JPH07312895A - Inverter and air conditioner - Google Patents

Abstract

PURPOSE:To realize high-speed operation of a motor without an increase in motor size by deciding a commutation timing based on compared result of the number of revolutions of a rotor with that of a target and positional information. CONSTITUTION:A microcomputer 41 sets a time point delayed by 30 degrees from a zero-crossing time point to a reference commutating timing. The timing is decided at the same time point of the reference commutation timing until a speed deviation becomes a deviation corresponding to 100% of the duty of a PWM signal P1 by comparing the number of revolutions of a rotor with that of a target, and the number of revolutions of the rotor is controlled by the duty control of the PWM signal P1. After the duty of the signal P1 is enhanced to 100%, if the number of revolutions of the rotor is lower than the target number, the commutation timing is earlier set with respect to the reference timing by a time responsive to the difference (speed deviation) between the number of revolutions of the motor and the target number. Even after the commutation timing is earlier set to the limit, when the number of revolutions of the rotor is lower than the target number, the OFF timing of a conducting signal is delayed by a time responsive to the speed deviation with respect to the reference OFF timing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a switching circuit for sequentially energizing each winding of a motor having a plurality of windings such as a brushless motor at commutation timing corresponding to a predetermined rotation position of a rotor. The present invention relates to an inverter device and an air conditioner.

[0002]

2. Description of the Related Art In recent years, in air conditioners and refrigerators, a brushless motor, which is a kind of DC motor, has been adopted and can be driven by an inverter device in order to change the compressor capacity and save power consumption. It is being appreciated. In the case of a brushless motor, the rotor rotation position signal is usually required to determine the energized phase of the winding, but the motor is exposed to refrigerant such as an air conditioner or refrigerator compressor. Depending on the situation, it may be difficult to arrange the position detection sensor. Therefore, the inventors of the present application have developed a technique for obtaining a rotational position signal by detecting an induced voltage in a winding of a motor and electrically processing the induced voltage, which is disclosed in Japanese Patent Application No. 62-1626.
Filed as No. 54.

Hereinafter, the case where the invention of the application is carried out by a pulse width modulation (hereinafter, simply referred to as PWM) system will be described as an example, which will be described as a prior art with reference to FIGS. 9 to 11.

In the inverter device shown in FIG. 9,
The DC power supply circuit 2 connected to the AC power supply 1 is composed of a full-wave rectification circuit 3, a reactor 4a and a smoothing capacitor 4b, and between the positive side DC power supply line 5 and the negative side DC power supply line 6 of the DC power supply circuit 2. A switching element, for example, a three-phase bridge circuit 13 including switching transistors 7 to 12 is connected to the output terminal 1 as a switching circuit.
The terminals of the windings 15u, 15v, 15w of the brushless motor 15 are connected to 4u, 14v, 14w.

In the three-phase bridge circuit 13, the three transistors 7, 9, 11 connected between the positive side DC power supply line 5 and the output terminals 14u, 14v, 14w correspond to the positive side switching elements, The three transistors 8, 10, 12 connected between the negative side DC power supply line 6 and the output terminals 14u, 14v, 14w correspond to negative side switching elements. When the transistors 7 to 12 are on / off controlled in a predetermined order, the brushless motor 15 has windings 15u to 15w of 120 degrees (electrical angle, the same applies hereinafter).
It is rotationally driven by successively energizing with a phase difference of. In this case, one transistor is 120
The duty is controlled by the PWM signal P1 shown in FIG. 10 during the ON / OFF cycle of 1 degree ON and 240 degrees OFF, and the terminal voltages Vu, Vv, Vw of the windings 15u to 15w of the brushless motor 15 are controlled. Has the waveform shown in FIG.

FIG. 11 shows the waveforms of the terminal voltage Vu and the current Iu of the winding 15u when PWM control is not involved. In this waveform, the sloped portion extending over an interval of about 60 degrees (period Ta) is the induced voltage of the winding 15u, and the elongated positive and negative pulses are the free wheel diode D1 connected in parallel with the respective transistors 7 to 12 of the three-phase bridge circuit 13. The pulse voltage from D6 to V6, and V0 are reference voltages formed by the resistance voltage dividing circuit 16 connected between the DC power supply lines 5 and 6.
Here, the reference voltage V0 is set to one half of the voltage of the DC power supply circuit 2 of the three-phase bridge circuit 13. This Figure 1
From 0, the commutation timing is the time when the induced voltage and the reference voltage V0 cross (hereinafter, simply referred to as the zero cross time).
It is understood that about 30 degrees behind.

The terminal voltages Vu, Vv, Vw are compared with the reference voltage V0 by the comparators 18 to 20 provided in the position signal circuit 17 as position detecting means, so that the position information of the rotor of the brushless motor 15 can be obtained. 1 of the terminal voltages Vu to Vw as shown in FIG.
Fundamental wave signals Vu ', Vv', Vw 'for 80-degree section recognition
Is converted to. Further, these fundamental wave signals Vu ′, Vv ′,
Vw 'is applied to the waveform synthesizing circuit 21 as the energizing signal forming means, and by comparison with the PWM signal P1, it consists of continuous square waves with a time width of 180 degrees and a phase difference of 120 degrees from each other. Recognition waveform signals Ua, V having
a, Wa. This recognition waveform signal Ua, Va,
Wa start point (rise time) and end point (fall time)
Coincides with the time of zero crossing.

Further, in the waveform synthesizing circuit 21, among the first and second timer functions possessed by the waveform synthesizing circuit 21, the three recognition waveform signals Ua, V are recognized by the first timer function.
a, Wa from the first six of the time width Tb is 60 degrees each
Phase division patterns X1 to X6 of the first phase division pattern X1 to X6 are formed by the second timer function.
Six second phase division patterns Y1 to Y6 each having a time width of 30 degrees starting from the end point of 6 are formed. Then, the waveform synthesizing circuit 21 finally uses the energizing signal U shown in FIG. 10 from the second phase section Y1 to Y6 signals as described above.
p, Un, Vp, Vn, Wp, Wn are combined.

Here, the energization signals Up, Un, Vp, V
The starting points of n, Wp, and Wn are the second phase division pattern Y.
Since it coincides with the end points of 1 to Y6, it is a point delayed by 30 degrees from the zero cross point.
The phase pattern of p, Un, Vp, Vn, Wp, Wn is
This corresponds to the commutation timing pattern required for the transistors 7 to 12 of the three-phase bridge circuit 13.

On the other hand, the speed judgment circuit 22 as the speed detection means judges the speed deviation from the energization signal Wn and the speed command signal Sc given as the rotation speed detection signal of the brushless motor 15 from the waveform synthesis circuit 21, and the speed deviation is determined. The speed deviation signal Sd corresponding to the speed deviation is output and this is applied to the winding 15u.
Pulse width modulation circuit 23 for controlling the applied voltage to
Give to. The pulse width modulation circuit 23 has a PWM signal P1.
Is controlled so as to correspond to the magnitude of the speed deviation signal Sd.

PWM whose duty is controlled in this way
The signal P1 is supplied by the gate portions 25, 27, 29 of the gate circuit 24 constituting the driving means to the energizing signals Up, V
It is supplied to the bases of the positive side transistors 7, 9, 11 of the three-phase bridge circuit 13 as base control signals while being combined with p, Wp, for example, and these are on / off controlled in the on / off mode of the PWM signal P1. . Further, only the energizing signals Un, Vn and Wn are supplied to the bases of the negative side transistors 8, 10 and 12 through the gate portions 26, 28 and 30, and ON / OFF control without PWM mode is performed. As a result, the transistors 7 to 12 are on / off controlled by the energization signals Up to Wn in the pattern shown in FIG. 10, whereby the brushless motor 15 continues to be driven and its speed is controlled by the duty control by the PWM signal P1 shown in FIG. Is done.

Here, the ON mode of the PWM signal P1 refers to the mode of the level (set to high level (H) in FIG. 10) for turning on the transistor among the high level and the low level of the pulse signal, and it is the off mode. Indicates a mode in which the transistor is turned off (set to the same low level (L)).

[0013]

FIG. 12 shows an operating range (a range surrounded by a solid line) of a brushless motor used as a drive motor for a compressor of an air conditioner, and a limit line A of the operating range is shown. The limit line B is due to the limit of the allowable current on the side of the AC power supply 1, the limit line B is due to the limit of the allowable current on the side of the DC power supply circuit 2, and the limit line C is the rotation speed-torque characteristic when the duty of the pulse width modulation signal P1 is 100%. It is due to the constraint of.

The range indicated by X in the figure is the operating range at the beginning of the heating operation, but if the engine can be operated at a higher rotational speed at the beginning of this operation, the indoor temperature can be reached faster than the set temperature. . Therefore, in order to operate at a high rotation speed at the beginning of the operation, the rotation speed in FIG.
The design of the brushless motor may be changed so that the limit line C due to the torque characteristic shifts to the high rotation side. However, in this case, the number of turns of the winding must be reduced, so that high speed rotation is required. There is a problem in that the efficiency in the normal operation is lost and the brushless motor becomes large in size.

The present invention has been made in view of the above circumstances, and an object thereof is an inverter device and an air conditioner which can be operated at a high rotation speed without causing a problem of efficiency reduction and size increase of a motor during normal operation. To provide a conditioner.

[0016]

According to another aspect of the present invention, an inverter device includes a switching circuit including a plurality of switching elements for sequentially energizing windings of a plurality of phases included in a motor, and position information of a rotor included in the motor. Position detecting means for obtaining the rotational speed information of the rotor, and the applied voltage to the winding according to the result of comparison between the rotor rotational speed obtained from the rotational speed information and the target rotational speed. The commutation timing is determined based on the voltage control means for controlling the rotor rotation speed obtained from the rotation speed information and the target rotation speed and the position information, and the energization signal corresponding to the commutation timing is obtained. An energization signal forming means and a driving means for driving the switching element based on the energization signal are provided.

According to another aspect of the inverter device of the present invention, the voltage control means comprises a pulse width modulation circuit, and the energization signal forming means has a pulse width modulation signal formed by the pulse width modulation circuit with a duty of 100% and a rotor rotation speed. Is lower than the target number of revolutions, the commutation timing is shifted to a time earlier than the reference commutation timing.

In the inverter device according to the third aspect of the present invention, the position detecting means provides the energization signal forming means with the time when the terminal voltage of the winding crosses the reference voltage as position information, and the energization signal forming means determines the crossing time. The base time measuring timer means for counting the time between the next crossing time point, and the time from the crossing time point to the reference commutation timing based on the base time counted by the base time measuring timer means and the rotor A calculating means for calculating an earlier time from the comparison result between the rotation speed and the target rotation speed and the base time, and calculating a difference between the calculated two times as a difference time, and a time difference measuring timer for starting time counting from the crossing time point. And a time point at which the time difference measuring timer means finishes counting the time difference, as a commutation timing.

According to another aspect of the inverter device of the present invention, the voltage control means comprises a pulse width modulation circuit, and the energization signal forming means has a duty of 100% of the pulse width modulation signal formed by the pulse width modulation circuit and a commutation timing. After shifting to a point earlier than the reference commutation timing,
When the rotor rotation speed is lower than the target rotation speed, the off timing of the energization signal is shifted to a time later than the reference off timing.

In the inverter device according to the fifth aspect of the present invention, the position detecting means provides the energization signal forming means with the time when the terminal voltage of the winding crosses the reference voltage as position information, and the energization signal forming means detects the crossing time. A base time measuring timer means for counting the time between the next crossing time and an extension time based on the comparison result of the rotor speed and the target speed and the base time counted by the base time measuring timer means. Computation means for computing and extension time measuring timer means for starting time counting from the crossing point, and the time when the extension time measuring timer means finishes counting the extension time is the off timing of the energizing signal. It is characterized by.

An air conditioner according to claim 6 comprises a heat pump in which a compressor, an outdoor heat exchanger, a pressure reducing device and an indoor heat exchanger are connected by a refrigerant passage, and the motor of the compressor is controlled by the inverter device. It is characterized by doing.

[0022]

In the inverter device according to the first aspect of the present invention, the energization signal forming means determines the commutation timing in consideration of not only the position information of the rotor but also the result of comparison between the rotor rotation speed and the target rotation speed. Therefore, when the rotor rotation speed is lower than the target rotation speed, the commutation timing is advanced according to the difference, and the rotor rotation speed increases due to the effect of the weakening magnetic field.

In the inverter device according to the second aspect of the present invention, when the duty of the pulse width modulation signal is 100% and the maximum voltage is applied to the winding and the rotor speed is still lower than the target speed, Since the commutation timing is earlier than the reference commutation timing, the rotation speed of the rotor increases.

In the inverter device according to the present invention, the energization signal forming means counts the time between the crossing time points of the terminal voltage of the winding and the reference voltage, and based on the count time, the reference voltage is changed from the crossing time point. The time up to the flow timing is calculated, and the advance time is calculated based on the count time and the result of comparison between the rotor speed and the target speed, and the difference between the two calculation times is obtained as the difference time, and the difference time is counted from the crossing point. Since the time point is the commutation timing, the commutation timing can be easily determined by the program software.

According to the fourth aspect of the present invention, when the rotor rotation speed is lower than the target rotation speed even though the commutation timing is set earlier than the reference commutation timing, the off timing of the energization signal is set to be lower than the reference off timing. Since it is also delayed, the energization period of the winding becomes longer and the rotation speed of the rotor increases.

In the inverter device according to the fifth aspect of the invention, the energization signal forming means counts the time between the crossing times of the terminal voltage of the winding and the reference voltage, and counts the time, the rotor speed and the target speed. Since the extension time is calculated based on the result of comparison with and the off-timing is the time when the extension time is counted from the crossing point, the off-timing can be easily determined by the program software.

In the air conditioner according to claim 6,
Since the motor of the compressor is controlled by the above-mentioned inverter device, the rotation speed of the motor can be increased at the beginning of the heating operation to bring the indoor temperature closer to the set temperature.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to FIGS.
9, the same parts as those in FIG. 9 will be assigned the same reference numerals and different parts will be described. First, in the heat pump 31 shown in FIG. 2, the compressor 32 is configured such that the compression unit 33 and the brushless motor 15 that drives the compression unit 33 are housed in the same iron hermetic container 34.
The compressor 32 is connected to the four-way valve 35, the indoor heat exchanger 36, the pressure reducing device 37, and the outdoor heat exchanger 38 by a refrigerant pipe so as to form a closed loop.

The four-way valve 35 is switched to a state shown by a solid line and a two-dot chain line in accordance with heating operation and cooling operation, and the refrigerant compressed by the compression section 33 of the compressor 32 is decompressed by the indoor heat exchanger 36 during heating. Control is performed so as to pass through the device 37 and the outdoor heat exchanger 38 in order and return to the compression unit 33, and during cooling, return to the compression unit 33 through the outdoor heat exchanger 38, the pressure reducing device 37, and the indoor heat exchanger 36 in order. To be done. Therefore,
The indoor heat exchanger 36 serves as a condenser for heating the room during heating, and serves as a cooler for cooling the room during cooling. The indoor air and the outdoor air are sent to the indoor heat exchanger 36 and the outdoor heat exchanger 38 by fan devices 39 and 40, respectively.

On the other hand, in the inverter device shown in FIG. 1, the microcomputer 41 functions as energization signal forming means and has the same function as the waveform synthesizing circuit 21 shown in FIG. Function for changing commutation timing, energization signals Up, Un, Vp, Vn, W
It has the function of changing the off timing of p and Wn (the timing of switching from high level to low level) and the function of recognizing the specific period Ti.

The recognition of the specific period Ti is performed in the vicinity of the rising and falling timings of the recognition waveform signals Ua, Va, Wa.
In other words, each winding 15u, 15 of the brushless motor 15
Terminal voltages Vu, Vv, Vw including induced voltages of v, 15w
This is for recognizing the vicinity of the time when the reference voltage V0 and the reference voltage V0 cross. Therefore, the microcomputer 41
Has a third timer function (timer means for recognizing a specific period). This third timer function is, as shown in FIG. 5, from the end point of each of the second phase division patterns Y1 to Y6, or FIG.
As shown in (1), the times Z1 to Z6 are measured from the end points of the extension times Q1 to Q6 described later.

As will be apparent from the following description, this third
By measuring the time Z1 to Z6 by the timer function, the microcomputer 41 has a time width of 15 degrees (Tb / 4) corresponding to the end point (zero crossing point) of the first phase division patterns X1 to X6. Of the comparator 18 within the specific period Ti
The fundamental wave signals Vu ′, Vv ′, and Vw ′ from ˜20 are input. By limiting the input of the fundamental wave signals Vu ', Vv', and Vw 'to the specific period Ti in this way, it is possible to prevent the time point at which the pulse voltage from the diodes D1 to D6 crosses the reference voltage V0 from being erroneously recognized as the zero-cross time point. To prevent.

Here, the microcomputer 41 recognizes the zero-crossing time point by the fundamental wave signals Vu ', Vv', Vw 'from the comparators 18 to 20 and the PWM signal P1 from the pulse width modulation circuit 23 and the microcomputer 41. This is performed by comparison with the comparison data for position detection stored in the memory included therein. The comparison data for position detection is
As shown in Table 1 below, each first phase division pattern X1
Up to X6, fundamental wave signals Vu ', Vv', Vw 'and P
It is configured as a high level / low level mode of the WM signal P1.

[0034]

[Table 1]

Then, the microcomputer 41 inputs the comparison data for position detection of the first phase division pattern which is currently in progress in each of the first phase division patterns X1 to X6, and the fundamental wave within the specific period Ti. Signal Vu
', Vv', Vw 'and the high / low states of the PWM signal P1 coincide with the input comparison data for position detection, at the zero crossing point, that is, at the end point of the first phase division pattern which was in progress and It is recognized as the start point of the next first phase division pattern.

Further, the microcomputer 41 has a function as a rotation speed detecting means and detects the rotation speed of the rotor like the speed determination circuit 22 of the conventional inverter device shown in FIG. That is, the microcomputer 41
In each of the first phase division patterns X1 to X6, six patterns (4
The number of rotations (rotation speed) per unit time of the rotor is determined from the sum of the time of half rotation in the case of a pole) or 12 patterns (the same one rotation), and this is determined from the speed command signal Sc given from the outside. The speed deviation is determined by comparing with the rotation speed (target rotation speed), and a signal Sd having a duty corresponding to the speed deviation is given to the pulse width modulation circuit 23. Then, the pulse width modulation circuit 23 outputs the PWM signal P1 having the duty indicated by the duty signal Sd, and controls the voltage applied to the windings 15u, 15v, 15w.

It should be noted that one of the AC power supply lines 42 and 43 connecting the AC power supply 1 and the full-wave rectification circuit 3 is one power supply line 43.
The negative side DC power supply line 6 is provided with current detection elements 44 and 45, and the detection signals of these elements are used as the current determination circuit 46.
And 47. When the current flowing through the AC power supply line 43 exceeds a predetermined value, the current determination circuit 46 gives a duty limit command to the pulse width modulation circuit 23 so that the current flowing through the AC power supply line 43 does not exceed the allowable current value. Suppress. Further, the current determination circuit 47 is configured to detect the pulse width modulation circuit 2 when the current flowing through the negative side DC power supply line 6 exceeds a predetermined value.
3 is given a duty limit command to the three-phase bridge circuit 13
The current flowing in the three-phase logic circuit 13 is prevented from exceeding the allowable current value, the operation in the overload state is suppressed, and the three-phase logic circuit 13 is prevented from being destroyed due to heat generation.

Next, the microcomputer 41 having the above structure
The action of will be explained. First, in this embodiment, the microcomputer 41 uses the time point delayed by 30 degrees from the zero cross time point as the reference commutation timing, and the speed deviation determined by comparing the rotor speed and the target speed is PWM.
Until the deviation corresponding to 100% duty of the signal P1 is reached, the commutation timing is determined to be the same point as the reference commutation timing, and the rotation speed of the rotor is controlled by the duty control of the PWM signal P1. And the microcomputer 4
1 is the commutation timing after the duty of the PWM signal P1 is increased to 100%, that is, even when the maximum voltage is applied to the windings 15u, 15v, 15w, when the rotor rotation speed is still lower than the target rotation speed. Is accelerated by a time corresponding to the difference (speed deviation) between the rotor rotation speed and the target rotation speed with respect to the reference timing, and even after the commutation timing is further advanced to the limit, the rotor rotation speed is still the target rotation speed. When it is lower than the number, the off timing of the energization signal is delayed with respect to the reference off timing by a time corresponding to the speed deviation.

This will be specifically described with reference to the flow charts shown in FIGS. 3 and 4. The routine shown in FIG. 4 is configured as an interrupt routine with respect to the routine shown in FIG. First, FIG. 4 is a routine for determining the rotation speed control mode, and this routine is performed once for each rotation of the rotor of the brushless motor 15, for example. When this rotation speed control mode determination routine is executed, the microcomputer 41 first inputs the speed command signal Sc to obtain the command rotation speed Nc (step S1), and then the actual rotation speed of the rotor of the brushless motor 15. Nm is obtained (step S2), and then the control mode Cm is determined (step S3).

Here, the initial value of the control mode Cm is "1".
Therefore, at the start of heating / cooling operation,
In step S3, the microcomputer 41 displays “Cm =
1 ”and the duty D is calculated by the following equation (1) (step S4). D = D + K1 * (Nc-Nm) (1) where K1 is a constant, 0≤D≤1.

Subsequently, the microcomputer 41 determines that the duty D obtained by the equation (1) is "1", that is, 10
It is determined whether or not it is 0% (step S5), and when D is less than "1", the process proceeds to step S7, the signal Sd of the duty D is output to the pulse width modulation circuit 23, and the process returns. When the rotation speed Nm of the rotor is much lower than the command rotation speed Nc and the duty D becomes "1", the microcomputer 41 determines "YES" in step S5 and determines the control mode in the next step S6. C
m is set to "2", and in the subsequent step S7, the signal Sd having the duty D (100%) is output to the pulse width modulation circuit 23, and the process returns.

When the rotational speed control mode determination routine is executed after Cm is set to "2", the microcomputer 41 proceeds from step S3 to step S8, where the variable E is calculated by the following equation (2). Is calculated. E = E + K2 * (Nc-Nm) (2) where K2 is a constant and the initial value of E is "0", and 0≤
It is set within the range of E ≦ 1.

Subsequently, the microcomputer 41 determines whether or not the variable E obtained by the above equation (2) is "0" (step S9), and when E exceeds 0, it is determined in step S9. If "NO", the process proceeds to step S11 to determine whether E is "1". Then, when E is less than "1", "NO" is determined in step S11, and the process returns. When the rotor rotation speed Nm is lower than the command rotation speed Nc and E becomes "1",
In step S11, the microcomputer 41 displays "YE
S ", the control mode Cm is set to" 3 "in the next step S12, and the process returns. On the other hand, when the rotational speed Nm of the rotor becomes higher than the command rotational speed Nc and E becomes "0", it is determined to be "YES" in step S9 and the process proceeds to step S10, where the control mode Cm is set to ""1" is set, and "NO" is determined in step S11, and the process returns. When the control mode Cm is set to "1" in this way, the microcomputer 41 shifts from step S3 to step S4 when the next rotation speed control method determination routine is executed.

When the rotational speed control mode determination routine is executed after Cm is set to "3", the microcomputer 41 proceeds from step S3 to step S13, where the variable F is calculated by the following equation (3). Is calculated. F = F + K3 × (Nc-Nm) (3) where K3 is a constant and the initial value of F is “0”, and 0 ≦
It is set within the range of F ≦ 1.

Subsequently, the microcomputer 41 determines whether or not the variable F obtained by the above equation (3) is "0" (step S14), and when F exceeds "0", step S14. Then, it is judged as "NO" and the process is returned. The rotor rotation speed Nm is the command rotation speed Nc.
When F becomes higher than 0 and F becomes "0", step S14
In step S15, the control mode Cm is set to "2" and the process returns. When the control mode Cm is set to "2", the microcomputer 41 shifts from step S3 to step S8 when the next rotation speed control mode determination routine is executed.

Now, in the main routine shown in FIG. 3, assuming that the specific period Ti of a certain number of the first phase division patterns among the first phase division patterns X1 to X6 is entered, the microcomputer 41 Is step S
At T1, the position detection comparison data (Table 1) of the first phase division pattern of the number of zones currently in progress is loaded, and the specific period T
fundamental wave signals Vu ′, Vv ′, Vw input at i
'And the high / low states of the PWM signal P1 are compared with the comparison data (step ST2). When the induced voltage and the reference voltage V0 cross, the fundamental wave signals Vu 'and Vv
′, Vw ′ and the high / low states of the PWM signal P1 match the comparison data (“YE” in step ST2).
S ”), the time required for the first phase division pattern of the next division to start and end the first phase division pattern Tb
While loading (measurement time of the first timer function),
The first timer function is restarted to measure the required time of the started first phase division pattern (step ST3).

As is clear from the above, the first timer function starts time counting with the start of the first phase division pattern of each section number and ends the first phase division pattern (the next section number of the first section number pattern). The start of the phase division pattern of 1) and the end of the time count are repeated. Therefore, the first
The timer function of 2 will function as a base time measuring timer means for counting the base time Tb (corresponding to 60 degrees) from the zero cross time point to the next zero cross time point.

Then, in the next step ST4, the microcomputer 41 increments the number of divisions of the first phase division pattern stored in the memory (not shown) and sets it to the number of divisions of the newly started first phase division pattern. . Next, the microcomputer 41 proceeds to step ST5 for determining whether the control mode Cm is "3", and if Cm is "3", the determination is "YES" and the routine proceeds to step ST10. If Cm is "2" and "1", the result is "NO" and the process proceeds to step ST6.
Then, the microcomputer 41 determines in step ST6 whether Cm is "2" and E is "1".

In order to explain the above in a concrete example, assuming that the specific period Ti of the first phase division pattern having the number X1 of zones is entered, the microcomputer 41 determines the number X1 of zones in Table 1 as follows. Comparison data for position detection Vu ′ = H, Vv
′ = L, Vw ′ = L, P1 = H is loaded (step S
T1), fundamental wave signals Vu ′, Vv ′, Vw ′ and PWM
Comparison with the high / low state of the signal P1 (step S
2). When they match, the next division number X2 starts, and the microcomputer 41 finishes the division number X1.
Number of wards started with loading the required time Tb of X2
The first timer function is started to measure the required time (step ST3). Next, the microcomputer 41 sets the number of sections X1 stored in the memory to the number of newly started sections X2 (step ST4), and step ST5.
To move to.

Now, assuming that Cm is "1" or Cm is "2" and E is less than "1", the microcomputer 41 determines in steps ST5 and ST6.
Both are determined to be "NO", and the process proceeds to step ST7.
In this step ST7, the microcomputer 41
Calculates the time Ty of the second phase division pattern (time Y1 to Y6 to be measured by the second timer function) by the following equation (4) and starts the second timer function. Ty = (1-E) x Tb / 2 (4)

Then, the second timer function has the above-mentioned time Ty.
When the counting of is finished (“YE
S ”), the microcomputer 41 performs the next step ST
At 9, the energizing signals Up, Un, Vp, Vn, Wp, Wn are switched. The high / low states of the energization signals Up, Un, Vp, Vn, Wp, Wn of the respective first phase division patterns X1 to X6 are as shown in Table 2 below, and the energization signal switching state in step S9 is as described above. To explain,
The number of divisions of the newly started first phase division pattern is X6
Therefore, the energization signals Up, Un, Vp, Wp are the number X of sections.
The same state as 1 is continued, and the energization signals Vn and Wn are switched from H to L and from L to H, respectively.

[0052]

[Table 2]

Here, when Cm is "1", E is "0", so Ty is always (Tb / 2), as is clear from the above equation (4), which is zero cross. This coincides with the reference commutation timing delayed by 30 degrees from the time point, which means that the commutation timing is determined at the time point delayed by 30 degrees from the zero cross time point. Further, when Cm is "2" and E is less than "1", E becomes larger as the rotor rotation speed Nm is lower than the command rotation speed Nc from the equation (2). As is clear from equation (4), T
The shorter y is, the shorter the rotational speed Nm of the rotor is lower than the command rotational speed Nc, and the commutation timing is earlier than the reference commutation timing as illustrated in FIGS. 7A to 7D. It will be decided at the time.

When Cm is "2" and E is "1", "YES" is determined in step ST6 and the process proceeds to step ST9, and energization signals Up, Un, Vp, V in Table 2 are performed.
n, Wp, Wn are formed. The reason why steps ST7 and ST8 are not executed when E is "1" is that Ty becomes "0" when E = 1 in the equation (4), which coincides with the zero-cross point. Energization signals Up, Un, Vp, Vn, W in synchronization with detection at the time of zero cross
This is because it is sufficient to switch between p and Wn.

As can be understood from the above, the microcomputer 41 calculates the time (Tb / 2) from the zero crossing time to the reference commutation timing based on the base time Tb, and is expressed by the equation (2). Rotor speed Nm
And the command rotation speed Nc and the base time Tb, the advance time (E × Tb / 2) is calculated, and the difference between the calculated times is calculated as the difference time Ty (the time of the second phase division patterns Y1 to Y6). ), And the second timer function of the microcomputer 41 functions as a time difference measuring timer for counting Ty from the time of zero cross. FIG. 5 shows the formation pattern of the energization signals Up, Un, Vp, Vn, Wp, Wn when Cm is “2”. The formation pattern of the energization signals Up, Un, Vp, Vn, Wp, Wn when Cm is "1" is the same as that of FIG. 10, while when Cm is "3", the microcomputer is 41 is step ST5
From step ST10, the energization signals Up, Un, Vp, Vn, Wp, W are synchronized with the detection at the time of zero crossing.
Switch to n. The switching state of the energization signal at this time is as shown in Table 3 below. When the switching state of the energization signal in step S10 is described using the specific example described above, the number of sections of the newly started first phase division pattern is Since it is X2, the energization signals Up, Un, Vp, Wp, Vn are kept in the same state as the section number X1, and only the energization signal Wn is switched from L to H.

[0056]

[Table 3]

As described above, when Cm is "3", among the energizing signals Up, Un, Vp, Vn, Wp, Wn, the one whose on period is started has Cm of "1" and "2". As in the case of, the L is switched from H to H, but when the ON period ends, the H state is maintained without being switched from H to L.

Then, the microcomputer 41 proceeds to step ST11, where the energization signals Up, Un, V are applied.
Extension time Tq of off timing of p, Vn, Wp, Wn
(Q1 to Q6) is calculated by the following equation (5), and the fourth timer function is started. Tq = F × Tb / 2 (5)

Then, the fourth timer function has an extension time Tq.
When the counting of is finished (“YE
S "), the microcomputer 41 sends energization signals Up, U
n, Vp, Vn, Wp, and Wn are switched to the states shown in Table 2 (step ST13). The actual switching of the energizing signal at this time is performed only for the energizing signal that has not been switched from H to L in step S10. In the specific example described above, the energization signal Vn is switched from H to L at the end point of Q2 of the first phase division pattern X2. FIG. 6 shows a formation pattern of the energization signal when the above Cm is “3”.

Such energization signals Up, Un, Vp, V
The delay in switching n, Wp, and Wn from H to L is the first
Since the same is done for the phase division patterns X1 to X6 of No. 3, after all, when Cm is "3", the energization signal Vn
The ON period of is 120 ° C. when Cm is “1” and “2”, but it is extended by the extension time Tq.

Here, the extension time Tq is the energization signal that should be turned off at the starting point of each of the first phase division patterns X1 to X6, that is, the energization signal Wp for X1, Vn for X2, and Up for X3. Wn for X4, Vp for X5,
X6 determines the Off timing of Un,
The extension time Tq is a reference off-timing, that is, a time point corresponding to 120 degrees from the on-timing point (commutation timing) of the energizing signals Up, Un, Vp, Vn, Wp, and Wn (starting of X1 to X6 in this embodiment). It is the delay time from (dot). Therefore, each energization signal Up, Un, Vp,
The energization period of Vn, Wp, and Wn is T than the original 120 degrees.
It has been extended by q. Then, as is clear from the equation (3), the value of F becomes larger as the rotational speed Nm of the rotor is lower than the target rotational speed Nc. Therefore, the extension time Tq is the rotational speed Nm of the rotor being the target rotational speed Nm. It becomes longer as it is lower than Nc (see (e) to (i) of FIG. 7).

As can be understood from the above, the microcomputer 41 determines the result of comparison between the rotor rotational speed Nm and the target rotational speed Nc shown in the equation (5) and the base time Tb.
The fourth timer function of the microcomputer 41 functions as an extension time measuring timer means for counting the extension time Tq from the zero-cross time point, as well as functioning as a calculation means for calculating the extension time Tq based on the above.

When step ST9 or step ST13 is completed as described above, the microcomputer 41 next determines in step ST14 the measurement time (Z1 to Z6) of the third timer function when Cm is "1" and ". When it is "2", it is calculated by the following equation (6), and when Cm is "3", it is calculated by the equation (7). Tz = (Tb / 4) + (Tb / 2) -Ty = (Tb / 4) + (E * Tb / 2) ... (6) Tz = (Tb / 4) + (Tb / 2) -Tq = (Tb / 4) + (1-F) × Tb / 2 (7)

Here, if the measurement time of the third timer function is set to 1/4 of the time Tb of the first phase division pattern, the time of the second phase division pattern is Ty or Tq from (Tb / 2). Therefore, the specific period Ti starts from an early point. Therefore, in the present embodiment, the measurement time of the third timer function is obtained by the above equation (6) or (7), and the specific period Ti is started approximately 15 degrees before the zero cross time. . Then, when the third timer function finishes counting the time and enters the specific period Ti (“YES” in step ST15),
The process returns to step ST1 in which the position detecting comparison data of the first phase division pattern which is currently being incremented and is incremented in step ST4 is loaded.

As described above, according to this embodiment, when the rotation speed Nm of the rotor is lower than the target rotation speed Nc, the duty of the pulse width modulation signal P1 as the voltage control means is first increased as in the conventional case. , Winding 15u, 15v,
The applied voltage of 15w is increased to control the rotation speed Nm of the rotor to approach the target rotation speed Nc (when Cm = 1).
The duty of the pulse width modulation signal P1 is 100%.
When the temperature reaches, the rotation speed Nm of the rotor cannot be further increased to the target rotation speed Nc by voltage control, so that the commutation timing is next to the reference commutation timing Ty.
Just make it faster (when Cm = 2). Therefore, the windings 15u, 15v, 15w are started to be energized at a time when the induced voltage is low, so that the rotation speed Nc of the rotor increases due to the effect of the weakening magnetic field.

There is a limit to increase the rotational speed Nc of the rotor by advancing this commutation timing. That is, the reference commutation timing is (Tb /
2) Since the time is determined to be delayed by time, the advance time Ty of the commutation timing cannot be set to (Tb / 2) or more. In view of this, in the present embodiment, even if the commutation timing is advanced by (Tb / 2) time from the reference commutation timing, if the rotor rotation speed Nm is still lower than the target rotation speed Nc, energization is performed. Signals Up, Un, Vp, Vn, W
The off timing of p and Wn is delayed by Tq (Cm =
3). As a result, the windings 15u, 15v, 15w
Energizing time becomes longer, so windings 15u, 15v, 1
The same effect as when the applied voltage of 5w is increased is obtained, and the rotation speed Nc of the rotor is increased.

FIG. 8 shows the experimental results to support the above. As is clear from the figure, E is shown in the method of advancing the commutation timing with respect to the characteristic line L with the duty D of 100%. The rotational speed Nm of the rotor increases as it increases to 0.5, 0.75, and 1, and E is 0.25 in the method of delaying the off timing of the energization signals Up, Un, Vp, Vn, Wp, and Wn. 0,5,
It is understood that the rotational speed Nm of the rotor further increases as it increases to 0.75.

Therefore, in this embodiment, the rotational speed Nm of the rotor can be increased without using the brushless motor 15 having a high rotational speed-torque characteristic.
In particular, at the beginning of the heating operation, the command rotation speed Nc can be increased to bring the room temperature close to the set temperature early, and the problems of the large-sized motor 15 and the reduction in efficiency in normal operation can be avoided.

On the contrary, when the commanded rotation speed Nc at the beginning of the cooling / heating operation is set to the same rotation speed as the conventional one, the brushless motor 15 having a low rotation speed-torque characteristic can be used, so that the brushless motor 15 can be downsized. be able to. Further, when the size of the brushless motor 15 is maintained as it is without downsizing, the number of turns of the windings 15u, 15v, 15w can be increased, so that the winding current can be reduced and the efficiency can be improved. be able to.

Further, in this embodiment, the position signal circuit 17 causes the terminal voltages Vu and V of the windings 15u, 15v and 15w.
The zero crossing point of v, Vw and the reference voltage V0 is detected,
The microcomputer 41 counts the time between the zero-cross points by the first timer function, finds the time from the zero-cross point to the reference commutation timing based on the counted time, and from the obtained time, the rotational speed Nm of the rotor.
Since the advance time Ty obtained on the basis of the command rotation speed Nc is subtracted from the commutation timing, the commutation timing that differs depending on the case can be easily determined by the computer program.

Similarly, when determining the off timing of the energization signal, the microcomputer 41 determines the time between the zero-cross points, the rotation speed Nm of the rotor, and the command rotation speed Nc.
The extension time Tq is calculated on the basis of the above, and the time when the extension time Tq is counted is determined as the off-timing by the fourth timer function that starts the time counting from the zero-crossing time. The timing can be easily determined by a computer program.

The voltage dividing resistor circuit 16 functions as a reference voltage generating means, and may be replaced with another reference voltage generating means. The reference voltage is ½ of the output voltage of the DC power supply circuit 2. Not limited. Further, the voltage control means is not limited to the pulse width modulation circuit and may be a chopper circuit. Further, the inverter device of the present invention is not limited to the case of controlling the brushless motor 15 of the air conditioner, but can be widely applied to control of the motor.

[0073]

As described above, according to the present invention, the following effects can be obtained. In the inverter device according to the first aspect, the energization signal forming unit determines the commutation timing in consideration of not only the position information of the rotor but also the result of comparison between the target rotation speed and the rotor rotation speed. Therefore, when the rotor rotation speed is lower than the target rotation speed, the commutation timing can be advanced, and the effect of the weakening magnetic field increases the rotation speed of the rotor. Therefore, the motor can be operated at a target high rotation speed without using a motor having a high rotation speed-torque characteristic, the motor can be downsized, and the problem of reduced efficiency during normal operation can be avoided.

According to another aspect of the inverter device of the present invention, when the duty of the pulse width modulation signal is 100% and the maximum voltage is applied to the winding, when the rotor rotation speed is still lower than the target rotation speed, Since the flow timing is advanced from the reference commutation timing, the rotation speed of the rotor increases.

In the inverter device according to the third aspect of the invention, the energization signal forming means counts the time from the crossing time of the terminal voltage of the winding and the reference voltage to the next crossing time, and based on the count time, the crossing time point. To the reference commutation timing is calculated, and the difference time is calculated by subtracting the advance time obtained from the rotor rotation speed and the target rotation speed from that time to calculate the difference time. Therefore, the commutation timing can be easily determined by the program software.

According to the fourth aspect of the present invention, when the rotor rotation speed is lower than the target rotation speed even though the commutation timing is set earlier than the reference commutation timing, the off timing of the energization signal is set to be lower than the reference off timing. Since it is also delayed, the energization period of the winding becomes longer and the rotation speed of the rotor increases.

In the inverter device according to the fifth aspect of the invention, the energization signal forming means counts the time from the crossing point of the terminal voltage of the winding and the reference voltage to the next crossing time, and the counting time and the rotor rotation speed. Also, since the extension time is calculated based on the comparison result of the target rotation speed and the time point when the extension time is counted from the cross time point is taken as the off timing, the off timing can be easily determined by the program software.

In the air conditioner according to claim 6,
Since the motor of the compressor is controlled by the above-described inverter device, it is possible to increase the rotation speed of the motor to bring the room temperature closer to the set temperature earlier at the beginning of the heating operation.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram of a heat pump

FIG. 3 is a flowchart 1 for explaining the operation of the microcomputer.

FIG. 4 is a flowchart 2 for explaining the operation of the microcomputer.

FIG. 5 is a waveform diagram of each part in FIG. 1 when the control mode Cm is “2”.

FIG. 6 is a waveform diagram of each part in FIG. 1 when the control mode Cm is “3”.

FIG. 7 is a waveform diagram showing the voltage applied to one winding of the brushless motor for each control mode.

FIG. 8 is a rotation speed-torque characteristic diagram showing experimental results.

FIG. 9 is a circuit diagram showing a conventional inverter device.

10 is a waveform diagram of each part of FIG.

FIG. 11 is an induced voltage of one winding of a brushless motor,
Waveform diagram of terminal voltage and current

FIG. 12 is a diagram showing an operating range of a brushless motor as a relationship between a rotation speed and torque.

[Explanation of symbols]

2 is a DC power supply circuit, 7 to 12 are switching transistors (switching elements), 13 is a three-phase bridge circuit (switching circuit), 15 is a brushless motor, 16
Is a resistance voltage dividing circuit, 17 is a position signal circuit (position detection means), 18 to 20 are comparators, 23 is a pulse width modulation circuit (voltage control means), 24 is a gate circuit (driving means), 31 is a heat pump, and 32 is Compressor, 35
Is a four-way valve, 36 is an indoor heat exchanger, 37 is a decompression device, 3
Reference numeral 8 is an outdoor heat exchanger, and 41 is a microcomputer (energization signal forming means, rotation speed detecting means, arithmetic means, base time measuring timer means, difference time measuring timer means, extension time measuring timer means).

Claims (6)

[Claims] 1. A switching circuit including a plurality of switching elements for sequentially energizing windings of a plurality of phases included in a motor, position detection means for obtaining position information of a rotor included in the motor, and rotational speed information of the rotor. And a voltage control means for controlling the voltage applied to the winding according to the result of comparison between the rotor rotation speed obtained from the rotation speed information and the target rotation speed, and obtained from the rotation speed information. Energization signal forming means for determining commutation timing based on the result of comparison between the rotor rotation speed and the target rotation speed and the position information, and energization signal forming means for obtaining an energization signal corresponding to the commutation timing; An inverter device comprising: a driving unit that drives a switching element. 2. The voltage control means comprises a pulse width modulation circuit, and the energization signal forming means has a duty of the pulse width modulation signal formed by the pulse width modulation circuit is 100% and the rotor speed is lower than the target speed. At this time, the commutation timing is shifted to a point earlier than the reference commutation timing, and the inverter device according to claim 1. 3. The position detecting means provides the energization signal forming means with the time when the terminal voltage of the winding crosses the reference voltage as position information, and the energization signal forming means is provided between the crossing time point and the next crossing time point. A base time measuring timer means for counting the time of
Based on the base time counted by the base time measuring timer means, the time from the cross point to the reference commutation timing is calculated, and the advance time is calculated from the comparison result of the rotor speed and the target speed and the base time. And a difference time measuring timer means for starting time counting from a crossing point, the difference time measuring timer means ending the counting of the difference time. The inverter device according to claim 1 or 2, wherein the point of time is set as a commutation timing. 4. The voltage control means comprises a pulse width modulation circuit, and the energization signal forming means has a duty of the pulse width modulation signal formed by the pulse width modulation circuit of 100% and the commutation timing is higher than the reference commutation timing. 2. The shift timing of the energization signal is shifted to a timing later than the reference off timing when the rotor rotation speed is lower than the target rotation speed after shifting to the early timing.
The inverter device according to any one of 1 to 3. 5. The position detecting means provides the energization signal forming means with a time point at which the terminal voltage of the winding and the reference voltage cross as position information, and the energization signal forming means is provided between the crossing time point and the next crossing time point. A base time measuring timer means for counting the time of
Calculating means for calculating the extension time based on the comparison result of the rotor rotation speed and the target rotation speed and the base time counted by the base time measuring timer means; and an extension time measuring timer means for starting the time counting from the crossing point. 5. The inverter device according to claim 1, further comprising: a time point at which the extension time measuring timer means finishes counting the extension time as an off timing of the energization signal. 6. A heat pump in which a compressor, an outdoor heat exchanger, a pressure reducing device, and an indoor heat exchanger are connected by a refrigerant passage, and the compressor motor is an inverter device according to any one of claims 1 to 5. An air conditioner characterized by being controlled.