, current detection means that detects a phase current flowing through the motor, and a DC voltage applied to the inverter. a DC voltage detecting means for a control unit included in the inverter to control the voltage applied to the motor, and a position phase error memory unit, before Symbol control means, said current detecting means quadrature phase current detected is 2 Coordinate conversion means for converting d-axis current Id and q-axis current Iq as currents on the axis coordinates, and voltage on the orthogonal two-axis coordinates applied to the motor based on the output of the coordinate conversion means and a predetermined reference value Voltage command value calculation means for outputting a d-axis voltage command value Vd * and a q-axis voltage command value Vq * as command values for the d-axis, and d-axis voltage command values Vd * and q which are voltage command values on the orthogonal two-axis coordinates Shaft electric A command value Vq *, the modulation factor calculating means for obtaining a modulation rate by said DC voltage, the voltage utilization rate is a percentage of the output voltage to the modulation factor and its the modulation rate which is the output of the modulation factor computation means previously Obtaining and storing the correspondence relationship between the modulation factor and the voltage utilization factor, and obtaining the voltage utilization factor, the voltage utilization for obtaining the voltage utilization factor from the modulation factor based on the correspondence relationship stored in advance Rate calculation means, d-axis voltage command value Vd * and q-axis voltage command value Vq * which are voltage command values on the orthogonal two-axis coordinates, and d-axis current Id and q-axis which are currents on the orthogonal two-axis coordinates obtains an inner product between current Iq, for the calculated inner product, by dividing the modulation factor as well as multiplying the voltage utilization rate, and a power consumption calculating means for calculating the power consumption of the electric motor, wherein Phase error The storage means stores in advance the relationship between the phase error between the voltage applied to the motor and the command value of the voltage, and the output of the modulation factor calculation means included in the control means or the modulation factor correction means included in the control means. The power consumption calculation means corrects the output of the voltage command value calculation means based on the phase error stored in the phase error storage means when determining the power consumption of the motor.

  According to the motor drive device of the present invention, power consumption can be calculated accurately even in an overmodulation region where the modulation factor, which is the ratio of the voltage command value to the DC voltage value supplied to the inverter, exceeds 1. It becomes possible to do.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of an electric motor drive device according to Embodiment 1 of the present invention.
In FIG. 1, 1 is a DC power source, 2 is a motor drive device according to the first embodiment, and 3 is an electric motor.

  FIG. 2 is an analysis model diagram of the electric motor 3. FIG. 2 shows U-phase, V-phase, and W-phase armature winding fixed axes. Reference numeral 4 denotes a permanent magnet constituting the rotor of the electric motor 3. In a rotating coordinate system that rotates at the same speed as the magnetic flux produced by the permanent magnet 4, the direction of the magnetic flux produced by the permanent magnet 4 is taken as the d-axis, and the estimated control axis corresponding to the d-axis is taken as the γ-axis. Although not shown, the q axis is taken as a phase advanced by 90 degrees in electrical angle from the d axis, and the estimated δ axis is taken as phase advanced by 90 degrees in electrical angle from the γ axis. The coordinate axis of the rotating coordinate system in which the d axis and the q axis are selected as the coordinate axes is referred to as the dq axis. The rotating coordinate system for control by the inverter is a coordinate system in which the γ axis and the δ axis are selected as coordinate axes, and the coordinate axes are called γδ axes.

  The dq axis is rotating, and the rotation speed of the electric motor 3 that is the rotation speed is referred to as an electric motor rotation speed ω. The γδ axis is also rotating, and the rotation speed is called an inverter rotation speed ω1. In addition, in the dq axis rotating at a certain moment, the phase of the d axis is represented by the motor rotation phase θ with reference to the U-phase armature winding fixed axis. Similarly, in the γδ axis that is rotating at a certain moment, the phase of the γ axis is expressed by the inverter rotation phase θ1 with the U-phase armature winding fixed axis as a reference. Then, the axis error Δθ between the d-axis and the γ-axis is expressed by Δθ = θ−θ1.

  As the γδ axis, the dq axis is estimated. In actual operation, the axis may be operated where the axis error Δθ is small, and the dq axis and the γδ axis can be regarded as the same. For this reason, the following description will be made assuming that the dq axis is used unless otherwise specified. Needless to say, the γδ axis can be realized with the same configuration.

  The electric motor drive device 2 includes an inverter main circuit 5, current detection means 6, DC voltage detection means 7, and inverter control means 8.

  The inverter main circuit 5 includes switching elements such as IGBTs and MOSFETs, and each switching element includes a free-wheeling diode connected in parallel.

The current detection means 6 detects U-phase current, V-phase current, and W-phase current flowing into the electric motor 3 and outputs them to the inverter control means 8.
The DC voltage detection means 7 detects the voltage of the DC power supply 1 applied to the inverter main circuit 5 and outputs it to the inverter control means 8.
The inverter control means 8 outputs a drive signal based on the outputs of the current detection means 6 and the DC voltage means 7 and controls on / off of the switching elements in the inverter main circuit 5.

  The inverter control means 8 is connected to the inverter main circuit 5 based on the outputs Iu, Iv, Iw of the current detection means 6, the output Vdc of the DC voltage detection means 7, the rotational speed command ω * and the d-axis current command Id * input from the outside. A drive signal for turning on / off the switching element is output, and includes a coordinate conversion unit 9, a voltage utilization rate calculation unit 10, a power consumption calculation unit 11, and an applied voltage control unit 12.

  The coordinate conversion means 9 uses the electric motor rotation phase θ obtained from the applied voltage control means 12 to convert the currents (Iu, Iv, Iw) output from the current detection means 6 into the d-axis current Id and the q-axis current Iq. Convert to and output.

  The voltage utilization rate calculating means 10 outputs a voltage utilization rate Kv based on the modulation rate Vk obtained from the applied voltage control means 12.

  The power consumption calculation means 11 includes outputs (Id, Iq) from the coordinate conversion means 9, dq axis voltage command values Vd * and Vq * output from the applied voltage control means 12, modulation rate Vk, and voltage utilization rate calculation means. Based on the voltage utilization rate Kv output from the motor, the power consumption P of the motor drive device is obtained by calculation. A method for calculating the power consumption P will be described later.

  The applied voltage control unit 12 includes a speed compensation unit 13, an integration unit 14, a voltage command calculation unit 15, a modulation factor / phase command calculation unit 16, and a drive signal generation unit 17.

  Based on the q-axis current Iq output from the coordinate conversion means 9, the speed compensation means 13 compensates the speed of the rotational speed command ω * by the following equation (1) and outputs an inverter rotational speed command ω1.

ここで、Ｋｍは定数、ωｓｐｉは定数、ｓはラプラス演算子である。

Here, Km is a constant, ωspi is a constant, and s is a Laplace operator.

  The integrating means 14 integrates ω1 output from the speed compensating means 13 and outputs the motor rotation phase θ.

The voltage command calculation means 15 outputs the dq axis voltage command values Vd * and Vq * based on the inverter rotation speed command ω1, the d axis current command value Id *, and the dq axis detection currents Id and Iq.
In the above example, the voltage command values Vd * and Vq * are output based on the rotation speed command ω * and the d-axis current command value Id *. However, the motors such as winding resistance, winding inductance, induced voltage constant, etc. Voltage command values Vd * and Vq * may be output based on parameters and torque commands.

  The modulation factor / phase command calculation means 16 is based on the DC voltage Vdc output from the DC voltage detection means 7, the dq axis voltage commands Vd * and Vq *, and the motor rotation phase θ, and the modulation rate Vk and phase command θ *. Is output. An equation for calculating the modulation factor Vk will be described later. The phase command θ * is calculated based on the following equation (2).

但し、θｖは図５で示すように、回転角θで回転している直交２軸の回転座標に存在する｜Ｖ＊｜とｄ軸とのなす位相角である。

However, as shown in FIG. 5, θv is a phase angle formed by | V * | present in the rotation coordinates of two orthogonal axes rotating at the rotation angle θ and the d-axis.

  The drive signal generation unit 17 outputs a drive signal based on the modulation rate Vk and the phase command θ *, which are outputs of the modulation rate / phase command calculation unit 16, and operates the inverter main circuit 5 to drive the electric motor 3. To drive.

Here, an example of the power consumption calculation method in the power consumption calculation means 11 will be described.
The power consumption, that is, the effective power of the motor 3 is generally expressed by the equation (3) using the effective value | V | of the voltage applied to the motor 3, the effective value | I | of the flowing current, and the phase difference φ between the voltage and the current. Is done.

  Here, assuming that the voltage and current vectors exist on the dq coordinate shown in FIG. 4, assuming that the angle between the d axis and the voltage is θv, and the angle between the d axis and the current is θi, the equation (3 ) Can be expressed by the following equation (4).

  As is apparent from the equation (4), the power consumption P of the motor 3 can be obtained by the inner product of the dq axis voltage and current. That is, even when the power consumption is similarly obtained using the voltages Vγ and Vδ on the γδ axis and the currents Iγ and Iδ described above, the power consumption calculation means 11 obtains the power consumption P by the inner product. Needless to say, there is no problem on the γδ axis because the inner product has no axis error Φ and is not affected by the axis error.

  However, as shown in FIG. 5, in the overmodulation region, the voltage vector exceeds the limit value of the output voltage, and the actually output voltage is saturated. Therefore, the value of the modulation factor Vk is larger than 1 as is apparent from the following equation (5).

  That is, when power is obtained using voltage commands Vd * and Vq * as in the prior art in the overmodulation region, there is a problem that the actual power consumption does not match the power consumption calculation value.

  Therefore, the power consumption calculating means 11 converts the voltage commands Vd1 and Vq1 corresponding to the modulation factor 1 using the following equations (6a) and (6b).

  However, actually, even if the modulation factor exceeds 1, the voltage can be output up to the output voltage limit value in FIG. Therefore, in the region where the modulation factor exceeds 1, the voltage utilization factor calculation means 10 obtains and stores in advance the relationship of the voltage utilization factor Kv, which is the ratio of the output voltage to the modulation factor Vk, as shown in FIG. The power consumption calculation means 11 is actually output by multiplying the expression (6a) and the expression (6b) by Kv output from the voltage utilization rate calculation means 10 as shown in the expressions (7a) and (7b). The voltages Vd_real and Vq_real can be obtained.

  The power consumption calculating means 11 can obtain the power consumption shown in the following equation (8) by using Vd_real and Vq_real in equations (7a) and (7b) instead of Vd and Vq in equation (4). it can.

  FIG. 7 shows a flowchart for obtaining the power consumption of the present invention. Next, the power consumption calculation operation will be described with reference to FIG. When the modulation rate Vk is 1 or less (No in step S1), the power consumption calculation unit 11 sets the modulation rate Vk and the voltage utilization rate Kv to 1 (step S2) and formula (8) To obtain the power (step S3). In the overmodulation region where the modulation factor Vk exceeds 1 (Yes in step S1), the power consumption calculation means 11 obtains the voltage utilization factor Kv based on the relationship of FIG. 6 (step S4), and the equations (7a) (7b) ) To obtain the actual voltage (step S5), and then obtain the power consumption by equation (8) (step S6). Thereby, it becomes possible to obtain | require power consumption accurately.

  Therefore, for example, the inverter control means 8 displays the power consumption P obtained by the power consumption calculation means 11 on a display device such as a liquid crystal provided outside the inverter control means 8 to inform the user of the power consumption P, and this consumption When the electric power P reaches a certain value, the notification information such as a buzzer is output and notified, so that it is possible to notify the waste of energy and to save energy.

Further, the inverter control means 8 can improve the energy saving performance by controlling the d-axis current command value in FIG. 3 so that the obtained power consumption P is minimized, so that the CO ₂ emission amount is also reduced. It is possible to provide a motor drive device capable of taking measures against global warming. For example, the power consumption as shown in FIG. 8 is obtained periodically during the operation of the electric motor 3 at a predetermined period to obtain the slope d represented by the following equation (9). When the slope d is negative, the d-axis current command value Id * Increase and decrease d-axis current command value Id * when the slope becomes positive. By periodically repeating such an operation, the minimum value of the power consumption P can be easily obtained.

但し、Ｐ(ｎ）は現在（ｎとする）の消費電力の演算値、Ｐ(ｎ−１)は１つ前の周期における消費電力の演算値、Ｉｄ＊(ｎ)は現在のｄ軸電流指令値、Ｉｄ＊(ｎ−１)は１つ前の周期におけるｄ軸電流指令値である。
また、消費電力が最小となることにより、発熱等も抑えられるため、熱による経年劣化も少なく、信頼性の高い電動機の駆動装置を提供できるだけでなく、放熱板等も小型化可能となり、低コスト化も図れる。

Where P (n) is the current (n) calculated power consumption value, P (n−1) is the previous power consumption calculated value, and Id * (n) is the current d-axis current. The command value, Id * (n−1), is the d-axis current command value in the previous cycle.
In addition, since heat generation is suppressed by minimizing power consumption, it is possible not only to provide a highly reliable motor drive device with little deterioration over time due to heat, but also to reduce the size of the heat sink, etc. Can also be achieved.

  Furthermore, the inverter control means 8 stores the upper limit value of the power consumption P in advance, and drives the motor at the maximum number of revolutions that does not exceed the upper limit value of the power consumption. Thereby, the electric motor 3 can exhibit the maximum capability, and when applied to a refrigeration air conditioner, for example, it becomes possible to greatly improve the cooling and heating capability. In addition, by setting the upper limit value of the power consumption P to be low, it is possible to suppress the power consumption P, and it is possible to provide a motor drive device with high energy savings.

  Further, step-out detection means (not shown) for detecting the step-out state of the electric motor 3 based on the change in the output of the power consumption calculation means 11 may be provided. Thereby, even when the load applied to the electric motor 3 changes suddenly and the electric motor 3 falls into a step-out state, the inverter control means 8 can detect the step-out state of the electric motor 3 based on the output of the step-out detection means. By restarting the electric motor 3, it is possible to quickly return the electric motor 3, and it is possible to provide an electric motor drive device with high reliability and customer satisfaction.

  The inverter control means 8 can also calculate the fee based on the output of the power consumption calculation means 11 and display it on a display device provided outside to support the charging service.

Embodiment 2. FIG.
In the first embodiment, the method for accurately obtaining the power consumption in the overmodulation region has been described.
Embodiment 2 of the present invention relates to a method for obtaining power consumption with high accuracy when the modulation factor Vk is corrected so that the voltage command and the output voltage are output on a one-to-one basis in the overmodulation region where the output voltage is saturated. explain.

FIG. 9 is a diagram showing the configuration of the electric motor drive device according to Embodiment 2 of the present invention.
Since the second embodiment is the same as the first embodiment except that it includes the modulation rate correction means 18, the same reference numerals as those in the first embodiment are given and the description thereof is omitted.

  First, the modulation rate correction means 18 will be described. The modulation rate correction means 18 receives the modulation rate Vk output from the modulation rate / phase command calculation means 16, outputs the correction modulation rate Vk ′, and operates the drive signal generation means 17.

  As shown in FIG. 10, the modulation factor correction means 18 has a linear relationship between the modulation factor Vk and the voltage utilization factor Kv in the region where the modulation factor Vk is 1 or less. The values match. However, in the overmodulation region where the modulation factor Vk exceeds 1, the output voltage is saturated and becomes a non-linear characteristic. Therefore, as shown in FIG. 11, the correction modulation rate Vk ′ is used for the modulation rate Vk as shown in FIG. 12 so that the voltage utilization rate Kv has a linear characteristic with respect to the modulation rate Vk. Note that the modulation factor correction means 18 may calculate the correction modulation factor Vk ′ in the overmodulation region by an inverse function of a function of the voltage utilization factor Kv with respect to the modulation factor Vk.

  However, when this method is used, the voltage can be effectively used by increasing the output voltage, but the method of the first embodiment has a problem that the power consumption cannot be obtained with high accuracy.

  Therefore, the voltage utilization rate calculation means 10 obtains the voltage utilization rate Kv based on the corrected modulation rate Vk ′ that is the output of the modulation rate correction means 18. Next, the power consumption calculating means 11 can accurately determine the power consumption P using the obtained voltage utilization rate Kv, the modulation rate Vk, the dq axis voltage, and the current.

  Therefore, since the capacity of the motor can be improved by increasing the output voltage and the power consumption can be calculated with high accuracy, the d-axis is obtained in the same manner as in the first embodiment so that the power consumption is minimized based on the power consumption obtained by the calculation. By controlling the current command value Id *, an energy-saving and high-performance motor drive device can be provided.

Embodiment 3 FIG.
In the first embodiment and the second embodiment, the calculation method of power consumption when there is no influence by the dead time has been described.
In the third embodiment, a method for reducing the influence of the short-circuit prevention time (dead time) used for preventing the short circuit of the upper and lower switching elements when the inverter main circuit is driven will be described.

  FIG. 13 is an example of the inverter main circuit 5. Here, the inverter main circuit 5 includes six switching elements 19a to 19f and six freewheeling diodes 20a to 20f. For example, if 19d is turned on at the moment when 19a is turned off, there is a possibility that a time for turning on at the same time may occur, and the inverter main circuit 5 may be destroyed. Therefore, as shown in FIG. 13, a method of preventing destruction of the inverter by providing a dead time and suppressing simultaneous ON is generally used. However, there is a problem that a voltage that should be output cannot be output due to the drive signal being cut due to dead time, and there is a problem that the voltage command and the actual output voltage value do not match. For this reason, for example, when the voltage command values Vd * and Vq * for the d-axis and the q-axis are used in the above-described power consumption calculation formula, there is a possibility that accurate power consumption cannot be obtained.

FIG. 14 is a diagram showing the configuration of the electric motor drive device according to Embodiment 3 of the present invention.
Since the third embodiment is the same as the first embodiment except that the dead time correcting means 21 is provided, the same reference numerals as those in the first embodiment are given and description thereof is omitted.

  The dead time correction means 21 generates dead time correction amounts ΔVu, ΔVv, ΔVw based on the U phase, V phase, and W phase currents Iu, Iv, Iw, and outputs the dead time correction amounts to the drive signal generation means 17. By correcting the voltage error caused by the time, the voltage command and the actual output voltage value can be matched, and the power consumption calculation error can be reduced.

  FIG. 15 shows a general dead time correction method. For example, the U-phase dead time correction amount ΔVu is obtained by the following equation (10) using the polarity of the U-phase current Iu.

ただし、Ｔｄはデッドタイム、fcはキャリア周波数、Vdcは直流電圧である。また、sign関数は次式（１１）の通りである。

However, Td is a dead time, fc is a carrier frequency, and Vdc is a DC voltage. The sign function is as shown in the following equation (11).

同様にＶ相、Ｗ相については次式（１２）及び（１３）となる。

Similarly, for the V phase and the W phase, the following equations (12) and (13) are obtained.

  In addition to the method of correcting the dead time of the drive signal output from the inverter control means 8, the dead time is determined by using the voltage error estimating means 22 for the voltage commands Vd * and Vq * on the dq axis as shown in FIG. A method for accurately calculating the power consumption of the motor by estimating the actual voltages Vd_real and Vq_real of the actual voltage dq axis by considering the voltage error generated by the above will be described. Vd_real and Vq_real are expressed by the following equation (14) using voltage errors ΔVd and ΔVq of the dq axis.

よって、このＶｄ＿ｒｅａｌおよびＶｑ＿ｒｅａｌを式（８）のＶｄ＊およびＶｑ＊と置き換えることで、デッドタイムによる電圧誤差の影響を考慮した精度の良い電動機の消費電力方法を得ることが出来る。

Therefore, by replacing these Vd_real and Vq_real with Vd * and Vq * in the equation (8), it is possible to obtain an accurate electric power consumption method of the motor in consideration of the influence of the voltage error due to the dead time.

  Next, how to obtain Vd_real and Vq_real will be described. According to FIG. 15, it is possible to match the voltage command with the actual output voltage value by correcting the drive signal by the drive signal generation means using the dead time correction amount for the voltage error due to the dead time. is there. In other words, the dead time correction amount can be regarded as a voltage error caused by the dead time. Since the equations (10), (12), and (13) are the values of the UVW phase, as shown in the equation (15), the values are converted into the αβ axis values ΔVα and ΔVβ of the orthogonal stator coordinates.

また、ｄｑ軸上の値には、回転位相θを用いて次式（１６）にて変換可能である。

The value on the dq axis can be converted by the following equation (16) using the rotational phase θ.

式（１６）により得られたΔＶｄおよびΔＶｑを式（１４）に適用することで、Ｖｄ＿ｒｅａｌおよびＶｑ＿ｒｅａｌを得ることができる。ここで説明しているデッドタイム補正やデッドタイムによる電圧誤差の求め方は一例であり、その他の方法を用いても問題ないことは言うまでもない。

By applying ΔVd and ΔVq obtained by Expression (16) to Expression (14), Vd_real and Vq_real can be obtained. The method for determining the dead time correction and the voltage error due to the dead time described here is merely an example, and it goes without saying that other methods can be used.

  However, if the above-described dead time correction is performed when this method is used, it is needless to say that only one of them needs to be used because the dead time is corrected.

Embodiment 4 FIG.
The inverter control means 8 is a discrete control in which an arithmetic unit such as a microcomputer detects a current every certain control cycle, calculates a voltage command value, and applies the calculated voltage command value as a voltage to the motor. Therefore, as shown in FIG. 17, an error (delay) occurs in the phase between the voltage command and the actual output voltage. In addition, in the overmodulation region where the modulation factor Vk exceeds 1, the output voltage is limited, and as shown in FIG. 18, when the output voltage becomes trapezoidal and the modulation factor becomes infinite, a rectangular wave shape is obtained. For this reason, harmonic components are superimposed on the voltage command, and similarly, an error occurs between the phase of the voltage command and the actual output voltage.
In the fourth embodiment, a correction method when an error occurs between the phase of the voltage command and the output voltage will be described.

FIG. 19 is a diagram showing a configuration of a motor drive device according to Embodiment 4 of the present invention.
Since the fourth embodiment is the same as the first embodiment except that the voltage correction means 23 is provided, the same reference numerals as those in the first embodiment are given and description thereof is omitted.

  The voltage correction unit 23 corrects the d-axis voltage command Vd * and the q-axis voltage command Vq * according to the modulation factor Vk, and outputs corrected voltages Vdh and Vqh.

  FIG. 20 is a diagram illustrating the operation of the voltage correction unit 23. The voltage correction unit 23 includes a voltage phase error calculation unit 24. The voltage phase error calculation means 24 outputs a voltage phase error Δθv based on the modulation factor Vk.

  Here, as shown in FIG. 21, when the length of the voltage vector is not changed and the phase of the voltage command vector and the output voltage vector is shifted by Δθv, the dq axis voltage Vdh of the output voltage vector and Vqh is obtained by the following equation (17) as shown in FIG.

  Δθv tends to depend on the modulation rate Vk. Therefore, the relationship between the modulation factor Vk and Δθv is obtained in advance, stored in a storage means such as a memory in a table, and this is referred to when necessary, thereby increasing the load on a processing device such as a microcomputer. Therefore, Δθv can be obtained, and the dq-axis voltages Vdh and Vqh of the output voltage vector can be obtained using the equation (14). By using Vdh and Vqh instead of Vd * and Vq * in Expression (6), it is possible to obtain power consumption with higher accuracy.

  That is, even in an inexpensive system in which the control cycle cannot be reduced, it is possible to obtain power consumption with high accuracy, and cost can be reduced.

  Here, in the configuration shown in the second embodiment, it goes without saying that there is no problem even if the voltage correction means 23 uses the correction modulation rate Vk ′ instead of the modulation rate Vk.

Embodiment 5 FIG.
As examples of the use of the electric motor drive device described in the first to fourth embodiments, there are refrigeration air conditioners such as an air conditioner and a refrigerator.

  The refrigerating and air-conditioning apparatus has a feature that the load applied to the driving device of the electric motor varies greatly depending on the operating environment such as the outside air temperature. If the load changes suddenly, the electric motor cannot withstand the load and may cause a phenomenon such as step-out.

  Therefore, the step-out state can be detected based on the power consumption obtained by the power consumption calculation unit 11 described in the first to fourth embodiments, and the step-out can be detected and restarted promptly. Thus, a highly reliable refrigeration air conditioner can be provided.

  Also, store the maximum power consumption of the refrigeration air conditioner in advance, and if there is a risk of reaching the maximum power consumption, take measures such as reducing the motor speed in advance to prevent step-out. The operation can be continued and a highly reliable refrigeration air conditioner can be provided.

Furthermore, by determining the power consumption to be used in advance and controlling the electric motor so as not to exceed the determined power consumption, it is possible to suppress power consumption, reduce CO ₂ emissions and reduce global warming. It is possible to provide a refrigeration air conditioner that takes into account.

  Examples of utilization of the present invention include compressor inverters and blower inverters. In addition, examples of utilizing a compressor include an air conditioner, a refrigerator, a refrigerator, a dehumidifier, and a hot water heater. Furthermore, a ventilation fan, an air cleaner, a humidifier, etc. are mentioned as an example of utilization which mounts an air blower.

It is a figure which shows the structure of the drive device of an electric motor. It is a figure which shows the coordinate relationship with respect to rotation of an electric motor. It is a figure which shows the structure of the drive device of the electric motor which concerns on Embodiment 1. FIG. It is a figure which shows the relationship between a voltage and an electric current vector. It is a figure which shows the relationship between a modulation factor and a voltage utilization factor. It is a figure which shows operation | movement of the drive device of the conventional electric motor. It is a figure which shows the flowchart for calculating | requiring power consumption. It is a figure which shows the relationship between d-axis current command and power consumption. FIG. 5 is a diagram illustrating a configuration of a drive device for an electric motor according to a second embodiment. It is a figure which shows the relationship between a modulation factor and a voltage utilization factor. It is the figure which showed the method of linearizing a voltage utilization factor. It is a figure which shows the relationship of the correction | amendment modulation rate with respect to a modulation rate. FIG. 3 is a diagram illustrating a configuration of an inverter main circuit 5. FIG. 5 is a diagram illustrating a configuration of a motor drive device according to a third embodiment. The correction of the voltage error due to the dead time will be described. FIG. 10 is a diagram showing a configuration of another electric motor drive device according to Embodiment 3; It is a figure showing the phase error of a voltage command and output voltage. It is a figure which shows the voltage command waveform in an overmodulation area | region. FIG. 10 is a diagram illustrating a configuration of a drive device for an electric motor according to a fourth embodiment. FIG. 6 is a diagram showing the operation of the voltage correction means 23. It is a figure which shows the relationship between an output voltage vector and a voltage command vector.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 DC power supply, 2 Motor drive device, 3 Electric motor, 4 Permanent magnet, 5 Inverter main circuit, 6 Current detection means, 7 DC voltage detection means, 8 Inverter control means, 9 Coordinate conversion means, 10 Voltage utilization rate calculation means, DESCRIPTION OF SYMBOLS 11 Power consumption calculating means, 12 Applied voltage control means, 13 Speed compensation means, 14 Integration means, 15 Voltage command calculation means, 16 Modulation rate / phase command calculation means, 17 Drive signal generation means, 18 Modulation rate correction means, 19 Switching 20 elements, 20 freewheeling diodes, 21 dead time correction means, 22 voltage error estimation means, 23 voltage correction means, 24 voltage phase error calculation means.

Claims (16)

An inverter that converts DC voltage to AC voltage and applies it to the motor;
Current detecting means for detecting a phase current flowing in the electric motor;
DC voltage detecting means for detecting a DC voltage applied to the inverter;
Control means for controlling the voltage applied to the electric motor by the inverter;
And phase error storage means,
Equipped with a,
Before Symbol control means,
Coordinate conversion means for converting the phase current detected by the current detection means into a d-axis current Id and a q-axis current Iq as a current on orthogonal two-axis coordinates;
A voltage that outputs a d-axis voltage command value Vd * and a q-axis voltage command value Vq * as a command value of a voltage on the orthogonal two-axis coordinate applied to the electric motor based on the output of the coordinate conversion means and a predetermined reference value. Command value calculation means;
A modulation rate calculation means for obtaining a modulation rate from the d-axis voltage command value Vd * and q-axis voltage command value Vq *, which are voltage command values on the orthogonal two-axis coordinates, and the DC voltage;
The modulation factor that is the output of the modulation factor calculator and a voltage utilization factor that is a ratio of the output voltage to the modulation factor are obtained in advance, and a correspondence relationship between the modulation factor and the voltage utilization factor is stored, When obtaining the voltage utilization factor, voltage utilization factor calculating means for obtaining the voltage utilization factor from the modulation factor based on the correspondence stored in advance,
The inner product of the d-axis voltage command value Vd * and q-axis voltage command value Vq *, which are voltage command values on the orthogonal two-axis coordinates, and the d-axis current Id and q-axis current Iq, which are currents on the orthogonal two-axis coordinates. Power consumption calculating means for determining the power consumption of the motor by multiplying the determined inner product by the voltage utilization factor and dividing the modulation factor;
With
The phase error storage means includes
Preliminarily storing the relationship between the phase error between the voltage applied to the electric motor and the command value of the voltage, and the output of the modulation factor correction unit included in the control unit or the modulation factor correction unit included in the control unit,
The electric power consumption calculation means corrects the output of the voltage command value calculation means based on the phase error stored in the phase error storage means when determining the electric power consumption of the electric motor. . An inverter that converts DC voltage to AC voltage and applies it to the motor;
Current detecting means for detecting a phase current flowing in the electric motor;
DC voltage detecting means for detecting a DC voltage applied to the inverter;
Control means for controlling the voltage applied to the electric motor by the inverter;
And phase error storage means,
Equipped with a,
Before Symbol control means,
Coordinate conversion means for converting the phase current detected by the current detection means into a d-axis current Id and a q-axis current Iq as a current on orthogonal two-axis coordinates;
A voltage that outputs a d-axis voltage command value Vd * and a q-axis voltage command value Vq * as a command value of a voltage on the orthogonal two-axis coordinate applied to the electric motor based on the output of the coordinate conversion means and a predetermined reference value. Command value calculation means;
A modulation rate calculation means for obtaining a modulation rate from the d-axis voltage command value Vd * and q-axis voltage command value Vq *, which are voltage command values on the orthogonal two-axis coordinates, and the DC voltage;
The modulation factor that is the output of the modulation factor calculator and a voltage utilization factor that is a ratio of the output voltage to the modulation factor are obtained in advance, and a correspondence relationship between the modulation factor and the voltage utilization factor is stored, When obtaining the voltage utilization factor, voltage utilization factor calculating means for obtaining the voltage utilization factor from the modulation factor based on the correspondence stored in advance,
The inner product of the d-axis voltage command value Vd * and q-axis voltage command value Vq *, which are voltage command values on the orthogonal two-axis coordinates, and the d-axis current Id and q-axis current Iq, which are currents on the orthogonal two-axis coordinates. Power consumption calculating means for determining the power consumption of the motor by multiplying the determined inner product by the voltage utilization factor and dividing the modulation factor;
With
The phase error storage means includes
Preliminarily storing the relationship between the phase error between the voltage applied to the electric motor and the command value of the voltage, and the output of the modulation factor correction unit included in the control unit or the modulation factor correction unit included in the control unit,
The power consumption calculation means corrects the output of the voltage command value calculation means based on the phase error stored in the phase error storage means when determining the power consumption of the electric motor,
The power consumption calculation means normalizes the output of the voltage command value calculation means with the modulation rate when the modulation rate exceeds 1, and further adds the voltage utilization rate calculation means to the result obtained by this normalization. The motor drive device is characterized in that the output is multiplied to be converted into a new voltage command value, and the power consumption is calculated based on the converted voltage command value. An inverter that converts DC voltage to AC voltage and applies it to the motor;
Current detecting means for detecting a phase current flowing in the electric motor;
DC voltage detecting means for detecting a DC voltage applied to the inverter;
Control means for controlling the voltage applied to the electric motor by the inverter;
And phase error storage means,
Equipped with a,
Before Symbol control means,
Coordinate conversion means for converting the phase current detected by the current detection means into a d-axis current Id and a q-axis current Iq as a current on orthogonal two-axis coordinates;
A voltage that outputs a d-axis voltage command value Vd * and a q-axis voltage command value Vq * as a command value of a voltage on the orthogonal two-axis coordinate applied to the electric motor based on the output of the coordinate conversion means and a predetermined reference value. Command value calculation means;
A modulation rate calculation means for obtaining a modulation rate from the d-axis voltage command value Vd * and q-axis voltage command value Vq *, which are voltage command values on the orthogonal two-axis coordinates, and the DC voltage;
Modulation rate correction means for correcting and outputting the modulation rate obtained by the modulation rate calculation means;
The modulation factor that is an output of the modulation factor correction means and a voltage utilization factor that is a ratio of an output voltage to the modulation factor are obtained in advance, and a correspondence relationship between the modulation factor and the voltage utilization factor is stored, When obtaining the voltage utilization factor, voltage utilization factor calculating means for obtaining the voltage utilization factor from the modulation factor based on the correspondence stored in advance,
The inner product of the d-axis voltage command value Vd * and q-axis voltage command value Vq *, which are voltage command values on the orthogonal two-axis coordinates, and the d-axis current Id and q-axis current Iq, which are currents on the orthogonal two-axis coordinates. Power consumption calculating means for determining power consumption of the electric motor and the inverter by multiplying the obtained inner product by the voltage utilization factor and dividing the modulation factor;
With
The phase error storage means includes
Preliminarily storing the relationship between the phase error between the voltage applied to the electric motor and the command value of the voltage, and the output of the modulation factor correction unit included in the control unit or the modulation factor correction unit included in the control unit,
The electric power consumption calculation means corrects the output of the voltage command value calculation means based on the phase error stored in the phase error storage means when determining the electric power consumption of the electric motor. .   4. The electric motor according to claim 3, wherein when the modulation rate exceeds 1, the modulation rate correction unit corrects the modulation rate by an inverse function of a function of a voltage utilization rate with respect to the modulation rate. Drive device.   2. The predetermined reference value is at least one of motor parameters such as winding resistance, winding inductance, induced voltage constant, torque command, rotation speed command, and d-axis current command value. The motor drive device according to claim 4.   The power consumption calculating means obtains the power consumption of the motor from the current of the orthogonal biaxial coordinate system and the voltage of the orthogonal biaxial coordinate system when the output of the modulation factor calculating means is 1 or less. The motor drive device according to any one of claims 1 to 5, characterized in that: A dead time voltage error estimating means for estimating an error caused by a dead time of the inverter between a voltage applied to the electric motor and a command value of the voltage;
7. The motor drive apparatus according to claim 1, wherein the control unit corrects the output of the voltage command value calculation unit based on the output of the dead time voltage error estimation unit. .   The control means includes dead time correction means for correcting an error caused by a dead time of the inverter between a voltage applied to the electric motor and a command value of the voltage based on a phase current detected by the current detection means. An electric motor drive device according to any one of claims 1 to 7, further comprising:   The control means calculates the error based on at least one of a phase current detected by the current detection means, a DC voltage detected by the DC voltage detection means, a carrier frequency of the inverter, and a dead time of the inverter. The motor drive device according to claim 7 or 8.   The control means controls the command value of the d-axis current on the orthogonal two-axis coordinates so that the output of the power consumption calculation means becomes the minimum power. The drive device of the electric motor described.   The control means detects an overload state of the electric motor based on an output of the power consumption calculation means, and when detecting that the electric motor has fallen into an overload state, reduces the rotational speed of the electric motor. The motor drive device according to any one of claims 1 to 10.   12. The electric motor according to claim 1, wherein the control unit performs display and notification output corresponding to power consumption to an external notification unit based on the output of the power consumption calculation unit. Drive device. Based on the output of the power consumption calculation means, provided with a step-out detection means for detecting a step-out state of the motor,
The motor drive device according to any one of claims 1 to 11, wherein the control unit restarts the motor when the step-out detection unit detects a step-out state of the motor.   A refrigerating and air-conditioning apparatus comprising: the motor drive device according to any one of claims 1 to 12; and a notification unit that performs notification such as display based on information from the drive device.   A refrigerating and air-conditioning apparatus comprising the electric motor drive device according to claim 13.   The refrigerating and air-conditioning apparatus according to claim 14 or 15, further comprising charge calculation means for obtaining a charge based on an output of the power consumption calculation means.

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