WO2007132889A1 - Air conditioner - Google Patents

Abstract

A control section (30) generates a pattern signal for energization control of winding wires (Lu, Lv, Lw) of a sensorless direct current motor (3M) by vector control, and controls operation of an indoor unit. A microcomputer is employed as such control section (30). The control section (30) is arranged on one indoor printed board (40) with an inverter (20).

Description

 Specification

 Air conditioner

 Technical field

 The present invention relates to an indoor fan housed in an indoor unit, and an air conditioner including a sensorless DC motor that drives the indoor fan.

 Background art

 [0002] A motor drive device of a sensorless DC motor (also referred to as a brushless DC motor) provided with a rotor position detecting element such as a Hall element is known (for example, Japanese Patent No. 3442024). A switching element that switches energization to each of the winding wires, a drive circuit that drives the switching element, a control circuit that controls the drive circuit to adjust the rotational speed of the sensorless DC motor, and the like. The control circuit is mounted on the motor internal board.

 [0003] FIG. 3 shows a configuration of a control circuit of the motor driving device.

 That is, the switching circuit 103 is connected to the commercial AC power supply 100 via the rectifier circuit 101 and the smoothing capacitor 102, and the sensorless DC motor 104 used as a fan motor is connected to the output terminal of the switching circuit 103. The sensorless DC motor 104 is mounted with rotor position detection elements such as Hall elements 105a, 105b, and 105c, and the outputs of these Hall elements are supplied to the control circuit 106. The control circuit 106 detects the rotational position of the rotor in the sensorless DC motor 104 as well as the output force of the hall elements 105a, 105b, and 105c, and controls the drive circuit 107 according to the detection result. The drive circuit 107 outputs a pattern signal for energization control in accordance with a command from the control circuit 106. The switching circuit 103 drives each switching element on and off in accordance with the pattern signal. The driving circuit 107 and the switching circuit 103 are connected by six signal lines 120 for supplying pattern signals.

[0004] The switching circuit 103, the sensorless DC motor 104, the Honoré elements 105a, 105b, 105c, the control circuit 106, the drive circuit 107, and the signal line 120 are mounted on the motor internal board of the motor indoor fan. [0005] Further, a control power supply circuit 111 is connected to the output terminal of the rectifier circuit 101, and a control operating voltage output from the control power supply circuit 111 is an indoor control circuit (MCU) 112 using a microcomputer. And supplied to the motor internal substrate. The indoor control circuit 112 supplies rotation speed setting data corresponding to various input data to the control circuit 106 of the motor internal board.

 [0006] The rectifier circuit 101, the smoothing capacitor 102, the control power supply circuit 111, the indoor control circuit 112, and the like are mounted on the indoor printed circuit board in the control component box. The indoor print board and the motor internal board are connected by two DC power supply lines 121, two control power supply lines 122, and two data signal lines 123.

 [0007] In such a motor drive device, the adoption force of the Hall elements 105a, 105b, and 105c used for detecting the rotor position increases the cost. Therefore, in recent years, vector control for estimating the rotational position of the rotor and driving the motor by vector calculation based on the current flowing in the motor winding without using a position detection element has begun to be applied (for example, Japanese Patent No. 3672876).

 Disclosure of the invention

 [0008] However, when performing fan motor vector control, a much more complex operation control is required compared to a drive device equipped with a rotor position detection element such as a hall element. Electronic components such as high-performance microcomputers must be used as circuits. Therefore, in addition to the indoor control circuit using a microcomputer, another microcomputer for fan motor vector control is required.

 [0009] Therefore, it is conceivable to adopt one microcomputer having both the function of the indoor control circuit and the function of vector control of the fan motor. However, in this case, when the microcomputer is mounted on the motor internal board as in the conventional device, many wirings for various indoor controls other than the motor originally executed in the indoor control circuit are connected to the motor internal board. It is not realistic. In addition, the temperature of the motor internal board may rise during operation of the motor, which may destroy the microcomputer.

[0010] As a countermeasure, a microcomputer is mounted on the indoor printed circuit board, and the force is also within the motor. It is conceivable to supply a pattern signal for energization control to the partial substrate side. However, in this arrangement, it is necessary to provide six signal lines for supplying pattern signals between the indoor printed board and the motor internal board. In addition, a detection terminal must be prepared on the motor's internal board to detect the winding current for the three phases of the sensorless DC motor. Therefore, even if a single microcomputer has the function of both the indoor control circuit function and the fan motor vector control function, the number of wires between the indoor printed circuit board and the motor internal circuit board can be reduced. There is a problem that will increase more than ever.

 [0011] An object of one aspect of the present invention is to take the above-mentioned circumstances into consideration, and the rotor position detection element requires no squeezing force, and the number of wires can be increased without worrying about destruction of the microcomputer. It is an object of the present invention to provide an air conditioner that can properly drive a sensorless direct current motor that does not cause any trouble.

 [0012] An air conditioner according to an aspect of the present invention includes:

 With indoor fans,

 A sensorless DC motor having a plurality of windings and driving the indoor fan, and vector control based on the current flowing in each winding of the sensorless DC motor, for energization control of each winding of the sensorless DC motor. A microcomputer that generates pattern signals;

 An inverter that switches energization to each winding of the sensorless DC motor by switching according to a pattern signal generated by the microcomputer;

 An indoor printed circuit board provided with both the microcomputer and the inverter;

 Is provided.

 Brief Description of Drawings

 FIG. 1 is an exploded view showing a configuration of a housing of an indoor unit according to an embodiment of the present invention.

 FIG. 2 is a block diagram showing an electric circuit of the indoor unit in one embodiment.

 FIG. 3 is a diagram showing a configuration of an electric circuit of a conventional air conditioner.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

 As shown in FIG. 1, the installation plate 1 is fixed to the indoor wall surface, and the rear plate 2 is pulled and fixed to the installation plate 1. An indoor fan 3 having a horizontally long shape and a crossflow fan power is provided inside the rear plate 2. One end of the indoor fan 3 is supported by a sensorless DC motor (also called a brushless DC motor) 3M, which is a fan motor, and the other end is supported by a bearing 3a. The rear plate 2 is further provided with a heat exchange 4 so as to surround the indoor fan 3, and a front plate 5 is provided so as to cover the heat exchange 4. A decorative plate 6 is provided on the front plate 5, and a filter 7 is detachably mounted between the front plate 5 and the decorative plate 6. A vertical louver 8 and a horizontal louver 9 are provided at the outlet formed at the lower part of the front plate 5 and the lower part of the decorative plate 6. A control component box 50 is mounted on the side of the fan motor 3M of the rear plate 2.

 [0016] An indoor unit is configured from the installation plate 1 by the configuration of the horizontal louver 9 and the control component box 50, and various electric circuits are accommodated in the control component box 50. FIG. 2 shows the indoor printed circuit board 40 accommodated in the control component box 50 and its peripheral circuits.

[0017] An inverter 20 is connected to a commercial AC power supply 10 via a rectifier circuit 11, and the output terminal of the inverter 20 via a connector 13 is connected to a sensorless DC motor 3M U-phase wire Lu, V-phase wire Lv, W Connection line Lw is connected. The inverter 20 converts the DC voltage output from the rectifier circuit 11 into an AC voltage having a predetermined frequency by switching according to control of the control unit 30 described later, and outputs the AC voltage. MOSF ET22u +, 22u-, 22v +, 22v-, 22w +, 22w- switching circuit, current detection resistor 23u connected to the series circuit of MOSFET22u +, 22u_ in this switching circuit, MOSFET22v +, 22v in the switching circuit The current detection resistor 23v is connected to the series circuit of-, and the current detection resistor 23w is connected to the series circuit of MOSFETs 22w + and 22w-. The drive circuit 21 drives each MOSFET of the switching circuit on and off in accordance with a pattern signal supplied from the control unit 30 described later. The drive circuit 21 and the switching circuit are connected by six signal lines (wirings) R1. The inverter 20 and the sensorless DC motor 3M are connected by three energizing lines (wiring) R2. In the current detection resistors 23u, 23v, and 23w, a voltage of a level corresponding to the current flowing in the feeder lines Lu, Lv, and Lw of the sensorless DC motor 3M is generated. [0018] A control power supply circuit 12 is connected to the output terminal of the rectifier circuit 11, and a control operating voltage Vdd output from the control power supply circuit 12 is supplied to a control unit (MCU) 30 using a microcomputer. The power supply terminal and the drive circuit 21 of the inverter 20 are supplied. In this case, the negative side of the power supply terminal of the control unit 30 is connected to the negative power supply line of the inverter 20. Therefore, the negative side of the control unit 30 and the inverter 20 is common, and the control unit 30 directly takes in the voltage generated in the current detection resistors 23u, 23v, 23w, and reads this as a voltage value by the internal AZD conversion function. Can do.

 [0019] The control unit 30 is connected with a display unit 31, an indoor / outdoor communication circuit 32, a louver drive circuit 33, and a light receiving unit 34. The drive circuit 21 of the inverter 20 and current detection resistors 23u, 23 V, 23w is connected. The display unit 31 displays various information related to the operation of the indoor unit. The indoor / outdoor communication circuit 32 transmits and receives data between the control unit 30 and an outdoor unit (not shown). The louver drive circuit 33 drives a louver motor 9M that drives the louver 9. The light receiving unit 34 receives infrared light emitted from a remote control type operating device (referred to as a remote control) 35. The control unit 30 and the drive circuit 21 are connected by six signal lines (wirings) R3 for supplying pattern signals.

 [0020] The control unit 30 detects the currents flowing in the wires Lu, Lv, and Lw of the sensorless DC motor 3M as well as the voltage forces generated in the current detection resistors 23u, 23v, and 23w, and performs vector control based on the detected currents. Generates a pattern signal for controlling the energization of the sensorless DC motor 3M's feeders Lu, Lv, and Lw, reads infrared light from the remote control 35, sends and receives data to and from the outdoor unit, and drives commands to the louver motor 9M. Control various operations of the indoor unit.

 The rectifier circuit 11, the inverter 20, the control power supply circuit 12, the control unit 30, the indoor / outside communication circuit 32, the louver drive circuit 33, and the like are mounted on the indoor printed board 40. This indoor printed circuit board 40 is accommodated in the control component box 50.

 [0022] The control component box 50 has a flow path of wind generated by the operation of the indoor fan 3. The control unit 30 on the indoor printed circuit board 40 corresponds to the windward side of the flow path, and the indoor print is on the leeward side. The indoor printed board 40 is accommodated so that the inverter 20 on the board 40 corresponds.

[0023] As described above, the sensor-less DC motor 3M's winding lines Lu, Lv, By providing a control unit 30 that generates a pattern signal for energization control for Lw and controls the operation of the indoor unit, and adopting a microcomputer as the control unit 30, a single microcomputer can be used for the sensorless DC motor 3M. Can be driven properly.

 [0024] Since the control unit 30 is provided on the one indoor printed board 40 together with the inverter 20, the wiring derived from the indoor printed board 40 is only the energization line R2 between the inverter 20 and the sensorless DC motor 3M. By reducing the number of wires derived from the indoor printed circuit board 40, the effects of noise can be reduced and costs can be reduced.

 [0025] Since the control unit 30 is not mounted on a sealed motor internal substrate as in the prior art, there is no concern about destruction of the control unit 30 due to heat.

 [0026] Further, in the indoor printed circuit board 40, the mounting position of the control unit 30 and the position of the connector 13 are separated as much as possible, and the control unit 30 that is a microcomputer is connected to the energization line between the inverter 20 and the sensorless DC motor 3M. It is located away from R2. This makes it difficult for noise generated from the energization line R2 to reach the control unit 30, which is a detailed electronic component. In this respect as well, an abnormal stop or malfunction can be avoided, and the control unit 30 can always operate stably.

 [0027] Generates pattern signals for energization control for the sensor-less DC motor 3M's feeder lines Lu, Lv, Lw by vector control based on the current values flowing in the motor feeders captured by the current detection resistors 23u, 23v, 23w Because of the configuration, the conventional rotor position detecting element is unnecessary, and the cost can be reduced. There is no risk of malfunction due to a failure of the rotor position detection element.

[0028] Since the wind generated by the operation of the indoor fan 3 flows into the control component box 50, the control unit 30 exists on the windward side of the ventilation path, and the inverter 20 exists on the leeward side. The heat generated by each of the 20 MOSFETs and the current detection resistance does not hit the control unit 30 and is efficiently discharged without being trapped in the control component box 50. As a result, stable operation of the control unit 30 becomes possible, and the reliability of control is greatly improved. In addition, by ensuring good air permeability of the control component box 50, it is possible to reduce the specifications regarding the heat resistance of the components mounted on the indoor printed circuit board 40. This leads to reduced component costs [0029] Since the power supply terminal of the control unit 30 is connected to the negative power supply line of the negative power inverter 20, the circuit configuration for current detection by the current detection resistors 23u, 23v, 23w is simplified. . Also in this respect, the influence of noise can be reduced, and the reliability of control is improved.

 [0030] In the above embodiment, the force is such that the current detection resistors 23u, 23v, and 23w are inserted into each series circuit of the inverter 20, as shown by the broken line in FIG. The current detection resistor 24 is inserted into the line, and the voltage generated in the current detection resistor 24 is supplied to the control unit 30 to detect the current flowing through the sensor-less DC motor 3M's feeder lines Lu, Lv, and Lw. Also good.

 In addition, the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

 Industrial applicability

The present invention can be applied to an air conditioner including a sensorless DC motor that drives an indoor fan.

Claims

The scope of the claims  [1] With indoor fans,  A sensorless DC motor having a plurality of windings and driving the indoor fan, and vector control based on the current flowing in each winding of the sensorless DC motor, for energization control of each winding of the sensorless DC motor. A microcomputer that generates pattern signals;  An inverter that switches energization to each winding of the sensorless DC motor by switching according to a pattern signal generated by the microcomputer;  An indoor printed circuit board provided with both the microcomputer and the inverter;  An air conditioner characterized by having!  2. The air conditioner according to claim 1, further comprising an indoor unit in which the indoor fan is accommodated.  [3] The air conditioner according to [2], wherein the microcomputer further controls an operation of the indoor unit. 4. The air conditioner according to claim 1, further comprising wiring for connecting the inverter and the sensorless DC motor. 5. The air conditioner according to claim 4, wherein the microcomputer on the indoor printed circuit board is provided at a position away from the wiring! [6] A flow path of wind generated by the operation of the indoor fan is provided, a microcomputer on the indoor printed circuit board is positioned on the windward side of the flow path, and the indoor print board is positioned on the leeward side of the flow path. 2. The air conditioner according to claim 1, further comprising an electric component box that accommodates the indoor printed circuit board so that the inverter is positioned. 7. The microcomputer has a power supply terminal to which a DC voltage for operation is input, and the negative side of the power supply terminal is connected to the negative power supply line of the inverter. Air conditioner as described in.