JPS6356190A - Protective device of brushless motor - Google Patents

Abstract

PURPOSE:To prevent semiconductors against destruction, by checking turning ON of all the semiconductor switching elements in case the DC voltage value is higher than the definite value, and by turning OFF the semiconductor switching elements in a definite time in case the DC voltage is lower than the definite one and the DC current value exceeds the definite value. CONSTITUTION:The DC voltage value between upper and lower arms of semiconductor group 2 is detected by a DC voltage detecting means 7. When this voltage value is decided to be above the definite value by a DC voltage judging means 8, all the elements of semiconductor switching group 2 are caused not to turn ON. When the DC voltage value is lower than the definite value and the value of the current flowing to the semiconductor switching group 2 is determined to be above the definite value by a DC current detecting means 9 and a DC current judging means 10, all the elements of semiconductor switching group 2 are turned OFF in a definite time by a timer means 11.

Description

[Detailed description of the invention] Industrial applications The present invention provides a brushless motor, for example, a Y adjustment machine.

The present invention relates to a brushless motor protection device when applied to driving an outdoor fan.

BACKGROUND OF THE INVENTION In recent years, efforts have been made to improve the operating efficiency of fan drive motors with the aim of operating air conditioners more efficiently. Therefore, the conventionally used induction motors are being replaced with brushless motors, which have higher operating efficiency.

Particularly in Separate Air Conditioners (9), many of the indoor fan motors are brushless motors, and brushless motors for the outdoor side will continue to be considered in the future.

Problems to be Solved by the Invention When a brushless motor is used as a motor for driving an outdoor fan of a separate air conditioner, the fan is forcibly driven from outside by abnormal wind force such as during a typhoon. This has the drawback that an excessive induced voltage is generated within the brushless motor, causing a short-circuit current to flow within the motor windings, which can destroy semiconductors.

Means for Solving the Problems In order to solve the above problems, the brushless motor protection device of the present invention includes DC voltage detection means for detecting DC voltage between the upper and lower arms of the semiconductor switching group that controls the motor winding current; DC voltage determination means for determining whether the output of the DC voltage detection means exceeds a certain value; DC current detection means for detecting the DC current flowing through the semiconductor switching group; and a timer means to hold the output of the DC current determining means for a certain period of time, and when the DC voltage value exceeds a certain value, all elements of the semiconductor switching group are turned on. In addition, if the DC voltage value is below a certain value and the DC current value exceeds a certain value during operation, all elements in the holding body switching group will be turned off for a certain period of time.
The configuration is such that the

Function: According to the brushless motor protection device of the present invention, even if the fan is forcibly driven from the outside due to abnormal wind power such as during a typhoon, short-circuit current will not flow through the motor windings, and semiconductors will not be overloaded. This can prevent damage caused by electric current.

Example Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 is a basic configuration diagram of the present invention, and in the figure, 1
2 is a semiconductor switching group for controlling the current flowing through the winding a of the brushless motor, and 4 is the rotor of the brushless motor, which is composed of a permanent magnet. 5 is a phase detection means for detecting the magnetic pole position of the rotor 4; 6 is a drive for generating a signal necessary for rotating the rotor 4 in a certain direction based on the output signal of the phase detection means 5 and outputting it to the semiconductor switching 2; means, 7 is a DC voltage detection means for detecting the DC voltage value between the upper and lower arms of the semiconductor switching group 2; 8 is a DC voltage detection means for determining force 1 whether the DC voltage value detected by the DC voltage detection means 7 exceeds a certain value; Voltage.”
It is a means of disconnection. Further, reference numeral 9 indicates a DC current detection means for detecting the value of the DC current flowing through the semiconductor switching group 2, 10 indicates a DC current determination means for determining whether the DC current value detected by the DC current detection means 9 exceeds a certain value, and 11 is a timer means for holding the output of the DC current determining means 10 for a certain period of time.

FIG. 2 is a configuration diagram of an outdoor unit of an air conditioner.

In the figure, 15 is a propeller fan, 16 is a brushless motor, and 17 is a heat exchanger. Turning on and off the semiconductor switching group when rotating the brushless motor 16 in a certain direction to cool the heat exchanger 17
The state will be explained with reference to FIGS. 4 and 5. FIG. 4 shows the state when the brushless motor 16 is rotated in the forward direction by external wind power, and in this state, there is no current in the motor winding 3. does not flow, and the DC voltage VDC between the upper and lower arms of the semiconductor switching group 2 simply increases.

- Figure 5 shows the state when the brushless motor 16 is rotated in the opposite direction by external wind power. In this state, the short circuit current (linear and wavy arrows) flow. Naturally, this current increases as the number of rotations of the brushless motor 16 increases, eventually causing wave damage in the semiconductor switching group. Therefore, when the outside wind speed exceeds a certain level or the rotational speed of the brushless motor exceeds a certain level, all elements of the semiconductor switch group 2 must be kept in the OFF state and never turned ON.

FIG. 3 shows that all elements of semiconductor switching group 2 are OF.
In state F, when the brushless motor 16 is rotated by external wind power, the relationship between the rotation E& of the brushless smoke 16 and the DC voltage VDC appearing between the upper and lower arms of the semiconductor switch group 2 with respect to the wind power is shown. In the present invention, the strength of the external wind force is detected by the DC voltage VDC, and when it exceeds a certain value, all the elements of the semiconductor switch group 2 are kept in the FF state, and when the VDC is below the certain value, the brushless motor 16 When the load on the brushless motor 16 increases due to an increase in external wind power while the motor is in operation, the load condition is detected by the DC current detection means 9, and all semiconductor switching groups 2 whose DC current value exceeds a certain value are By turning off the element for a certain period of time, excessive current flowing through the winding 3 and the semiconductor switching group 2 of the brushless motor 16 is prevented, and at the same time, pinching is also prevented.

The flowchart in FIG. 6 is shown.

FIG. 7 shows a specific embodiment in which the DC voltage between the upper and lower arms of the semiconductor switching group 2 is detected by resistors 21 and 22, compared with the reference voltage 26 by the comparator 23, and when the DC voltage value exceeds a certain level. or resistance 28
．． 29.30 detects the DC current, compares it with the reference voltage 34 and the comparator 31, and when the DC current value exceeds a certain value, the monostable multipipe rake 32 holds the output signal of the comparator a1 for a certain period of time. As a result, the power supply of the IC 25 which incorporates the functions of the phase detection means 5 and the driving means 6 is kept at 0FFL by the transistor 24, and all the elements of the semiconductor switching group 2 are kept in the OFF state.

As described in detail, the brushless motor protection device of the present invention has the following features:
In a system in which a brushless motor is applied to drive an outdoor fan of an air conditioner, there is provided a DC voltage detection means for detecting the DC voltage between the upper and lower arms of a semiconductor switching group that controls the motor winding current, and whether the DC voltage value exceeds a certain value. a DC voltage determining means for determining the DC current flowing through the switching element group, a DC current determining means for determining whether the DC current value exceeds a certain value, and an output of the DC current determining means. A timer means is provided to hold the voltage for a certain period of time, and when the DC voltage value is above a certain value, all elements of the semiconductor switching group are kept in the OFF state.In other words, only when the DC voltage value is below a certain value is the condition for starting operation of the brushless motor. Furthermore, when the load increases during operation, the load condition is detected by DC current, and if the DC current value exceeds a certain value, all elements of the semiconductor switching group are turned off for a certain period of time. Even if the brushless motor is forcibly rotated by abnormal external wind force, as in .

[Brief explanation of drawings]

Figure 1 is a basic configuration diagram of the brushless motor protection device of the present invention, Figure 2 is a configuration diagram of the outdoor unit of an air conditioner, and Figure 3 is the brushless motor protection device of the present invention in which all elements of the semiconductor switch group are in an OFF state. Figure 4 is a state diagram of the same brushless smoke protection device during forward rotation, and Figure 5 is a state diagram of the same brushless smoke protection device during reverse rotation. FIG. 6 is a 70-chart of the brushless smoke protection device, and FIG. 7 is a circuit diagram showing an embodiment of the brushless smoke protection device. 2... Semiconductor switching group, 5...
Phase detection means, 6... Drive means, 7...
...DC voltage detection means, 8... Judgment means, 9.
. . . DC current detection means, 10 . . . DC current judgment means, 11 . . . Timer means. Name of agent: Patent attorney Toshio Nakao and one other person? −
--Semiconductor Zuitte 3 Sheep 5-I L phase, Kenfu ■Child role 1O-Ella L Motsu Kisenshiko role 1 Figure 11-11 Dimer hand role 2
Figure 1/. No. 30 Kazeyari No. 4 Ward No. 6

Claims (1)

[Claims] a semiconductor switching group that controls motor winding current;
A phase detection means for detecting the magnetic pole position of the rotor, which is composed of a permanent magnet, and a signal necessary for rotating the rotor in a certain direction based on the output signal of the phase detection means, and outputting the signal to the semiconductor switching group. a driving means, a DC voltage detection means for detecting a DC voltage between the upper and lower arms of the semiconductor switching group, and a voltage determination means for determining whether the DC voltage value detected by the DC voltage detection means exceeds a certain value; DC current detection means for detecting the DC current flowing through the semiconductor switching group; DC current judgment means for determining whether the DC current value exceeds a certain value; and a timer for holding the output signal of the DC judgment means for a certain period of time. means for turning on the semiconductor switching group element when the DC voltage value is equal to or higher than a certain value.
In addition to not allowing short-circuit current to flow through the motor windings,
A brushless motor protection device configured to turn off the semiconductor switching element for a certain period of time if the DC current value exceeds a certain value during operation when the DC voltage value is below a certain value.