JPH0989352A - Driver for outdoor blower - Google Patents

Abstract

PROBLEM TO BE SOLVED: To assuredly start an outdoor blower irrespective of a wind direction upon its start by making the current supply mode of a driving signal coincide with the combination mode of a detecting signal and supplying the current when a rotating speed before starting is not higher than a preset specified value and a rotating direction is reversed and stopping the rotation of a brushless motor. SOLUTION: The start control function of an outdoor fan has a deciding function for detecting the rotating direction and rotating speed of a brushless motor 50 and a reverse stop function for stopping the rotation of the brushless motor 50 when the rotating speed before starting is not higher than a preset specified value and the rotating direction is reverse. When a setting mode set meeting a normal rotation and a reverse rotation is not detected after the normal rotation or the reverse rotation of the brushless motor 50 is detected from the change of the combination mode of the detected signal of a position detecting means 52, the abnormality of the position detecting means 52 is decided, and the driving of an outdoor blower is stopped. As a result, even when the state of the outdoor fan changes depending on the difference in wind direction and wind velocity, the outdoor fan can be readily started.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive device for an outdoor blower for controlling the speed of a brushless motor for driving an outdoor blower through a drive circuit formed by connecting a plurality of switching means in a bridge.

[0002]

2. Description of the Related Art Recent air conditioners employ a brushless motor to drive a compressor and an outdoor blower, respectively. A three-phase brushless motor is a type of DC motor that has u-, v-, and w-three-phase windings and is drive-controlled by a drive circuit formed by connecting a plurality of switching means in a bridge. In particular, a variable speed is required. It is used for various purposes.

In controlling the speed of this brushless motor, one of the upper and lower arms of a drive circuit in which the switching means is bridge-connected is ON-controlled, and the other switching means is PWM-controlled.
The on / off control was performed according to the (pulse width modulation) signal. In this case, it may be activated during the rotation of the outdoor blower by the wind. Therefore, when the brushless motor is stopped by applying a large voltage to only one phase for a certain period of time at startup, the on / off control is started according to the PWM signal having a predetermined on-duty ratio.

On the other hand, during the speed control after the start-up, the speed may decrease due to the strong wind. At this time, if the on-duty ratio of the switching means is increased so that a predetermined speed is obtained based on the speed feedback signal, the current naturally increases. Therefore, the current flowing through the switching means is detected, and the detected value is prevented from exceeding a preset value to prevent the switching means from being destroyed.

[0005]

In the conventional air conditioner described above, the brushless motor is stopped by applying a large voltage to only one phase for a certain period of time at startup, and then according to the PWM signal of a predetermined on-duty ratio. Although the on / off control was performed, in such a system, it may be difficult to completely stop depending on the wind speed and the wind direction, and it may be difficult to start the system. Moreover, since a current transformer (CT) or the like is used as a means for detecting the current of the switching means, the control device is inevitably increased in size. It should be noted that these problems are not limited to the air conditioner, and are problems that are common to drive devices for general outdoor blowers.

The present invention has been made to solve the above problems, and a first object thereof is to drive an outdoor blower that can be accurately started even when the wind speed and the wind direction at the time of start differ. To provide a device.

A second object of the present invention is to provide a drive device for an outdoor blower which can eliminate the need for a sensor such as a CT and thereby realize a downsizing of the control device.

[0008]

According to a first aspect of the present invention, before starting a brushless motor, a discriminating means for detecting a rotating direction and a rotating speed of the brushless motor based on an output signal of a position detecting means, and the detected starting. When the previous rotation speed is equal to or lower than the predetermined value and the rotation direction is reverse, the brushless motor is rotated by matching the conduction mode of the drive signal of the switching means to the combination mode of the detection signals from the position detection means. Since it has a reverse rotation stop means for stopping
Even when the wind direction is reversed at the time of startup, it can be reliably stopped and started.

In the second aspect of the invention, the reverse rotation stop means is configured to gradually increase and correct the on-duty ratio of the drive signal, so that the stop can be surely performed in a short time.

In the third aspect of the invention, when the reverse rotation stop means stops the motor during reverse rotation, the on-duty ratio of the drive signal at the time of stop is stored, and the drive signal of this on-tuity ratio is used to start in the forward rotation direction. Since the control is started, the transition of the startup control in the normal rotation direction after stopping the fan that has been rotating in the reverse direction is smooth, and the startup can be improved.

In the fourth aspect of the invention, the discriminating means detects the forward rotation or the reverse rotation of the brushless motor from the change of the combination mode of the detection signals of the position detecting means, and then is set corresponding to the forward rotation and the reverse rotation. When the mode is not detected, it is determined that the position detecting means is abnormal and the driving of the outdoor blower is stopped. Therefore, the abnormality of the position detecting means can be determined at the same time when the forward rotation and the reverse rotation are determined.

According to a fifth aspect of the present invention, one of the upper and lower arm switching means is ON-controlled, and the other switching means is ON / OFF-controlled according to a PWM signal, and the rotation speed command and the rotation speed detection value are combined. When performing on / off control according to a PWM signal having a different on-duty ratio depending on the difference, when the on-duty ratio of the PWM signal reaches a first limit value that is predetermined corresponding to the rotation speed command of the brushless motor, the brushless Ignoring the rotation speed command of the motor, having a means for ON / OFF control according to the PWM signal corresponding to the lower rotation speed command,
In the sixth aspect of the invention, even if control is performed by ignoring the rotation speed command,
Since the brushless motor is stopped when the on-duty ratio of the PWM signal reaches a second limit value which is predetermined so as to be larger than the first limit value, when the outdoor blower is started. Also, it is possible to prevent overcurrent from flowing to the motor due to disturbance during continuous rotation. Also, it is possible to eliminate the need for sensors such as CT,
As a result, it is possible to reduce the size of the control device.

According to the seventh aspect of the invention, the rotation cycle of the brushless motor is detected based on the output signal of the position detecting means, and when the detected rotation cycle is lower than the command rotation cycle of the drive device by a predetermined value or more, the brushless motor is detected. On to,
Since the off control is stopped, it is possible to prevent an overcurrent from flowing to the motor due to a disturbance during continuous rotation. Further, when the actual rotation cycle during operation is short, the blower is rotated by using natural wind, so that power consumption can be saved.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the preferred embodiments shown in the drawings. FIG. 9 shows a schematic configuration of an indoor / outdoor separation type air conditioner including an outdoor blower (hereinafter, the blower is referred to as a fan) as one embodiment of the present invention. In the figure, 1 is a compressor whose speed is controlled via a power converter (not shown), and a four-way valve 2,
A well-known refrigeration cycle is formed with the outdoor heat exchanger 3, the outdoor fan 4, the expansion valve 5, the indoor heat exchanger 6, the indoor fan 7, and the bypass valve 8. This corresponds to the cooling operation mode, and the bypass valve 8 is closed in this mode. In the heating operation mode, the four-way valve 2 is switched to the side opposite to that shown. The outdoor heat exchanger 3 may be frosted in this heating mode. The bypass valve 8 is opened during frost formation,
A high-temperature refrigerant is supplied to the inlet side of the outdoor heat exchanger 3.

The constituent elements of this refrigeration cycle are separately housed in an indoor unit 10 and an outdoor unit 30. The indoor unit 10 includes a remote control device 11 and an indoor unit body 20. In the remote control device 11, a microcomputer (abbreviated as a microcomputer in the figure) 16 processes a signal from the operation unit 12 which is appropriately operated by the user, and the indoor unit main body 20 is transmitted via a transmission circuit 17.
Then, for example, an infrared signal is transmitted. The operation unit 12
Includes a heating / cooling changeover switch 13, a temperature setting switch 14, an air volume changeover switch 15, and the like.

The indoor heat exchanger 6 and the indoor fan 7 are housed in the indoor unit body 20. Further, the indoor unit main body 20 receives an output signal of an indoor detection unit 21 including a temperature sensor 22 for detecting an indoor temperature, a humidity sensor 23 for detecting an indoor humidity, etc.
(Multi control unit: Multi control unit) 25
Is added to To the MCU 25, a signal from the remote control device 11 received by the receiving circuit 24 and an output signal from the heat exchange temperature sensor 29 for detecting the temperature of the indoor heat exchanger 6 are also added. The MCU 25 uses the PMV (Predict
ed Mean Vote), which is used to calculate the comfort level, to calculate the correction value for the set room temperature, and to calculate the rotational speed of the compressor drive motor using these calculation results. In addition, MCU25
Transmits the operation mode signal and the compressor rotation speed command to the outdoor unit 30 via the serial transmission circuit 26, displays the operation state on the display unit 27, and further drives the indoor fan with a control signal according to the air volume. In addition to the circuit 28, the indoor fan 7 is driven.

The outdoor unit 30 includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3, and an outdoor fan 4 which form a refrigeration cycle.
And the expansion valve 5 is stored. Further, the signal sent from the indoor unit main body 20 is received by the serial reception circuit 31 and the MCU is received.
Add to 32. The MCU 32 also inputs the signal of the temperature sensor 34 that detects the temperature of the outdoor heat exchanger 3, drives the compressor 1, the four-way valve 2 and the bypass valve 8 via the drive circuit 33, and directly connects the expansion valve 5 to the expansion valve 5. Control.

Among the operations of the conventional air conditioner, the setting signal is transmitted from the remote controller 11 to the indoor unit body 20, and the MCU 25 of the indoor unit body 20 rotates the compressor 1 based on the signals of various sensors. The point where the speed and the rotation speed of the outdoor fan 4 are calculated, the MCU 32 of the outdoor unit 30 is the compressor 1
Regarding the control of the four-way valve 2 and the opening of the bypass valve 8 during frost formation, various proposals are publicly known and therefore the description thereof will be omitted. The control of the outdoor fan directly related to the present invention will be described in detail below. explain.

FIG. 10 shows the details of the drive circuit for the outdoor fan 4. In the figure, reference numeral 50 is a three-phase brushless motor that drives the outdoor fan 4, and is provided with a drive circuit 44 for supplying an AC voltage to the three-phase windings u, v, and w. The drive power source control circuit 44 includes three power FETs (U, V, W) (upper arm) and three lower FETs, which are configured by bridge-connecting six power M0SFETs (hereinafter referred to as FETs). To turn on and off the inverter circuit composed of (X, Y, Z) (lower arm) and the FETs (U to Z) of this inverter circuit (hereinafter, abbreviated as ON and OFF as OFF). Drive circuits P _{1 to} P ₆ and capacitors C _{1 to} C _{2 serving as} a power source of the drive circuit for the upper arm.

A power supply circuit 41 for driving these compressors including a compressor drive motor (not shown) is provided. The power supply circuit 41 is composed of a rectification circuit 42 that rectifies the alternating current from the commercial AC power supply 40 and a smoothing circuit 43 that smoothes the rectified output of the rectification circuit 42. The positive side output of the DC voltage obtained by the smoothing circuit 43 is supplied to the three-phase windings u, v, w of the brushless motor 50 via the FETs (U to W) forming the upper arm of the drive circuit 44. It is like this. Further, the negative side output of the DC voltage obtained by the smoothing circuit 43 is the FET that constitutes the lower arm of the drive circuit 44.
(X to Z) through the three-phase winding u of the brushless motor 50,
It is supplied to v and w.

The DC output output from the smoothing circuit 43 is branched and connected to the switching regulator 45. The switching regulator 45 includes a control element such as a transistor (described as a transistor in the present embodiment) 46, a transformer 47 having six windings on the secondary side,
Half-wave rectifier circuits (diodes) 48a to 48f and smoothing circuits (electric field capacitors) 49a connected between the terminals of each secondary winding.
.About.49f, the DC voltage sources from the smoothing circuits 49a to 49f are configured to be stabilized DC voltage sources by controlling the transistor 46 by the MCU described later.

Of the stabilized DC voltage sources, five in the upper part of the drawing are supplied to the control circuit of the compressor drive motor (not shown), and the remaining one is the FET of the lower arm of the drive circuit 44.
It is supplied to the drive circuit 44 as a gate drive power source (lower stage power source) for (X to Z). The drive circuit 44 includes the FETs (U to W) that form the upper arm and the FETs (X to Z) that form the lower arm, and L that is each FET drive circuit.
Photocoupler P ₁ equipped with ED, phototransistor, etc.
~ P ₆ and upper arm power supply (upper side power supply) capacitor C
_{1 to} C ₃ and flywheel diodes F _{1 to} F ₆ connected to the respective FETs (U to Z).

Photocoupler (driving circuit) P on the lower arm side
_{4 to} P ₆ are respectively connected in parallel to a DC voltage source (lower side power source) obtained via a half-wave rectifier circuit 48f and a smoothing circuit 49f connected to one secondary winding of the transformer 47. . Further, the positive side output of the same DC output voltage source is branched, and a diode D ₁ ,
The anodes of D ₂ and D ₃ are connected. The cathodes of the diodes D ₁ , D ₂ and D ₃ are connected to the electrolytic capacitors C ₁ and C, respectively.
₂ and C ₃ are respectively connected to the positive electrode side.

On the other hand, the MCU 32 has six combinations of ON and OFF output signals of the three Hall elements 51 provided in the U, V and W phases provided in the brushless motor 50 (hereinafter referred to as combination mode). The position detecting circuit 52 is connected to detect the position of the rotor depending on which one is present, and applies a detection signal to the MCU 32 even when the rotor is stopped. The MCU 32 performs commutation control for switching the energization of the brushless motor 50 according to the position detection signal based on the position of the rotor of the brushless motor 50 detected by the position detection circuit 52, and the actual detection from the position detection signal. Detects the rotation speed and adjusts the pulse width according to the difference from the command speed P
Perform WM control. That is, as shown in FIG. 11, the MCU 32 controls the FET (U, V, W) ON time (pulse width in PMW control) and ON (commutation) timing, and the FET
The current (X, Y, Z) ON (commutation) timing is changed to generate a current for rotating the brushless motor 50 in a predetermined direction at a predetermined speed.
drive power supply control circuit 4 for supplying control signals G _{1 to} G ₆ for flowing to w
It is sent to the four photocouplers P _{1 to} P ₆ . At this time, the photo couplers P _{1 to} P ₆ are controlled by the control signals G ₁ to
By applying a gate output to each FET (U-Z) according to G ₆ and turning the FET (U-Z) ON / OFF at the ON time and ON timing, the brushless motor 50
The magnitude and direction of the average voltage applied to the three-phase windings u, v, and w are varied so that a current of a predetermined magnitude and direction is applied to each winding current to control the brushless motor 50 at a variable speed. Has become.

Before starting the brushless motor 50, the MCU 32 sends control signals G ₄ ′ to G ₆ ′ to the photocouplers P _{4 to} P ₆ of the drive circuit of each FET (X 1 Z) of the lower arm, and the same. The FETs (X to Z) are sequentially turned on for a predetermined time via the photocouplers P _{4 to} P ₆ .

Now, a method of supplying drive power to the FETs (U1W) in the drive circuit 44 will be described. When the commercial AC power supply 40 is turned on to operate the air conditioner, the rectifier circuit 42. of the power supply circuit 41. The DC voltage is sent to the photocouplers P _{4 to} P ₆ of the FETs (X to Z) of the lower arm of the drive circuit 44 via the smoothing circuit 43 and the switching regulator 45. On the other hand, in order to supply the DC voltage to the photocouplers P _{1 to} P ₃ of the FET (U 1 W) of the upper arm, the electric charges must be supplied to the electric field capacitors C _{1 to} C ₃ . However, in the initial state, the electric field capacitors C _{1 to} C ₃ of the upper power supply are not charged, and the DC voltage is not supplied to the photocouplers P _{1 to} P ₃ . In order to supply electric charges to the electric field capacitors C _{1 to} C ₃ , the potential of the negative electrode of the electric field capacitor of the smoothing circuit 49f which is the lower side power supply and the electric field capacitors C of the upper side power supply C
The potential on the negative side of _{1 to} C ₃ must be the same. In other words, if each FET (X to Z) of the lower arm is turned on, the negative electrode of the electric field capacitor of the smoothing circuit 49f and each FE of the upper arm.
The electric field capacitors C _{1 to} C ₃ of T (U to W) are connected to the negative electrodes, and the above conditions are satisfied.

Therefore, before starting the brushless motor 50,
Control signal G is sent to photo couplers P _{4 to} P ₆ via MCU 32.
₄ '~G _6' is sent, each of the lower arm FET (X~W)
The drive signal is supplied to the gate terminal of the FET (X ~
When W) are turned on at the same time, each FET (U ~
W) capacitors C _{1 to} C ₃ are charged (charged up) from the DC power source smoothed by the smoothing circuit 49f, and each of the capacitors C _{1 to} C ₃ has substantially the same terminal voltage as the electric field capacitor of the smoothing circuit 49f. Terminal voltage is generated. In this way, the electric charges are charged up in the capacitors C _{1 to} C ₃ of the FETs (U to W) of the upper arm, so that the photocouplers P ₁ to
A drive output is sent to P ₃ using the capacitors C _{1 to} C ₃ as power sources. That is, the variable speed control of the brushless motor 50 can be reliably performed even after the brushless motor 50 is started.

By the way, in order to continuously rotate the brushless motor 50 is sequentially charge-up current flows in the upper arm FET (U one W), not Pa have been charged capacitor C ₁ -C _3. However, according to the configuration of FIG. 10, as described above, the FET of the lower arm is in the initial state.
(X-Z) is turned on to charge up the capacitor of the upper arm from the output power of the smoothing circuit 49f, so that the brushless motor 50 can be recharged. In accordance with ON / OFF driving of the FETs (U to W) of the arms and the FETs (X to Z) of the lower arms, capacitors C ₁ to automatically serve as power sources for the drive circuits of the FETs (U to W) of the upper arms It is configured such that C ₃ is charged up.

After the brushless motor 50 is started, the control signals G _{1 to} G ₃ from the MCU 32 cause the upper arm FET (U
~ W) are sequentially turned on and off (chopping) according to the pulse width (based on the velocity feed pack) and commutation timing (based on the rotor position feedback) based on the PWM control, and the FET (X to
Z) is sequentially turned on according to the commutation timing, so that the brushless motor 50 is rotationally driven and can be controlled by changing the chopping pulse width.

FIG. 12 shows each F when performing this variable speed control.
It represents the ON / OFF state of ET (U-Z),
In the figure, PWM-ON indicates the state of the PWM signal in which the FET is chopped with a predetermined pulse width.
F is the OFF of the PWM signal where the FET is chopped
It shows the state. Each FET (U is controlled by the MCU 32 to sequentially switch to each energization mode (01-5) in FIG.
~ Z) ON / OFF drive is controlled and the on-duty ratio is increased / decreased to control the direction and magnitude of the current (voltage) flowing through each winding of the brushless motor 50 to perform the above-described variable speed control. ing.

Here, for example, if the brushless motor 50 is energized in the "mode 5" state, the FET (U) of the upper arm is (PWM) ON-driven, and the F of the lower arm is F.
Since ET (Z) is ON-driven, the drive current based on the DC voltage obtained via the rectifier circuit 42 and the smoothing circuit 43 is F
Brushless motor 50 via ET (U) and FET (Z)
Is supplied to. On the other hand, since the FET (Z) of the lower arm is turned on, the first charge-up current emitted from the electric field capacitor of the smoothing circuit 49f is the resistance r for the same reason as the charge-up before the brushless motor is started. , The capacitor C ₃ of the upper arm FET (W) is charged via the diode D ₃ .

Then, the FET (U) is turned off (PWM).
When transitioning to the state, the flywheel diode F of the lower arm FET (X) facing the FET (U)
A circulating current flows in a closed loop between ₄ and the FET (Z) in the ON state. And the flywheel diode F
By turning on _4, the negative potential of the electric field capacitor of the smoothing circuit 49f and the negative potential of the capacitor C ₁ become the same, and a new charge-up current charges the capacitor C ₁ via the resistor r and diode D _1. To do. FE
Since T (Z) is in the ON state, the charge-up current also flows through the capacitor C ₃ of the FET (W).

Similarly, in each of the other energization modes (04), each phase (U to U) of the FET corresponding to the mode shown in FIG.
Capacitor C ₁ -C ₃ corresponding to W) is charged by the charge-up current. Thus, each FET of the upper arm
The charge in the capacitor C ₁ -C ₃ of (U to W) is charged up, the drive output is sent to each photocoupler P ₁ to P ₃ through the capacitor C ₁ -C _3. That is, when the brushless motor 50 is operating by switching the energization, the FETs (X to Z) of the lower arm are turned ON and the FETs (U1W) of the upper arm are turned ON (PWM) →
With the shift to (PWM) OFF, the FET of the same arm
Since the charge-up current flows through (U to W), the drive output can be charged up to each FET (U 1 W) (capacitors C _{1 to} C ₃ ) of the upper arm.

The configuration of the air conditioner including the outdoor fan and the detailed configuration and operation of the drive circuit for the outdoor fan have been described above. In the present embodiment, the start control function of the outdoor fan capable of coping with the outdoor wind, In addition, the MPU 32 has a current control function after starting.

Of these, the outdoor fan startup control function is
Discrimination function that detects the rotation direction and rotation speed of the brushless motor, reverse rotation stop function that stops the rotation of the brushless motor when the rotation speed before startup is less than a specified value and the rotation direction is reverse rotation, and the drive signal is turned on. From the change of the combination mode of the correction means that gradually increases the duty ratio, the start function that starts the start control in the forward rotation direction by the drive signal of the on-duty ratio when stopped, and the change of the detection signal of the position detection means. After detecting the normal rotation or the reverse rotation of the brushless motor, when the setting mode set corresponding to the normal rotation and the reverse rotation is not detected, it is determined that the position detection means is abnormal, and the function of stopping the driving of the outdoor blower. I have it.

That is, the wind speed is detected by the rotation speed of the outdoor fan and the wind direction is detected by the rotation direction of the outdoor fan before starting, and whether or not the start control is possible is determined according to the detection result. The operation mode is set and the on-duty ratio is corrected according to the rotation, the reverse rotation, and the stop, and when the preset reference speed is reached, the normal speed control is performed.

In general, if the outdoor fan is stopped before starting, no problem will occur in starting control.
The control signals G ₄ ′ to the photo couplers P _{4 to} P ₆ shown in FIG.
It can be activated by sending G ₆ ′ and charging up the capacitors C _{1 to} C ₃ , and then activation control can be performed by a predetermined PWM signal. Further, when the outdoor fan is rotating in the normal direction before starting and the rotation speed thereof is considerably high, the outdoor heat exchanger is cooled by natural wind, so it can be said that there is no need to drive the outdoor fan. Therefore,
In this case, control signals G ₄ ′ to G ₄ for enabling activation
There is no need to send a ₆ '. However, even if the speed is normal, if the speed is low, the startup control that gradually increases the speed is required. On the other hand, even if the outdoor fan is rotating in reverse before starting, there is no need to drive the outdoor fan because the outdoor heat exchanger is sufficiently cooled by the natural wind when the rotation speed is considerably high. . However, even if the speed is reverse, if the speed is low, it is necessary to gradually slow down the speed and stop it, and perform start control in the normal direction in the stopped state.

FIG. 1 and FIG. 2 are flow charts showing a concrete processing procedure relating to the above-mentioned discrimination function for discriminating the wind speed and the wind direction. The determination operation will be described below according to this flowchart and also with reference to FIG.

Now, F which constitutes the upper arm shown in FIG.
ET (U to W) and FET (X to
Z) and PW respectively as shown in FIG.
Hall element provided in the brushless motor 50 when the brushless motor 50 is driven by executing M control and commutation control
51 outputs the three-phase AC position detection signal shown in FIG. 3B, and in response to this, the position detection circuit 52 outputs the logic level signal shown in FIG. The MCU 32 determines the wind speed and the wind direction on the basis of the logic level signal shown in FIG. 3 (c), on the condition that the same determination result is obtained twice in succession to improve the accuracy.

Therefore, first, at step 101, the counter A for counting the number of rotation determinations of the fan, the counter B for counting the number of stop determinations, the counter C for counting the number of forward rotation determinations, and the number of the reverse rotation determinations are counted. The counter D and the counter E for counting the number of times of abnormality determination of the hall element 51 are reset to zero. Then, in step 102, the U port of the position detection circuit 52 that takes in the U-phase signal is set to the signal input state, and the V port and W port of the position detection circuit 52 that takes in the V-phase signal and the W-phase signal is set to the signal output state. It is set and fixed to the L level so that no signal is actually input to the V port and the W port. And the next step
At 103, it is determined whether the U-phase signal input from the U port is at H level. That is, it is determined whether or not the rotor is in any one of the modes 0, 1, and 2.
If it is determined in step 103 that the U-phase signal is at the H level, and if the fan is rotating, then the L-level signal is input to the U port. Therefore,
In step 104, the reference value for detecting that the L level has been set to L, and then in step 105, whether or not the U phase signal has changed to the L level, that is, the U phase signal changes from the H level to the L level. An edge (a rising or falling edge of a signal) that changes to a level is detected.

When the edge of the U-phase signal is detected, the value of the counter A for counting the number of rotation judgments is incremented by 1 in step 106, and the counted value is 1 or 2 in step 107.
To determine. In this case, since the value of the counter A is 1, the process of step 108, that is, the integration operation by the counter for measuring the time from when the value of the counter A changes from 1 to 2 is started. Then, in step 109, the V port and the W port that take in the V phase signal and the W phase signal of the position detection circuit 52 are switched to the signal input state, and the signal levels of the U phase, V phase, and W phase are checked, and step 110 , The U-phase, V-phase, and W-phase signal levels are L,
Whether or not it is H or L, that is, whether or not it is the combination mode 3 which is always detected when the U-phase signal shifts from the H level to the L level during the normal rotation is determined. Therefore,
If it is the mode 3, the fan is determined to be forward rotation in step 111, and subsequently, the value of the counter C for counting the number of forward rotation determinations is incremented by 1 in step 112, and step 113 is performed.
Then, it is determined whether or not the count value is 2. In this case, since the value of the counter C is 1, the process proceeds to step 134, where the counters B, D and E are reset to 0 again, and then the process returns to step 102, where U
After the port is set to the signal input state and the V port and the W port are set to the signal output state, the process of step 103 is executed. After the U-phase signal is at the H level, the U-phase signal is at the L level. Therefore, from step 103 to step 20 shown in FIG.
Move on to step 4. Steps shown in the flowchart of FIG.
The processing of 204 to 232 corresponds to the processing of steps 104 to 132. Instead of setting the next judgment level to L in step 104, the next judgment level is set to H in step 204. Further, instead of determining whether it is L level in step 105, it is determined whether it is H level in step 205, and mode 3 is determined in step 110.
Instead of determining whether or not it is the mode 0 in step 210.
It is determined whether or not the mote is 5 in step 123.
Instead of determining whether or not it is, it is different in that it is determined whether or not it is the mode 2 in step 223. Other than these steps, the processing in step 200 is the corresponding step.
It is the same as the 100th generation.

In step 204, the reference value for detecting the H level is set to H, and in step 205 it is determined whether or not the U phase signal has changed to the H level, that is, the U phase signal is changed from the L level to the H level. Detect edges that change to.

When the edge of the U-phase signal is detected, the value of the counter A for counting the number of rotation determinations is incremented by 1 in step 206, and the counted value is 1 or 2 in step 207.
To determine. In this case, since the value of the counter A is 2, the counting operation of the counter for measuring time is stopped in step 222, and the fan counts from the count value at that time, that is, the time from the fall to the rise of the U-phase signal. Calculate the rotation speed of. Then, in step 209, the position detection circuit 52
The V port and W port that take in the V phase signal and the W phase signal of are switched to the signal input state, and the signal levels of the U phase, V phase, and W phase are checked, and in step 210, the U phase, V phase, and W phase It is determined whether or not the signal levels of the phases are H, L, and H, that is, whether or not the mode is 0. Therefore, assuming that the mode is 0, in step 211, the fan is determined to be normal rotation, then in step 212, the value of the counter C that counts the number of forward rotation determinations is incremented by 1, and in step 113 the count value is increased. Is determined to be 2. In this case, since the value of the counter C is 2, the process proceeds to step 214.

In step 214, it is determined whether or not the rotation speed of the fan calculated in step 222 is equal to or higher than a prescribed value, and if it is equal to or higher than the prescribed value, sufficient cooling is performed by natural wind in that state. Therefore, it is assumed that the driving of the compressor is started in step 215 and the fan cannot be driven in step 216, and the process of step 101 is performed without performing the process of supplying driving power to the FET (U1W) for the driving circuit 44. Return to.

On the other hand, if it is determined in step 214 that the fan rotation speed is lower than the specified value, the starting control, which will be described in detail later, is executed in step 231, and when the fan rotation speed exceeds the specified value, step 232 At, the well-known speed control based on the speed feedback signal is executed, and the process ends.

Thus, when the same determination result is obtained twice consecutively, the rotation of the fan, that is, the wind, and the forward rotation of the fan, that is, the normal wind, are determined, and the rotation speed of the fan at that time is detected. It

By the way, if there is no wind, step 103
Even if it is detected that the U-phase signal level is H, the state (stopped state) continues, so step 10
At 5, L level is not detected. In this case, the timer is started in step 117 to start measuring the time, the predetermined time is confirmed in step 118, the fan stop is judged in step 119, and the step 119 is executed. The count value of the counter B that counts the number of stop determinations is incremented by 1. And step 121
Then, it is determined whether or not the count value is 2. In this case, since the value of the counter B is 1, the process proceeds to step 133, where the counters C, D and E are reset to 0 again, and then the processes of steps 102 to 105 and the processes of steps 117 to 121 are performed. Is executed and the count value of the counter B for counting the number of stop determinations becomes 2, step 131
Move on to start control.

Thus, when the same determination result is obtained twice consecutively, it is detected that the fan is in the stopped state.

On the other hand, if it is not in the mode 3 in the processing of step 110, the fan may be rotating in the reverse direction or the position detecting circuit 52 may be abnormal. Therefore, in step 123, it is determined whether the signal levels of the U phase, V phase, and W phase are L, L, and H, that is, when the U phase signal shifts from H level to L level during reverse rotation. It is determined whether or not the combination mode 5 is always detected, and in the case of the mode 5, it is determined in step 124 that the rotation is the reverse rotation. Then, the value of the counter D is incremented by 1 in order to make the judgment again, and it is judged in step 126 whether the counted value is 1 or 2. In this case, since the value of the counter A is 1, the other counters B, C, and E are reset to 0 in step 135, and the process proceeds to step 102 and subsequent steps.

In this state, the U-phase signal level is L
Therefore, after executing the process of step 103, when it is determined again by the processes of steps 204 to 210 and steps 223 to 226 that the reverse rotation is performed, the processes of step 214 and subsequent steps are executed.

Thus, when the same determination result is obtained twice in succession, it is determined that the fan is rotating normally, and processing is performed according to the rotation speed of the fan at that time.

If the mode 2 is not set in step 223, it is determined that the hall element 51 or the position detection circuit 52 is abnormal, and the value of the counter E is incremented by 1 in order to make the determination again. Determine whether the count value is 1 or 2. In this case, since the value of the counter E is 1, the counters B, C and D are reset to 0 in step 136, and the processing in step 102 and subsequent steps is started. In this case, step 103
After performing the processing in steps 204 to 210,
223, it is determined again by the processing of steps 227 to 229 that there is an abnormality, and in step 230 the hall element 51 or the position detection circuit 52
It is determined to be abnormal and the subsequent processing is stopped.

Thus, when the same determination result is obtained twice consecutively, it is determined that the hall element 51 or the position detection circuit 52 is abnormal, and the driving of the outdoor blower is stopped.

As described above, the U input to the U port of the MCU 32
The case where the phase signal level is first at the H level has been described. However, when the U phase signal level is first at the L level, the processing after step 103 is step 20.
After performing the 0th generation process, the step number 100th generation process is performed, whereby the same determination as the above-described determination is performed.

As described above, when the state of the outdoor fan before the start is normal rotation or reverse rotation and the rotation speed is below the specified value, or when it is determined that the outdoor fan is stopped, the start processing of step 131 is performed. I do.

FIG. 4 is a flow chart showing the detailed processing procedure of step 131. First, in the first step 301, it is determined whether the rotation is normal rotation, normal rotation, or reverse rotation. When it is determined that the rotation is normal rotation or stop, in step 308, the rotor is energized in the current position mode. Incidentally, the energization mode of one rotation of the brushless motor is shown in FIG. When the current position is set to the mode A ₀ , for example, when moving to the next mode of A ₁ = A ₀ +1
_In order to instantly energize _one mode without control delay, the mode A ₀ +1 is set in the register of the MCU in step 309, and it is determined in step 310 whether the position has moved to the mode A ₁ position. Then, when it is confirmed that it has moved to the position of the mode A ₁ , the power is supplied in the A ₁ mode in step 311. Then, in step 312, it is determined whether or not the rotation speed of the outdoor fan has exceeded the specified value, and steps 309 to 312 are repeated until the rotation speed exceeds the specified value. Transfer to control. In addition,
If it is not detected in step 310 that the device has moved to A ₁ mode, in step 313 the FETs (U to W)
The increase of the on-duty ratio of the PWM signal for ON / OFF control of the (upper arm) is corrected, and the processes from step 310 are repeated.

Next, in the first step 301, when it is determined that the rotor is rotating in the reverse direction, in step 314 the power is supplied in the mode A ₀ in which the rotor is currently located. Then, the current mode position A ₀
In order to instantly energize the A ₁ mode without control delay when moving to the mode of A ₁ = A ₀ -1, which is deviated by one in the reverse direction as seen from the view point, the mode A ₀ -1 is set to MC in step 315.
It is set in the U register, and it is determined in step 316 whether or not it has moved to the position of mode A ₁ . And mode A ₁
When it is confirmed that it has moved to the position, the power is turned on in the A ₁ mode in step 317. Then, in step 318, the FET
PWM for ON / OFF control of (U to W) (upper arm)
The on-duty ratio of the signal is increased and corrected, and the processing from step 315 is repeated. If, if it has moved to the A ₁ mode is not detected at step 316, the outdoor fan motor will be stopped. Therefore, the on-duty ratio of the PWM signal when stopped in step 319 is stored (initialized), and the process proceeds to step 308 when stopped, and the outdoor blower is rotated in the forward direction.

Thus, according to the processing shown in FIG. 4, for each of the cases where the state of the outdoor fan before starting is normal rotation or reverse rotation, and the rotation speed is below a specified value or is stopped. It is possible to increase the rotation speed of the outdoor fan in the forward rotation direction beyond the specified value.

In particular, as seen in step 318, P
Since it has a function of gradually increasing and correcting the on-duty ratio of the WM signal, the reverse rotation of the fan can be stopped in a shorter time than in the conventional case. Also, as shown in step 319, the on-duty ratio P when the fan in reverse rotation is stopped
Since the start control in the forward rotation direction is performed by the WM signal,
The transition from reverse rotation to forward rotation is smooth, and the startup at startup can be improved. As a result, even if the state of the outdoor fan changes variously due to the difference in the wind direction and the wind speed, the outdoor fan can be easily started.

By the way, it goes without saying that the wind does not affect only the outdoor fan at the time of startup, but also affects the stage when the startup control is shifted to the speed control.
As a general process in this case, the actual speed of the outdoor fan is detected, and if the detected speed is higher than the command speed, the on-duty ratio of the PWM control signal is corrected to be decreased according to the difference between the detected speed and the command speed. , P if the speed is less than or equal to the command speed
A so-called feedback control of increasing and correcting the on-duty ratio of the WM control signal has been executed.

Then, in order to prevent the current actually flowing in the FET from exceeding the reference value, the on-duty ratio of the PWM control signal is increased when the current is detected by CT or the like and reaches a preset value. He was taking steps to curb it.

In this embodiment, the current value is not detected and P
It has a current control function that performs overcurrent prevention control only by the on-duty ratio (based on the estimation of the current value) of the WM control signal. As a specific function, the on-duty ratio of the PWM signal is the first limit value. When the rotation speed command of the brushless motor is reached, the release control function that ignores the rotation speed command of the brushless motor and controls according to the PWM signal corresponding to the lower rotation speed command
When the on-duty ratio of the signal reaches the second limit value that is set in advance so as to be larger than the first limit value, the function of stopping the brushless motor and the rotation cycle of the brushless motor are detected and detected. When the rotation cycle is lower than the command rotation cycle of the drive device by a certain value or more,
It has a function of stopping the on / off control of the brushless motor. FIG. 6 shows the relationship between the rotation speed command value and the on-duty ratio of the PWM control signal in order to explain its schematic operation. In the figure, a straight line A represents a value that reduces the on-duty ratio by decreasing the rotation speed command value so that the current value does not increase any more when the on-duty ratio reaches the value on the line, and the straight line B represents the on-value. It represents a value at which the energization of the motor is stopped when the duty ratio reaches the value on the line. Since suppressing the on-duty ratio means ignoring the feedback control, this is referred to as a release in this specification, and hereinafter, the value on the straight line A is the release duty ratio, and the value on the straight line B is the stop duty ratio. I will call it. Incidentally, FIG. 7 shows an example of the release duty ratio which is the first limit value and the stop duty ratio which is the second limit value with respect to the rotation speed command. These values are stored in the ROM of the MCU 32 to perform overcurrent prevention control.

This overcurrent prevention control is, for example, as indicated by the broken line when the outdoor fan is rotationally driven at point C in FIG. 6 and the commanded rotational speed cannot be obtained due to the influence of the wind. The on-duty ratio is increased and corrected. When the release duty ratio on the straight line A is reached in the process of the increase, the rotation speed command value is lowered and the PWM signal with a low on-duty ratio is changed so that the on-duty ratio does not exceed the straight-line A value. However, the on-duty ratio may exceed the straight line A in the process of executing the on-duty ratio suppression control. Therefore, when the outdoor fan is rotationally driven at point C and the on-duty ratio increases to reach the stop duty ratio on the straight line B, the energization is stopped at that point.

FIG. 8 shows an MC corresponding to this overcurrent prevention control.
It is a flow chart which shows a processing procedure of U32. That is, in step 401, feedback control is executed.
Then, in step 401, the release duty ratio and the stop duty ratio for the rotation speed command value are read. Then, in step 403, the PWM corresponding to the rotation speed command value
It is determined whether the on-duty ratio of the signal is larger than the release duty ratio. If the on-duty ratio of the PWM signal is larger than the release duty ratio, it is further determined in step 404 whether the on-duty ratio of the PWM signal is larger than the stop duty ratio. As a result, when the on-duty ratio of the PWM signal is larger than the stop duty ratio, the energization is stopped in step 406 to stop the outdoor fan. That is, the on-duty ratio of the PWM signal is set to 0%. Then, in step 106, the system is restarted when a predetermined stop time (6 seconds) has elapsed.

On the other hand, if it is determined in step 404 that the on-duty ratio of the PWM signal is not greater than the stop duty ratio, the feedback process is ignored in step 407, and then P is determined in step 404.
By lowering the WM signal on-duty ratio, the processing for lowering the rotation speed command value is substantially executed.

Thus, during the speed control, the overcurrent prevention control can be performed by estimating the current from the on-duty ratio of the PWM control signal without using CT or the like, thereby avoiding an increase in the size of the control device. To be

In the above embodiment, the release duty ratio and the stop duty ratio are stored in the ROM, the values are read in step 402 and the subsequent processing is executed. Instead, for example, the following equation is used. Alternatively, the release duty ratio Y ₁ and the stop duty ratio Y ₂ may be calculated. Y ₁ = Ux + a (1) Y ₂ = Ux + b (2) where x: rotational speed command value U: proportional constant (slope of straight lines A and B in FIG. 6) a, b: constant (intercept in FIG. 6) Is.

It is also predicted that a gust of wind will blow during speed control. At this time, the speed of the outdoor fan may be rapidly reduced, and the current value may be rapidly increased. As a countermeasure against this, the cycle L _a of one rotation of the brushless motor is detected based on the position detection signal of the position detection circuit 52, and this cycle L _a is detected.
Is less than the command rotation speed cycle L _s by a constant value C (C>) or more, the outdoor fan stop control may be executed.
The control procedure in this case is as shown in the flowchart of FIG.

That is, in step 501, the set room temperature T _{s is} set.
Reading, after having been read to detect room temperature T _a at step 502, calculates the temperature difference ΔT (= T _s -T _a) between the set room temperature T _s and the detected room temperature T _a at step 503. Then, in step 504, the rotation speed of the outdoor fan corresponding to the temperature difference ΔT is
For example, the PW corresponding to the value is selected from the values stored in the ROM of the MCU and the obtained rotational speed is used as the command rotational speed.
Output M signal. Next, in step 505, the cycle L _s corresponding to the command rotation speed is calculated or the MCU ROM
Read the value stored in.

Next, in step 506, the position detection circuit 52
It is checked whether or not the edge of the U-phase signal obtained via the is detected, and if the edge is detected, step 507
Starts the time measurement operation by the timer. Then, in step 508, it is checked again whether or not the edge of the U-phase signal is detected. If the edge is detected, the step is determined.
At 509, stop the time measurement operation of the timer and read the count value at that time. Outdoor fan based on the count value of step 510 timer calculates the period L _a corresponding to the actual speed. Furthermore, compares the value L _s -C subtracting the constant value C from the period L _s corresponding to the command rotation speed in step 511, and a period L _a corresponding to the actual speed at L _a <L _s -C If not, that is, if L _a ≧ L _s −C, step 512
Speed feedback control is executed at L _a <L _s -C
If so, in step 513, the outdoor fan stop control is executed and the control ends. As a result, the process shown in FIG. 8 can be controlled more quickly and the safety can be increased.

Further, in the above embodiment, the start control and the speed control for the outdoor fan that constitutes the outdoor unit of the air conditioner have been described, but the present invention is not limited to this application, and other than the air conditioner. It can also be applied to the control of outdoor fans.

[0072]

As is apparent from the above description, according to the present invention, the outdoor blower can be reliably started without being affected by the wind speed and the wind direction at the time of starting.

Further, according to another invention, a sensor such as a CT can be made unnecessary when performing the overcurrent prevention control during the speed control after the start-up, whereby the size of the control device can be reduced. Can be realized.

[Brief description of drawings]

FIG. 1 is a flowchart showing a specific processing procedure of main components for explaining the operation of an embodiment of the present invention.

FIG. 2 is a flowchart showing a specific processing procedure of main components for explaining the operation of the embodiment of the invention.

FIG. 3 is a diagram showing output waveforms of main components for explaining the operation of the embodiment of the invention.

FIG. 4 is a flowchart showing a specific processing procedure of main components for explaining the operation of the embodiment of the present invention.

FIG. 5 is an energization mode diagram for one rotation of the outdoor fan to explain the operation of the embodiment of the invention.

FIG. 6 is a diagram showing a relationship between an on-duty ratio of a PWM signal and a rotation speed command in order to explain the operation of the embodiment of the invention.

FIG. 7 is a chart showing a relationship between an on-duty ratio of a PWM signal and a rotation speed command in order to explain the operation of the embodiment of the invention.

FIG. 8 is a flowchart showing a specific processing procedure of main components for explaining the operation of the embodiment of the invention.

FIG. 9 is a block diagram showing a schematic configuration of an embodiment of the present invention.

FIG. 10 is a circuit diagram showing a detailed configuration of a drive circuit according to an embodiment of the present invention.

FIG. 11 is a waveform diagram showing ON / OFF states of main components for explaining the operation of the embodiment of the invention.

FIG. 12 is a chart showing ON / OFF states of main components for explaining the operation of the embodiment of the invention.

FIG. 13 is a flowchart showing a specific processing procedure of main components for explaining the operation of the embodiment of the invention.

[Explanation of symbols]

3 Outdoor heat exchanger 7 Outdoor blower 30 Outdoor unit 32 MCU 41 Power supply circuit 44 Drive circuit 45 Switching regulator 50 Three-phase brushless motor 51 Hall element 51 52 Position detection circuit U, V, W, X, Y, Z M0SFET P ₁ ~ P ₆ photo coupler F _{1 to} F ₆ flywheel diode C ₁ , C ₂ , C ₃ electric field capacitor

Claims (7)

[Claims] 1. A brushless motor for driving an outdoor blower, an upper arm comprising a plurality of switching means for switching connection between a positive terminal of a DC power source and a plurality of terminals of the brushless motor, and a negative terminal of the DC power source, and the brushless motor. A drive circuit having a lower arm composed of a plurality of switching means for switching the connection with a plurality of terminals, a plurality of position detecting means for detecting the position of the rotor of the brushless motor, and an output signal of the position detecting means. The rotation speed of the brushless motor is detected, and the outdoor fan is provided with a speed control means for turning on and off a plurality of switching means of the drive circuit so that the detected rotation speed matches a rotation speed command. In the apparatus, before starting the brushless motor, the brushless motor is detected based on the output signal of the position detecting means. When the detected rotation speed and the rotation speed before rotation are less than or equal to a predetermined specified value and the rotation direction is reverse, the detection signal from the position detection means is set to the combination mode. And a reverse rotation stop unit for stopping the rotation of the brushless motor by matching the power supply modes of the drive signals of the switching units to supply power, and a drive device for the outdoor blower. 2. The drive device for an outdoor blower according to claim 1, wherein the reverse rotation stop means has a correction means for gradually increasing and correcting the on-duty ratio of the drive signal. 3. The reverse rotation stop means stores the on-duty ratio of the drive signal when the motor is stopped during reverse rotation, and starts the start control in the forward rotation direction by the drive signal of the on-duty ratio. The drive device for an outdoor blower according to claim 2, further comprising a starting unit that operates. 4. A setting mode in which the discriminating means detects a forward rotation or a reverse rotation of the brushless motor from a change in a combination mode of detection signals of the position detecting means, and is set corresponding to the forward rotation or the reverse rotation. The drive device for the outdoor blower according to claim 1, wherein when the position is not detected, it is determined that the position detection means is abnormal and the drive of the outdoor blower is stopped. 5. A brushless motor for driving an outdoor blower, an upper arm comprising a plurality of switching means for switching connection between a positive terminal of a DC power source and a plurality of terminals of the brushless motor, and a negative terminal of the DC power source and the brushless motor. A drive circuit having a lower arm made up of a plurality of switching means for switching the connection with a plurality of terminals, and position detection means for detecting the position of the rotor of the brushless motor,
The position detecting means detects the rotational speed of the brushless motor based on the output signal of the position detecting means, and includes a switching means connected to different terminals of the upper arm and the lower arm of the drive circuit. According to a combination mode defined in advance according to the position of the rotor of the brushless motor detected by the ON control of one of the switching means of the upper and lower arms, the other switching means is turned on according to the PWM signal,
Along with the OFF control, according to a PWM signal of a different on-duty ratio according to the difference between the rotation speed command and the rotation speed detection value of the brushless motor, ON / OFF according to the speed control means, the drive device of the outdoor blower, When the on-duty ratio of the PWM signal reaches a predetermined first limit value corresponding to the rotation speed command of the brushless motor, the rotation speed command of the brushless motor is ignored and a lower rotation speed command is obtained. Corresponding PWM
Depending on the signal, the switching of the other one is turned on,
A drive device for an outdoor blower, comprising release control means for controlling off. 6. A second limit value set in advance so that the on-duty ratio of the PWM signal becomes larger than the first limit value even if the release control means controls the rotation speed command to be ignored. 6. The drive device for an outdoor blower according to claim 5, further comprising means for stopping the brushless motor when the temperature reaches 0. 7. The brushless motor detects a rotation cycle of the brushless motor based on an output signal of the position detecting means, and when the detected rotation cycle is lower than a command rotation cycle of the drive device by a predetermined value or more, the brushless motor. On to,
The drive device for the outdoor blower according to claim 6, further comprising means for stopping the off control.