JP3140030B2 - Lock alarm device for brushless motor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a lock alarm device for a brushless motor,
In particular, the present invention relates to a device that issues an alarm to the outside when the motor stops rotating for some reason.

2. Description of the Related Art In recent years, small DC motors have been recognized for their good controllability not only in the acoustic field but also in the information and industrial fields, and their applications are expanding at an extremely rapid pace. Among them, a brushless motor has no contact portion such as a brush and a commutator and has an advantage of a long life, and therefore its use as an industrial motor in which reliability is particularly important is expanding.

Under these circumstances, the driving method of small axial fans has been switched from AC to DC in recent years, and DC axial fans using brushless motors have been increasing.

As the mounting density of industrial equipment such as computer-related equipment becomes higher, the DC axial-flow fan is required to be used for cooling the fan and to have higher reliability. In other words, if the motor stops for some reason, it will of course prevent the motor coil from burning.
In addition to issuing an alarm to the device body to prevent an accident from occurring, it has been required to automatically return to normal rotation when the cause is removed.

In FIG. 3, a magnetic detection circuit 1, a position signal amplification circuit 3,
The output circuit 3 and the coil 4 constitute a fan driving motor. In this case, if the motor is stopped due to an external factor or is operating at a low speed in an overload state, the coil 4 is burned out due to an excessive current and the motor cannot function. In order to eliminate these problems, the output circuit 3 is cut off by the following circuit configuration so that an excessive current does not flow. That is, reference numeral 5 denotes transistors 10 and 11 constituting an operational amplifier having a resistor 12 as a load, and transistors 15 and 16 constituting a differential amplifier having an active load having transistors 17 and 18 constituting a current mirror circuit. And the above resistor 12
A pulse output from the common collector is generated in synchronism with the rotational position of the rotor by a rotation pulse circuit composed of the transistors 13 and 19 sharing the collector receiving the signal from the transistor 18. 6 is an inversion detection transistor 25
A flip-flop circuit that receives a signal from the inverter 29 and stores a charge and connects the capacitor 22 to a constant current source 23 to be in a charged state, or is connected to a constant current source 24 to be in a discharged state. 7 is a resistor that determines hysteresis 26
When the rotor is locked by a lock detection circuit composed of the inverter 27, the comparator 28 and the inverter 29, and the potential of the capacitor 22 rises to the point A of the second (a), the lock protection transistor 30 is driven and output. Shut off circuit 3,
When the output circuit 3 descends to the point C, the output circuit 3 is output so as to be energized. Under normal conditions, the discharge transistor 21 discharges the charge of the capacitor 22 by the pulse output from the rotation pulse circuit 5. Reference numeral 41 denotes a lock warning transistor which receives a signal from the lock detection circuit and outputs an H level signal when locked. 9, 14, and 20 are constant current sources.

 The operation at this time will be described with reference to FIG.

In Figure 2, (a) represents the shows the state of charging and discharging of the capacitor 22, since the steady regular rotation pulse signal exits by T ₁ interval potential of the capacitor 22 is the output circuit It does not reach the potential V _OFF for blocking 3.
Therefore, the motor continues to rotate without stopping. on the other hand,
When the motor stops due to an external factor, the potential of the capacitor 22 continues to rise and reaches the point A. When the point A is reached, the lock detection circuit 7 operates and shuts off the output circuit 3 via the lock protection transistor 30. When the potential further rises and reaches point B, ie, V _H = V _refl + V _BE , the inversion detection transistor 25 _operates to switch the contact point of the flip-flop circuit 6 to the constant current source 24 side, and the capacitor 22 Is discharged. Therefore, the potential continues to drop and reaches point C. Then, the lock detection circuit 7 operates to activate the output circuit 3 via the lock protection transistor 30 and at the same time switch the contact of the flip-flop circuit 6 to the constant current source 23 side. When the potential of the capacitor 22 continues to rise again and reaches the point D, the same operation as at the point A is performed. During this time, the motor repeatedly turns off and on at intervals of T ₃ and T ₄ until an external factor is removed. If external factors are removed in the interval T ₄ motor is energized to generate a rotation pulse. With this pulse, the discharging transistor 21 operates and the capacitor 22 is discharged, returning to a steady state. (B) shows the operation of the lock alarm circuit 41 corresponding to (a). In this case, while the rotor is locked and the lock protection circuit 30 shuts off the output circuit 3, the alarm circuit 41 outputs an "H" level. Conversely, when the lock protection circuit is released, the output of the alarm circuit 41 is output. Becomes “L” level.

Problems to be Solved by the Invention As described with reference to FIG.
There outputs "H" level signal when operating but the interval T ₄ to restart pulse is generated the "L" level, it is difficult processing of the output signal. With respect to such a problem, the present invention outputs a signal of only "H" (or "L") level until the rotor is locked and the lock protection circuit operates once and then the cause is removed and a rotation pulse is generated. It is intended to facilitate the processing of the output signal.

Means for Solving the Problems The present invention is connected to a position signal amplification circuit and generates a pulse in synchronization with the rotation position of the rotor, a rotation pulse circuit, a capacitor, and in synchronization with an output signal of the rotation pulse circuit. A discharging transistor for discharging the capacitor, a charging constant current source for charging the capacitor, a discharging constant current source for discharging the capacitor, and transistors for the charging constant current source and the discharging constant current source. A flip-flop circuit provided with a switch to hold the capacitor in a charged state or a discharged state, an inversion transfer transistor for inverting the flip-flop circuit at a timing when the capacitor transitions from a charged state to a discharged state, and the capacitor Lock detection with hysteresis that detects the terminal voltage of the coil and controls ON / OFF of the output circuit connected to the coil A lock alarm circuit for a brushless motor, comprising a circuit and a lock alarm circuit that outputs an alarm signal based on signals from the rotation pulse circuit and the lock detection circuit. A signal (for example, “L”) indicating normality is output by a signal. On the other hand, when the terminal voltage of the capacitor rises to the first potential in the charged state when the motor is locked, the output circuit is cut off and the lock detection circuit A signal (for example, “H”) indicating an abnormality is output by the output signal, and further, when the cause of the lock failure is removed, the output circuit is driven when the terminal voltage of the capacitor falls to the second potential in the discharged state, The output signal of the rotation pulse circuit outputs a signal indicating normality (for example, “L”).

Operation With this configuration, once the rotor locks and receives a signal from the lock detection circuit, this state is maintained until the next signal is received from the rotation pulse circuit, and the influence of the restart pulse is not received.

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the circuit configuration of the magnetic detection circuit 1,
The position signal amplifier circuit 2, the output circuit 3, and the coil 4 constitute a fan drive motor. The rotation pulse circuit 5, the flip-flop circuit 6, and the lock detection circuit 7 have the same configuration as the conventional example. Detailed description of the same operations as those described above is omitted.

Reference numeral 8 denotes resistors 34 and 3 constituting a flip-flop circuit.
5.Transistors 32, 33, 36 and 37 and output transistor 39
A signal from the lock detection circuit 7 and the rotation pulse circuit 5 is received and output from the transistor 39. 9, 14, 20, 31, and 38 are constant current sources.

FIG. 2C shows the operation of the lock alarm circuit 8. In a steady state, the transistor 36 is turned off by the transistor 32 by the pulse output from the rotation pulse circuit 5, and the output transistor 39 is set to the "L" level. Output. At this time, when the rotor is locked, the rotation pulse circuit stops outputting the rotation pulse, and the potential of the capacitor 22 rises.
When the voltage rises to the point A, the lock detection circuit 7 operates to turn on the transistor 37. Therefore, the flip-flop circuit in the lock detecting circuit 8 is inverted, the transistor 36 is turned on, and the output transistor 39 outputs "H" level. Even if the potential of the capacitor 22 drops to the point C and the output of the lock detecting circuit 7 goes to "L" level to try to energize the motor, the rotor is locked and there is no output from the rotation pulse circuit. Therefore, the flip-flop circuit in the lock detection circuit 8 keeps outputting "H" level without being inverted. Next, when an external factor is removed, the potential of the capacitor drops to the second potential (point C) in the discharged state, the output circuit is driven, the motor rotates, and the rotation pulse circuit operates. By the pulse output at this time, the flip-flop circuit in the lock detecting circuit 8 is again inverted and returns to the original state, and the output transistor 39 becomes "L" level.

Effect of the Invention As described in detail above, according to the present invention, the alarm output generated when the rotor is locked is an output of only the "H" (or "L") level, which facilitates the subsequent circuit processing and reduces the number of parts. The effect such as reduction is significant.

[Brief description of the drawings]

FIG. 1 is a circuit configuration diagram of one embodiment according to the present invention, FIG. 2 is an operation explanatory diagram, and FIG. 3 is a circuit configuration diagram of a conventional example. 1 ... magnetic detection circuit, 2 ... position signal amplifier circuit, 3 ...
Output circuit, 4 ... Coil, 5 ... Rotary pulse circuit, 6 ...
... Flip-flop circuit, 7 ... Lock detection circuit, 8
…… Lock alarm circuit, 21 …… Discharge transistor, 22…
... capacitors for storing electric charges, 25 ... inversion detection transistors.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02P 6/00 H02H 7/00

Claims (1)

(57) [Claims] A rotation pulse circuit connected to a position signal amplification circuit for generating a pulse in synchronization with a rotation position of a rotor;
A capacitor, a discharging transistor for discharging the capacitor in synchronization with an output signal of the rotation pulse circuit, a charging constant current source for charging the capacitor, a discharging constant current source for discharging the capacitor, A flip-flop circuit that provides a transistor switch for the constant current source and the constant current source for discharging and holds the capacitor in a charged state or a discharged state; and the flip-flop circuit switches the capacitor from a charged state to a discharged state. An inversion detection transistor for inverting the flop circuit, a lock detection circuit with hysteresis for detecting the terminal voltage of the capacitor and controlling ON / OFF of an output circuit connected to the coil, and the rotation pulse circuit and the lock detection circuit. Of a brushless motor consisting of a lock alarm circuit that outputs an alarm signal according to the signal of A click alarm device, the lock alarm circuit during steady rotation outputs a single signal representative of the normal by an output signal of the rotational pulse circuit, whereas at the time of motor lock the first terminal voltage state of charge of the capacitor
When the potential of the capacitor rises, the output circuit is cut off and a single signal indicating an abnormality is output by the output signal of the lock detection circuit. The output is output when the terminal voltage of the capacitor falls to the second potential in the discharged state. Even when the circuit is driven, the state is maintained, and when the cause of the lock failure is removed and the terminal voltage of the capacitor falls to the second potential in the discharged state, the output circuit is driven only when the output circuit is driven. A lock alarm device for a brushless motor in which a single signal indicating normality is output by an output signal.