JP6530174B2 - Refrigeration cycle device - Google Patents

Description

  The present invention relates to a refrigeration cycle apparatus.

  In recent years, in many refrigeration cycle apparatuses, the refrigeration capacity can be variably adjusted by adjusting the rotational speed of the compressor. That is, the refrigeration capacity of the refrigeration cycle apparatus can be enhanced by operating the compressor at high rotation (rated operation). A compressor is usually incorporated with a motor, and the number of revolutions is controlled electrically. In addition, by performing intermediate operation (operation in which the capacity is about half the rating) with the number of revolutions of the motor reduced, the refrigeration capacity can be adjusted as necessary.

  For example, it is assumed that the refrigeration cycle apparatus is used in an air conditioner. When cooling or heating is performed immediately after power-on of the air conditioner, the compressor is rated, the refrigeration capacity of the refrigeration cycle apparatus is increased, and the output of cooling or heating is increased. When the temperature reaches a certain level and cooling or heating to maintain the temperature is sufficient, the compressor is operated in the middle, the refrigeration capacity of the refrigeration cycle apparatus is kept low, and the room temperature is stabilized with low power consumption.

  Most of the power consumption of the refrigeration cycle apparatus is consumed by the compressor. Then, increasing the efficiency of the compressor (motor included in the compressor) leads to a reduction in power consumption. The characteristics of the motor vary depending on the number of turns of the coil, and the number of turns determines the number of revolutions that achieves the highest efficiency. That is, it has been difficult to increase the efficiency in the entire range from low rotation to high rotation with the motor of the conventional configuration.

  In view of the above, there has been proposed an electric motor which can be operated in a state of high efficiency even if the number of revolutions changes, such as a winding switching type rotary electric machine described in JP-A-6-205573. In this winding switching type rotary electric machine, the coil to which power is supplied is switched according to the number of revolutions of the motor, and the number of windings of the coil is changed to achieve efficiency in high speed operation (rated operation) and low speed operation (intermediate operation). Control the decline of

Japanese Patent Laid-Open No. 6-205573

  The switched-winding type rotary electric machine disclosed in Japanese Patent Laid-Open No. 6-205573 switches between a coil on the high rotation side and a coil on the low rotation side to use. The air conditioner provided with the refrigeration cycle apparatus is configured to perform cooling for cooling the living room and heating for warming the living room by using the compressor. In the air conditioner, since the required refrigeration capacity fluctuates due to the difference between the cooling operation and the heating operation, the difference in the outside air temperature, etc., it is necessary to finely control the rotation speed of the compressor. Even when the winding switching type rotating electric machine is used for the motor of the compressor, which needs to control the number of revolutions finely, power consumption can not always be reduced in long-term operation.

  When the coil is switched and used as in the winding switching type rotary electric machine, if the relative change in the winding ratio is large before and after the switching, a large current is generated instantaneously when the coil is switched, It causes the breakdown or damage of the rotating electric machine (motor) itself or the control circuit, which causes the shortening of the life.

  Therefore, an object of the present invention is to provide a long-life, low waste refrigeration cycle device that can increase the time for performing high-efficiency operation.

  In order to achieve the above object, the present invention is a refrigeration cycle apparatus equipped with a compressor including a stator on which a plurality of coil units including a plurality of coils are arranged, and a rotor on which a plurality of poles are formed. A control unit that switches connection states of coils included in each of the plurality of coil units, and the control unit switches the connection states of the plurality of coil units according to operating conditions. It features.

  According to this configuration, by switching the coil unit, the compressor can be efficiently driven under many operating conditions. As a result, the time of high efficiency operation can be extended, and energy consumption can be reduced over a long period of time.

  In the above configuration, the control unit switches the connection state of the plurality of coil units based on at least one of the number of revolutions and the torque of the compressor. With this configuration, switching of the connection state of the coil unit can be finely adjusted, and driving can be performed in a state of high efficiency.

  In the above configuration, the control unit switches the connection state of the coil unit in a state in which the rotational speed of the compressor is temporarily reduced. According to this configuration, the compressor has a simple configuration, and the generation of instantaneous large current when switching the connection state of the coil unit is suppressed. Since a momentary large current does not flow, the circuit and the motor can be prevented from being broken or broken, and the life can be extended.

  In the above configuration, each of the plurality of coil units may be provided with a preliminary load, and the connection state of the coil units may be switched after the preliminary load is connected to supply power. According to this configuration, generation of instantaneous large current when switching the connection state of the coil unit is suppressed. Since a momentary large current does not flow, the circuit and the motor can be prevented from being broken or broken, and the life can be extended. In addition, when switching a coil unit, a preliminary | backup load can mention what has the impedance which can suppress an instantaneous large current reliably.

  In the above configuration, the coil unit includes two coils of the same configuration, and a first state in which coil units in which two coils are connected in series are connected by star connection and two coils are connected in series The second state in which the connected coil units are connected by delta connection, the third state in which the coil units in which two coils are connected in parallel are connected by star connection, and the coil connection in which two coils are connected in parallel Can be switched to the fourth state connected in FIG.

  According to the present invention, a high efficiency operation can be performed under a wide operating condition, and a long life and a low waste refrigeration cycle device can be provided.

It is the schematic of an air conditioner. It is the schematic of an example of the refrigerating-cycle apparatus concerning this invention. FIG. 2 is a cross-sectional view of the motor disposed in the compressor according to the present invention, taken along a plane perpendicular to the shaft. It is a wiring diagram of the motor provided in the compressor. It is the wiring diagram which star-connected the coil unit which connected the 1st coil part and the 2nd coil part in series. It is the wiring diagram which delta-connected the coil unit which connected the 1st coil part and the 2nd coil part in series. It is the wiring diagram which star-connected the coil unit which connected the 1st coil part and the 2nd coil part in parallel. It is the wiring diagram which delta-connected the coil unit which connected the 1st coil part and the 2nd coil part in parallel. It is a table | surface which compares the driving | running condition of an air conditioner, the driving | running state of a refrigerating-cycle apparatus, the rotational speed of an electric motor, and the connection state of a coil unit. It is a wiring diagram showing the middle state in the middle of the change of electric motor. It is a wiring diagram showing the middle state in the middle of the change of electric motor. It is a graph which shows the relationship between the number of rotations and motor efficiency when the motor is driven in different coil connection states. It is a circuit diagram of the electric motor provided with the compressor of the refrigerating cycle device concerning the present invention.

The present invention will be described below with reference to the drawings.
First Embodiment
FIG. 1 is a schematic view of an air conditioner, and FIG. 2 is a schematic view of an example of a refrigeration cycle apparatus according to the present invention. As shown in FIG. 1, the air conditioner Ac has an indoor unit IM installed inside (a wall) of the living room Rm and an outdoor unit OM installed outside the living room Rm. In addition, since opening of a door, a window, etc. is closed when performing air conditioning and may be considered to be integral with a wall, a ceiling, etc., it is omitted. The air conditioner A takes in air in the room Rm into the indoor unit IM and discharges conditioned air to perform air conditioning in the room Rm.

  As shown in FIG. 2, the refrigeration cycle apparatus Rc includes devices such as a compressor 11, a four-way valve 12, an outdoor heat exchanger 13, a pressure reducing unit 14, an indoor heat exchanger 15 and the like. And while these apparatuses are connected by refrigerant | coolant piping, the refrigerant | coolant is enclosed with the inside and the well-known refrigerant circuit is comprised.

  As shown in FIG. 2, in the refrigeration cycle apparatus Rc, the compressor 11, the four-way valve 12, the outdoor heat exchanger 13, the pressure reducing unit 14, the outdoor fan 131 and the accumulator 16 are disposed in the outdoor unit OM. The unit 15 and the indoor fan 151 are disposed in the indoor unit IM. The pressure reducing unit 14 may be provided not in the outdoor unit OM but in the indoor unit IM.

  The compressor 11 is a device that compresses a refrigerant. The compressor 11 is connected to an outflow pipe Po from which the refrigerant flows out and an inflow pipe Pi to which the refrigerant flows, and both the outflow pipe Po and the inflow pipe Pi are connected to the four-way valve 12. Further, an accumulator 16 is attached to an inflow pipe where the refrigerant flows into the compressor 11. The refrigerant returned to the compressor 11 is in a state in which the gas phase and the liquid phase are mixed. The refrigerant is separated into a liquid and a gas by passing through the accumulator 16. Then, the gaseous refrigerant flows into the compressor 11.

  The four-way valve 12 changes the flow direction of the refrigerant circuit. That is, the connection destination (outdoor heat exchanger 13 or indoor heat exchanger 15) of the outflow piping Po and the inflow piping Pi is switched. For example, when the four-way valve 12 connects the outflow pipe Po to the outdoor heat exchanger 13 and connects the inflow pipe Pi to the indoor heat exchanger 15, the air conditioner Ac performs a cooling operation to cool the inside of the living room Rm. When the four-way valve 12 is reversely connected, the heating operation for heating the inside of the living room Rm is performed.

  The pressure reducing unit 14 reduces the pressure of the refrigerant, and an expansion valve is employed here. The outdoor heat exchanger 13 and the indoor heat exchanger 15 are for performing heat exchange between the refrigerant outside and inside the living room Rm and the refrigerant, and for example, fins for increasing the cross-sectional area of the refrigerant piping Can be mentioned. It is possible to increase the efficiency of heat exchange by blowing air to the fins and forcibly feeding the air. Therefore, in the refrigeration cycle apparatus A, the outdoor fan 131 is provided in the vicinity of the outdoor heat exchanger 13, and the indoor fan 151 is provided in the vicinity of the indoor heat exchanger 15, and the heat is blown to each heat exchanger. Exchange heat efficiently between the two.

  The compressor 11 compresses the refrigerant by a motor disposed inside. Next, the motor A included in the compressor 11 will be described with reference to the drawings. FIG. 3 is a cross-sectional view taken along a plane perpendicular to the axis of the motor disposed in the compressor according to the present invention, and FIG. 4 is a wiring diagram of the motor provided in the compressor.

  The motor A is a three-phase DC brushless motor. In the motor A, a stator 20 is provided with nine slots 21. A rotor 22 is disposed inside the stator 20. The output shaft 221 is integrally fixed to the center of the rotor 22. The rotor 22 is provided with permanent magnets (not shown). As the rotor 22, for example, one having eight permanent magnets (eight poles formed) can be mentioned.

  A conducting wire is wound around each slot 21 of the motor A, and each slot 21 constitutes a coil (field). These coil portions 23 are supplied with AC power U-phase power, V-phase power, and W-phase power that are out of phase by 120 °, respectively. So, in the following description, the coil to which the electric power of each phase of 3 phases is applied is divided into 3 system of U phase coil unit 23U, V phase coil unit 23V, and W phase coil unit 23W, respectively. The electric motor A supplies power of a phase corresponding to each of the U-phase coil unit 23U, the V-phase coil unit 23V, and the W-phase coil unit 23W, whereby the rotor 20 rotates, that is, a rotational force is generated. The generated rotational force is taken out of the motor A via the output shaft 21 fixed integrally with the rotor 20.

  As shown in FIG. 4, the U-phase coil unit 23 U, the V-phase coil unit 23 V, and the W-phase coil unit 23 W include a first coil portion 231 and a second coil portion 232. Further, in the U-phase coil unit 23U, the V-phase coil unit 23V, and the W-phase coil unit 23W, preliminary loads Z1, Z2, and Z3 are provided separately from the first coil portion 231 and the second coil portion 232, respectively. Since alternating current is supplied to the motor A, the preliminary loads Z1, Z2, and Z3 may be inductive (coils), capacitive (capacitors), or the like, in addition to normal resistances. A combination is used.

  Furthermore, the electric motor A changes the combination of connection of the first coil portion 231 and the second coil portion 232 of each of the U-phase coil unit 23U, the V-phase coil unit 23V and the W-phase coil unit 23W, and And a drive circuit 3 for supplying The U-phase coil unit 23U, the V-phase coil unit 23V, and the W-phase coil unit 23W have the same configuration.

  The drive circuit 3 includes a motor controller 31, switching elements 321, 322, 323, 331 to 334, 341 to 344, 351 to 354, and a control unit 36. The motor controller 31 is a driver circuit that supplies power to each of the U-phase coil unit 23U, the V-phase coil unit 23V, and the W-phase coil unit 23W. The motor controller 31 converts power from a power supply (not shown) into power (waveform of voltage, frequency, period, etc.) suitable for driving the motor A. The motor controller 31 includes a U terminal 311 that outputs U-phase power, a V terminal 312 that outputs V-phase power, and a W terminal 313 that outputs W-phase power.

  Next, the switching element will be described. Switching elements 321, 322, and 323 are connected to the U-phase coil unit 23U, the V-phase coil unit 23V, and the U-terminal 311, the V-terminal 312, and the W-terminal 313 of the W-phase coil unit 23W, respectively. Is attached. The switching elements 321, 322, and 323 are switching elements for switching the wiring. When the switching elements 321, 322, 323 are connected to the A-contact, the U-phase coil unit 23U, the V-phase coil unit 23V, and the W-phase coil unit 23W are connected by star connection. Conversely, when the switching elements 321, 322, 323 are connected to the B contacts, the U-phase coil unit 23U, the V-phase coil unit 23V, and the W-phase coil unit 23W are wired in a delta connection.

  That is, the switching elements 321, 322, and 323 are switches for switching the U-phase coil unit 23U, the V-phase coil unit 23V, and the W-phase coil unit 23W into star connection and delta connection. Therefore, the control unit 36 synchronously controls the switching elements 321, 322, and 323. For example, in the case of star connection, the control unit 36 connects the switching elements 321, 322, and 323 to the respective A contacts at the same timing.

  The switching elements 331, 332, 333, 334 are provided in the U-phase coil unit 23U. The switching element 331 and the switching element 334 are switching switches for switching the connection direction. The switching elements 332 and 333 are switches that switch ON or OFF (connection or disconnection of a circuit).

  The switching element 331 and the switching element 332 are switches that connect the first coil portion 231 and the second coil portion 232 by either a series connection method or a parallel connection method. The first coil portion 231 and the second coil portion 232 can be connected in series by connecting the switching element 331 to the A contact and turning off the switching element 332. Further, by connecting the switching element 331 to the B contact and turning on the switching element 332, the first coil portion 231 and the second coil portion 232 can be connected in parallel.

  The switching element 333 is an ON / OFF switch that connects or disconnects a circuit that supplies power to the preliminary load Z1. The switching element 334 is a changeover switch which switches and connects the preparatory load Z1 to a wire of a star connection or a wire of a delta contact.

  The switching elements 341, 342, 343, and 344 are switching elements for switching the connection of the V-phase coil unit 23V. The switching elements 351, 352, 353, 354 are switching elements for switching the connection of the V-phase coil unit 23V. The switching elements 341 and 351 are switching elements corresponding to the switching element 331, the switching elements 342 and 352 are switching elements 332, the switching elements 343 and 353 are switching elements 333, and the switching elements 344 and 354 are switching elements . Therefore, each switching element provided in V-phase coil unit 23V and W-phase coil unit 23W performs the same configuration and operation as the switching element of corresponding U-phase coil unit 23U.

  Examples of the switching elements 321, 322, 323, 331 to 343, 341 to 344, and 351 to 354 include elements such as IGBTs and power MOSFETs and combinations of these elements, but the present invention is not limited thereto.

  Next, the motor A provided in the compressor according to the present invention will be described. The motor A is configured to be able to switch and use a three-phase coil unit between star connection and delta connection. Further, in the motor A according to the present invention, the first coil portion 231 and the second coil unit 232 of each coil unit can be switched in series or in parallel. Hereinafter, the state of the motor when the switching element is switched will be described with reference to the drawings.

  5-8 is a wiring diagram when the coil connection which connected the 1st coil part and the 2nd coil part in series or in parallel is star-connected or delta-connected. Since the corresponding switching elements in the motor A are driven in synchronization, in the following description, switching elements included in the U-phase coil unit 23U will be mainly described. The V-phase coil unit 23V, W-phase The switching elements of the coil unit 23W will be described as performing the same operation at the same time. In the following description, in the wiring diagram, circuits to which power is supplied (current flows or voltage is applied) are indicated by thick lines.

  FIG. 5: is the wiring diagram which carried out the star connection of the coil unit which connected the 1st coil part and the 2nd coil part in series. As shown in FIG. 5, the control unit 36 connects the switching element 331 of the U-phase coil unit 23U to the A contact, and turns off the switching element 332, whereby the first coil section 231 and the second coil section 232 Are connected in series. Similarly, the V-phase coil unit 23V and the W-phase coil unit 23W operate the corresponding switching elements to connect the first coil portion 231 and the second coil portion 232 of each coil unit in series. Then, the switching elements 321, 322, 323 are connected to the A contact. As a result, the motor A is in a serial star state in which coil units in which the first coil portion 231 and the second coil portion 232 are connected in series are star-connected.

  FIG. 6 is a wiring diagram in which coil units in which a first coil portion and a second coil portion are connected in series are delta-connected. As shown in FIG. 6, by switching the switching elements 321, 322, and 323 to the B contacts from the state of FIG. 5, the motor A has a coil unit in which the first coil portion 231 and the second coil portion 232 are connected in series. It becomes a series delta state connected with delta connection.

  FIG. 7 is a wiring diagram in which a coil unit in which a first coil portion and a second coil portion are connected in parallel is star connected. As shown in FIG. 7, the control unit 36 connects the switching element 331 of the U-phase coil unit 23U to the B contact, and turns on the switching element 332 to make the first coil portion 231 and the second coil portion 232 Are connected in parallel. The V-phase coil unit 23V and the W-phase coil unit 23W similarly operate the corresponding switching elements to connect the first coil portion 231 and the second coil portion 232 of each coil unit in parallel. Then, the switching elements 321, 322, 323 are connected to the A contact. As a result, a coil unit in which the first coil portion 231 and the second coil portion 232 are connected in parallel is star-connected to form a parallel star state.

  FIG. 8 is a wiring diagram in which coil units in which a first coil portion and a second coil portion are connected in parallel are delta-connected. As shown in FIG. 8, by switching the switching elements 321, 322, 323 to the B contacts from the state of FIG. 7, the motor A has a coil unit in which the first coil portion 231 and the second coil portion 232 are connected in parallel. It becomes a parallel delta state connected with delta connection.

  Next, the drive of the refrigeration cycle apparatus Rc according to the present invention will be described. In the refrigeration cycle apparatus Rc, by adjusting the number of rotations of the compressor 11, that is, the number of rotations of the motor A, the refrigeration capacity (for example, the cooling capacity or the heating capacity in the air conditioner Ac) is adjusted.

  In the motor A, which is a three-phase brushless motor, generally, when the number of windings is large, the efficiency at low rotation is high (the maximum efficiency is reached), and the efficiency decreases at high rotation. On the other hand, when the number of windings is small, the efficiency at low rotation is low but the efficiency at high rotation is high (the highest efficiency is reached).

  As described above, the motor A is configured to change the relative number of windings by switching the switching element. For example, based on the number of turns in the serial star state, the relative turns ratio is 1 / √3 in the serial delta state, 1/2 in the parallel star state, 1 in the parallel delta state. / 2√3. That is, in the motor A, the same effect as changing the number of windings can be obtained by switching the state.

  Using this, in the refrigeration cycle apparatus Rc according to the present invention, control is performed to switch the winding number ratio (connection state of the coil) of the motor A according to the operating condition (required output) of the refrigeration cycle apparatus Rc. Has been done. Hereinafter, the refrigeration cycle apparatus Rc used for the air conditioner Ac will be described as an example. In addition, the case where air conditioner Ac is used as a cooling device is assumed.

  In the refrigeration cycle apparatus Rc used for the air conditioner Ac, the required output (operating condition) fluctuates depending on the operating condition of the air conditioner Ac. FIG. 9 shows a table for comparing the operating condition of the air conditioner, the operating condition of the refrigeration cycle apparatus, the rotational speed of the motor, and the connection condition of the coil unit.

  When the power of the air conditioner Ac is turned on (at the start of operation), the refrigeration cycle apparatus Rc starts the rotation of the compressor 11 (starting the operation). When the compressor 11 is in the start state, the motor A operates at an extremely low speed. Therefore, when the refrigeration cycle apparatus Rc is in the start state, the control unit 36 controls the switching element so as to be in the series star state in which the number of windings (the relative turns ratio) is the largest. As a result, smooth operation can be performed at the start of operation and efficient operation can be performed.

  When the indoor temperature and the set temperature are close to each other, the refrigeration cycle apparatus Rc can perform indoor air conditioning with a small output. And, the air conditioner A is also affected by the outside air temperature. For example, when the temperature difference between the room and the outside is low, as in nighttime, and the room temperature is close to the set temperature (set to nighttime operation), the refrigeration cycle apparatus Rc can maintain the room temperature with low output ( Low power state). When the refrigeration cycle apparatus Rc is in a low output state, the compressor 11 (electric motor A) is driven at a low rotation speed. When the refrigeration cycle apparatus Rc is in the low output state, the control unit 36 controls the switching element so as to be in the series delta state in which the number of turns (the relative turns ratio) is the second largest.

  On the other hand, when the temperature difference between the room and the outside is high (daytime normal operation) as in the daytime, it is difficult to maintain the room temperature if there is no more than a certain amount of output from the refrigeration cycle device Rc. Therefore, in the refrigeration cycle apparatus Rc, the room temperature is maintained (a middle output state) by driving with a constant output (a middle output). When the refrigeration cycle apparatus Rc is in the middle output state, the compressor 11 (motor A) is driven at medium speed rotation. When the refrigeration cycle apparatus Rc is in the middle output state, the control unit 36 controls the switching element so as to be in the parallel star state in which the number of turns (relative turn ratio) is the second smallest.

  Furthermore, when the temperature difference between the room and the outside during the daytime is high and the room temperature and the set temperature are separated (rapid cooling operation is required), the refrigeration cycle apparatus Rc is required to have a high output (high output) State). When the refrigeration cycle apparatus Rc is in the high output state, the compressor 11 is driven at high speed rotation. When the refrigeration cycle apparatus Rc is in the high output state, the control unit 36 controls the switching element so as to be in the parallel delta state in which the number of turns (relative turn ratio) is the smallest.

  The switching of the state of the coil can be switched based on the operating state of the refrigeration cycle device Rc, whereby the motor A (compressor 11) can be driven in the most efficient state in each operating state. Thus, the refrigeration cycle apparatus Rc has high efficiency in a wide operating state.

  The start state, low power state, medium power state, and high power state are determined based on the number of coil windings of the motor A and the relative turns ratio so that the efficiency is improved in each state. Is preferred.

  On the other hand, when the connection state of the coil is switched in a state where the motor A is driven, a large current may instantaneously flow at the time of switching. The electric motor A of the present invention supplies a current to the pre-load at the time of switching, thereby suppressing an instantaneous large current flow. The switching of the switching element will be described below. Although the case of switching from the serial star state to the serial delta state will be described here, the same switching is performed other than this. 10 and 11 are wiring diagrams showing an intermediate state during switching of the motor.

  When the compressor 11 of the refrigeration cycle apparatus Rc is in the extremely low rotation state, the motor A is in the series star state, and each switching element is in the state shown in FIG. That is, the control unit 36 connects the switching element 331 of the U-phase coil unit 23U to the A contact, and connects the switching element 321 to the A contact. Further, the control unit 36 synchronously switches the switching elements corresponding to the V-phase coil unit 23V and the W-phase coil unit 23W.

  And refrigerating cycle device Rc is adjusting output with number of rotations. Therefore, when the operation of increasing the output is performed, the number of rotations of the compressor 11, that is, the motor A also increases. Then, when the refrigeration cycle apparatus Rc is in the low rotation state, the efficiency is lowered in the serial star state. Therefore, the control unit 36 connects the switching element 334 to the A contact and turns the switching element 333 ON in order to switch to the series delta state (see FIG. 10).

  By connecting in this manner, the preliminary load Z1 is connected in parallel with the coil in which the first coil portion 231 and the second coil portion 232 are connected in series. The U-phase coil unit 23U, the V-phase coil unit 23V, and the W-phase coil unit 23W are star-connected in such a manner that the preliminary loads Z1, Z2, and Z3 are connected in parallel. The connection of the preliminary loads Z1, Z2, and Z3 is controlled by the switching elements 334, 344, and 354. Therefore, the connection state can be switched independently of the coil unit.

  Then, the control unit 36 switches the switching elements 321, 322, and 323 from the A contact to the B contact. The moment the contacts of the switching elements 321, 322, 323 are switched, the first coil portion 231 and the second coil portion 232 are disconnected. On the other hand, the preliminary loads Z1, Z2, and Z3 are star-connected. Then, when the switching elements 321, 322, 323 are connected to the B contacts (see FIG. 11), the first coil portion 231 and the second coil portion 232 are maintained while the preliminary loads Z1, Z2, Z3 maintain the star state. The coil units 23U, 23V, 23W in series are delta-connected.

  The wiring state of FIG. 10 is switched to the wiring state of FIG. 11 in a state where current flows through the preliminary loads Z1, Z2, and Z3. Therefore, the generation of instantaneous large current due to the switching of the switching elements 321, 322, 323 can be suppressed.

  Then, the control unit 36 turns off the switching element 333 to stop the supply of power to the backup load Z1. The control unit 36 simultaneously turns off the switching elements 343 and 353 in the V-phase coil unit 23V and the W-phase coil unit 23W (see FIG. 7).

  When switching from the wiring state of FIG. 10 to the wiring state of FIG. 11, the spare loads Z1, Z2, and Z3 are switched while maintaining the star connection. That is, in the motor A according to the present invention, when switching the wiring of the coil unit, a preparatory load is used to form a pseudo circuit, and after switching the circuit, the preparatory load is released. Continue to flow a constant current to the preload when switching. As a result, the voltage hardly changes rapidly at the time of switching, so that it is possible to suppress the generation of instantaneous large current.

  As described above, when switching from the in-series star state to the in-series delta state, generation of an instantaneous large current in the circuit of the motor A can be suppressed by switching while supplying current to the preparatory load.

  As described above, the refrigeration cycle apparatus Rc can maintain the efficiency of the compressor 11 (electric motor A) high in many states by switching the connection state of the coils according to the operating state. This makes it possible to suppress power consumption when used intermittently or continuously over a long period of time. In addition, since coil switching is performed after an intermediate state using a pre-load, momentary large current is less likely to be generated, and the circuit may be damaged or the life may be shortened. It can be suppressed.

Second Embodiment
Another example of the refrigeration cycle apparatus according to the present invention will be described with reference to the drawings. The basic configuration of a refrigeration cycle apparatus Rc according to the present invention is the same as that of the refrigeration cycle apparatus Rc according to the first embodiment, except that control for switching the state of the coil is different. Therefore, the detailed description of the refrigeration cycle apparatus Rc is omitted.

  In the first embodiment, the motor A is driven corresponding to the operating state of the refrigeration cycle apparatus Rc. Therefore, it is possible to switch the state of the coil simply and appropriately. In the case of such a configuration, it is possible to increase the efficiency to some extent in each operating state. On the other hand, depending on the refrigeration capacity required of the refrigeration cycle apparatus Rc, an operation at an output during each operating state may be required.

  Then, the procedure which determines the timing which switches the connection state of a coil is demonstrated. FIG. 12 is a graph showing the relationship between the number of revolutions and the motor efficiency when the motor is driven in different coil connection states. In the graph shown in FIG. 12, the ordinate represents the motor efficiency, and the abscissa represents the motor rotational speed. In the graph shown in FIG. 12, the broken line L1 is a series star state, the solid line L2 is a series delta state, the alternate long and short dash line L3 is a parallel star state, and the thick line L4 is a motor efficiency and rotational speed when coil units are connected in a parallel delta state. Is shown.

  As shown in FIG. 12, in the refrigeration cycle apparatus Rc, the motor efficiency is higher in the broken line L1 than in the solid line L2 from the start of operation to the first rotation speed R1. That is, in the region less than the first rotation speed R1, the connection state of the coil unit of the compressor 11 (motor A) is more efficient in the serial star state than in the serial delta state. Therefore, the control unit 36 is driven in the serial star state when the rotation speed of the motor A is less than the first rotation speed R1, and switches to the series delta state when the rotation speed becomes equal to or more than the first rotation speed R1.

  Further, as shown in FIG. 12, the solid line L2 is higher than the alternate long and short dash line L3 up to the second rotation speed R2. That is, in the range from the first rotation speed R1 to the second rotation speed R2, the compressor 11 (motor A) is more efficient in the connection state of the coil units in the serial star state than in the serial delta state. Therefore, the control unit 36 drives in the series delta state when the number of revolutions of the motor A is equal to or greater than the first number of revolutions R1 and less than the second number of revolutions R2.

  Similarly, the upper and lower sides of the motor efficiency are switched, in other words, the connection state of the coil unit is switched at the rotational speed at which the graphs of the motor efficiency intersect. As described above, it is possible to perform more detailed control by detecting the motor efficiency for each connection state of the coil unit and switching the connection state of the coil unit at the rotational speed at which the magnitude of the motor efficiency switches.

  In the present embodiment, the switching rotation number is stored, and the connection state of the coil unit is switched each time the rotation number is reached, but the present invention is not limited to this. For example, the motor efficiency when the connection state of the coil unit is switched is stored, and when the motor efficiency of the motor A in operation is stored, the connection state of the coil unit is switched. Good.

  Further, in the case of the configuration for detecting the motor efficiency during the operation of the motor A, the relationship between the rotational speed and the motor efficiency is graphed as shown in FIG. 12 and the graph is successively updated to switch the motor efficiency. The value of may be updated. By doing this, even if variations occur in the coil portion, the switching element, etc., it is possible to drive the motor A, that is, the compressor 11 with high efficiency. It is also possible to absorb variations due to refrigerant changes and piping changes.

  In the present embodiment, the connection state of the coil unit is switched using the relationship between the rotational speed of the motor A and the motor efficiency, but the present invention is not limited to this. For example, the rotational speed of the motor A and The connection state of the coil unit may be switched using the relationship between (or) torque and motor efficiency. For example, in the case of rapidly increasing the rotational speed, etc., it may result that the efficiency may be higher as a result of raising the rotational speed at a high torque and ignoring the motor efficiency. In such a case, the connection state of the coil unit may be selected, which has high motor efficiency to some extent at high torque. Further, in the case of high torque, since the current increases, a connection state having a smaller electric resistance may be selected to reduce copper loss.

  The other features are the same as in the first embodiment.

Third Embodiment
Another example of the refrigeration cycle apparatus according to the present invention will be described with reference to the drawings. FIG. 13 is a circuit diagram of a motor provided with a compressor of a refrigeration cycle apparatus according to the present invention. The motor B shown in FIG. 13 has a configuration in which the preliminary loads Z1, Z2, and Z3 and the switching elements 333, 334, 343, 344, 353, and 354 are omitted from the motor A.

  Similarly to the motor A, the motor B can be combined with the connection state (series or parallel) of the first coil portion 231 and the second coil portion 232 and the connection state (star connection and delta connection) of the coil unit. That is, the motor B can be switched to the series star state, the series delta state, the parallel star state, and the parallel delta state.

  Then, when the connection state of the coil unit is switched while the operation of the motor B is continued, a large current is generated instantaneously when switching the connection state of the coil unit. It is known that this large current is generated when switching is performed in the state where the rotational speed of the motor B is high. Therefore, when switching the connection state of the coil unit, the number of rotations is once lowered, the connection state of the coil unit is switched, and then the number of rotations of the switching timing is raised. By doing this, the rotational speed is reduced, so the efficiency may be reduced to some extent, but there is no need for a preload and a switching element for switching, and the compressor 11 including the electric motor B, that is, refrigeration It is possible to simplify the configuration of the cycle device Rc.

  And since the structure of the compressor 11 containing the electric motor B is simple, it is also possible to reduce the effort (cost) concerning maintenance inspection.

  The other features are the same as those of the first and second embodiments.

  Although the thing which connects the 1st coil part and 2nd coil part of the coil unit of each phase in series or parallel is mentioned in each above-mentioned embodiment, it is not limited to this. By appropriately arranging the switching element, it is also possible to adopt a configuration in which either one of the first coil portion or the second coil portion is used. Moreover, as a 1st coil part and a 2nd coil part, although it is set as the same structure (the number of turns, impedance), it is not limited to this.

  In each of the above-described embodiments, the coil unit of each phase is described as an example having two coils of the first coil portion and the second coil portion, but it is not limited to this. For example, three or more coil units may be provided. In addition, when the coil unit is configured of one coil portion, and the coil unit is switched from the star connection to the delta connection, a configuration using a preliminary load can also obtain the same effect as that of the present invention.

  Moreover, although what has a fixed impedance is used as a pre-load, a variable thing may be used and it is equipped with several pre-loads, and using the switching element, the pre-load used is used. You may switch and use.

  Although the above-mentioned embodiment mentions what uses a refrigerating cycle device for an air conditioner, it is not limited to this, for example, heat exchange over a long period of time, such as a refrigerator, a drying washing machine, a water heater, etc. And can be used as a heat exchange device of the device whose operating condition changes.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to this content. Moreover, the embodiment of the present invention can add various modifications without departing from the spirit of the invention.

Rc Refrigeration cycle device 11 Compressor 12 Four-way valve 13 Outdoor heat exchanger 131 Outdoor fan 14 Decompression unit 15 Indoor heat exchanger 151 Indoor fan 16 Accumulator A Motor 20 Stator 21 Slot 22 Rotor 221 Output shaft 23U U-phase coil unit 23V V phase Coil unit 23 W W-phase coil unit 231 first coil portion 232 second coil portion 31 motor controller 311 U terminal 312 V terminal 313 W terminal 321, 322, 323 switching element 331, 332, 333, 334, 335 switching element (U phase Coil unit)
341, 342, 343, 344, 345 switching elements (V phase coil unit)
351, 352, 353, 354, 355 switching elements (W-phase coil unit)
36 Control unit

Claims (3)

A refrigeration cycle apparatus mounted with a compressor comprising: a stator on which a plurality of coil units including a plurality of coils are arranged; and a rotor on which a plurality of poles are formed,
A control unit that switches connection states of coils included in each of the plurality of coil units;
Each of the plurality of coil units is provided with a preload,
The control unit switches connection states of the plurality of coil units according to operating conditions;
The control unit connects the pre-load independently with the plurality of coils to provide an intermediate state in which current is supplied to the plurality of coils and the pre-load, and the plurality of the plurality of pre-loads are maintained while maintaining the connection state of the pre-load. Switch the wire connection of the coil unit,
The intermediate state, the plurality of coils delta connection, the refrigeration cycle the preliminary load is the current to the plurality of coils and the preloaded state of the star connection, characterized in connected state der Rukoto can be supplied apparatus. The refrigeration cycle apparatus according to claim 1, wherein the control unit switches the connection state of the plurality of coils based on at least one of a rotation speed and a torque of the compressor . The coil unit comprises two coils of the same configuration,
A first state in which coil units in which two coils are connected in series are connected by star connection;
A second state in which coil units in which two coils are connected in series are connected by delta connection;
A third state in which coil units in which two coils are connected in parallel are connected by star connection;
The refrigeration cycle apparatus according to claim 1 or 2, which can be switched to a fourth state in which coil units in which two coils are connected in parallel are connected by delta connection .

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