JP4515115B2 - Synchronous induction motor protection device, compressor, refrigeration cycle device - Google Patents

Description

  The present invention relates to a protection device for a synchronous induction motor that uses a reluctance torque to start using an induction torque without using a permanent magnet in a rotor, and a compressor using a synchronous induction motor including the protection device, And a refrigeration cycle apparatus using the compressor.

  In a synchronous induction motor, if there is a large load fluctuation, voltage drop, pull-in failure, etc., it will lead to a step-out state such as an operating state driven at a rotational speed other than the synchronous rotational speed or an operating state that vibrates without rotating. There is a case. When the step-out state occurs, an excessive current exceeding a specified value flows and causes the motor to burn out. Therefore, it is necessary to provide a means for detecting the step-out state and protect the motor from the burn-out.

  For example, in Patent Document 1 and Patent Document 2, in a compressor using a synchronous induction motor of a type that uses a permanent magnet as a rotor (sealed electric compressor), the synchronous induction motor and the compressor are protected from an abnormal temperature rise. Technology is disclosed.

  That is, in Patent Document 1, a current-sensitive protection means for detecting a line current is provided in the power supply circuit of the stator winding. This protection means comprises a line current detector for detecting a line current and a protection switch connected in series to the other of the main windings. The line current detector is configured such that when a predetermined current set in advance is detected, the protection switch is operated to cut off the power supply to the stator winding.

  Further, in Patent Document 2, when the temperature of the compressor becomes high, the temperature of the stator winding rises, and the thermistor changes its resistance value to detect the temperature rise of the stator winding. The controller is configured to pass a current through the control relay coil when the detected temperature is higher than a preset temperature, and to open the control relay contact to cut off the energization of the stator winding.

  Conventionally, in an induction motor, a bimetal is disposed in the power supply line of the motor, and when the bimetal detects abnormal heat generation of the motor coil or abnormal temperature rise in the compressor storing the motor, the stator circuit is opened. The method of stopping the motor is adopted.

JP 2001-275286 A JP 2001-295367 A

  By the way, in a compressor and a refrigeration cycle apparatus using the same, a synchronous induction motor that starts using an induction torque without using a permanent magnet for a rotor and performs a synchronous operation using a reluctance torque is also used. In order to provide a high-quality and safe synchronous induction motor that does not use a permanent magnet for the rotor, a method for detecting and stopping the step-out is necessary, but it has not yet been proposed. Absent.

  As a method of protecting a synchronous induction motor that does not use a permanent magnet for the rotor, the techniques described in Patent Documents 1 and 2 are insufficient. Further, in the method using bimetal, it takes a considerable time from the occurrence of the step-out until the current is actually cut off and the electric motor is stopped. Therefore, there is a problem that noise and vibration become very large during the operation time, and the electric motor and the compressor storing it are damaged.

  The present invention has been made in view of the above, and a synchronous induction motor that can quickly detect a step-out state of a synchronous induction motor of a type that does not use a permanent magnet for a rotor and prevent burnout or the like in advance. It is an object of the present invention to provide a protective device, a compressor using a synchronous induction motor equipped with the protective device, and a refrigeration cycle apparatus using the compressor.

In order to achieve the above object, a protection apparatus for a synchronous induction motor according to the present invention starts out using an induction torque without using a permanent magnet in a rotor and performs a step-out of a synchronous induction motor that operates synchronously using a reluctance torque. A detection unit that detects a state; and a control unit that stops the synchronous induction motor when the detection unit detects a step-out state.

  According to the present invention, it is possible to quickly detect the step-out state of a synchronous induction motor of a type that does not use a permanent magnet for the rotor and to stop the synchronous induction motor. it can.

  According to the present invention, it is possible to prevent burnout or the like due to step-out of a synchronous induction motor of a type that does not use a permanent magnet for the rotor, so that it is possible to obtain a high-quality and safe synchronous induction motor. .

  Exemplary embodiments of a protection device for a synchronous induction motor according to the present invention, a compressor using a synchronous induction motor including the protection device, and a refrigeration cycle device using the compressor will be described in detail below with reference to the drawings. Explained.

  Prior to the description of each embodiment, a synchronous induction motor of the type that does not use a permanent magnet for the rotor according to the present invention will be schematically described with reference to FIGS. FIG. 1 is a cross-sectional view showing the structure of a rotor of a synchronous induction motor of a type that does not use a permanent magnet for the rotor that is the subject of the present invention. FIG. 2 is a perspective view showing an appearance of the rotor shown in FIG.

  In FIG. 1, the code | symbol 1 is the rotor core comprised by laminating | stacking the electromagnetic steel plate about 0.1-1 mm thick. Reference numeral 2 denotes a slit which is filled with, for example, aluminum (shown by a lattice display) as a conductive material, which is a nonmagnetic material. Reference numeral 3 denotes a slot provided in the vicinity of the outer peripheral portion of the rotor core 1 and filled with aluminum (indicated by a lattice display) in the same manner as the slit 2. Reference numeral 4 denotes a strip formed between adjacent slits 2. Reference numeral 5 denotes a thin portion formed on the outer peripheral portion of the rotor core 1 and connected by a thin portion of about 0.1 to 2 mm, for example. Reference numeral 6 denotes a shaft fixed to the rotor core 1 by press fitting or shrink fitting. In FIG. 1, the vertical direction is the q axis indicating the direction in which the magnetic flux does not easily flow, and the horizontal direction is the d axis indicating the direction in which the current easily flows.

  As shown in FIG. 2, first and second end rings 7 a and 7 b are formed at both ends of the rotor core 1 in the stacking direction. The conductive material (in this case, aluminum) that forms the slit 2 and the slot 3 and the end rings 7a and 7b is produced by a die casting method, but the slot 3 and the end rings 7a and 7b are electrically connected by the conductive material. Are connected to each other to form a cage-shaped secondary conductor.

  In this type of synchronous induction motor that does not use a permanent magnet for the rotor, when a current is passed through a stator winding (not shown), an induced current flows through the cage secondary conductor of the rotor and a starting torque is generated. And can be started. In the rotor, when the slit 2 filled with a non-magnetic material is arranged as shown in FIG. 1, the d-axis that is the direction in which the magnetic flux easily flows and the q-axis that is the direction in which the magnetic flux does not easily flow A difference occurs, and the magnetic flux generated by a stator winding (not shown) forms a magnetic pole projection depending on the position of the rotor. Since the reluctance torque is generated by the magnetic pole projection, synchronous operation is possible.

  Here, aluminum that is a non-magnetic material and used as a conductive material shows a configuration in which both the slit 2 and the slot 3 are filled, but it is sufficient that at least the slot 3 is filled. The structure which is not filled may be sufficient. This also forms the d-axis and the q-axis.

  With the above configuration, when a synchronous induction motor is operated with a 50 Hz or 60 Hz commercial power supply connected to the stator winding, a secondary current flows through the squirrel-cage secondary conductor, requiring a special starting device. Therefore, it is possible to obtain a low-cost synchronous induction motor. Moreover, since it has a magnetic pole protrusion, synchronous operation is possible and a highly efficient synchronous induction motor with reduced secondary copper loss can be obtained.

Embodiment 1 FIG.
FIG. 3 is a block diagram showing the configuration of the protection device for a synchronous induction motor according to the first embodiment of the present invention. In this specification, step-out means that the synchronous induction motor is in an operating state in which the synchronous induction motor is driven at a rotational speed other than the synchronous rotational speed, or is in an operating state in which the synchronous induction motor vibrates without rotating. Suppose you are. These step-out states occur due to large load fluctuations, voltage drop, synchronization pull-in failure, and the like. When this occurs, an overcurrent flows through the synchronous induction motor, and vibration occurs and noise is generated.

  The protection device shown in FIG. 3 detects the vibration of the circuit breaker 12 arranged on the power supply line from the AC power supply 10 to the synchronous induction motor 11 of the type that does not use a permanent magnet for the rotor described above, and the synchronous induction motor 11. And a control unit 14 that turns off the circuit breaker 12 when the vibration state detected by the vibration detection unit 13 indicates a step-out state.

  The AC power supply 10 is a three-phase power supply in the illustrated example. When a single-phase power source is used, it is preferable to interpose a capacitor between the main winding and the auxiliary winding. The vibration detection unit 13 is disposed at a place where vibration of the synchronous induction motor 11 is directly transmitted, such as a motor case of the synchronous induction motor 11 and a side surface of a compressor that stores and uses the synchronous induction motor 11. The circuit breaker 12 is configured with, for example, a relay as a main element. The control unit 14 includes a comparator and a circuit that prevents a malfunction of the comparator as main elements.

  In the above configuration, when the synchronous induction motor 11 is oscillated without rotating, that is, when the stepping out occurs, the vibration level detected by the vibration detection unit 13 becomes higher than that in the steady state. Therefore, the control unit 14 uses, for example, a setting value that is twice the steady-state vibration level as the setting value of the comparator, and when the detected vibration level of the vibration detection unit 13 exceeds the set value, the relay of the circuit breaker 12 is turned off. Thus, the synchronous induction motor 11 can be stopped by interrupting the drive current supplied to the synchronous induction motor 11.

  Here, when the synchronous induction motor 11 is started, vibration may occur. When the vibration level at that time exceeds the set value of the comparator, the same operation as described above is performed. The operation in this case is a so-called malfunction. As a circuit for preventing this malfunction, the control unit 14 is provided with, for example, any one of the following first circuit, second circuit, and third circuit.

  That is, the first circuit is a reset circuit that resets the comparator for a predetermined time when the power is turned on. The second circuit is a delay circuit that delays the vibration detection signal input to the comparator when the power is turned on by a predetermined time. The third circuit is a timed circuit provided between the comparator and the relay of the circuit breaker 12. That is, the relay of the circuit breaker 12 is turned off when the signal output from the comparator for turning off the relay of the circuit breaker 12 continues for a certain time (for example, 0.5 seconds) or longer.

  As described above, according to the first embodiment, when the vibration level is monitored and it is detected that the synchronous induction motor has reached the step-out state due to a large load fluctuation, voltage drop, or pull-in failure, the synchronization is immediately performed. Since the drive current of the induction motor can be cut off, the synchronous induction motor can be quickly stopped. Therefore, increase in vibration and noise can be suppressed, and burning due to overcurrent can be prevented in advance. In addition, in the compressor that stores the synchronous induction motor, it is possible to prevent damage to the compressor and to suppress increase in vibration and noise.

Embodiment 2. FIG.
FIG. 4 is a block diagram showing a configuration of a protection device for a synchronous induction motor according to Embodiment 2 of the present invention. In FIG. 4, the same or similar components as those shown in FIG. 3 (Embodiment 1) are denoted by the same reference numerals. Here, the description will focus on the parts related to the second embodiment.

  That is, as shown in FIG. 4, in the second embodiment, in the configuration shown in FIG. 3 (first embodiment), a control unit 15 is provided instead of the control unit 14.

  The control unit 15 includes a frequency analysis circuit that analyzes the frequency of the vibration detected by the vibration detection unit 11, a determination circuit that determines whether the analyzed frequency matches the frequency at the normal time, and a frequency other than the frequency at the normal time. An output circuit that turns off the relay of the circuit breaker 12 in the case of a frequency and a circuit that prevents a malfunction that erroneously turns off the relay of the circuit breaker 12 are configured as main elements.

  In the above configuration, when the synchronous induction motor 11 is oscillated without rotating, that is, when it is out of step, the frequency of vibration detected by the vibration detection unit 13 is analyzed by the frequency analysis circuit of the control unit 15. When the determination circuit determines that the frequency is different from the normal frequency, a signal for turning off the relay of the circuit breaker 12 is output from the output circuit. That is, as in the first embodiment, the synchronous induction motor 11 can be stopped by interrupting the drive current supplied to the synchronous induction motor 11.

  Here, when the synchronous induction motor 11 is started, vibration may occur, and therefore the frequency analysis circuit of the control unit 15 similarly performs frequency analysis. When the analysis frequency at that time is different from the steady-state frequency, the same operation as described above is performed. The operation in this case is a so-called malfunction. As a circuit for preventing this malfunction, the controller 15 is provided with, for example, any one of the following first circuit, second circuit, and third circuit.

  That is, the first circuit is a reset circuit that resets the frequency analysis circuit for a predetermined time when the power is turned on. The second circuit is a delay circuit that delays the vibration detection signal input to the frequency analysis circuit when the power is turned on by a predetermined time. The third circuit is a timed circuit provided between the output circuit and the relay of the circuit breaker 12. That is, the relay of the circuit breaker 12 is turned off when the signal for turning off the relay of the circuit breaker 12 output from the output circuit continues for a certain time (for example, 0.5 seconds) or longer.

  As described above, according to the second embodiment, when the vibration frequency is monitored and it is detected that the synchronous induction motor has reached the step-out state due to a large load fluctuation, voltage drop, or pull-in failure, the synchronization is immediately performed. Since the drive current of the induction motor can be cut off, the synchronous induction motor can be quickly stopped. Therefore, the same operation and effect as in the first embodiment can be obtained.

Embodiment 3 FIG.
FIG. 5 is a block diagram showing a configuration of a protection device for a synchronous induction motor according to Embodiment 3 of the present invention. In FIG. 5, the same or similar components as those shown in FIG. 3 (Embodiment 1) are denoted by the same reference numerals. Here, the description will be focused on the portion related to the third embodiment.

  That is, as shown in FIG. 5, in the third embodiment, in the configuration shown in FIG. 3 (Embodiment 1), current detection for detecting the supply current to the synchronous induction motor 11 instead of the vibration detector 13 is performed. A portion 16 is provided.

  In the above configuration, when the synchronous induction motor 11 is in an operation state where the synchronous induction motor 11 is driven at a rotational speed other than the synchronous rotational speed, that is, when the step out occurs, a large current that is not in a steady state flows through the synchronous induction motor 11. Therefore, the control unit 17 uses, for example, a setting value that is twice the steady-state current level as the setting value of the comparator, and when the detected current level of the current detection unit 16 exceeds the setting value, the relay of the circuit breaker 12 is turned off. Thus, the synchronous induction motor 11 can be stopped by interrupting the drive current supplied to the synchronous induction motor 11.

  Here, when starting the synchronous induction motor 11, a large inrush current flows. When the inrush current level at that time exceeds the set value of the comparator, the same operation as described above is performed. The operation in this case is a so-called malfunction. As a circuit for preventing this malfunction, the controller 14 is provided with one of the following first circuit, second circuit, and third circuit, as in the first embodiment.

  That is, the first circuit is a reset circuit that resets the comparator for a predetermined time when the power is turned on. The second circuit is a delay circuit that delays a current detection signal input to the comparator when power is turned on by a predetermined time. The third circuit is a timed circuit provided between the comparator and the relay of the circuit breaker 12. That is, the relay of the circuit breaker 12 is turned off when the signal output from the comparator for turning off the relay of the circuit breaker 12 continues for a certain time (for example, 0.5 seconds) or longer.

  As described above, according to the third embodiment, when the supply current level is monitored and it is detected that the synchronous induction motor has reached a step-out state due to a large load fluctuation, voltage drop, or pull-in failure, immediately, Since the drive current of the synchronous induction motor can be cut off, the synchronous induction motor can be quickly stopped. Therefore, the same operation and effect as in the first embodiment can be obtained.

Embodiment 4 FIG.
FIG. 6 is a block diagram showing a configuration of a protection device for a synchronous induction motor according to Embodiment 4 of the present invention. In FIG. 6, the same or similar components as those shown in FIG. 5 (Embodiment 3) are denoted by the same reference numerals. Here, the description will be focused on the portion related to the fourth embodiment.

  That is, as shown in FIG. 6, in the fourth embodiment, in the configuration shown in FIG. 5 (third embodiment), a control unit 15 is provided instead of the control unit 14.

  The control unit 15 includes a frequency analysis circuit that analyzes the frequency of the current waveform detected by the current detection unit 16, a determination circuit that determines whether the analyzed frequency matches the frequency at the normal time, and a frequency other than the frequency at the normal time. An output circuit that turns off the relay of the circuit breaker 12 in the case of a frequency and a circuit that prevents a malfunction that erroneously turns off the relay of the circuit breaker 12 are configured as main elements.

  In the above configuration, when the synchronous induction motor 11 is in an operation state where the synchronous induction motor 11 is driven at a rotational speed other than the synchronous rotational speed, that is, out of step, a current having a disturbed waveform that is not in a steady state flows through the synchronous induction motor 11. When the frequency of the current waveform detected by the current detection unit 16 is analyzed by the frequency analysis circuit of the control unit 15 and the determination circuit determines that the frequency is different from the steady-state frequency, the output circuit breaks the circuit breaker. A signal for turning off the 12 relays is output. That is, as in the third embodiment, the synchronous induction motor 11 can be stopped by interrupting the drive current supplied to the synchronous induction motor 11.

  Here, when the synchronous induction motor 11 is started, since a current having a distorted waveform flows, the frequency analysis circuit of the control unit 15 similarly performs frequency analysis. When the analysis frequency at that time is different from the steady-state frequency, the same operation as described above is performed. The operation in this case is a so-called malfunction. As a circuit for preventing this malfunction, the controller 15 is provided with any one of the following first circuit, second circuit, and third circuit as in the third embodiment.

  That is, the first circuit is a reset circuit that resets the frequency analysis circuit for a predetermined time when the power is turned on. The second circuit is a delay circuit that delays a current detection signal input to the frequency analysis circuit when power is turned on by a predetermined time. The third circuit is a timed circuit provided between the output circuit and the relay of the circuit breaker 12. That is, the relay of the circuit breaker 12 is turned off when the signal for turning off the relay of the circuit breaker 12 output from the output circuit continues for a certain time (for example, 0.5 seconds) or longer.

  As described above, according to the fourth embodiment, when the frequency of the supply current is monitored and it is detected that the synchronous induction motor has reached a step-out state due to a large load fluctuation, voltage drop, or pull-in failure, Since the drive current of the synchronous induction motor can be cut off immediately, the synchronous induction motor can be quickly stopped. Therefore, the same operation and effect as in the first embodiment can be obtained.

Embodiment 5 FIG.
FIG. 7 is a block diagram showing a configuration of a protection device for a synchronous induction motor according to Embodiment 5 of the present invention. In FIG. 7, the same reference numerals are given to components that are the same as or equivalent to the components shown in FIG. 3 (Embodiment 1). Here, the description will be focused on the portion related to the fifth embodiment.

  That is, as shown in FIG. 7, in the fifth embodiment, in the configuration shown in FIG. 3 (first embodiment), a search coil for detecting the magnetic flux of the rotor is mainly used in place of the vibration detector 13. A magnetic flux detection unit 17 configured as an element is provided.

  In the above configuration, when the synchronous induction motor 11 steps out, the rotor slip increases, the rotor magnetic flux increases, and a voltage higher than that in the steady state is induced in the search coil of the magnetic flux detector 17. Therefore, the control unit 14 uses, for example, an induced voltage when the rotor slip is 8% or more as the set value of the comparator, and when the detected induced voltage level of the magnetic flux detecting unit 17 exceeds the set value, the circuit breaker 12 The synchronous induction motor 11 can be stopped by shutting off the relay, and interrupting the drive current supplied to the synchronous induction motor 11.

  Here, since the slip when starting the synchronous induction motor 11 is also large, the operation similar to the above is performed when the induced voltage level at that time exceeds the set value of the comparator. The operation in this case is a so-called malfunction. As a circuit for preventing this malfunction, the controller 14 is provided with one of the following first circuit, second circuit, and third circuit, as in the first embodiment.

  That is, the first circuit is a reset circuit that resets the comparator for a predetermined time when the power is turned on. The second circuit is a delay circuit that delays the magnetic flux detection signal input to the comparator when the power is turned on by a predetermined time. The third circuit is a timed circuit provided between the comparator and the relay of the circuit breaker 12. That is, the relay of the circuit breaker 12 is turned off when the signal output from the comparator for turning off the relay of the circuit breaker 12 continues for a certain time (for example, 0.5 seconds) or longer.

  As described above, according to the fifth embodiment, when the slip amount of the rotor is monitored and it is detected that the synchronous induction motor has reached the step-out state due to a large load fluctuation, voltage drop, or pull-in failure. Since the drive current of the synchronous induction motor can be cut off immediately, the synchronous induction motor can be quickly stopped. Therefore, the same operation and effect as in the first embodiment can be obtained.

Embodiment 6 FIG.
FIG. 8 is a block diagram showing a configuration of a protection device for a synchronous induction motor according to Embodiment 6 of the present invention. In FIG. 8, components that are the same as or equivalent to the components shown in FIG. 3 (Embodiment 1) are assigned the same reference numerals. Here, the description will focus on the parts related to the sixth embodiment.

  That is, as shown in FIG. 8, in the sixth embodiment, in the configuration shown in FIG. 3 (Embodiment 1), in place of the vibration detector 13, a rotation speed detection unit 18 that detects the rotation speed of the rotor. And a control unit 19 is provided instead of the control unit 14.

  The rotation speed detection unit 18 rotates using a circuit that measures the rotation speed from the state of vibration, a circuit that measures the rotation speed from a current waveform, a circuit that measures the rotation speed from voltage fluctuations of a search coil that detects magnetic flux, and an encoder. One of the circuits for measuring the number is provided.

  The control unit 19 determines whether or not the rotation number detected by the rotation number detection unit 18 is a predetermined rotation number (for example, 50 r / s, 60 r / s) and an off command from the determination circuit. A circuit for receiving and turning off the relay of the circuit breaker 12 and a circuit for preventing malfunction are provided.

  In the above configuration, when the synchronous induction motor 11 steps out, the rotational speed of the rotor becomes a rotational speed other than a predetermined rotational speed (for example, 50 r / s, 60 r / s). Therefore, in the determination circuit of the control unit 19, when the rotation number detected by the rotation number detection unit 18 is a rotation number other than a predetermined rotation number (for example, 50 r / s, 60 r / s), the output circuit An OFF command is issued, the relay of the circuit breaker 12 is turned off, the drive current supplied to the synchronous induction motor 11 is interrupted, and the synchronous induction motor 11 can be stopped.

  Here, when the synchronous induction motor 11 is started, the rotational speed of the rotor is similarly a rotational speed other than a predetermined rotational speed (for example, 50 r / s, 60 r / s). In this case, the same operation as described above is performed, but the operation in this case is a so-called malfunction. As a circuit for preventing this malfunction, the control unit 19 is provided with, for example, any one of the following first circuit, second circuit, and third circuit.

  That is, the first circuit is a reset circuit that resets the determination circuit for a predetermined time when the power is turned on. The second circuit is a delay circuit that delays the rotation speed detection signal input to the determination circuit when the power is turned on by a predetermined time. The third circuit is a timed circuit provided between the output circuit and the relay of the circuit breaker 12. That is, the relay of the circuit breaker 12 is turned off when the signal for turning off the relay of the circuit breaker 12 output from the output circuit continues for a certain time (for example, 1 second) or longer.

  As described above, according to the sixth embodiment, when the number of rotations of the rotor is monitored and it is detected that the synchronous induction motor has reached a step-out state due to a large load fluctuation, voltage drop, or pull-in failure. Since the drive current of the synchronous induction motor can be cut off immediately, the synchronous induction motor can be quickly stopped. Therefore, the same operation and effect as in the first embodiment can be obtained.

Embodiment 7 FIG.
FIG. 9 is a block diagram showing a configuration of a protection device for a synchronous induction motor according to Embodiment 7 of the present invention. In FIG. 9, the same or similar components as those shown in FIG. 3 (Embodiment 1) are denoted by the same reference numerals. Here, the description will be focused on the portion related to the seventh embodiment.

  That is, as shown in FIG. 9, in the seventh embodiment, in the configuration shown in FIG. 3 (Embodiment 1), a temperature detection unit 20 is provided instead of the vibration detection unit 13, and the control unit 14 is replaced. The control unit 21 is provided.

  The temperature detection unit 20 detects the temperature of the stator winding or the rotor of the synchronous induction motor 11. The controller 21 is mainly configured by a comparator that turns off the circuit breaker 12 when the temperature value detected by the temperature detector 20 exceeds a predetermined value.

  In the above configuration, when the synchronous induction motor 11 steps out, the supply current increases significantly, and the temperature of the stator winding increases. In addition, since the rotor slip increases, the current value of the secondary conductor increases and the rotor temperature rises. Therefore, the control unit 14 uses a predetermined value indicating the abnormal temperature as the set value of the comparator, and when the detected temperature value of the temperature detection unit 20 exceeds the predetermined value, the relay of the circuit breaker 12 is turned off to synchronize the induction motor 11. The synchronous induction motor 11 can be stopped by interrupting the drive current supplied to the motor.

  As described above, according to the seventh embodiment, when the presence or absence of an abnormal temperature rise is monitored and it is detected that the synchronous induction motor has reached a step-out state due to a large load fluctuation, voltage drop, or pull-in failure. Since the drive current of the synchronous induction motor can be cut off immediately, the synchronous induction motor can be quickly stopped. Therefore, the same operation and effect as in the first embodiment can be obtained.

Embodiment 8 FIG.
FIG. 10 is a block diagram showing a configuration of a compressor using a synchronous induction motor provided with a protection device according to an eighth embodiment of the present invention, and a refrigeration cycle apparatus using the compressor.

  In FIG. 11, the compressor 31 is used as a drive source for circulating the refrigerant in the refrigeration cycle apparatus 40. That is, the refrigeration cycle apparatus 40 includes a compressor 31, a four-way valve 41, an indoor heat exchanger (evaporator) 42, an outdoor heat exchanger (condenser) 43, and a throttling device 44. 45 is connected.

  In the refrigeration cycle, the refrigerant is compressor 31 → four-way valve 41 → indoor heat exchanger (evaporator) 42 or outdoor heat exchanger (condenser) 43 → throttle device 44 → indoor heat exchanger (evaporator) 42 or outdoor. It implement | achieves by circulating in order of the heat exchanger (condenser) 43-> four-way valve 41-> compressor 31. FIG. As the refrigerant, an HFC refrigerant typified by R134a, R410a, R407c, or a natural refrigerant typified by R744, R717, R600a, R290, or the like is used. As the refrigerating machine oil, weakly compatible oil typified by alkylbenzene oil or compatible oil typified by ester oil is used.

  As the compressor 31, a reciprocating type, a rotary type, a scroll type, or the like can be used. The synchronous induction motor 11 incorporated in the compressor 31 is a type of synchronous induction motor that does not use a permanent magnet for the rotor described with reference to FIGS. 1 and 2 and is stored in a state where it is shut off from the outside air. . Moreover, since it is filled with a refrigerant, it has a refrigerant resistance specification.

  Then, as described in the first to seventh embodiments, the protection device 25 includes the circuit breaker 12 arranged in the power supply line from the AC power supply 10 to the synchronous induction motor 11, and the synchronous induction motor 11. A detection unit 26 that detects the step-out state and a control unit 27 that turns off the circuit breaker 12 when the detection unit 26 detects the step-out state are provided.

  According to this configuration, when the synchronous induction motor 11 that drives the compressor 31 has stepped out, the protective device 25 immediately cuts off the power supply path to the synchronous induction motor 11, so that the synchronous induction motor 11 is promptly stopped. Can do. Therefore, the quality and safety of the compressor 31 and the refrigeration cycle apparatus 40 can be improved by incorporating the synchronous induction motor 11 equipped with the protection device 25.

  As described above, the protection device for a synchronous induction motor according to the present invention is useful for protecting a synchronous induction motor of a type that does not use a permanent magnet for a rotor from burning or the like at the time of step-out. It is suitable for improving the quality and safety of refrigeration cycle equipment.

It is a cross-sectional view which shows the structure of the rotor of the synchronous induction motor of the type which does not use a permanent magnet for the rotor which is the object of this invention. It is a perspective view which shows the external appearance of the rotor shown in FIG. It is a block diagram which shows the structure of the protection apparatus of the synchronous induction motor which is Embodiment 1 of this invention. It is a block diagram which shows the structure of the protection apparatus of the synchronous induction motor which is Embodiment 2 of this invention. It is a block diagram which shows the structure of the protection apparatus of the synchronous induction motor which is Embodiment 3 of this invention. It is a block diagram which shows the structure of the protection apparatus of the synchronous induction motor which is Embodiment 4 of this invention. It is a block diagram which shows the structure of the protection apparatus of the synchronous induction motor which is Embodiment 5 of this invention. It is a block diagram which shows the structure of the protection apparatus of the synchronous induction motor which is Embodiment 6 of this invention. It is a block diagram which shows the structure of the protection apparatus of the synchronous induction motor which is Embodiment 7 of this invention. It is a block diagram which shows the structure of the compressor using a synchronous induction motor provided with the protection device which is Embodiment 8 of this invention, and the refrigerating cycle apparatus using the said compressor.

Explanation of symbols

1 Rotor core,
2 slits,
3 slots,
4 strips,
5 Thin part,
6 shaft,
7a first end ring,
7b second end ring,
10 AC power supply,
11 Synchronous induction motor (M),
12 Circuit breakers,
13 Vibration detector,
14, 15, 19, 21, 27 control unit,
16 current detector,
17 Magnetic flux detector,
18 Rotation speed detector
20 temperature detector,
25 protection device,
26 detector,
31 compressor,
40 refrigeration cycle equipment,
41 Four-way valve,
42 Indoor heat exchanger (evaporator),
43 Outdoor heat exchanger (condenser),
44 Aperture device,
45 Refrigerant piping.

Claims (13)

A detection unit for detecting a step-out state of a synchronous induction motor that starts using an induction torque without using a permanent magnet for a rotor and performs synchronous operation using a reluctance torque ;
A control unit that stops the synchronous induction motor when the detection unit detects a step-out state;
A protective device for a synchronous induction motor, comprising: The detection unit is a vibration detection unit that detects vibration of the synchronous induction motor,
The control unit stops the synchronous induction motor when a level of vibration detected by the vibration detection unit exceeds a predetermined value;
The protective device for a synchronous induction motor according to claim 1. The detection unit is a vibration detection unit that detects vibration of the synchronous induction motor,
The control unit stops the synchronous induction motor when the frequency of vibration detected by the vibration detection unit is different from the frequency during steady operation,
The protective device for a synchronous induction motor according to claim 1. The detection unit is a current detection unit that detects a supply current to the synchronous induction motor,
The control unit stops the synchronous induction motor when a level of a supply current detected by the current detection unit exceeds a predetermined value;
The protective device for a synchronous induction motor according to claim 1. The detection unit is a current detection unit that detects a supply current to the synchronous induction motor,
The control unit stops the synchronous induction motor when the frequency of the supply current detected by the current detection unit is different from the frequency during steady operation,
The protective device for a synchronous induction motor according to claim 1. The detection unit is a magnetic flux detection unit that detects a magnetic flux of a rotor of the synchronous induction motor,
The control unit stops the synchronous induction motor when the magnetic flux detection unit detects a magnetic flux density equal to or higher than a predetermined value.
The protective device for a synchronous induction motor according to claim 1. The detection unit is a rotation number detection unit that detects a rotation number of a rotor of the synchronous induction motor, and the control unit is configured such that the rotation number detected by the rotation number detection unit is different from the rotation number during normal operation. To stop the synchronous induction motor,
The protective device for a synchronous induction motor according to claim 1. The detection unit is a temperature detection unit that detects the temperature of the synchronous induction motor,
The control unit stops the synchronous induction motor when the temperature detected by the temperature detection unit exceeds a predetermined value;
The protective device for a synchronous induction motor according to claim 1. The control unit stops the synchronous induction motor when the step-out state detected by the detection unit continues for a predetermined time or longer.
The protective device for a synchronous induction motor according to any one of claims 1 to 8.   The said control part is provided with a means to invalidate the step-out state which the said detection part detected at the time of power activation, The protection apparatus of the synchronous induction motor in any one of Claims 1-8 characterized by the above-mentioned. In a compressor storing a synchronous induction motor that starts using an induction torque and uses a reluctance torque without using a permanent magnet in a rotor,
A compressor provided with the protection device according to claim 1. In a compressor storing a synchronous induction motor that starts using an induction torque and uses a reluctance torque without using a permanent magnet in a rotor,
Compressor equipped with a protection device according to claim 2 or claim 3, wherein the vibration detection unit is characterized in that provided in the compressor. In the refrigeration cycle apparatus composed of a compressor, a four-way valve, a condenser, a throttling device, and an evaporator, and connecting them with a refrigerant pipe,
The compressor is the compressor according to claim 11 or claim 12,
A refrigeration cycle apparatus characterized by that.

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