JP3763256B2 - Air conditioner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air conditioner.
[0002]
[Prior art]
In the conventional air conditioner, as shown in FIG. 3, the low voltage detection circuit 13 is connected to the power source of the fan motor power transistor array drive circuit 9, and the fan motor power transistor due to an instantaneous power failure or voltage drop of the commercial AC power source 1. A drop in the power supply voltage of the array drive circuit 9 is detected, and the fan motor drive signal 11 is forcibly changed to the side where all the transistors of the fan motor power transistor array 8 are turned off, and the power supply of the fan motor power transistor array drive circuit 9 is changed. The destruction of the power transistor array 8 for the fan motor due to the unstable operation at the time of the voltage drop was prevented.
[0003]
[Problems to be solved by the invention]
The drop in the power supply voltage of the fan motor transistor array drive circuit in an air conditioner reduces the voltage of the inverter capacitor by cutting off the current supply from the commercial AC power supply such as a power failure of the commercial AC power supply or disconnecting the power plug from the outlet. This occurs when the output of the DC / DC converter decreases.
[0004]
Especially when the current supply of the commercial AC power supply is cut off during the compressor operation, the power supply for the compressor and the power transistor array drive circuit for the fan motor use a common inverter capacitor. The voltage of the capacitor rapidly decreases, and the power supply voltage of the fan motor transistor array drive circuit rapidly decreases.
[0005]
For this reason, in the conventional technology, the response speed of the low voltage detection circuit is made very fast, and the power supply voltage of the transistor array drive circuit for the fan motor is set to be high so that the drop of the power supply voltage of the transistor array drive circuit for the fan motor is detected. Was set high and the time to start the protection operation was taken. Increasing the response speed of the low voltage detection circuit increases the possibility of the low voltage detection circuit malfunctioning due to external noise to the air conditioner. If the power supply voltage of the fan motor transistor array drive circuit is set high, the fan motor transistor There has been a problem that the power loss of the array drive circuit increases.
[0006]
[Means for Solving the Problems]
In order to solve the above-described problems, the present invention focuses on a characteristic unique to an air conditioner in which a drop in power supply voltage of a transistor array drive circuit for a fan motor is caused by a cut-off or drop in a commercial AC power supply. Detecting the voltage of other parts of the air conditioner rather than detecting the power supply voltage itself of the fan motor transistor array drive circuit to prevent the destruction of the power transistor array for the fan motor due to a decrease in the power supply voltage of the drive circuit Thus, the above problem is solved by starting the protection operation before the power supply voltage of the transistor array drive circuit for the fan motor decreases.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
In order to solve the above-described problems, the invention of claim 1 is provided with a circuit for detecting a drop in commercial AC power, and applies a protection operation to the fan motor drive signal by the drop or cut-off of the commercial AC power.
[0008]
According to a second aspect of the present invention, a circuit for detecting a drop in the DC voltage smoothed by the inverter capacitor is provided, and the fan motor drive signal is protected by the drop in the DC voltage smoothed by the inverter capacitor. It is.
[0009]
Embodiments of the present invention will be described below with reference to the drawings.
(Embodiment 1)
As shown in FIG. 1, the low voltage detection circuit 13 is connected to the commercial AC power supply 1, and when the voltage of the commercial AC power supply 1 drops, all the transistors of the fan motor power transistor array 8 turn off the fan motor drive signal 11. Operates to force change to the side.
[0010]
In the above configuration, when the voltage of the commercial AC power supply 1 is cut off due to a power failure or the like, the voltage of the inverter capacitor 3 is lowered, and the fan motor is not the first time when the DC / DC converter 12 has changed the input voltage range in which voltage output is possible. Since the power supply voltage of the power transistor array drive circuit 9 for power supply starts to drop, there is a sufficient time from when the low voltage detection circuit 13 detects the voltage drop of the commercial AC power supply 1 until the fan motor drive signal 11 is protected. The responsiveness of the low voltage detection circuit 13 can be delayed and the power supply voltage of the fan motor power transistor array drive circuit 9 can be set low, and an air conditioner with high reliability against external noise and low power consumption can be realized.
(Embodiment 2)
FIG. 2 shows a fan motor drive signal in which the low voltage detection circuit 13 in the first embodiment is connected to a DC voltage smoothed by the inverter capacitor 3 to detect a decrease in the DC voltage smoothed by the inverter capacitor 3. 11 is operated to forcibly change all the transistors of the power transistor array 8 for fan motor to the side where the transistors are turned off.
[0011]
In the present embodiment, in addition to the first embodiment, the DC voltage smoothed by the inverter capacitor 3 is suddenly lowered by the lock of the compressor motor 4, and the power supply voltage of the fan motor power transistor array drive circuit 9 is lowered. In this case, the low voltage detection circuit works to reliably protect the fan motor power transistor array 8 and further improve the reliability of the air conditioner.
[0012]
【The invention's effect】
As is apparent from the above description, according to the present invention, the low voltage detection circuit is connected to a commercial AC power source, and the power transistor array for the fan motor is protected by shutting down or lowering the voltage. Since the responsiveness of the detection circuit can be delayed and the power supply voltage of the power transistor array drive circuit for the fan motor can be lowered, an air conditioner that is resistant to external noise and has low power consumption can be realized.
[0013]
According to another invention of the present application, the low voltage detection circuit is connected to the DC voltage smoothed by the inverter capacitor, and the power transistor array for the fan motor is protected by the reduction, thereby locking the compressor motor. Since the power transistor array for the fan motor can be protected even when the DC voltage is drastically reduced due to the above, the reliability can be further improved.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of an air conditioner showing an embodiment of the present invention. FIG. 2 is a circuit diagram of an air conditioner showing another embodiment of the present invention. Circuit diagram of the harmony machine [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Commercial AC power supply 2 Diode bridge 3 Capacitor for inverter 4 Compressor motor 5 Power transistor array for compressor motor 6 Power transistor array drive circuit for compressor motor 7 Fan motor 8 Power transistor array for fan motor 9 Power transistor array for fan motor Drive circuit 10 Control unit 11 Fan motor drive signal line 12 DC / DC converter 13 Low voltage detection circuit

Claims (2)

A diode bridge that rectifies a commercial AC power supply, an inverter capacitor that smoothes a voltage rectified by the diode bridge, a compressor motor that drives a compressor, and a DC voltage that is smoothed by the inverter capacitor by switching. A power transistor array for a compressor motor that is sequentially supplied to each winding of the compressor motor; a power transistor array drive circuit for a compressor motor that controls the power transistor array for the compressor motor; a fan motor that drives a fan; A power transistor array for a fan motor that sequentially supplies a DC voltage smoothed by an inverter capacitor to each winding of the fan motor by switching, and a power motor for a fan motor that controls the power transistor array for the fan motor. A transistor array drive circuit, a compressor motor power transistor array drive circuit, a fan motor power transistor array drive circuit control unit, and a fan motor power transistor array drive circuit and the control unit. A fan motor drive signal line for transmitting a control signal of the fan transistor power transistor array drive circuit from the control unit, and a DC voltage smoothed by the inverter capacitor as inputs, and the control unit and the compressor motor power transistor A DC / DC converter that outputs a power supply voltage to the array drive circuit, the fan motor power transistor array drive circuit, and a low voltage detection circuit connected to the fan motor drive signal line and the commercial AC power supply. In the air conditioner provided, when the low voltage detection circuit detects that the voltage of the commercial AC power supply is below a predetermined value, all the transistors of the fan motor power transistor array are turned off for the fan motor drive signal. An air conditioner that operates to forcibly change to the side. A diode bridge that rectifies a commercial AC power supply, an inverter capacitor that smoothes a voltage rectified by the diode bridge, a compressor motor that drives a compressor, and a DC voltage that is smoothed by the inverter capacitor by switching. A power transistor array for a compressor motor that is sequentially supplied to each winding of the compressor motor; a power transistor array drive circuit for a compressor motor that controls the power transistor array for the compressor motor; a fan motor that drives a fan; A power transistor array for a fan motor that sequentially supplies a DC voltage smoothed by an inverter capacitor to each winding of the fan motor by switching, and a power motor for a fan motor that controls the power transistor array for the fan motor. A transistor array drive circuit, a compressor motor power transistor array drive circuit, a fan motor power transistor array drive circuit control unit, and a fan motor power transistor array drive circuit and the control unit. A fan motor drive signal line for transmitting a control signal of the fan transistor power transistor array drive circuit from the control unit, and a DC voltage smoothed by the inverter capacitor as inputs, and the control unit and the compressor motor power transistor A DC / DC converter that outputs a power supply voltage to the array drive circuit, the fan motor power transistor array drive circuit, and a low voltage detection circuit connected to the fan motor drive signal line and the commercial AC power supply. In the air conditioner provided, the low voltage detection circuit detects a DC voltage smoothed by the inverter capacitor, and when the low voltage detection circuit detects that the DC voltage is a predetermined value or less, a fan motor An air conditioner that operates to forcibly change a drive signal to a side in which all transistors of a power transistor array for a fan motor are turned off.

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