JPH09294397A - Motor controller for air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize at the same time both the improvement of input power factor by a power rectifier and the suppression of harmonics components in power silly current and the suppression electromagnetic noise and power loss by giving switching operation to the power rectifier when the load current is larger than the prescribed value and by providing a power rectifier circuit start and stop means for stopping when the load current is smaller. SOLUTION: Power rectifier block start and stop means 16 (power rectifier start and stop means) gives a switching operation to the power rectifier 8 when a load current detected by load current detection means 15 is larger than prescribed value, and the switching operation of the power rectifier circuit 8 is stopped when the load current is smaller than the prescribed value. By doing this, electromagnetic noise and power loss in the power rectifier block 10 due to unnecessary operation can be suppressed, and the improvement of input power factor in power rectifier 8 and the suppression of harmonic components of power supply current and the suppression of electromagnetic noise and power loss can be realized at the same time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter type air conditioner motor controller, and more particularly to an air conditioner motor controller of the type having a forward conversion circuit as a rectifier circuit.

[0002]

2. Description of the Related Art FIG. 12 shows a conventional example of an inverter type air conditioner and its control device. Air conditioner 1
Composes a refrigeration cycle by the compressor 2, the condenser 3, the evaporator 4, the expansion device 5, and the refrigerant pipe 6 connecting them.

The compressor 2 is driven by a driving (AC) electric motor 2a, and as a control device for the driving electric motor 2a, a diode rectifier 60 to which an alternating current from an AC power source 7 is given.
Of the smoothing capacitor 11 connected to the output of the diode rectifier 60, the inverse conversion circuit 12 connected to the output of the smoothing capacitor 11, and the inverse conversion circuit control means 13 for controlling the driving of the inverse conversion circuit 12. A motor controller is used.

In the electric motor control device as described above,
Since the input current flows only when the smoothing capacitor 11 is charged, the input power factor decreases, and since the power supply current contains harmonic components, the capacity of the power supply equipment cannot be effectively used, and the power supply equipment such as the power supply transformer. May be damaged.

In order to deal with the above problem, as shown in FIG. 13, a forward conversion circuit 8 is used as a rectifying circuit, and the forward conversion circuit 8 and the inverse conversion circuit 12 are driven by the forward conversion circuit 8.
An electric motor control device (an air conditioner control device disclosed in Japanese Patent Laid-Open No. 4-71393) configured to be controlled by the inverse conversion circuit control means 70 has been proposed.

In this electric motor control device, the forward conversion / inverse conversion circuit control means 70 controls the operation of the compressor, and at the same time controls the switching operation of the switching elements provided in the forward conversion circuit 8. The effects of improving the input power factor and reducing harmonics in the power supply current can be obtained.

[0007]

However, the forward conversion circuit 8 induces electromagnetic noise due to transient voltage fluctuations at the time of switching on / off due to switching operation, and power consumption due to transient voltage and current fluctuations at the time of switching on / off. It has the drawback of causing losses. In addition, such a thing is the forward conversion circuit 8
Conversion / inverse conversion circuit control means 70 which is a drive circuit of
But it happens. Therefore, in the conventional motor control device,
Another problem is the generation of electromagnetic noise and power loss.

Further, in the conventional motor control device, even if the forward conversion circuit 8 is in an abnormal state where the switching operation cannot be performed, the inverse conversion circuit 12 is driven according to the load regardless of that, so that the load is high when the load is high. A large harmonic current, which is almost proportional to the current, may flow and damage the power supply equipment such as the power supply transformer.

Further, in the conventional motor control device, the components of the forward conversion circuit 8 and the inverse conversion circuit 12 and their control means are all configured as the same (single) control block. In the motor controller for an air conditioner before improvement, which is composed of a diode rectifier and a diode rectifier, when it is necessary to improve the input power factor and suppress harmonic components of the power supply current, it is necessary to redesign the entire controller. There is a problem to say.

The present invention has been made to solve the above-mentioned problems, and improves the input power factor by a forward conversion circuit, suppresses harmonic components of power supply current, and suppresses electromagnetic noise and power loss. In addition, it is possible to optimize the driving of the reverse conversion circuit in the abnormal state where the forward conversion circuit cannot perform the switching operation, and the input power can be applied to the existing motor control device that does not have the forward conversion circuit without making a drastic change. An object of the present invention is to obtain an electric motor control device for an air conditioner that can easily add a function of improving the rate and suppressing a harmonic component of a power supply current.

[0011]

In order to achieve the above object, an air conditioner electric motor control device according to the present invention comprises:
A forward conversion circuit that rectifies the AC power supply and substantially matches the input current and the input voltage phase to reduce the harmonic component of the power supply current, and a forward conversion circuit control means that controls the driving of the forward conversion circuit,
A smoothing capacitor connected to the output of the forward conversion circuit,
An inverter type air conditioner electric motor controller having an inverse conversion circuit connected to the output of the smoothing capacitor, for controlling the shift of a compressor drive motor, and an inverse conversion circuit control means for controlling the drive of the inverse conversion circuit. A load current detection unit that detects a load current of the compressor drive motor, and the forward conversion circuit control unit converts the forward current when the load current detected by the load current detection unit is larger than a specified value. The circuit includes a forward conversion circuit starting / stopping means for switching the circuit and stopping the switching operation of the forward conversion circuit when the load current is smaller than a specified value.

In the motor controller for an air conditioner according to the present invention, when the load current is detected by the load current detecting means and the load current is larger than the specified value due to the start / stop operation of the forward conversion circuit starting / stopping means, the forward conversion circuit. The switching operation of the forward conversion circuit is stopped when the load current is smaller than the specified value. When the load current is small, the harmonic current to the power supply is correspondingly small, so even if the switching operation of the forward conversion circuit is stopped, problems due to harmonic components do not occur, and the electromagnetic waves caused by this switching operation do not occur. No noise and power loss.

In order to achieve the above-mentioned object, an air conditioner motor controller according to the next invention rectifies an AC power source to substantially match an input current and an input voltage phase to reduce a harmonic component of the power source current. A forward conversion circuit, a forward conversion circuit control means for controlling driving of the forward conversion circuit, a smoothing capacitor connected to the output of the forward conversion circuit, and a compressor drive motor connected to the output of the smoothing capacitor. In an inverter type air conditioner motor control device having an inverse conversion circuit for controlling shift and an inverse conversion circuit control means for controlling driving of the inverse conversion circuit, a load current harmonic detecting a harmonic component of a load current It is provided with a detection means.

In the motor controller for an air conditioner according to the present invention, the harmonic component of the load current is detected by the load current harmonic detecting means, and the harmonic component is reduced to a predetermined value or less according to the detected value of the harmonic component. It becomes possible to control the drive of the forward conversion circuit so as to suppress it.

A motor controller for an air conditioner according to the next invention is the motor controller for an air conditioner as described above,
The forward conversion circuit control means includes a forward conversion circuit start / stop means for controlling the operation / stop of the forward conversion circuit according to the magnitude of the harmonic component of the power supply current detected by the load current harmonic detection means. It is what you are leaving.

In the motor controller for an air conditioner according to the present invention, the operation / stop of the forward conversion circuit is controlled by the forward conversion circuit start / stop means according to the magnitude of the harmonic component detected by the load current harmonic detection means. To be done. Thereby, the harmonic component is suppressed to a predetermined value or less, and at the same time, electromagnetic noise and power loss due to the switching operation of the forward conversion circuit are reduced.

An air conditioner electric motor controller according to the next invention is the same as the air conditioner electric motor controller described above,
The forward conversion circuit control means includes a switching frequency control means for controlling the switching frequency of the forward conversion circuit so that the harmonic becomes smaller according to the magnitude of the harmonic component detected by the load current harmonic detection means. It is what you are leaving.

In the motor controller for an air conditioner according to the present invention, the switching frequency of the forward conversion circuit is controlled by the switching frequency control means according to the magnitude of the harmonic component detected by the load current harmonic detection means. As a result, the harmonic component is suppressed to a low level, and at the same time, electromagnetic noise and power loss caused by the switching operation of the forward conversion circuit are reduced.

In order to achieve the above object, an air conditioner motor control device according to the next invention rectifies an AC power supply to substantially match an input current phase with an input voltage phase and reduces a harmonic component of the power supply current. A forward conversion circuit, a forward conversion circuit control means for controlling driving of the forward conversion circuit, a smoothing capacitor connected to the output of the forward conversion circuit, and a compressor drive motor connected to the output of the smoothing capacitor. In an inverter type air conditioner motor control device having an inverse conversion circuit for controlling a shift and an inverse conversion circuit control means for controlling the driving of the inverse conversion circuit, a bus voltage detection means for detecting a DC bus voltage, and The DC bus voltage detected by the bus voltage detecting means is not within the first specified voltage range determined by the output voltage of the forward conversion circuit under the switching operation, and is not a switch. Forward conversion circuit abnormality detection means for detecting an abnormal stop state of the forward conversion circuit depending on whether or not it is within a second specified voltage range determined by the output voltage of the forward conversion circuit under the stopped state. It is equipped with.

In the air conditioner motor control device according to the present invention, the DC bus voltage is detected by the bus voltage detecting means, and the DC bus voltage is within the second specified voltage range, not within the first specified voltage range. Depending on whether or not the forward conversion circuit abnormality detection means detects the abnormal stop state of the forward conversion circuit. By detecting this abnormal stop state, adaptive control that limits the operation of the inverse conversion circuit becomes possible.

A motor controller for an air conditioner according to the next invention is the above-mentioned motor controller for an air conditioner,
The inverse conversion circuit control means includes an abnormal condition control means for bringing the inverse conversion circuit into a low output operation when the forward conversion circuit abnormality detection means detects that the forward conversion circuit is in an abnormal stop state. It is a thing.

In the motor controller for an air conditioner according to the present invention, when the forward conversion circuit abnormality detection means detects that the forward conversion circuit is in an abnormal stop state, the abnormal time control means operates the inverse conversion circuit at a low output. To limit the operation of the inverse conversion circuit. As a result, when the forward conversion circuit stops abnormally, the reverse conversion circuit does not operate at high output, and a large harmonic current does not flow to the power supply.

In order to achieve the above object, an air conditioner electric motor control device according to the next invention is the same as the air conditioner electric motor control device, in which the forward conversion circuit and the forward conversion circuit control means are provided. As the forward conversion block, the inverse conversion circuit and the inverse conversion circuit control means are individually and independently configured as the inverse conversion block.

In the motor controller for an air conditioner according to the present invention, the forward conversion block including the forward conversion circuit and the forward conversion circuit control means, and the inverse conversion block including the inverse conversion circuit and the inverse conversion circuit control means are each provided. Compared to existing air conditioner control devices that are configured independently and do not include a forward conversion circuit by incorporating a forward conversion block, the input power factor can be improved and harmonic components of the power supply current can be A suppression function can be added, and at the same time, in a region where the load current is small, the switching operation of the forward conversion block is stopped, and noise and loss in the forward conversion block due to unnecessary operation can be suppressed.

[0025]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In the embodiments of the present invention described below, the same parts as those in the above-described conventional example are designated by the same reference numerals as those in the above-described conventional example, and the description thereof will be omitted.

(First Embodiment) FIG. 1 shows a first embodiment of a motor control device for an air conditioner according to the present invention. This electric motor control device individually has a forward conversion circuit control means 9 for controlling the drive of the forward conversion circuit 8 and an inverse conversion circuit control means 13 for controlling the drive of the inverse conversion circuit 12, and the forward conversion circuit 8 and The forward conversion circuit control means 9 and the inverse conversion circuit 12 and the inverse conversion circuit control means 13 are individually and independently configured as one forward conversion block 10 and one inverse conversion block 14, respectively. In this embodiment, the smoothing capacitor 11 is incorporated in the inverse conversion block 14.

The forward conversion circuit 8 rectifies the AC power supply 7 to substantially match the input current and the input voltage phase with each other to reduce the harmonic component of the power supply current. In addition, a switching element such as a transistor is bidirectionally provided for each phase, a diode is bidirectionally provided in parallel with the switching element circuit of each phase, and the switching operation by the switching element is controlled by the forward conversion circuit control means 9. To be done.

The forward conversion block 10 includes load current detecting means 15 for detecting the load current of the drive motor 2a of the compressor 2.
Is provided.

The forward conversion circuit control means 9 incorporates a forward conversion block start / stop means (forward conversion circuit start / stop means) 16. The forward conversion block start / stop means 16 causes the forward conversion circuit 8 to perform a switching operation when the load current detected by the load current detection means 15 is larger than a specified value, and when the load current is smaller than the specified value. The switching operation of 8 is stopped.

Next, the operation of the air conditioner motor control device will be described with reference to the flowchart of FIG.

First, the operating state of the forward conversion block 10 is determined (step S1), and the forward conversion block 10 is in a stopped state (a state in which the switching operation of the forward conversion circuit 8 is stopped).
If so, it is determined whether or not the load current i detected by the load current detecting means 15 is equal to or greater than a preset on-side specified value iref1 (step S2), and the forward conversion block 10 is in the operating state. If (the forward conversion circuit 8 is in the switching operation), it is determined whether or not the load current i is equal to or less than a preset off-side specified value iref2 (step S3).

When the forward conversion block 10 is stopped, i ≧ i
If it is not ref1 (No at Step S2), the stopped state of the forward conversion block 10 is maintained. On the other hand, if i ≧ iref1 (Yes at Step S2), the forward conversion block start / stop unit 1 is executed.
The operation of the forward conversion block 10 is started by step 6 (step S4).

In the operation state of the forward conversion block 10,
If i ≦ iref2 is not satisfied (No at step S3), the operation of the forward conversion block 10 is continued. On the other hand, if i ≦ iref2 is satisfied (Yes at step S3), the forward conversion block start / stop means 16 causes the forward conversion block 10 to operate. Is stopped (step S5). Note that iref1> iref2, and a predetermined hysteresis is set for the operation / stop of the forward conversion block 10.

As a result, the switching operation of the forward conversion circuit 8 is stopped in the region where the load current is small. In the region where the load current is small, the harmonic current to the power supply is accordingly small, and therefore, even if the switching operation of the forward conversion circuit 10 is stopped, the problem due to the harmonic component does not occur. Necessary operation is avoided, and generation of electromagnetic noise and power loss due to the switching operation at this time is avoided.

Further, as described above, since the forward conversion block 10 and the inverse conversion block 14 are individually configured as blocks, the forward conversion circuit and the like are not included, and the inverse conversion circuit components and the inverse conversion circuit control means are used. In addition to the existing air conditioner motor control device, it is possible to add functions to improve the input power factor and suppress harmonic components of the power supply current without making major changes, and in the area of low load current, a forward conversion block When the operation of 10 is stopped, noise and loss in the forward conversion block 10 due to unnecessary operation can be suppressed.

(Second Embodiment) FIG. 3 shows a second embodiment of the motor controller for an air conditioner according to the present invention. This electric motor control device also has a forward conversion circuit control means 9 for controlling the drive of the forward conversion circuit 8, as in the first embodiment.
Inverse conversion circuit control means 1 for controlling driving of the inverse conversion circuit 12
3, and the forward conversion circuit 8 and the forward conversion circuit control means 9 form a single forward conversion block 10 and the inverse conversion circuit 1
2 and the inverse conversion circuit control means 13 are individually and independently configured as one inverse conversion block 14.

The forward conversion block 10 includes load current detecting means 15 for detecting the load current of the drive motor 2a of the compressor 2.
Is provided.

The forward conversion circuit control means 9 incorporates load current harmonic detection means 21 for detecting a harmonic component in the load current from the waveform of the load current detected by the load current detection means 15.

In this motor control device, in the motor control device of the air conditioner having the forward conversion part and the inverse conversion part, the load current harmonic detection means 21 detects the harmonic component of the load current, and the harmonic component of this harmonic component is detected. It becomes possible to control the drive of the forward conversion circuit 8 so as to suppress the harmonic component to a predetermined value or less according to the detected value. As a result, it becomes possible to use various control means for suppressing the harmonic of the load current, which is a particular problem, regardless of the state of the power supply, and for appropriately controlling the air conditioner 1.

(Third Embodiment) FIG. 4 shows a third embodiment of the motor controller for an air conditioner according to the present invention. Note that, in FIG. 4, the portions corresponding to those in FIG. 3 are denoted by the same reference numerals as those in FIG. 3, and the description thereof will be omitted.

In this embodiment, the forward conversion circuit control means 9 controls the operation / stop of the forward conversion circuit 8 according to the magnitude of the harmonic component of the power supply current detected by the load current harmonic detection means 21. The forward conversion block starting / stopping means 31 is incorporated. The forward conversion block starting / stopping means 31 stops the switching operation of the forward conversion circuit 8 when the harmonic component is large.

Next, the operation of the air conditioner motor control device will be described with reference to the flowchart of FIG.

First, the operation state of the forward conversion block 10 is determined (step S11). If the forward conversion block 10 is in the stopped state, the harmonic detection value in of the load current detected by the load current harmonic detection means 21 is It is determined whether or not it is equal to or greater than the preset ON-side specified value inref1 (step S
12) On the other hand, if the forward conversion block 10 is in the operating state, it is determined whether or not the harmonic detection value in of the load current is less than or equal to the preset off-side specified value inref2 (step S13).

With the forward conversion block 10 stopped, in ≧
If not inref1 (No at step S12), the stop state of the forward conversion block 10 is maintained, and in ≧ in
In the case of ref1 (Yes at step S12), the forward conversion block starting / stopping means 31 starts the operation of the forward conversion block 10 (step S14).

In the operation state of the forward conversion block 10,
If not in ≦ inref2 (No in step S13), the operation of the forward conversion block 10 is continued, and in ≦ i
In the case of nref2 (Yes at step S13), the operation of the forward conversion block 10 is stopped by the forward conversion block start / stop means 31 (step S15). Note that inref1> inref2
Therefore, a predetermined hysteresis is set for the operation / stop of the forward conversion block 10.

As described above, the operation of the forward conversion block 10 is stopped in the region where the harmonics of the load current are small, so that noise and loss in the forward conversion block 10 due to unnecessary operation can be suppressed, and the higher harmonics can be suppressed. The component can be suppressed to a predetermined value or less, and electromagnetic noise and power loss due to the switching operation of the forward conversion circuit 8 can be reduced. Further, by detecting the harmonics of the load current, it is possible to accurately control the start / stop regardless of the state of the power supply in consideration of the influence of the harmonic currents.

Also in this embodiment, since the forward transform block 10 and the inverse transform block 14 are individually configured, the forward transform circuit is not included, and the inverse transform circuit component and the inverse transform circuit control means are included. In addition to the existing motor controller for air conditioners, the input power factor can be improved and the harmonic components of the power supply current can be suppressed without major changes, and the harmonic components can be used within the specified range. Then, by stopping the operation of the forward conversion block 10, it is possible to suppress noise and loss in the forward conversion block 10 due to unnecessary operation.

(Embodiment 4) FIG. 6 shows Embodiment 4 of the motor controller for an air conditioner according to the present invention. In FIG. 6 as well, portions corresponding to those in FIG. 3 are designated by the same reference numerals as those in FIG. 3 and their description is omitted.

In this embodiment, the switching frequency control means 41 is incorporated in the forward conversion circuit control means 9. The switching frequency control means 41 controls the switching frequency of the forward conversion circuit 8 so that the harmonic becomes smaller according to the magnitude of the harmonic component detected by the load current harmonic detection means 21. This switching frequency control means 41 raises the switching frequency when the harmonic detection value by the load current harmonic detection means 21 is large, and lowers the switching frequency when the harmonic detection value is small. This is because when the switching frequency of the forward conversion circuit 8 is high, harmonics are reduced, but electromagnetic noise and power loss due to the switching operation of the forward conversion circuit 8 are increased, and when the switching frequency is low, the switching of the forward conversion circuit 8 is switched. This is because electromagnetic noise and power loss due to operation are reduced, but harmonics tend to increase.

Next, the operation of the air conditioner motor control device will be described with reference to the flowchart of FIG.

First, the operating state of the forward conversion block 10 is determined (step S21). If the forward conversion block 10 is in the operating state, it is determined whether or not the harmonic detection value in of the load current detected by the load current harmonic detection means 21 is equal to or greater than a preset frequency increasing side specified value inref3. (Step S22).

If in ≧ inref3 (step S2
2), the switching frequency control means 41 increases the switching frequency of the forward conversion circuit 8 by a predetermined amount (increases the frequency) (step S23).

On the other hand, if in ≧ inref3 is not satisfied (No at step S22), the load current harmonics detecting means 21
It is determined whether or not the harmonic detection value in of the load current detected by is less than or equal to the preset frequency increasing side specified value inref4 (step S24).

If in ≧ inref4 is not satisfied (step S2)
If NO, the routine ends to maintain the current switching frequency.

If in ≧ inref4 (step S2
4), the switching frequency control means 41 reduces the switching frequency of the forward conversion circuit 8 by a predetermined amount (decreases the frequency) (step S25). Note that inref3> in
ref4, and a predetermined hysteresis is set for this switching frequency control.

In this way, the switching frequency of the forward conversion circuit 8 is appropriately controlled according to the detected harmonic value, so that the harmonic component is suppressed to a predetermined value or less and unnecessary operation noise in the forward conversion block 10 occurs. Also, loss can be suppressed.

Also in this embodiment, since the forward transform block 10 and the inverse transform block 14 are individually configured, the forward transform circuit is not included and the inverse transform circuit component and the inverse transform circuit control means are included. The existing air conditioner motor control device consisting of can be added functions to improve the input power factor and suppress the harmonic component of the power supply current without making significant changes, and it can be applied in order according to the harmonic detection value. By controlling the switching frequency of the conversion circuit 8, the harmonic component is suppressed to a predetermined value or less, and noise and loss in the forward conversion block 10 are suppressed.

(Fifth Embodiment) FIG. 8 shows a fifth embodiment of the motor controller for an air conditioner according to the present invention. In FIG. 6, the parts corresponding to those in FIG. 1 are designated by the same reference numerals as those in FIG. 1 and their description is omitted.

In this embodiment, the inverse transform block 14
A bus voltage detecting means 51 for detecting a DC bus voltage is provided in the. Forward conversion block abnormality detection means 52 is incorporated in the inverse conversion circuit control means 13. The forward conversion block abnormality detecting means 52 stops the switching operation when the DC bus voltage detected by the bus voltage detecting means 51 is not within the first specified voltage range determined by the output voltage of the forward conversion circuit 8 under the switching operation. The abnormal stop state of the forward conversion circuit 8 is detected depending on whether or not it is within the second specified voltage range determined by the output voltage of the forward conversion circuit 8 under the existing state.

The output voltage of the forward conversion circuit 8 under the switching operation is determined by the control condition of the forward conversion circuit 8, and in general,
The target value of the output voltage of the forward conversion circuit 8 under the switching operation is set to a value higher than the peak value of the power supply voltage. The output voltage of the forward conversion circuit 8 when the switching operation is stopped is determined by the DC current output by the rectifying element of the forward conversion circuit 8, and this is generally about the peak value of the power supply voltage.

Next, the operation of the air conditioner motor control device will be described with reference to the flowchart of FIG.

First, the direct-current bus voltage is detected by the bus-voltage detecting means 51, and it is determined whether or not the bus voltage is within the first specified voltage range (step S31). If the bus voltage is within the first specified voltage range (Yes in step S31), the forward conversion block 10 is determined to be operating normally, and this routine ends.

On the other hand, if the bus voltage is outside the first specified voltage range (No at step S31), then it is determined whether the bus voltage is within the second specified voltage range (step S32). If the bus voltage is within the second specified voltage range (Yes in step S32), it is determined that the forward conversion block 10 is in the abnormal stop state (however, the rectifying element is in the rectifying operation) (step S33). In this case, the operation of the inverse conversion block 14 is stopped (step S3).
4).

As a result, in the inverse conversion block 14, it is detected that the forward conversion block 10 is in the abnormal stop state and the rectifying operation by the rectifying element of the forward conversion circuit 8 is normal, and various measures suitable for the abnormal state are taken. It will be possible to take.

(Embodiment 6) FIG. 10 shows Embodiment 6 of the motor controller for an air conditioner according to the present invention. In FIG. 10, the parts corresponding to those in FIG. 8 are designated by the same reference numerals as those in FIG. 8 and their description is omitted.

In this embodiment, in addition to that of the fifth embodiment, the reverse conversion circuit control means 13 detects that the forward conversion circuit 8 is in the abnormal stop state by the forward conversion block abnormality detection means 52. In this case, an abnormal time control means 53 for making the inverse conversion circuit 12 operate at a low output is incorporated.

Next, the operation of the air conditioner motor control device will be described with reference to the flowchart of FIG.

First, the DC voltage of the bus is detected by the bus voltage detecting means 51, and it is determined whether or not this bus voltage is within the first specified voltage range (step S41). If the bus voltage is within the first specified voltage range (Yes at step S41), it is determined that the forward conversion block 10 is operating normally, and the abnormal-time control means 53 operates the inverse conversion block 14 under low load (low output limit). Cancel operation (step S4)
3).

On the other hand, if the bus voltage is out of the first specified voltage range (No in step S41), then it is determined whether or not the bus voltage is in the second specified voltage range (step S42). If the bus voltage is within the second specified voltage range (Yes in step S42), it is determined that the forward conversion block 10 is in the abnormal stop state (however, the rectifying element is in the rectifying operation) (step S44). In this case, the abnormal state control means 53 starts the low load operation (low output limiting operation) of the inverse conversion block 14 (step S4).
6). If the bus voltage is not within the second specified voltage range (No at Step S42), the operation of the inverse conversion block 14 is stopped.

As a result, when the forward conversion block 10 is in the abnormal stop state (however, the rectifying element is in the rectifying operation), the operation state of the reverse conversion block 10 is limited to the low output operation state, and the air conditioner Unnecessary stoppages are suppressed,
Further, it becomes possible to reduce the influence of harmonics of the load current on the power supply.

[0071]

As can be understood from the above description, according to the motor controller for an air conditioner of the present invention, the switching operation of the forward conversion circuit is stopped when the load current is smaller than the specified value. Electromagnetic noise and power loss in the forward conversion block due to unnecessary operation can be suppressed without causing problems due to wave components, the input power factor is improved by the forward conversion circuit, harmonic components of power supply current are suppressed, and Both suppression of noise and power loss are achieved.

In the motor controller for an air conditioner according to the next invention, the load current harmonic detecting means detects the harmonic component of the load current, and the harmonic component is set to a predetermined value in accordance with the detected value of the harmonic component. It becomes possible to control the drive of the forward conversion circuit so as to be suppressed as follows.

In the motor controller for an air conditioner according to the next invention, the forward conversion circuit start / stop means operates / stops the forward conversion circuit according to the magnitude of the harmonic component detected by the load current harmonic detection means. Is controlled, the harmonic component can be suppressed to a predetermined value or less to reduce the electromagnetic noise and power loss due to the switching operation of the forward conversion circuit. The forward conversion circuit improves the input power factor and the power supply current. The suppression of the higher harmonic component and the suppression of electromagnetic noise and power loss are compatible with each other.

In the motor controller for an air conditioner according to the next invention, the switching frequency control means controls the switching frequency of the forward conversion circuit in accordance with the magnitude of the harmonic component detected by the load current harmonic detection means. Therefore, the harmonic component can be suppressed to a low level to reduce the electromagnetic noise and power loss caused by the switching operation of the forward conversion circuit, and the forward conversion circuit can improve the input power factor and suppress the harmonic component of the power supply current Both suppression of noise and power loss are achieved.

In the motor controller for an air conditioner according to the next invention, the DC bus voltage is detected by the bus voltage detecting means, and the DC bus voltage is within the second prescribed range, not within the first prescribed range. Depending on whether or not the forward conversion circuit abnormality detection means detects the abnormal stop state of the forward conversion circuit, the adaptive control for limiting the operation of the inverse conversion circuit becomes possible by detecting the abnormal stop state.

In the motor controller for an air conditioner according to the next invention, when the forward conversion circuit abnormality detection means detects that the forward conversion circuit is in an abnormal stop state, the abnormal time control means turns down the inverse conversion circuit. Since the output conversion is performed and the operation of the reverse conversion circuit is limited, the reverse conversion circuit does not operate at high output when the forward conversion circuit stops abnormally, and it is possible to prevent a large harmonic current from flowing to the power supply, and It will not damage the power supply equipment.

In the motor controller for an air conditioner according to the next invention, a forward conversion block including a forward conversion circuit and a forward conversion circuit control means, and an inverse conversion block including an inverse conversion circuit and an inverse conversion circuit control means. Since each of them is configured independently, the control unit of the existing air conditioner that does not include the forward conversion circuit by incorporating the forward conversion block can improve the input power factor and the power supply current without making a drastic change. It is possible to add a function to suppress the harmonic components of, and at the same time, to suppress the noise and loss in the forward conversion block due to unnecessary operation by stopping the switching operation of the forward conversion block in the area where the load current is small. Become.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an air conditioner electric motor control device according to the present invention.

FIG. 2 is a control flowchart showing the operation of the air-conditioner electric motor control device according to the first embodiment.

FIG. 3 is a block diagram showing a second embodiment of a motor control device for an air conditioner according to the present invention.

FIG. 4 is a block diagram showing a third embodiment of an air conditioner electric motor control device according to the present invention.

FIG. 5 is a control flowchart showing the operation of the air-conditioner electric motor control device according to the third embodiment.

FIG. 6 is a block diagram showing a fourth embodiment of the air conditioner electric motor control device according to the present invention.

FIG. 7 is a control flowchart showing the operation of the air-conditioner electric motor control device according to the fourth embodiment.

FIG. 8 is a block diagram showing a fifth embodiment of a motor control device for an air conditioner according to the present invention.

FIG. 9 is a control flowchart showing the operation of the air-conditioner electric motor control device according to the fifth embodiment.

FIG. 10 is a block diagram showing a sixth embodiment of the air-conditioner electric motor control device according to the present invention.

FIG. 11 is a control flowchart showing an operation of the air-conditioner electric motor control device according to the sixth embodiment.

FIG. 12 is a block diagram showing the configuration of a general air conditioner electric motor control device.

FIG. 13 is a block diagram showing a configuration of a conventional air conditioner electric motor control device.

[Explanation of symbols]

1 air conditioner, 2 compressor, 2a drive motor, 3
Condenser, 4 evaporator, 5 throttling device, 6 refrigerant piping, 7
AC power supply, 8 forward conversion circuit, 9 forward conversion circuit control means, 10 forward conversion block, 11 smoothing capacitor, 1
2 inverse conversion circuit, 13 inverse conversion circuit control means, 14 inverse conversion block, 15 load current detection means, 16 forward conversion block start / stop means, 21 load current harmonic detection means, 3
1 forward conversion block start / stop means, 41 switching frequency control means, 51 bus voltage detection means, 52 forward conversion block abnormality detection means, 53 abnormal time control means

Claims (7)

[Claims] 1. A forward conversion circuit for rectifying an AC power supply to substantially match an input current and an input voltage phase to reduce a harmonic component of a power supply current, and a forward conversion circuit control means for controlling driving of the forward conversion circuit. A smoothing capacitor connected to the output of the forward conversion circuit, and connected to the output of the smoothing capacitor,
An inverter type air conditioner motor controller having an inverse conversion circuit for controlling a shift of a compressor drive motor and an inverse conversion circuit control means for controlling driving of the inverse conversion circuit, wherein a load current of the compressor drive motor When the load current detected by the load current detection means is larger than a specified value, the forward conversion circuit control means causes the forward conversion circuit to perform a switching operation to detect the load current. An air conditioner electric motor control device comprising a forward conversion circuit starting / stopping means for stopping the switching operation of the forward conversion circuit when the value is smaller than a specified value. 2. A forward conversion circuit for rectifying an AC power supply to substantially match an input current and an input voltage phase to reduce a harmonic component of a power supply current, and a forward conversion circuit control means for controlling driving of the forward conversion circuit. A smoothing capacitor connected to the output of the forward conversion circuit, and connected to the output of the smoothing capacitor,
An inverter type air conditioner electric motor control device having an inverse conversion circuit for controlling the shift of a compressor drive motor and an inverse conversion circuit control means for controlling the driving of the inverse conversion circuit detects a harmonic component of a load current. A motor control device for an air conditioner, comprising: 3. The forward conversion circuit control means controls the operation / stop of the forward conversion circuit according to the magnitude of the harmonic component of the load current detected by the load current harmonic detection means. The motor control device for an air conditioner according to claim 2, further comprising a start / stop means. 4. The forward conversion circuit control means operates according to the magnitude of the harmonic component of the load current detected by the load current harmonic detection means to reduce the harmonics. The motor control device for an air conditioner according to claim 2, further comprising switching frequency control means for controlling the switching frequency. 5. A forward conversion circuit for rectifying an AC power supply to substantially match an input current and an input voltage phase to reduce a harmonic component of a power supply current, and a forward conversion circuit control means for controlling driving of the forward conversion circuit. A smoothing capacitor connected to the output of the forward conversion circuit, and connected to the output of the smoothing capacitor,
In an inverter type air conditioner electric motor control device having an inverse conversion circuit for controlling the shift of a compressor drive motor and an inverse conversion circuit control means for controlling the drive of the inverse conversion circuit, a bus voltage for detecting a DC bus voltage The detecting means and the DC bus voltage detected by the bus voltage detecting means are not within the first specified voltage range determined by the output voltage of the forward conversion circuit under the switching operation, and the switching operation is stopped. Air comprising a forward conversion circuit abnormality detecting means for detecting an abnormal stop state of the forward conversion circuit depending on whether or not it is within a second specified voltage range determined by the output voltage of the forward conversion circuit. Electric motor control device for a harmony machine. 6. The abnormal conversion circuit control means, when the forward conversion circuit abnormality detection means detects that the forward conversion circuit is in an abnormal stop state, performs an abnormal-time control to bring the inverse conversion circuit into a low output operation. The motor control device for an air conditioner according to claim 5, further comprising means. 7. The forward transform circuit and the forward transform circuit control means are individually configured as forward transform blocks, and the inverse transform circuit and the inverse transform circuit control means are individually configured as inverse transform blocks, respectively. The motor controller for an air conditioner according to any one of claims 1 to 6.