JPH05344741A - Inverter unit, air-conditioner, electric washing machine, and electric cleaner equipped with inverter unit - Google Patents

Abstract

PURPOSE:To provide an inverter unit having high control accuracy by measuring ON/OFF delay of inverter and performing control operation at a timing subjected to correction of delay. CONSTITUTION:A controller 107 detects variation time of DC side current Id, AC side current, or AC side voltage of an inverter 101. Signal propagation delay times of a drive circuit 106 and switching elements T1... are thin measured based on the difference between the variation time thus detected and a time when ON or OFF driving signal is delivered. Signal propagation delay times thus measured are then employed in current control or conduction rate control with reference to actual timing of applying voltage on AC side of inverter. Correction with actually measured values realizes highly accurate control at all times.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse width modulation type inverter device and an electric device using the same, and more particularly to driving an electric motor in an electric product such as an air conditioner, an electric washing machine, or a vacuum cleaner. The present invention relates to an inverter device suitable for use.

[0002]

2. Description of the Related Art As is well known, in a pulse width modulation type inverter device, a pulse width modulation signal to be supplied thereto is controlled so that the detected value of its output current matches a command value. However, at this time, when the phase in which the current is flowing among the three-phase outputs is always between the two phases, as in the conventional 120-degree conduction type inverter used for driving brushless DC motors, etc. Japanese Patent Application Laid-Open No. 3-11992 discloses that the DC current of an inverter is detected and the detection result is used to control the current. On the other hand, a sine wave for driving an induction motor is used. In an inverter device that obtains a wave output, the AC side current output from the inverter is detected, and the current control is performed using the detection result.

First, FIG. 6 is a block diagram showing a conventional example of a 120-degree conduction type inverter device disclosed in Japanese Patent Application Laid-Open No. 3-11992, in which an inverter 101 includes switching elements T1 to T6 composed of six transistors and the like. Similarly, it is composed of six return diodes D1 to D6, and the inverter 101 converts the DC power supplied from the DC power supply 102 into the three-phase AC power, and the three-phase AC output current 1Ia, The brushless DC motor 103 is driven by obtaining 1Ib and 1Ic. At this time, of these three-phase output currents 1Ia, 1Ib, and 1Ic, only the two-phase current is always flowing. The current flowing on the AC side of the inverter 101 is the current Id on the DC side.
Since it is almost equal to, the current can be controlled only by detecting the current Id on the DC side.

Therefore, in this conventional example, as shown in the figure, a detection resistor R is provided in the DC current path between the DC power source 102 and the inverter 101, and the current flowing through the detection resistor R is controlled by the controller 4.
The current detector 407e in 07 detects the signal, and the signal generator 407a thereby detects the drive signal 1 for driving the inverter 101 so that the detected current matches the command value.
P1 is generated and the switching signal 1P2 is output from the drive circuit 106 to control the inverter 101. FIG. 7 shows the waveforms of the drive signal 1P1 and the detection current 1V1 at this time.

Next, FIG. 8 is a block diagram showing an example of an inverter device for obtaining a conventional sine wave output. An inverter 301 having the same configuration as the inverter 101 in the conventional example of FIG. DC power supplied from 102 is converted into three-phase power, and three-phase AC output current 3I
a, 3Ib, 3Ic are generated to drive the electric motor 303. At this time, the output currents 3Ia, 3Ib, 3Ic on the AC side are supplied to the current detection circuit 304a,
304b, 304c and a current detector 307e are used for detection, and as a result, the signal generator 307a in the controller 307 is detected.
Is configured to output an inverter drive signal 3P1 for controlling the inverter 301 so that the detected current has a sine wave shape. The drive signal 3P1 is input to the drive circuit 306, and the switching signal 3P2 for driving the switching elements T1 to T6 is output from the drive circuit 306. FIG. 9 shows the drive signal 3P1 and the detection current 3 at this time.
It shows a waveform of Va.

[0006]

By the way, as shown in the above-mentioned prior art, in such an inverter device, as is apparent from FIGS. 7 and 9, the current detection signal (1V1, 3Va, etc.) to be detected is detected. Is pulsating, and therefore, by sampling the current detection signal at every predetermined timing, the required current detection value is obtained, but at this time, if the sampling timing is different,
The detection position of the current on the time axis changes, and a detection value different from the desired value is obtained.

Therefore, in the conventional technique, for example, the inverter drive signal 1P1, the time points t1 and t3 in FIGS.
Timing for this current detection is set with reference to 3P1, and as a result, detection of the current at a specific time axis position representing the average value or maximum value of the pulsating current can be obtained, if necessary. I am allowed to do so.

However, in such an inverter device, the inverter is operated by the inverter drive signal output from the control device, and the signal is output via the drive circuit (106, 306) until the output current actually flows. Since the switching elements (T1 to T6) of the inverter (101, 301) are operated in response to the transmission, the inverter drive signal (1P1, 3P1) and the output current generated thereby, that is, the detection Current (Id,
3Ia, 3Ib, 3Ic) (hereinafter referred to as drive delay).

Since the drive delay is affected by the delay time of the circuit elements such as semiconductors forming the inverter and the control device, it differs for each inverter device.
Even in the same inverter device, it differs for each phase.

However, in the prior art, as described above, only the timing for current detection is taken with the inverter drive signal as a reference, and this drive delay is not taken into consideration. Therefore, high accuracy of control is achieved. There was a problem that it was difficult to convert.

However, in order to cope with the drive delay in the conventional technique, it is necessary to select circuit elements such as semiconductors used in drive circuits and inverter circuits.
There is a problem that it takes a lot of time and labor to obtain an inverter device capable of high-precision control, resulting in a large cost increase.

Further, in such an inverter device, it is necessary to control the inverter drive signal to be an extremely thin pulse in order to operate in a light load state. As a result, in the light load state, the inverter drive signal is controlled. The influence of the phase difference between the drive signal and the current appears significantly, the current detection error due to the drive delay increases, and the current control accuracy deteriorates significantly.

Therefore, in the prior art, when an electric product such as an air conditioner, a washing machine, or an electric vacuum cleaner is operated at a variable speed,
Current control accuracy decreases on the light load side, that is, on the low speed side,
There is a problem that high-precision variable speed operation cannot be performed, and fluctuations in rotation occur and noise and the like cannot be suppressed.

An object of the present invention is to reduce the cost of an inverter device that can always be controlled with high accuracy and can be easily applied to electrical products to achieve high performance despite the existence of variations in the characteristics of circuit elements. It is provided in.

[0015]

In order to achieve the above object, the present invention provides a change detecting means for detecting a change time point of an AC side output current of an inverter, a change time point of the pulse width modulation signal and the change detection means. And a processing means for calculating a time interval between the change time point detected by the above as a delay time, and the timing necessary for controlling the inverter is determined on the basis of the time interval thus calculated. Specifically, based on the embodiments of the present invention, the present invention further includes the following means.

In order to achieve the above object, according to one aspect of the present invention, a modulation signal having a specific pattern is output to each phase of the electric motor before the electric motor, which is the load of the inverter, is started, and the processing is performed in this state. The delay time is calculated by means. Further, according to one aspect of the present invention, the delay time is calculated by the current detection value for each phase of the AC side output of the inverter.

Further, according to one aspect of the present invention, the delay time is calculated from the detected value of the DC side current of the inverter.

Similarly, according to the present invention, the delay time is calculated from the detected value of the AC side phase voltage of the inverter. Similarly, according to the present invention, the delay time is calculated from the detected value of the AC side line voltage of the inverter. Similarly, according to the present invention, the timing required for controlling the inverter is the timing for detecting the current value of the output current. Similarly, according to the present invention, the timing required for controlling the inverter is the timing for controlling the change time point of the pulse width modulation signal. Further, according to one aspect of the present invention, the timing required for controlling the inverter is the timing required for controlling the pulse width of the pulse width modulation signal.

Further, according to one aspect of the present invention, the capacity control of the air conditioner is performed by using the above-mentioned inverter device. Similarly, in some of the inventions,
The above-mentioned inverter device is used to control the rotation speed of the washing machine. Further, according to one aspect of the present invention, the rotation speed of the electric vacuum cleaner is controlled by using the above-mentioned inverter device.

[0020]

The processing means functions to calculate the time from the time when the inverter drive signal is generated until the time when the output current on the AC side actually changes, that is, the drive delay. Therefore, the timing required for controlling the inverter can be set in consideration of the actual drive delay appearing in the inverter device, so that the influence of the drive delay can be removed and high-precision control can be surely obtained.

As a result, when the electric motor is driven by using the inverter device, the rotation speed can be controlled with extremely high precision even under a light load condition, that is, in a condition where the output capacity is small, so that the rotation speed fluctuation and the like can be prevented. It is possible to easily obtain an electric product such as an air conditioner, an electric washing machine, or an electric vacuum cleaner which is sufficiently suppressed and has good performance.

[0022]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. FIG. 1 is a block diagram of an inverter device according to an embodiment of the present invention. In this embodiment, as in the prior art of FIG. 6, power is supplied from a DC power supply 102 to a brushless DC motor 103 via a 120-degree conduction type inverter 101. The electric motor 103 is supplied and is driven at a variable speed. In FIG. 1, reference numeral 107 denotes a control device, which includes a pulse width modulation signal generator 107a, a timing generation circuit 107b, and a timing device 1 as shown in detail in FIG.
07c, storage device 107d, current detector 107e, sequence generator 107f, and pulse width command device 10
It has 7g.

First, the sequence generator 107f determines the timing of a signal to be generated from the control device 107 and the operation timing of other constituent elements in the control device 107. Therefore, the advance control operation is performed. The procedure for generating the trigger Tg from the timing generation circuit 107b to another element is stored in the storage device 107d according to the procedure determined to be performed.
Functions to memorize in.

The timing device 107c is always performing the timing operation, and the timing generation circuit 107b operates in the timing device 1c.
The trigger Tg is output every time the measured value of 07c matches the set time stored in the storage device 107d. The pulse width command device 107g functions to compare the current detection value detected by the current detector 107e with the current value to be actually flown, and set the pulse width in the signal generator 107a.

The trigger Tg thus generated from the timing generation circuit 107b is the pulse width modulation signal generator 107.
The operation of a and the operation of the current detector 107e are started.
That is, when the pulse width modulation signal generator 107a is operated, the inverter drive signal 1P1 is turned on or off, and when the current detector 107e is operated, the value of the current detection signal 1V1 at that time is held and is set as the detection value. Take in.

Then, the control device 107 uses the inverter 1
Instead of detecting the current of each phase of the AC output of 01, the current detection signal 1V1 proportional to the DC side current Id is detected by the detection resistor R.
Of the drive signal 1 to drive the inverter 101 so that the voltage drop of
The pulse width modulation signal is superimposed on P1 and output, and this drive signal 1P1 becomes the switching signal 1P2 via the drive circuit 106, and this is supplied to the switching elements T1 to T6 of each phase of the inverter 101 in a predetermined manner. , Conversion operation is performed.

Reference numeral 110 is a change detector, and this change detector 1
10 emphasizes and detects the inflection point of the current detection signal 1V1,
It functions to output the change detection signal 1S1 that changes at the timing when the current detection signal 1V1 changes from increase to decrease and the timing when the current detection signal 1V1 changes from decrease or constant value to increase.

Next, the operation of this embodiment will be described with reference to FIG. The timing generation circuit 107b includes a timing device 107b.
When the value of d reaches the time t1 stored in the storage device 107d, the pulse width modulation signal generator 107a receives a trigger T
generate g. Therefore, the pulse width modulation signal generator 107
The a outputs at least one kind of the inverter drive signal 1P1 pulse-width modulated by the trigger Tg. Since the inverter drive signal 1P1 becomes the switching signal 1P2 of the inverter 101 via the drive circuit 106, the switching signal 1P2 becomes a signal slightly delayed from the inverter drive signal 1P1.

Switching element T1 of the inverter 101
.About.T6 are turned on by the switching signal 1P2, and the DC power supply voltage is applied to the brushless DC electric motor 102 which is a load.
Due to the delay in switching from 1 to T6, the current is applied to the electric motor 102 with a further delay, and as a result, the AC side currents 1Ia, 1Ib, and 1Ic are also delayed from the switching signal 1P2 as shown in FIG. Then an inflection point appears.

On the other hand, the DC side current Id flows in conformity with the AC side current while the voltage is applied, and does not flow while the voltage is not applied.
In No. 1, an inflection point occurs at the timing when the voltage is actually applied and the current starts to increase.

As described above, the change detector 110 functions to output the change detection signal 1S1 whose value changes rapidly at the inflection point of the current detection signal 1V1.
Detects the time point (time) t2 at which this change detection signal 1S1 occurs, and from the time interval between this time point t2 and the time point t1 when the pulse width modulated inverter drive signal 1P1 turns on, the drive delay time at the time of turning on Calculate dTon. Similarly, the drive delay time dToff when off is
It can be obtained from the time interval between the time t3 when the pulse-width modulated inverter drive signal 1P1 is turned off and the time t4 when the change detection signal 1S1 is generated.

Therefore, the control device 107 stores the drive delay time dTon at the time of on-state and the drive delay time dToff at the time of off thus obtained in the memory device 107d, and this is stored from the current detection signal 1V1, for example. Inverter 10 such as the timing required to detect the value
It is used as a reference of the timing required for the control of 1.

FIG. 4 is a detailed explanatory view of the change detector 110 in one embodiment of the present invention, and FIG. 5 is an operation explanatory view thereof. The current detection signal 1V1 is branched into two systems in the change detector 101. , One is supplied to the positive input to the comparator 113 as it is, but the other is added to the offset signal 1OF, then amplified to a predetermined level by the amplifier 111, and then delayed by the delay circuit 112 to obtain the delay signal 1DY. After being generated, it is supplied to the negative input of the comparator.

As a result, as shown in FIG. 5, the delay signal 1
Since DY is delayed after the offset is added, it becomes like a broken line in the figure. And this delay signal 1
Since DY and the directly input current detection signal 1V1 are compared, as shown in the figure, the change detection signal 1S1 whose value suddenly changes at the inflection point of the current detection signal 1V1 is obtained.

Next, the storage device 10 obtained in this way is obtained.
Timing control of the inverter using the drive delay time dTon at the time of ON and the drive delay time dToff at the time of OFF stored in 7d will be described. 10 and 1
In No. 1 of the embodiment of the present invention, the drive delay time dTon at the time of ON and the drive delay time dToff at the time of OFF are used to accurately control the timing of detecting the current value from the current detection signal 1V1. In the timing chart, FIG. 10 shows a case where the current value is detected at the time when the current shows the maximum value during the period when the current detection signal 1V1 appears, and FIG. 11 shows that the current also shows the average value. It shows the case of detection at the time. In each of these examples, the configuration is as shown in FIG.

The sequence generator 107f turns on the inverter drive signal 1P1 at a time point t1 in each constant cycle, and thereafter, at a time point t3 when a time t corresponding to the pulse width of the inverter drive signal 1P1 has elapsed, the inverter drive signal 1P1.
Turn off P1. First, FIG. 10 shows a case in which the maximum value of the current is detected as described above. In the embodiment of FIG. 1, the current detection signal 1V1 increases at a constant rate after turning on, and at the time of turning off. Since it becomes the maximum value, the trigger Tg is generated at the time point represented by the following (Equation 1), which is delayed by the drive delay time dToff at the time of turning off from the time point t3 at which the inverter drive signal 1P1 is turned off. The current value is sampled by the detector 7e.

[0037]

[Equation 1]

The current detection signal 1V1 indicates the current that actually flows because the switching elements T1 to T6 are controlled by the inverter drive signal 1P1.
As shown in the figure, if the trigger Tg is used to detect the current value at the timing of (Equation 1), even if the current waveform deviates from the pulse-width-modulated inverter drive signal 1P1, the current at the maximum position can be accurately measured. Various detections are possible.

Next, FIG. 11 shows a case in which the average value of the current is detected. As described above, in the embodiment of FIG. 1, the current detection signal 1V1 increases at a constant rate after being turned on. Since it becomes the maximum value at the off time, it becomes an average value at about 1/2 of the duration of the current detection signal 1V1 as shown in the figure. Therefore, the occurrence time of the trigger Tg is set to the time expressed by (Equation 2). Then, the current can be detected at the center of the on time of the actual current detection signal 1V1.

[0040]

[Equation 2]

Next, FIG. 12 shows that the ON delay time dTon and the OFF delay time dToff obtained as described above can be used to generate an output current at the same timing as the current command signal 1P1S. If you do,
In the timing diagram showing the operation in one embodiment of the present invention, the sequence generator 107f is a voltage command signal 1P
The ON delay time dTon is earlier than the time when 1S is turned on, that is, the inverter drive signal 1P1 is turned on at the time t1-dTon, and the delay time dToff is before the time when the voltage command signal 1P1S is turned off, that is, t.
It is configured to generate a trigger Tg for operating the pulse width modulation signal generator 107a so as to turn off the inverter drive signal 1P1 at 3-dToff.

Therefore, according to this embodiment, as shown in the figure, the current 1Ia or the like actually flowing is the voltage command signal 1P1S.
As a result, control can be performed with the ON delay and the OFF delay removed.

Further, FIG. 13 shows the time when the voltage is actually applied to the brushless DC electric motor 103, which is the load of the inverter, using the ON delay time dTon and the OFF delay time dToff obtained as described above. In the timing diagram showing the operation of one embodiment of the present invention, which allows the current passage time to be matched with the pulse width t of the voltage command signal 1P1S, the sequence generator 107f shows the time t1 when the voltage command signal 1P1S turns on. Then, the inverter drive signal 1P1 is turned on, and the on delay time dTon and the off delay time d from the time t1 when the inverter drive signal 1P1 is turned on with respect to the flow time t.
The inverter drive signal 1P1 is turned off at the time t3 shown by (Equation 3) obtained by performing the correction by Toff.

[0044]

[Equation 3]

Therefore, according to this embodiment, the time when the voltage is actually applied to the DC motor 103 is t when the on time.
At 1 + dTon, the turn-off time point becomes t3 + dToff, and its phase is different from that of the voltage command signal 1P1S, but the voltage application time takes the difference between the off-time and the on-time and is corrected according to (Equation 4). Signal 1P1S
Can be equal to.

[0046]

[Equation 4]

By the way, in the embodiment shown in FIG.
ON delay time dTon and OFF delay time dT
Regarding the off calculation process, there is no particular limitation as to when it is executed, but one embodiment of the present invention in which this calculation process is executed prior to the start of operation of the inverter. This will be described with reference to the timing chart of FIG.

Also in this embodiment, the configuration is the same as that of the embodiment shown in FIG. 1, but the operation of the control device 107 is different. First, since current does not flow before the electric motor is started, the ON delay time dTon and the OFF delay time dToff are not calculated when the electric motor is started. Therefore, in this embodiment, the delay measurement mode is set before the motor is started, and in this mode, each phase of the AC output is made to flow with a minute pulse width, and the signal obtained by this is used. The ON delay time dTon and the OFF delay time dToff are measured.

FIG. 14 is a timing chart in this delay measurement mode. In this figure, the inverter drive signal 1P1 is used.
For each of the A phase, B phase, and C phase, the upper arm drive signal (a signal supplied to the switching elements T1, T2, and T3, which is represented by A +, B +, and C +) and the lower arm drive signal (switching). The signals supplied to the elements T4, T5, and T6 are shown separately as A-, B-, and C-).
Ib and 1Ic are shown.

In this embodiment, each drive signal A +, B
Of the 6 types of signals, +, C +, A-, B- and C-, the upper arm drive signal is the one that actually performs pulse width modulation during operation.
It shows a case of an inverter device having only (A +, B +, C +).

First, in the A + measurement section, a current is not passed through the B phase but a current is passed between the A and C phases, and the A + phase is modulated with a pulse width modulation signal having a minute pulse width. And during this time A +
Measure the phase drive delay. Next, in the B + measurement period, a current is passed through the B-C phase, and the drive delay of the B + phase is measured by the pulse superimposed on the B + phase. Then, after the phase switching period, a current is caused to flow between the C and A phases, and the drive delay of the C + phase is measured by the pulse superimposed on the C + phase.

By this operation, the delay time with respect to each of the A +, B +, and C + signals that should output the pulse width modulated signal can be independently measured. As a result, the sequence generator 107f can measure the delay time. As described above, various timing controls in the subsequent operation period are performed using the delay time for each.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described using 5. In the embodiment of FIG. 15, the same reference numerals as those in the embodiment of FIG. 1 represent the same parts. In this embodiment, the output current of the inverter is detected on the AC side of the inverter.
The difference from the conventional example is that the current detection signals 3Va, 3Vb,
A change detector 810 for generating change detection signals 8Sa, 8Sb, 8Sc from 3Vc is provided, and the change detection signal is taken into the control device 807, and the inverter drive signal 3P1 output by the control device 807 and the change detection signal 8S.
The means for measuring the drive delay from the time difference between a, 8Sb, and 8Sc and correcting the control timing is provided.

The control device 807 includes a pulse width modulation signal generator 807a, a timing generation circuit 807b, and a clock device 8.
07c, a storage device 807d, a current detector 807e, and a sequence generator 807f. It should be noted that these components are the same as the control device 107 in the embodiment shown in FIG.
The alphanumeric characters 107a to 107f in FIG. 6 correspond to the same elements and perform the same operation. The difference from the control device 107 is that there are three types of change detection signals 8Sa, 8Sb, and 8Sc that are input, and each corresponds to a voltage change in each phase, so the drive delay measurement corresponds to each. That is, the drive delay for each phase is obtained by measuring the time difference between the phase and the inverter drive signal 3P1.

Next, the change detector 81 in this embodiment.
The operation of 0 will be described. FIG. 16 shows an example of measuring the drive delay of the A phase.
Shows the details of the change detector 810. The change detector 810 in this embodiment is composed of a differentiating circuit 812, which enlarges the slope (change) of the current detection signal 3Va and outputs the change detection signal 8Sa. It is supposed to work.

First, the controller 807 superimposes the pulse width modulation signal on the inverter drive signal 3P1 and outputs it. Since this signal passes through the drive circuit 306, the switching signal 3P2 is output with a delay, turning on / off the switching elements T1 to T6 of the inverter. As a result, an inflection point of the AC side current 3Ia appears after a delay of the switching element.

While the voltage is applied to the AC side, the AC side current 3Ia increases, and when the voltage is not applied to the AC side, the AC side current 3Ia decreases. Then, the current detection signal 3Va changes in proportion to the alternating current 3Ia. Therefore, when this current detection signal 3Va is input to the change detector 810, its differential value is output. By outputting this differential amount with a large gain, the change detection signal 8Sa is output as shown in FIG. It is possible to obtain an output that takes a binary state as.

Therefore, the control unit 807 controls the time difference t2- between the inverter drive signal 3P1 and the change detection signal 8Sa.
By measuring t1 and t4-t3, the drive delay dTon at the time of ON and the drive delay dTof at the time of OFF
It will be possible to measure f.

Next, another embodiment of the present invention will be described with reference to FIG. In the embodiment of FIG. 18, the same symbols as in FIG. 1 represent the same parts. In this embodiment, the drive delay time is set to the applied voltage 1Ea, 1E of each phase.
b, 1Ec is used for measurement, and the control device 10
7 and other parts are the same as in FIG. Applied voltage for each phase 1
Since Ea, 1Eb, and 1Ec directly detect the voltage applied to the AC side, they have the same waveform as the signal 8Sa in FIG. Then, from this signal, the voltage detectors Ra, R
b, Rc using change detection signals 1Sa, 1Sb, 1Sc
Trying to get. According to this embodiment, since the applied voltage is directly detected, the delay of the change detection signal is further reduced, and therefore a more accurate drive delay time can be obtained.

Next, still another embodiment of the present invention will be described with reference to FIG. In the embodiment shown in FIG.
The same reference numerals as those in FIGS. 1 and 18 represent the same parts.
In this embodiment, the drive delay time is set to the applied voltage 1E of each phase.
a, 1Eb, 1Ec difference 1Ea-1Eb and 1Eb-1
The measurement is performed using Ec, and the control device 107 and other parts are the same as in FIG.

The applied voltages 1Ea, 1Eb, 1Ec of the respective phases are voltages applied to the alternating current side. Therefore, according to this embodiment, two types of differences are applied when only two phases among the three phases are applied. The applied voltage of each phase can be detected from the voltage, and the drive delay can be measured by detecting the change in this voltage. In this embodiment, the voltage detectors Rab and Rbc are used, and the change detection signals 1Sab and 1Sbc are obtained from the two types of differential voltages detected by the voltage detectors Rab and Rbc.

Next, FIG. 2 shows the inverter control range when there is a drive delay with respect to the inverter drive signal.
0 and FIG. 21 will be described. First, FIG. 20 shows a current controllable duty ratio range when there is a drive delay, and then FIG. 21 shows a load characteristic of the electric motor.

When there is a drive delay, when current detection is performed in synchronization with the inverter drive signal, if the inverter drive signal having a narrow pulse width as shown in FIG. 20 is output, the phase of the inverter drive signal is actually applied. The phase of the voltage is completely deviated, and it becomes impossible to detect the current in synchronization with the pulse.

As shown in FIG. 20, in the conventional inverter, if a pulse whose pulse width is shorter than the drive delay dTon time at the time of turning on is output, the current cannot be detected especially in the case of the 120-degree conduction type inverter. As a result, highly accurate rotation speed control cannot be performed. Therefore, the conduction ratio control range in which sufficient accuracy can be maintained is the portion excluding the narrow pulse, as shown in FIG. On the other hand, when the inverter device of the present invention is used, the current control can be performed in synchronization with the actual applied voltage. Therefore, as shown in FIG.
Control is possible even for pulses shorter than n hours.

Next, FIG. 21 shows the difference in the current control range between the conventional inverter device and the inverter device of the present invention, and the difference in the control range of the electric motor caused thereby. Since the driving torque of the electric motor using the permanent magnet rotor is almost proportional to the current flowing through the armature winding, the narrow pulse width region corresponds to the current, that is, the control position where the torque is small. Therefore, in the conventional inverter device, sufficient control accuracy cannot be obtained particularly when the electric motor is operated in a low speed and low torque state.

On the other hand, in the inverter device according to the present invention, current control is possible even in a sufficiently narrow pulse state. Therefore, as shown in FIG. 21, the operating range in the low speed and low torque region should be expanded. Therefore, there are merits by applying the inverter according to the present invention to various application examples. Therefore, next, a system to which the inverter device according to the present invention is applied will be described with reference to FIGS. 22 to 24.

First, FIG. 22 shows an embodiment of an air conditioner according to the present invention. In the drawing, reference numeral 901 denotes an inverter device according to the present invention, and in this embodiment, an indoor unit 9
The detected value of the temperature sensor 905 provided in 06 is sent to the air conditioner control device of the outdoor device 907, the air conditioner 907 outputs the speed command Ns according to the detected value, and the inverter device 901 is sent in this way. In order to rotate the compressor 902 with the speed command Ns, the drive torque of the electric motor incorporated in the compressor, that is, the current of the armature winding is controlled.

The compressor whose speed is controlled by the inverter device 901 compresses the refrigerant in the heat exchange system to perform the cooling operation or the heating operation. At this time, according to this embodiment, the cooling operation is performed. Since the heat transfer capacity at the time of heating or during heating can be changed according to the rotation speed of the compressor 902, when the indoor temperature is close to the appropriate temperature, the rotation speed is lowered to operate at low capacity, and the indoor temperature is kept at the appropriate temperature. When the vehicle is away from the vehicle, the number of rotations can be increased to perform high-performance operation, and accurate air conditioning control can be easily obtained.

Next, FIG. 23 shows an embodiment of an electric washing machine according to the present invention, which is an operation control device 204 in this embodiment.
Is a weight sensor 202 provided under the washing tub 205.
The amount of laundry put in the washing tub 205 is detected by, and the washing machine is operated at a variable speed according to the detected amount, that is, the speed command Ns is changed according to the amount of laundry to be operated. Is configured.

Therefore, in the inverter device 901 according to the present invention, the torque of the drive motor 203, that is, the armature winding, is adjusted so that the rotation speed of the drive motor 203 matches the speed command Ns output from the operation control device 204. Control the current in the line.

Therefore, according to this embodiment, the number of rotations of the washing tub 205 is always controlled in an optimum state in accordance with the amount of laundry, so that no power is wasted and a sufficient washing state is facilitated. Obtainable.

FIG. 24 shows an embodiment of the electric vacuum cleaner according to the present invention, which is an operation control device 504 in this embodiment.
Is a pressure sensor 5 provided near the electric blower 505.
02, the pressure (negative pressure) of the mouthpiece is measured, and the electric blower 505 is operated at a variable speed according to the detection result of this pressure, that is,
The speed command Ns is changed according to the pressure of the suction port to perform variable speed operation. Therefore, in the inverter device 901 according to the present invention, the rotation speed of the electric blower 505 is output from the operation control device 204. Speed command Ns
The torque of the drive motor 503, that is, the armature winding current is controlled so that

Therefore, according to this embodiment, the pressure at the suction port can be controlled to an optimum state at all times with high accuracy, and a convenient electric vacuum cleaner can be easily obtained.

[0074]

According to the present invention, the timing at which a voltage is actually applied to each phase on the AC side is detected from the time when the DC side current changes, and the timing when the modulation signal output by the modulation signal output means changes. The drive delay time from the output of the inverter drive signal until the voltage is actually applied to the AC side is measured using this difference, and the control timing is changed according to the drive delay. This has the effect of eliminating the influence and realizing an inverter device that performs highly accurate control.

Further, according to the present invention, a modulation signal having a specific pattern is output to each phase of the electric motor before the electric motor is started, the drive delay is detected before the electric motor is started, and the drive delay is detected from the start. Since the control timing can be changed immediately by the control, there is an effect of realizing an inverter device that performs high-precision control with the influence of the drive delay removed, with respect to control when the electric motor is unstable at startup.

Further, according to the present invention, the timing at which the voltage is actually applied to the phase is detected from the time when the winding current of the motor changes for each phase, and the time when the modulation signal output by the modulation signal output means changes. The drive delay time from when the difference is obtained and the inverter drive signal is output until the voltage is actually transmitted to the AC side is measured, and the control timing is changed according to the drive delay. Is independently and parallelly detected, and the effect of realizing an inverter device that performs highly accurate control by removing the influence of the drive delay is provided.

Further, according to the present invention, the timing at which the voltage is actually applied to the phase is detected by detecting the change time point of the phase voltage of the motor for each phase, and the change of the modulation signal output by the modulation signal output means is detected. The drive delay from when the inverter drive signal is output to obtain the difference from the time and until the voltage is actually applied to the AC side is measured, and the control timing is changed according to the drive delay. There is an effect of realizing an inverter device which detects a delay with high accuracy without a delay of a change detection circuit and removes an influence of a drive delay without considering an influence of a delay of the change detection circuit and performs a highly accurate control.

Further, according to the present invention, the timing at which the voltage is actually applied to the phase is detected by detecting the change time point of the line voltage of the motor for each phase, and the modulation signal output by the modulation signal output means is detected. The drive delay from when the inverter drive signal is output after the difference from the change time is output to when the voltage is actually applied to the AC side is detected, and the control timing is changed according to the drive delay, so a small voltage detector can be used. Realize an inverter device that detects the drive delay of each phase with high accuracy without the delay of the change detection circuit and removes the influence of the drive delay without considering the effect of the delay of the change detection circuit. effective.

Further, according to the present invention, the current is detected and controlled according to the phase in which the current actually flows according to the detected drive delay, so that the current detection accuracy is improved,
This has the effect of realizing an inverter device that performs highly accurate current control.

Further, according to the present invention, the inverter drive signal is changed so that the voltage actually applied to the AC side is in accordance with the command according to the detected drive delay, so that the phase-to-phase variation due to the drive delay is eliminated. This has the effect of realizing an inverter device that realizes highly accurate control.

Furthermore, the capacity of the air conditioner is controlled by using the above-mentioned inverter device, the rotation speed is controlled with high accuracy under a light load condition, that is, the output power is small, and the operation is performed with a small fluctuation in the rotation speed. Noise has the effect of realizing low capacity operation and expanding the capacity control range.

Further, the rotation speed of the washing machine is controlled by using the above-described inverter device, and the rotation speed is controlled with high precision under a light load condition, that is, a condition where the amount of laundry is small or a condition where the machine is operated at a low speed. By operating with a small rotation speed fluctuation, low noise and low speed operation are possible even with a small amount of laundry and a small amount of water, and the range of laundry amount and cloth quality that can be operated under optimal conditions is expanded. be able to.

Further, the rotation speed of the electric vacuum cleaner is controlled by using the above-mentioned inverter device, the rotation speed is controlled with high accuracy under a light load condition, that is, the condition of clogging, and the vacuum cleaner is operated with a small fluctuation in rotation speed. Even in a light load state such as a clogging state, there is an effect of realizing low noise operation.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an inverter device according to the present invention.

FIG. 2 is a detailed explanatory diagram of a control device according to an embodiment of the present invention.

FIG. 3 is an operation explanatory diagram according to the embodiment of the present invention.

FIG. 4 is a detailed explanatory diagram of a change detector according to an embodiment of the present invention.

FIG. 5 is an operation explanatory diagram of the change detector according to the embodiment of the present invention.

FIG. 6 is a configuration diagram showing a conventional example of a 120-degree conduction type inverter device.

FIG. 7 is an operation explanatory diagram in a conventional example of a 120-degree conduction type inverter device.

FIG. 8 is a configuration diagram showing a conventional example of a sine wave drive type inverter device.

FIG. 9 is an operation explanatory diagram of a conventional example of a sine wave drive type inverter device.

FIG. 10 is a timing diagram relating to current detection timing control in one embodiment of the present invention.

FIG. 11 is a timing diagram relating to current detection timing control in one embodiment of the present invention.

FIG. 12 is a timing diagram related to voltage correction for performing output phase control in an embodiment of the present invention.

FIG. 13 is a timing diagram relating to voltage correction for performing the duty ratio correction according to an embodiment of the present invention.

FIG. 14 is a timing diagram illustrating the operation of another embodiment of the present invention.

FIG. 15 is a configuration diagram showing still another embodiment of the inverter device according to the present invention.

FIG. 16 is an operation explanatory diagram according to the embodiment of the present invention.

FIG. 17 is a detailed explanatory diagram of a change detector according to an embodiment of the present invention.

FIG. 18 is a configuration diagram showing still another embodiment of the inverter device according to the present invention.

FIG. 19 is a configuration diagram showing still another embodiment of the inverter device according to the present invention.

FIG. 20 is an explanatory diagram showing a current flow rate range in which current control is possible in the inverter device.

FIG. 21 is an explanatory diagram of load characteristics of an electric motor by an inverter device.

FIG. 22 is a configuration diagram showing an embodiment of an air conditioner according to the present invention.

FIG. 23 is a configuration diagram showing an embodiment of an electric washing machine according to the present invention.

FIG. 24 is a configuration diagram showing an embodiment of an electric vacuum cleaner according to the present invention.

[Explanation of symbols]

101, 301 Inverter 102 DC power supply 106 Drive circuit 103 Brushless DC motor 107, 307, 407, 807 Control device 110, 810 Change detector 203, 503 Drive motor 204, 504 Operation control device 303 Electric motor 901 Inverter device 902 Compressor 903 Air conditioning Machine control device 1P1, 3P1 Inverter drive signal dTon Delay time when ON dToff Delay time when OFF Ra, Rb, Rc, Rab, Rbc Voltage detectors T1, T2, T3, T4, T5, T6 Switching element R Detection resistance

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tsunehiro Endo 4026 Kuji Town, Hitachi City, Ibaraki Prefecture Hitachi Research Laboratory, Hitachi Ltd. Hitachi Tochigi Plant (72) Inventor Akihiko Kuramochi 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Prefecture Hitachi Tochigi Plant

Claims (13)

[Claims] 1. A pulse width modulation type inverter is provided,
In the inverter device configured to control the pulse width modulation signal to be supplied to the inverter so that the detected value of the output current of the inverter matches the command value, change detection means for detecting a change time point of the output current, A processing means for calculating a time interval between the change time point of the pulse width modulated signal and the change time point detected by the change detection means is provided, and the timing required for controlling the inverter is determined based on the time interval. An inverter device characterized by being configured as described above. 2. The inverter according to claim 1, wherein the change time point of the pulse width modulated signal is at least one of a rising time point and a falling time point of the signal. apparatus. 3. Having a pulse width modulation type inverter,
In the inverter device configured to control the pulse width modulation signal to be supplied to the inverter so that the detected value of the output current of the inverter matches the command value, means for measuring the signal transmission delay of the inverter device, Means for supplying a measurement pulse width modulation signal of a predetermined pattern to the inverter before the start of the load current supply operation by the inverter is provided, and the inverter device is provided during the period in which the measurement pulse width modulation signal is supplied. An inverter device characterized by being configured to measure the signal transmission delay of the. 4. The invention according to claim 1 or 3,
An inverter device characterized in that the change detecting means is configured to detect a change time point of a current detection value for each phase of an AC side output of the inverter. 5. The invention according to claim 1 or 3,
An inverter device, wherein the change detecting means is configured to detect a time point when a detected value of a DC side current of the inverter changes. 6. The invention according to claim 1 or 3,
An inverter device characterized in that the change detecting means is configured to detect a time point when a detected value of an AC side phase voltage of the inverter changes. 7. The invention according to claim 1 or 3,
An inverter device characterized in that the change detecting means is configured to detect a change time point of a detected value of an AC side line voltage of the inverter. 8. The invention according to claim 1, wherein the timing required for controlling the inverter is a timing for detecting the current value of the output current. Inverter device. 9. The invention according to claim 1, wherein the timing required for controlling the inverter is a timing for controlling a change time point of the pulse width modulation signal. Inverter device characterized by. 10. The invention according to any one of claims 1 to 7, wherein the timing required to control the inverter is the timing required to control the pulse width of the pulse width modulation signal. An inverter device characterized in that 11. An air conditioner configured to drive a compressor electric motor by using the inverter device according to any one of claims 1 to 10. 12. An electric washing machine configured to drive an impeller rotating electric motor for stirring wash water using the inverter device according to claim 1. Description: 13. An electric vacuum cleaner configured to drive an impeller rotating electric motor for vacuum generation by using the inverter device according to any one of claims 1 to 10.