JPH11127600A - Controlling device for permanent-magnet type synchronous electric motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the voltage distortion of arm short-circuiting prevention time from being generated, when a permanent magnet-type synchronous electric motor is subjected to PWM control. SOLUTION: A coordinate conversion means 22 inputs an output current 6a of an inverter and angle data 8a of an electric motor and outputs a torque current feedback value 22b and a reactive (excitation) current feedback value 22a. The torque current feedback value 22b is compared with a torque current command value iq* for controlling, and the reactive current feedback value 22a is compared with a reactive current command value id* for controlling. At this time, the reactive current command value id* is set to a specific value Kid, the output current of the inverter is set to a value other than zero, and a phase voltage is maintained at a stable potential.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for performing pulse width modulation (PWM) control of a permanent magnet synchronous motor in accordance with a torque current command value and a reactive current command value.

[0002]

2. Description of the Related Art FIGS. 1, 2, 4 and 13 show a conventional permanent magnet type synchronous motor control device in which a part of a circuit is added to, for example, the one described in Japanese Patent Application Laid-Open No. 4-69066. 1 is an overall configuration diagram, FIG. 2 is a block diagram of a hardware portion of the current control operation means, FIG.
FIG. 13 is a block diagram of a software portion of the current control operation means, and the same reference numerals in the drawing indicate the same portions.

[0003] Each of the above drawings is also used in the present invention, except for a part, and will be described later in detail, but only the main points will be described here. AC of three-phase AC power supply 1 is converter 2
Is converted into DC and input to the inverter 4. The inverter 4 turns on and off the upper and lower switching elements 4A and 4B in accordance with the PWM control signals 12a and 12b, converts DC to three-phase AC, and drives the permanent magnet synchronous motor 7.

The output current 6a of the inverter 4 and the motor 7
The angle data 8a is fed back to the current control calculation means 9, and the output current 6a is separated into two components, a reactive current feedback value 22a and a torque current feedback value 22b. Reactive current feedback value 22a
Is controlled by collating with the reactive current command value id ^* (= zero) set by the reactive current command control means 23C, and the torque current feedback value 22b is calculated by the torque current command calculation means 24 ^. And sent to the output circuit 12 as the voltage command value 9a.

On the other hand, based on the phase voltage detected by the phase voltage detection circuit 5, a short-circuit prevention time Td for simultaneously turning off the upper and lower switching elements 4A and 4B is set. FIG. 4 shows the operation waveform of each part.

[0006]

In the conventional permanent magnet type synchronous motor control device as described above, the short-circuit prevention time Td
Is a period during which the upper and lower switching elements 4A and 4B are simultaneously turned off. When the current iu flowing through the motor 7 is near zero, the phase voltage Vu is not established as shown in FIG. Becomes FIG. 4F shows the state of the output signal of the phase voltage detection circuit 5 when this phenomenon occurs. For this reason, there is a problem that the influence of voltage distortion appears on the electric motor 7 and the rotation of the electric motor 7 becomes uneven.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a control device for a permanent magnet type synchronous motor which eliminates distortion of a current waveform flowing through the motor and allows the motor to rotate smoothly. With the goal.

[0008]

A control device for a permanent magnet type synchronous motor according to a first aspect of the present invention controls a reactive current command value when controlling a motor current separately from a torque current and a reactive current. It is like that.

Further, a control device for a permanent magnet synchronous motor according to a second aspect of the present invention is the control device of the first aspect, wherein the reactive current command value is caused to flow in a direction to increase the field of the motor.

A control device for a permanent magnet synchronous motor according to a third aspect of the present invention is the control device of the first or second aspect, wherein the reactive current command value is set to a predetermined value.

According to a fourth aspect of the present invention, in the permanent magnet type synchronous motor control device according to the first to third aspects, when the torque current feedback value is equal to or less than the first predetermined value, the reactive current command value is set to the second value. It is set to a predetermined value, and when the torque current feedback value is larger than the first predetermined value, the reactive current command value is set to zero.

According to a fifth aspect of the present invention, there is provided a permanent magnet type synchronous motor control device according to the first to third aspects, wherein the reactive current command value is set to a second predetermined value when the motor current value is equal to or less than a first predetermined value. The reactive current command value is set to zero when the motor current value is larger than a first predetermined value.

According to a sixth aspect of the present invention, there is provided a permanent magnet type synchronous motor control device according to the first to third aspects, wherein when the torque current command value is equal to or less than a third predetermined value, the reactive current command value is set to a second value. It is set to a predetermined value, and when the torque current command value is larger than the third predetermined value, the reactive current command value is set to zero.

According to a seventh aspect of the present invention, there is provided a permanent magnet synchronous motor control device according to the fourth to sixth aspects, wherein the reactive current command value is gradually increased at the time of startup and gradually decreased at the time of startup. It is like that.

According to an eighth aspect of the present invention, in the permanent magnet type synchronous motor control apparatus according to the first to third aspects, when the torque current feedback value is equal to or less than the first predetermined value, the reactive current command value is set to the second value. After the predetermined value is set, the second predetermined value is maintained until the torque current feedback value exceeds a fourth predetermined value which is larger than the first predetermined value.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. 1 to 4 show one embodiment of the first, second and third inventions of the present invention. FIG. 1 is an overall configuration diagram, and FIG. 2 is a block diagram of a hardware portion of a current control operation means. , FIG. 3 is a block diagram of the software part, and FIG. 4 is an explanatory diagram of the operation. The same reference numerals in the figure denote the same parts (the same applies to the following embodiments).

In FIG. 1, 1 is a three-phase AC power supply, 2 is a converter composed of a transistor and a diode and converts the AC of the three-phase AC power supply 1 to DC, 3 is a smoothing capacitor connected to the output side of the converter 2, An inverter 4 is connected to the smoothing capacitor 3 and converts direct current into three-phase alternating current. An upper switching element 4A and a lower switching element 4B connected in series per phase and flywheel diodes 4a and 4b connected in parallel to these elements. It consists of.

Reference numeral 5 denotes a phase voltage detection circuit which comprises current limiting resistors 5A and 5B and a photocoupler 5C, detects a phase voltage Vu, 6 denotes a current detector which detects an output current 6a of the inverter 4, and 7 denotes a The permanent magnet type synchronous motor connected to the output side, 8 is the angle data 8a of the motor 7,
That is, the encoder 9 outputs the speed, and the current control arithmetic means 9 inputs and calculates the current 6a and the angle data 8a and outputs the voltage command value 9a.

A short circuit 10 receives the phase voltage Vu detected by the phase voltage detection circuit 5, corrects a short circuit prevention time Td for simultaneously turning off the upper and lower switching elements 4A and 4B based on the input signal, and outputs the corrected short circuit prevention time Td. The prevention time correction means 11 is connected to the current control calculation means 9 and the short-circuit prevention time creation means 11. The short-circuit prevention time creation means 11 sets an optimum short-circuit prevention time Td based on the output of the short-circuit prevention time correction means 10. PWM for upper and lower switching elements 4A, 4B
(Pulse width modulation) An output circuit for outputting control signals 12a and 12b.

In FIG. 2, 15 is a CPU, 16 is a ROM in which a current control calculation program is stored, and 17 is RA
M and 18 are analog switches to which the output current 6a of the inverter 4 is input, 19 is an A / D converter connected to the analog switch 18, and 20 is an encoder gate array to which angle data 8a is input. ~ 17,
19, 20 and the output circuit 12 are mutually connected.

In FIG. 3, reference numeral 21 denotes a sine / cosine function calculating means for calculating a sine function and a cosine function from the angle data 8a, and 22 denotes an output current 6a and a sine / cosine
Coordinate conversion means for inputting the output signal of the cosine function calculating means 21 to convert the three-phase alternating current into two-axis direct current and outputting the reactive current feedback value 22a and the torque current feedback value 22b, and 23 as a reactive current command value id ^* Reactive current command control means 24 for giving a predetermined value Kid is a torque current command calculation means for calculating a torque current command value iq ^* from a speed command value and an actual speed.

Reference numerals 25 and 26 denote addition means, 27 denotes an input of the reactive current feedback value 22a and torque current feedback value 22b, and an interference voltage compensating means for compensating for an error generated by their interaction. 28 is connected to the addition means 25. The calculated reactive current control means 29, the torque current control calculation means 29 connected to the addition means 26, the addition means 30, 31 are connected to the addition means 30, 31 and the sine / cosine function calculation means 21 and the two axes This is a coordinate conversion unit that converts DC to three-phase AC and outputs a voltage command value 9a.

Next, the operation of this embodiment will be described.
Since all three phases of the inverter 4 have the same configuration, only one phase (U phase) will be described. The AC of the three-phase AC power supply 1 is converted to DC by the converter 2, smoothed by the smoothing capacitor 3 and input to the inverter 4. The inverter 4 controls the PWM control signal 1 input from the output circuit 12
2a, 12b, the upper and lower switching elements 4
A and 4B are turned on and off to convert DC to three-phase AC and supply it to the permanent magnet synchronous motor 7 to drive it.

The output current 6a detected by the current detector 6 and the angle data 8a detected by the encoder 8 are fed back to the current control calculation means 9. Then, the output current 6a is input to the coordinate conversion means 22, and the sine and cosine functions of the angle data 8a are calculated through the sine / cosine function calculation means 21 and input to the coordinate conversion means 22, and the reactive current feedback value 22a And a torque current feedback value 22b are output.

The reactive current command value id ^* = predetermined value Kid supplied from the reactive current command control means 23 is compared with the reactive current feedback value 22a by the adding means 25, and the difference is inputted to the reactive current control calculating means 28. , Is controlled so that the deviation becomes zero. Also, the torque current command value iq ^* calculated by the torque current command calculation means 24 and the torque current feedback value 22b are collated by the addition means 26, and the deviation is input to the torque current control calculation means 29, and the deviation is reduced to zero. Is controlled so that

The output of the reactive current control calculating means 28, the output of the torque current control calculating means 29 and the interference voltage compensating means 27
Are input to the coordinate conversion means 32 after being collated by the addition means 30 and 31, respectively, and are converted into three-phase alternating current to become the voltage command value 9a. On the other hand, the phase voltage detection circuit 5 detects the U-phase phase voltage Vu via the photocoupler 5C, and based on the input signal, the short-circuit prevention time correction means 10 turns off the upper and lower switching elements 4A and 4B simultaneously. The short-circuit prevention time Td (FIG. 4) is corrected. Then, the short-circuit prevention time creating means 11 sets an optimum short-circuit prevention time signal 11a.

The output circuit 12 receives the voltage command value 9a calculated by the current control calculation means 9 and the short-circuit prevention time signal 11a set by the short-circuit prevention time creation means 11 and outputs PWM control signals 12a and 12b. , And on / off control of the upper and lower switching elements 4A and 4B.

Next, the operation of this embodiment will be described with reference to FIG. FIG. 4A shows the output phase voltage of the ideal inverter, and FIG.
A is on, the lower switching element 4B is off,
An operation signal of the upper switching element when the upper switching element 4A is turned off and shifts to the short-circuit prevention time Td in a state where the output current Iu flows in the direction shown in the drawing. FIG. While the current Iu is flowing in the direction shown, the upper switching element 4A is off and the lower flywheel diode 4b is
5 shows an operation signal of the lower switching element when the lower switching element 4B is turned off from the state in which the induced current is flowing and shifts to the short-circuit prevention time Td.

FIG. 4D shows the phase voltage Vu at this time. The short circuit prevention time Td is equal to the upper and lower switching elements 4
Since A and 4B are off at the same time, the potential of the phase voltage Vu is not established when the current flowing through the electric motor 7 is near zero in the conventional device, and the unstable value shown in FIG. Become. Therefore, when the on / off detection values of the upper and lower switching elements 4A, 4B are set to several tens of volts, the on / off of both elements 4A, 4B are almost on during the short circuit prevention time Td when an unstable voltage occurs. Thus, the output of the phase voltage detection circuit 5 is as shown in FIG.

In this embodiment, the reactive current command value id
^Since the predetermined value Kid is given to ^* , even if the torque current command value iq ^* becomes zero, the reactive current continues to flow, and the output current Iu does not become close to zero. Therefore, the potential of the phase voltage Vu is also established, and the waveform shown in FIG. 4D is obtained, and the output of the phase voltage detection circuit 5 becomes the waveform shown in FIG. 4A, and a stable short-circuit prevention time Td can be obtained. Become.

At this time, the magnetic flux on the field side of the electric motor 7 is composed of a permanent magnet and an exciting current component, that is, a reactive current component. In this case, since the latter is sufficiently smaller than the former, the electric motor field becomes a stronger field because the magnetic flux due to the reactive current component is superimposed on the magnetic flux due to the permanent magnet. When the rotation speed of the electric motor 7 is controlled, the torque current acts to further increase.
The effect is small.

That is, when the rotation speed of the electric motor 7 is controlled, the direction of the current of the reactive current component to be injected is set to the stronger field side, so that the torque current component is automatically increased. Thus, the absolute value of the reactive current component to be injected can be set small. That is,
The basic relational expression of the motor is expressed as N = E / kφ = IR / kφ. Here, N is a rotation speed, E is a voltage, k is a constant, φ is a magnetic flux, I is a current, and R is a winding resistance. In the above equation, when the rotation speed N is fixed, the current I increases if the magnetic flux φ increases.

Embodiment 2 FIG. 5 and 6 are diagrams showing one embodiment of the fourth and fifth inventions of the present invention. FIG. 5 is a block diagram of a software portion of the current control operation means, and FIG. 6 is a reactive current command control operation flowchart. is there. FIGS. 1, 2 and 4 are also used in the second embodiment.
In FIG. 5, reference numeral 23A denotes a reactive current command control means for controlling the reactive current command value id ^* by inputting the torque current feedback value 22b, and is otherwise the same as FIG.

Next, the operation of this embodiment will be described with reference to FIG. In step S1, the torque current feedback value 22b
Is determined to be greater than the first predetermined value Kiq, and if so, the reactive current command value id ^* is set to zero in step S2. If the value is equal to or less than the first predetermined value Kig, step S3
Sets the reactive current command value id ^* to the second predetermined value Kid. Thus, only when the torque current feedback value 22b is close to zero, that is, when the torque current feedback value 22b is equal to or less than the first predetermined value Kiq, the reactive current is injected so that the output current Iu does not become a value near zero.

Therefore, it is possible to prevent the temperature of the motor 7 from rising without flowing an unnecessary reactive current except when necessary.
It is possible to improve the operation efficiency of the vehicle. In the second embodiment, the injection of the reactive current is determined based on the torque current feedback value 22b after the output current 6a is separated into the torque current component and the reactive current component. The same effect can be obtained by detecting near zero current by itself and judging the injection of the reactive current component (not shown).

Embodiment 3 7 and 8 are views showing an embodiment of the sixth invention of the present invention. FIG. 7 is a block diagram of a software portion of a current control operation means, and FIG. 8 is a reactive current command control operation flowchart. In addition, FIG.
2 and 4 are also used in the third embodiment. In FIG. 7, reference numeral 23B denotes a reactive current command control means for inputting the torque current command value iq ^* and controlling the reactive current command value id ^* , and is otherwise the same as FIG.

Next, the operation of this embodiment will be described with reference to FIG. In step S5, the torque current command value iq ^*
Is determined to be greater than a third predetermined value Kiq, and if it is, the reactive current command value id ^* is set to zero in step S2. If the value is equal to or smaller than the third predetermined value Kiq, step S3
To set the reactive current command value id ^* to a second predetermined value. In the second embodiment, the actual motor current is monitored, and the reactive current is caused to flow when it approaches zero. However, here, the torque current command value iq ^* is monitored, and In other words, the reactive current is injected by predicting that the reactive current will become zero.

In this case, the injection is determined not by the current value but by the command value. For example, as described in the second embodiment, when the injection of the reactive current is determined by the motor current value, the motor current value is determined. Becomes less than a predetermined value, the reactive current is injected, and when the combined current flows, the operation becomes larger than the predetermined value and the injection stops. In other words, the presence or absence of injection occurs repeatedly, resulting in a so-called oscillation state. However, this oscillation can be prevented by judging injection based on the command value.

Embodiment 4 9 and 10 show an embodiment of the seventh invention of the present invention. FIG. 9 is a flowchart of a reactive current command control operation, and FIG. 10 is a curve diagram of a torque current feedback value and a reactive current command value. 1, 2, 4 and 5 are also used in the fourth embodiment.

Next, the operation of this embodiment will be described.
In step S1, the torque current feedback value 22b is set to the first predetermined value K.
It is determined whether it is larger than iq.
At 1, it is determined whether the flag Fid is "1". Step S1
As described later in FIG. 5, before the time T _{1 in} FIG.
Since id is "0", the process proceeds to step S2, where the reactive current command value id ^* is set to zero.
Set id to "0".

The time T ₁ at a torque current feedback value 22b is first
When the value becomes equal to or smaller than the predetermined value Kiq, the process proceeds from step S1 to step S15, and the flag Fid is set to “1”. In step S16, the reactive current command value id ^* is changed to the second predetermined value Kid.
It is determined whether it is the above. Since it has not yet reached the second predetermined value Kid, in step S17 the reactive current command value i
By adding a small value Δid ^* to d ^* every calculation cycle,
The reactive current command value id ^* gradually increases at a predetermined inclination (first-order lag). As a result, the reactive current command value id ^* becomes the second predetermined value K
When id is reached, that state is maintained.

At time T ₂ , the torque current feedback value 22 b becomes the first
If it becomes larger than the predetermined value Kiq, steps S1 → S11
The process proceeds to S12 to determine whether the reactive current command value id ^* is equal to or less than zero. Yet, since maintaining a second predetermined value Kid, is subtracted from the reactive current command value id ^* at step S13 the minute value .DELTA.id ^* for each calculation cycle, the reactive current command value id ^* is gradually decreased at a predetermined inclination I do. As a result, when the reactive current command value id ^* becomes zero, steps S12 → S2
Then, the reactive current command value id ^* is set to zero, and the flag Fid is set to "0" in step S14.

Although the case where the reactive current command value id ^* is controlled by monitoring the torque current feedback value 22b as shown in FIG. 5 has been described above, as shown in FIG.
It is also applicable to the case where the reactive current command value id ^* is controlled by monitoring q ^* . The present invention is also applicable to a case where the motor current 6a is monitored to control the reactive current command value id ^* .

As described above, in the second and third embodiments, when a command is issued in a stepwise manner when injecting a reactive current, the torque of the electric motor 7 is affected depending on the response of the control system. As a result, vibration of the rotation direction component may occur. In other words, applying a predetermined value as the reactive current at once causes an abrupt change in the input of the control system, and the rotational speed of the electric motor 7 may fluctuate in response to the change. Here, when injecting a reactive current, a lamp input is used to suppress the occurrence of vibration,
The rotation can be made smooth.

When the reactive current is injected, the magnetic field of the motor changes due to the magnetic flux due to the reactive current in addition to the magnetic flux of the permanent magnet, and the rotational speed becomes a reference command in the rotational speed control system. It will be affected by the value. Therefore, the lamp input is a torque current change,
That is, it is desirable that the torque current control system has a value that can sufficiently follow up.

Embodiment 5 FIG. 11 and 12 show an embodiment of the eighth invention of the present invention. FIG. 11 is a flowchart of a reactive current command control operation, and FIG. 12 is a curve diagram of a torque current feedback value and a reactive current command value. In addition, FIG.
2, 4 and 5 are also used in the fifth embodiment.

Next, the operation of this embodiment will be described.
In step S1, the torque current feedback value 22b is set to the first predetermined value K.
It is determined whether it is larger than iq.
At 1, it is determined whether the flag Fid is "1". Since the time T ₁ previous 12 flag Fid is "0", to "0" and the flag Fid fly to step S22, sets the reactive current command value id ^* to zero.

The time T ₁ at a torque current feedback value 22b is first
When the value becomes equal to or smaller than the predetermined value Kiq, the process proceeds from step S1 to step S15, and the flag Fid is set to “1”. In step S23, the reactive current command value id ^{* is changed} to the second predetermined value Kid.
(The rising of the reactive current command value id ^* is gradually increased as described above, but the description is omitted). When the torque current feedback value 22b at time T _2, is in the larger than the first predetermined value Kiq, step S1 → S11 → S21
And the torque current feedback value 22b becomes the fourth predetermined value Kiqm
ax is determined to be larger than the fourth predetermined value Kiqmax
If not, the reactive current command value id ^{* is} set in step S23 ^.
Is set to the second predetermined value Kid.

If it is larger than the fourth predetermined value Kiqmax, the flag Fid is set to "0" and the reactive current command value id ^* is set to zero in step S22. That is, the flag Fi
In the section where d is “1”, the torque current feedback value 22b is the first
Even if it becomes larger than the predetermined value Kiq, steps S1 → S1
The process proceeds from 1 to S21, and the reactive current command value id ^* does not become zero unless the torque current feedback value 22b becomes larger than the fourth predetermined value Kiqmax.

As described above, the period from when the reactive current command value id ^* is given to when the reactive current command value is returned to zero is set to the fourth predetermined value Kiqma.
Since the determination is made by x, the potential of the phase voltage is established, the distortion of the current waveform is corrected, and the vibration of the electric motor 7 can be suppressed. That is, when the reactive current is injected, the torque current command value iq ^* is also affected, and in some cases, the torque current command value iq ^* or the torque current itself increases, and the reactive current is injected across the first predetermined value Kiq. Is interrupted, and there is a concern that a so-called oscillation state may occur.

Further, the output current 6a of the current detector 6 is separated into a torque current and a reactive current, and the injection of the reactive current is determined in the former case. In this case, immediately after the injection of the reactive current, the first
In some cases, the predetermined value Kiq may be exceeded, and the injection of the reactive current may be interrupted, causing a so-called oscillation state. Here, by giving the injection conditions hysteresis,
Oscillation is prevented.

[0052]

As described above, in the first invention of the present invention, the reactive current command value is controlled, and in the third invention, the reactive current command value is set to a predetermined value. Does not become zero, the potential of the phase voltage is established, the current waveform is not distorted, and the vibration of the motor can be suppressed.

Further, in the second invention, the reactive current command value is caused to flow in a direction to increase the field of the motor, so that the absolute value of the reactive current component to be injected can be reduced.

In the fourth invention, the reactive current command value is set to the second predetermined value when the torque current feedback value is equal to or less than the first predetermined value, and when the torque current feedback value is larger than the first predetermined value. Since the reactive current command value is set to zero, it is possible to prevent the output current of the inverter from becoming close to zero, thereby suppressing the vibration of the motor, and without causing the reactive current to flow unless necessary. Prevent temperature rise of
The operation efficiency of the electric motor can be improved.

In the fifth aspect, the motor current value is set to the first value.
The reactive current command value is set to a second predetermined value when the current value is equal to or less than a predetermined value, and the reactive current command value is set to zero when the motor current value is larger than the first predetermined value. In addition, it is possible to prevent a rise in temperature, to improve the operation efficiency, and to omit means for separating a torque current component from a motor current.

In the sixth invention, the reactive current command value is set to the second predetermined value when the torque current command value is equal to or less than the third predetermined value, and when the torque current command value is larger than the third predetermined value. Since the reactive current command value is set to zero, vibration of the electric motor is suppressed, temperature rise is prevented, and operation efficiency can be improved.By determining the injection of the reactive current based on the command value, Oscillation of the control system can be prevented.

Further, in the seventh invention, the reactive current command value is
Because it is gradually increased at the time of start-up and gradually decreased at the time of fall, the vibration of the electric motor is suppressed, and the temperature rise is prevented.
In addition, the operating efficiency can be improved, and the rotation of the electric motor can be made smooth by easing the injection of the reactive current command value.

In the eighth invention, when the torque current command value is equal to or less than the first predetermined value, the reactive current command value is set to the second predetermined value, and then the torque current feedback value is larger than the first predetermined value. (4) Since the second predetermined value is maintained until the predetermined value is exceeded, vibration of the electric motor is suppressed, temperature rise is prevented,
In addition, the operating efficiency can be improved, and the occurrence of the oscillation state can be prevented by maintaining the second predetermined value.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram showing a control device of a first embodiment of the present invention and a conventional permanent magnet synchronous motor.

FIG. 2 is a block diagram of a hardware portion of a current control operation unit in FIG. 1;

FIG. 3 is a block diagram of a software portion of a current control operation unit according to the first embodiment of the present invention.

FIG. 4 is an operation explanatory diagram showing the control device of the first embodiment of the present invention and a conventional permanent magnet synchronous motor.

FIG. 5 is a block diagram of a software portion of a current control operation unit according to the second embodiment of the present invention.

FIG. 6 is a flowchart showing a reactive current command control operation according to the second embodiment of the present invention.

FIG. 7 is a block diagram of a software portion of a current control operation unit according to a third embodiment of the present invention.

FIG. 8 is a flowchart showing a reactive current command control operation according to the third embodiment of the present invention.

FIG. 9 is a flowchart showing a reactive current command control operation according to the fourth embodiment of the present invention.

FIG. 10 is a torque current feedback value and reactive current command value curve diagram showing Embodiment 4 of the present invention.

FIG. 11 is a flowchart showing a reactive current command control operation according to the fifth embodiment of the present invention.

FIG. 12 is a torque current feedback value and reactive current command value curve diagram showing Embodiment 5 of the present invention.

FIG. 13 is a block diagram of a software portion of a current control operation unit of a control device for a conventional permanent magnet synchronous motor.

[Explanation of symbols]

Reference Signs List 4 inverter, 4A upper switching element, 4B lower switching element, 5 phase voltage detection circuit, 6 current detector, 6a inverter output current, 7 permanent magnet type synchronous motor, 8 encoder, 8a angle data, 9 current control calculation means, 10 Short-circuit prevention time correction means, 11 short-circuit prevention time creation means, 12 output means, 22 coordinate conversion means, 22a reactive current feedback value, 22b torque current feedback value, 23, 23A, 23B reactive current command control means, 2
4 Torque current command calculation means, 28 reactive current control calculation means, 29 torque current control calculation means, id ^* reactive current command value, iq ^* torque current command value, Iu inverter output current.

Claims (8)

[Claims] 1. An inverter comprising switching elements connected in series and controlled alternately with a time delay from each other, and a permanent magnet type synchronous motor connected to the inverter, The torque current flowing through the motor is controlled by comparing the torque current command value with the torque current feedback value, and the reactive current flowing through the motor is controlled by comparing the reactive current command value with the reactive current feedback value. In an apparatus for controlling a pulse width modulation of an electric motor,
A control device for a permanent magnet type synchronous motor, comprising: a reactive current command control means for controlling the reactive current command value. 2. The control device for a permanent magnet synchronous motor according to claim 1, wherein the reactive current command value is set so as to flow in a direction in which the field of the motor is strengthened. 3. The control device for a permanent magnet synchronous motor according to claim 1, wherein the reactive current command control means is configured to set the reactive current command value to a predetermined value. 4. The reactive current command control means sets the reactive current command value to a second predetermined value when the torque current feedback value is equal to or less than a first predetermined value, and sets the torque current feedback value to be less than the first predetermined value. The permanent magnet synchronous motor control device according to any one of claims 1 to 3, wherein the reactive current command value is set to zero when the value is larger than zero. 5. The reactive current command control means sets the reactive current command value to a second predetermined value when the motor current value is equal to or less than a first predetermined value, and the motor current value is larger than the first predetermined value. The control device for a permanent magnet type synchronous motor according to any one of claims 1 to 3, wherein the reactive current command value is set to zero at the time. 6. The reactive current command control means sets the reactive current command value to a second predetermined value when the torque current command value is equal to or less than a third predetermined value, and sets the torque current command value to be less than the third predetermined value. The permanent magnet synchronous motor control device according to any one of claims 1 to 3, wherein the reactive current command value is set to zero when the value is larger than zero. 7. The permanent magnet type synchronous motor according to claim 4, wherein the reactive current command value is gradually increased when rising, and gradually reduced when falling. Motor control device. 8. The reactive current command control means sets the reactive current command value to a second predetermined value when the torque current feedback value is equal to or less than a first predetermined value, and then sets the torque current feedback value to the first predetermined value. 2. The apparatus according to claim 1, wherein the second predetermined value is maintained until the second predetermined value is exceeded.
A control device for a permanent magnet synchronous motor according to any one of claims 1 to 3.