JP6286669B2 - Inverter control device - Google Patents

Description

  The present invention relates to an inverter control device that drives a motor of a compressor used in an air conditioner or the like at an arbitrary rotational speed.

  2. Description of the Related Art Conventionally, a compressor is used as a compressor motor control device that can reduce the cost and reduce the number of man-hours for mounting the heat source member without separately installing a dedicated heat source member for heating the lubricating oil of the compressor. A torque control means for controlling the current value for driving the compressor motor so that the output torque of the motor becomes a required torque, and a phase shifting means for shifting the current phase of the compressor motor from the optimum point at which the maximum efficiency is achieved, Some motors are driven by operating torque control means while operating phase shifting means during defrosting (see, for example, Patent Document 1).

  According to the technique disclosed in Patent Document 1, in order to perform torque control while shifting the phase of the current for driving the motor from the optimum point during defrosting, an excessive current is loaded on the motor, and the amount of heat generated by the motor And the refrigerant temperature and lubricating oil temperature inside the compressor can be quickly raised.

JP 2012-251713 A

  However, the conventional control device has a problem that the load fluctuation of the motor output torque in the torque control is considered only zero or more, and the maximum motor heat generation effect is not obtained.

  The present invention solves the above-mentioned conventional problems, and by providing a regeneration mode in which the motor output torque is negative, the motor output torque fluctuation range is expanded, and the motor heat generation effect is maximized to maximize the refrigerant in the compressor. An object of the present invention is to provide an inverter control device capable of quickly raising the temperature and the lubricating oil temperature.

  In order to solve the above conventional problems, an inverter control device according to the present invention includes a compressor that compresses a refrigerant, a motor that drives the compressor, and an inverter that converts DC power into AC power and supplies the motor with power. And an inverter control device for controlling the current value for driving the motor so that the output torque of the motor becomes a required torque in the defrosting operation mode. The positive power running mode including zero output torque and the regenerative mode in which the output torque is negative are periodically switched.

  Thus, by providing a regenerative mode in which the output torque of the compressor motor is negative, the fluctuation range of the output torque is expanded, an excessive current is applied to the motor to increase the amount of heat generated by the motor, and the refrigerant inside the compressor Temperature and lubricating oil temperature can be raised quickly. In particular, during defrosting of an air conditioner or the like, the defrosting time can be shortened by increasing the refrigerant temperature, and can be quickly switched to heating operation.

  The inverter control device of the present invention provides a regenerative mode in which the motor output torque is negative, thereby expanding the range of fluctuation of the motor output torque, maximizing the motor heat generation effect, and reducing the refrigerant temperature and lubricating oil temperature inside the compressor. It can be raised quickly.

Configuration diagram of a refrigeration cycle apparatus using the inverter control apparatus of the present invention System configuration diagram of inverter control device of the present invention Configuration diagram of a current command generator in the inverter control device according to Embodiment 1 of the present invention. Configuration diagram of a current command generator in the inverter control device in Embodiment 2 of the present invention Configuration diagram of a current command generator in the inverter control device in Embodiment 3 of the present invention Motor torque characteristics for current phase First operation characteristic diagram of the inverter control device of the present invention Second operational characteristic diagram of inverter control device of the present invention Third characteristic diagram of the inverter control device of the present invention Fourth operation characteristic diagram of inverter control apparatus of the present invention Operation explanatory diagram of powering regeneration switching means in the inverter control device of the present invention

  1st invention is the compressor which compresses a refrigerant | coolant, the motor which drives a compressor, the inverter which converts direct-current power into alternating current power, and supplies electric power to a motor, and the electric current which detects the electric current value which drives a motor In the inverter control device that includes a detecting means and controls a current value for driving the motor so that the output torque of the motor becomes a required torque, in the defrosting operation mode, the power output mode in which the motor output torque is positive including zero The regeneration mode in which the output torque is negative is periodically switched.By providing the regeneration mode in which the output torque of the compressor motor is negative, the fluctuation range of the output torque is expanded, and an excessive current is supplied to the motor. When the load is applied, the amount of heat generated by the motor can be increased, and the refrigerant temperature and lubricating oil temperature inside the compressor can be quickly raised. In particular, during defrosting of an air conditioner or the like, the defrosting time can be shortened by increasing the refrigerant temperature, and can be quickly switched to heating operation.

  According to a second aspect of the invention, particularly in the inverter control device of the first aspect of the invention, the inverter control device further includes a current phase adjusting unit that adjusts a current phase of the motor. The current phase is adjusted from the phase where the output torque is maximum to the direction in which the output torque is positive within the positive range, and in the regeneration mode, the motor current phase is adjusted to the phase where the output torque is minimum. While operating in the power running mode to shift the current phase of the compressor motor from the optimum point, the maximum negative torque is generated in the regenerative mode, thereby maximizing the motor heat generation effect and increasing the refrigerant temperature and lubricating oil inside the compressor. The temperature can be raised more quickly.

  In the third aspect of the invention, in particular, in the inverter control device of the first or second aspect, the absolute value of the ratio of the cumulative value of the output torque in the regeneration mode to the cumulative value of the output torque in the powering mode in a predetermined time is 3 minutes. The regenerative mode is provided so as to be 1 or less, and the driving of the compressor motor can be maintained by suppressing excessive negative torque due to the regenerative mode.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
As an application example of the refrigeration cycle apparatus of the inverter control apparatus of the present invention, an air conditioner used in a general household will be described. FIG. 1 is a configuration diagram of a refrigeration cycle apparatus (air conditioner) provided with an inverter control apparatus of the present invention.

  The refrigeration cycle apparatus includes a compressor 31 that compresses refrigerant, a four-way valve 32 that switches a refrigerant circuit during cooling and heating operation, an outdoor heat exchanger 33 that exchanges heat of the outside air with a refrigerant that functions as a condenser during cooling and serves as an evaporator during heating. The outdoor fan 37 that promotes heat exchange between the refrigerant flowing in the outdoor heat exchanger 33 and the outside air, the expansion device 34 that depressurizes the refrigerant, the evaporator and the air during the cooling by exchanging the heat of the refrigerant and the indoor air, and the condenser during the heating. An indoor heat exchanger 35, an indoor fan 38 that promotes heat exchange between the refrigerant flowing in the indoor heat exchanger 35 and room air, and an accumulator 36 provided on the suction side of the compressor 31 are provided.

  The indoor unit 41 includes an indoor heat exchanger 35 and an indoor fan 38. The outdoor unit 42 includes a compressor 31, a four-way valve 32, an outdoor heat exchanger 33, an expansion device 34, an accumulator 36, and an outdoor fan 37. The indoor unit 41 and the outdoor unit 42 are connected by a liquid side connection pipe 43 and a gas side connection pipe 44.

  A compressor motor 5 is provided inside the compressor 31 and rotationally drives a compression mechanism (not shown) that compresses the refrigerant. The compressor motor 5 is electrically connected to inverter control means 6 described later.

  The outdoor unit 42 includes a control device (not shown) that controls the four-way valve 32, the expansion device 34, the outdoor fan 37, and the like. In addition, the inverter control means 6 mentioned later may be provided in the control apparatus.

  Operation | movement is demonstrated about the refrigeration cycle apparatus comprised in this way. First, the cooling operation and the heating operation which are normal operation modes will be described.

  During the cooling operation, the refrigerant compressed by the compressor 31 becomes a high-temperature and high-pressure refrigerant and is sent to the outdoor heat exchanger 33 through the four-way valve 32. Then, the outdoor fan 37 promotes heat exchange with the outside air to dissipate heat and becomes a high-pressure liquid refrigerant that is sent to the expansion device 34. In the expansion device 34, the pressure is reduced to form a low-temperature and low-pressure two-phase refrigerant, which is sent to the indoor heat exchanger 35 through the liquid side connection pipe 43.

  The indoor air sucked by the indoor fan 38 exchanges heat with the refrigerant through the indoor heat exchanger 35, and the refrigerant absorbs the heat of the indoor air and evaporates to become a low-temperature gas refrigerant. At this time, the indoor air absorbed by the refrigerant is lowered in temperature and humidity and blown out into the room by the indoor fan 38 to cool the room.

  The gas refrigerant passes through the gas side connection pipe 44 and enters the four-way valve 32, and returns to the compressor 31 through the accumulator 36.

On the other hand, during the heating operation, the refrigerant compressed by the compressor 31 passes through the four-way valve 32 and is sent to the gas side connection pipe 44 as a high-temperature and high-pressure refrigerant. The indoor air sucked in by the indoor fan 38 exchanges heat with the refrigerant through the indoor heat exchanger 35, and the refrigerant dissipates heat to the indoor air and condenses to become high-pressure liquid refrigerant. At this time, the indoor air absorbs the heat of the refrigerant and is blown into the room by the indoor fan 38 in a state where the temperature is raised, thereby heating the room. Thereafter, the refrigerant is sent to the expansion device 34 through the liquid side connection pipe 43, and is reduced in pressure by the expansion device 34 to become a low-temperature and low-pressure two-phase refrigerant, and is sent to the outdoor heat exchanger 33, and the outdoor fan 37 Heat exchange is promoted to evaporate, and the vapor is returned to the compressor 31 through the accumulator 36 through the four-way valve 32.

  Next, the defrosting operation mode will be described. When frost is generated in the outdoor heat exchanger 33 during the heating operation described above and the frost grows, the ventilation resistance of the outdoor heat exchanger 33 increases and the air volume decreases, and the evaporation temperature in the outdoor heat exchanger 33 is reduced. descend. When a temperature sensor (not shown) that detects the piping temperature of the outdoor heat exchanger 33 detects that the evaporation temperature has decreased as compared to the time of non-frosting, the control device (not shown) shifts from the heating operation. A defrosting operation instruction is output.

  When the heating operation is shifted to the defrosting operation, the four-way valve 32 is switched, and the refrigerant flows during the cooling operation described above. During the defrosting operation, the outdoor fan 37 and the indoor fan 38 are stopped. Thereby, the high-temperature refrigerant | coolant compressed by the compressor 31 is sent to the outdoor heat exchanger 33 via the four-way valve 32, and the frost generated in the outdoor heat exchanger 33 can be melted.

  When the frost melts and the detection value of the temperature sensor of the outdoor heat exchanger 33 increases due to the defrosting operation, a defrosting operation release instruction for returning to the heating operation (normal operation mode) is output again from the control device.

  FIG. 2 is a system configuration diagram of the inverter control apparatus of the present invention. This inverter control device is supplied with electric power from an AC power source 1 such as a commercial power source, rectifying means 2 for rectifying the supplied electric power, smoothing means 3 for smoothing the output voltage from the rectifying means 2, and smoothing means 3 Are provided with an orthogonal transform means 4 for converting the smoothed voltage into an alternating voltage having a desired frequency and voltage value, and an inverter control means 6 for transmitting information for driving the compressor motor 5 to the orthogonal transform means 4.

  The inverter control means 6 can be configured by a microcomputer, a system LSI, or the like. Each of the base driver 10, the PWM signal generation unit 11, the current command generation unit 12, the rotor position speed estimation unit 13, and the phase current conversion unit 14 is provided. Has functional blocks.

  The phase current conversion unit 14 observes the direct current side bus current of the orthogonal conversion unit 4 flowing in the current detection unit 7 and converts the bus current into the phase current of the compressor motor 5 (specific phase current conversion unit 14 specific For the method, see, for example, Japanese Patent Application Laid-Open No. 2003-189670.

  Needless to say, the phase current of the compressor motor 5 may be directly detected using a current sensor or the like.

  In the rotor position speed estimation unit 13, the compressor current is calculated based on the phase current of the compressor motor 5 converted by the phase current conversion unit 14 and the voltage applied to the compressor motor 5 calculated by the PWM signal generation unit 11. The rotor magnetic pole position and the rotation speed of the motor 5 are estimated (for a specific method of the rotor position / speed estimation unit 13, refer to, for example, Japanese Patent Laid-Open No. 2001-37281).

  In the PWM signal generation unit 11, the current command value derived by the current command generation unit 12, the phase current of the compressor motor 5 converted by the phase current conversion unit 14, and the rotor position speed estimation unit 13 are estimated. A PWM signal for driving the compressor motor 5 is generated based on information on the rotor magnetic pole position of the compressor motor 5.

  The PWM signal obtained as described above is finally output to the base driver 10 to drive the switching elements constituting the orthogonal transform means 4.

FIG. 3 is a configuration diagram of the current command generation unit 12 in the first embodiment. The current command generation unit 12 includes functional blocks of a speed control unit 12a, a torque control unit 12b, a rotating coordinate system current command calculation unit 12c, a current phase adjustment unit 12d, and an operation mode switching unit 12e. .

  In the operation mode switching unit 12e, the operation mode is switched between the normal operation mode and the defrosting operation mode in accordance with a defrosting operation instruction given from the outside.

  In the inverter control device of the present invention, the compressor motor 5 is operated only in the power running mode (when the output torque of the compressor motor 5 is positive including zero) in the normal operation mode, and the power running mode in the defrost operation mode. And the regenerative mode (when the output torque of the compressor motor 5 is negative) are periodically switched to operate the compressor motor 5.

  In the speed controller 12a, the rotational speed of the compressor motor 5 is converted into a speed command based on deviation information between the estimated speed value of the compressor motor 5 estimated by the rotor position speed estimator 13 and a speed command value given from the outside. The first current command value Is1 (current value corresponding to the output torque average value of the compressor motor 5) is derived using PI calculation or the like so as to coincide with the value.

  In the torque control unit 12b, based on the speed information of the compressor motor 5 estimated by the rotor position speed estimation unit 13, the output torque of the compressor motor 5 is matched with the load torque generated by the load element. Current command value Is2 (current value corresponding to the output torque fluctuation value of the compressor motor 5) is derived, and a current command value that is a composite value of the first current command value Is1 and the second current command value Is2. Is is output.

  The second current command value Is2 is set as in the following equation, for example.

Is2 = K × Is1 × SIN (ω1 × t + δ) (1)
Here, K is a gain, ω1 is a speed estimation value, and δ is a phase angle.

  Therefore, when the second current command value Is2 is set as shown in Equation (1), the current command value Is is expressed by the following equation.

Is = {1 + K × SIN (ω1 × t + δ)} × Is1 (2)
Needless to say, the method described in documents such as Japanese Patent Application Laid-Open No. 2001-37281 may be used to derive the second current command value Is2.

  Further, in the torque control unit 12b, when the operation mode output from the operation mode switching unit 12e is the normal operation mode, for example, even when the gain K in Expression (2) is greater than 1, the current command value Is is By providing the first lower limit value (zero) in the current command value Is so as not to be negative, the compressor motor 5 can be operated only in the powering mode.

  Examples of operation waveforms in the normal operation mode are shown in FIGS. For each operation waveform, (a) is the current command value Is, (b) is the motor phase current, and (c) is the output torque of the compressor motor 5.

  When the gain K is 1, the current command value Is changes sinusoidally in the range from the lower limit (zero) to the maximum value (2 × Is1) as shown in FIG. As shown in FIG. 7C, the output torque varies in a sine wave shape with a value equal to or greater than zero.

  When the gain K is larger than 1, the current command value Is has a waveform shape in which the lower limit side is restricted as shown in FIG. 8A, and the motor phase current changes as shown in FIG. 8B. Thus, as shown in FIG. 8C, the output torque fluctuates in a waveform shape with a value of zero or more and a lower limit value side limited.

  Further, in the torque control unit 12b, when the operation mode output from the operation mode switching unit 12e is the defrosting operation mode, the gain of the expression (2) is set to be larger than 1 and the current command value Is is set. By providing the second lower limit value (a predetermined value smaller than zero), the power running mode and the regeneration mode can be switched periodically. However, if the gain K is increased too much, excessive negative torque is generated and it becomes difficult to maintain the drive of the compressor motor 5. Therefore, for example, based on actual machine test results and simulation analysis results, the compressor motor Therefore, it is necessary to set in advance the gain K and the second lower limit value of the current command value Is such that the drive of 5 can be maintained.

  An example of operation waveforms in the defrosting operation mode is shown in FIG. For each operation waveform, (a) is the current command value Is, (b) is the motor phase current, and (c) is the output torque of the compressor motor 5.

  In the example of the operation waveform of FIG. 9, the gain K in the equation (2) is set to be larger than 1, but the lower limit value side is not limited by the second lower limit value (predetermined value smaller than zero) of the current command value Is. As shown in FIG. 9A, the current command value Is changes to a sine wave with respect to the average value Is1 while taking a negative value, and the motor phase current changes as shown in FIG. 9B. As shown in FIG. 9C, the output torque fluctuates in a sine wave shape while taking a negative value.

  7 to 9, the gain K is changed so that the average value of the output torque is the same in a predetermined compressor motor specification. In the case of FIG. 7 (the gain K is 1 and the fluctuation range of the output torque is shown). If the effective motor phase current value from zero to twice the average value is 1, the case of FIG. 9 (the gain K is greater than 1 and the current command value Is is a second lower limit value (a predetermined value less than zero). )), The motor phase current effective value is about 1.37 times, and the heat generation amount (copper loss, etc.) of the motor is about 1.87 times. By increasing the motor heat generation amount, the refrigerant temperature and the lubricating oil temperature inside the compressor can be quickly raised.

  In the rotating coordinate system current command calculation unit 12c, based on the operation mode information output from the operation mode switching unit 12e and the current phase βm output from the current phase adjustment unit 12d (for example, actual machine test results and simulation analysis results). The current command value of the rotational coordinate system is derived from the current phase setting value as table data such as the power supply voltage and the rotational speed in advance.

  First, when the operation mode output from the operation mode switching unit 12e is the normal operation mode, the compressor motor 5 is operated only in the power running mode. , Iqs).

Ids = − | Is | × SIN (βm) (3)
Iqs = + | Is | × COS (βm) (4)
Here, | Is | is the absolute value of the current command value Is.

  When the operation mode output from the operation mode switching unit 12e is the defrosting operation mode, the compressor motor 5 is operated by periodically switching between the power running mode and the regeneration mode. The derivation of the current command values (Ids, Iqs) of the rotating coordinate system is switched.

  In the power running mode in which the current command value Is is zero or more, the current command values (Ids, Iqs) of the rotating coordinate system are derived from the equations (3) and (4) as in the normal operation mode, and the current command value Is In the regenerative mode in which is negative, current command values (Ids, Iqs) of the rotating coordinate system are derived as in the following equation.

Ids = − | Is | × SIN (π−βm) = − | Is | × SIN (βm)
... (5)
Iqs = + | Is | × COS (π−βm) = − | Is | × COS (βm)
... (6)
Therefore, in the defrosting operation mode, according to the sign of the current command value Is, in the power running mode, the rotation is performed from the equations (3) and (4), and in the regeneration mode, from the equations (5) and (6). A current command value (Ids, Iqs) of the coordinate system is derived.

  In the PWM signal generation unit 11, the current command value (Ids, Iqs) of the rotating coordinate system obtained as described above and the current detection value (Id, Iq) of the compressor motor 5 (converted by the phase current conversion unit 14). The voltage command values (Vds, Vqs) of the rotating coordinate system are derived using PI calculation or the like so that the phase current of the compressor motor 5 is calculated by converting the phase current of the compressor motor 5 by three-phase / two-phase conversion. A phase voltage command value (Vus, Vvs, Vws) is derived by performing a two-phase / three-phase conversion on the voltage command value (Vds, Vqs) of the rotating coordinate system, and this phase voltage command value (Vus, Vvs, Vws). Thus, a PWM signal for driving the compressor motor 5 is generated.

In this way, by providing a regenerative mode in which the output torque of the compressor motor is negative, the fluctuation range of the output torque is expanded, and an excessive current is applied to the motor to increase the heat generation amount of the motor. Refrigerant temperature and lubricating oil temperature can be raised rapidly. In particular, during defrosting of an air conditioner or the like, the defrosting time can be shortened by increasing the refrigerant temperature, and can be quickly switched to heating operation.
(Embodiment 2)
Hereinafter, the inverter control apparatus in the 2nd Embodiment of this invention is demonstrated. The main system configuration is the same as that of the inverter control device in the first embodiment, and the description thereof is omitted because it is redundant. Here, only the contents of the operation different with respect to the current command generation unit 12 having a different configuration will be described. .

  FIG. 4 is a configuration diagram of the current command generation unit 12 in the second embodiment. The current command generation unit 12 includes functional blocks of a speed control unit 12a, a torque control unit 12b, a rotating coordinate system current command calculation unit 12c, a current phase adjustment unit 12d, and an operation mode switching unit 12e. .

  The functional blocks other than the rotating coordinate system current command calculation unit 12c and the current phase adjustment unit 12d are the same as those of the inverter control device according to the first embodiment, and are not described because they are redundantly described.

  In the current phase adjustment unit 12d, the current phase is switched between the normal operation mode and the defrost operation mode based on the operation mode information output from the operation mode switching unit 12e.

  FIG. 6 shows an example of a motor torque characteristic with respect to a current phase under a constant motor current value. In a motor utilizing reluctance torque such as an embedded magnet field type synchronous motor (IPMSM), magnet torque and reluctance are shown. The combined value with the torque becomes the output torque of the motor, the current phase βm1 is the phase that becomes the maximum torque, and the current phase βm3 is the phase that becomes the minimum torque (negative torque).

  In the current phase adjustment unit 12d, when the operation mode output from the operation mode switching unit 12e is the normal operation mode, only the power running mode (output torque is zero or more) and the current phase βm (for example, actual machine test results, etc.) In consideration of the above, a current phase set value is provided in advance as table data such as the power supply voltage and the number of revolutions, and the current phase βm1 (the phase that provides the maximum torque) within the operable range of the compressor motor 5 from the viewpoint of reducing power consumption. Is preferably set).

  Further, in the current phase adjustment unit 12d, when the operation mode output from the operation mode switching unit 12e is the defrosting operation mode, the motor is periodically switched between the power running mode and the regenerative mode (output torque is negative). In the powering mode, the output torque is adjusted in the forward direction within the positive range in the powering mode (in the range of less than 90 deg from the current phase βm1, for example, Setting the current phase βm2) enhances the effect of field weakening control. In the regenerative mode, setting the current phase βm3 (the phase that results in the minimum torque) generates the maximum negative torque. Both the power running mode and the regenerative mode In this mode, the motor can be loaded with an excessive current with respect to the inverter control device of the first embodiment.

  Therefore, in the current phase adjustment unit 12d, one current phase set value of the current phase βm is set in the normal operation mode, and the current phase βm2 (power running mode) and βm3 (regenerative mode) in the defrosting operation mode. Two current set values are output.

  In the rotating coordinate system current command calculation unit 12c, the operation mode information output from the operation mode switching unit 12e and the current phase output from the current phase adjustment unit 12d (current phase βm in the normal operation mode, defrosting) In the operation mode, current command values (Ids, Iqs) of the rotating coordinate system are derived from the current phases βm2 and βm3).

  First, when the operation mode output from the operation mode switching unit 12e is the normal operation mode, the compressor motor 5 is operated only in the power running mode. , Iqs).

Ids = − | Is | × SIN (βm) (7)
Iqs = + | Is | × COS (βm) (8)
Here, | Is | is the absolute value of the current command value Is.

  When the operation mode output from the operation mode switching unit 12e is the defrosting operation mode, the compressor motor 5 is operated by periodically switching between the power running mode and the regeneration mode. The derivation of the current command values (Ids, Iqs) of the rotating coordinate system is switched.

  In the power running mode in which the current command value Is is zero or more, the current command values (Ids, Iqs) of the rotating coordinate system are derived from the current phase βm2 (power running mode) as in the following equation.

Ids = − | Is | × SIN (βm2) (9)
Iqs = + | Is | × COS (βm2) (10)
In the regenerative mode in which the current command value Is is negative, the current command values (Ids, Iqs) of the rotating coordinate system are derived from the current phase βm3 (regenerative mode) as in the following equation.

Ids = − | Is | × SIN (π−βm3) = − | Is | × SIN (βm3)
(11)
Iqs = + | Is | × COS (π−βm3) = − | Is | × COS (βm3)
(12)
Therefore, in the defrosting operation mode, according to the sign of the current command value Is, the power running mode is rotated from the equations (9) and (10), and the regeneration mode is rotated from the equations (11) and (12). A current command value (Ids, Iqs) of the coordinate system is derived.

  An example of an operation waveform in the defrosting operation mode is shown in FIG. For each operation waveform, (a) is the current command value Is, (b) is the motor phase current, and (c) is the output torque of the compressor motor 5.

  In the example of the operation waveform of FIG. 10, the gain K in the equation (2) is set to be larger than 1, but the lower limit value side is not limited by the second lower limit value (predetermined value smaller than zero) of the current command value Is. As shown in FIG. 10A, the current command value Is changes in a sine wave shape with respect to the average value Is1 while taking a negative value, and the motor phase current changes as shown in FIG. 10B. As shown in FIG. 10C, the output torque fluctuates in a sine wave shape while taking a negative value. However, in FIG. 10, the current phase βm2 is switched in the power running mode, and the current phase βm3 is switched in the regeneration mode.

  In FIG. 9 (example of operation waveform of the inverter control device in the first embodiment) and FIG. 10, the gain K and the current phase are changed so that the average value of the output torque is the same in a predetermined compressor motor specification. If the effective motor phase current value is 1 in the case of FIG. 9 (the common current phase βm is set in the power running mode and the regenerative mode), the current phase βm2 in the regenerative mode in the case of FIG. In this case, the motor phase current effective value is about 1.37 times and the motor heat generation amount (copper loss, etc.) is about 1.87 times. By increasing the motor heat generation amount, the refrigerant temperature and lubricating oil temperature inside the compressor can be increased more rapidly.

  In the PWM signal generation unit 11, the current command value (Ids, Iqs) of the rotating coordinate system obtained as described above and the current detection value (Id, Iq) of the compressor motor 5 (converted by the phase current conversion unit 14). The voltage command values (Vds, Vqs) of the rotating coordinate system are derived using PI calculation or the like so that the phase current of the compressor motor 5 is calculated by converting the phase current of the compressor motor 5 by three-phase / two-phase conversion. A phase voltage command value (Vus, Vvs, Vws) is derived by performing a two-phase / three-phase conversion on the voltage command value (Vds, Vqs) of the rotating coordinate system, and this phase voltage command value (Vus, Vvs, Vws). Thus, a PWM signal for driving the compressor motor 5 is generated.

In this way, by providing the regeneration mode in which the output torque of the compressor motor is negative, the fluctuation range of the output torque is expanded, and in the power running mode, the operation is performed by shifting the current phase of the compressor motor from the optimum point. Sometimes, by generating the maximum negative torque, the motor heat generation effect can be maximized and the refrigerant temperature and lubricating oil temperature inside the compressor can be increased more rapidly. In particular, during defrosting of an air conditioner or the like, the defrosting time can be shortened by increasing the refrigerant temperature, and the heating operation can be switched more rapidly.
(Embodiment 3)
Hereinafter, the inverter control apparatus in the 3rd Embodiment of this invention is demonstrated. The main system configuration is the same as that of the inverter control device in the first embodiment, and the description thereof is omitted because it is redundant. Here, only the contents of the operation different with respect to the current command generation unit 12 having a different configuration will be described. .

  FIG. 5 is a configuration diagram of the current command generation unit 12 in the third embodiment. The current command generation unit 12 includes a speed control unit 12a, a torque control unit 12b, a rotating coordinate system current command calculation unit 12c, a current phase adjustment unit 12d, an operation mode switching unit 12e, and a power running regeneration ratio calculation unit 12f. Each functional block is provided.

  The functional blocks other than the torque control unit 12b and the power regeneration ratio calculation unit 12f are the same as those of the inverter control device according to the second embodiment, and are not described because they are redundantly described.

  Further, the basic operation of the torque control unit 12b is the same as that of the inverter control device in the first embodiment, and only the contents different in operation will be described here.

In the torque control unit 12b, when the operation mode output from the operation mode switching unit 12e is the defrosting operation mode, the gain of the expression (2) is set to be larger than 1 and the current command value Is is set to the second value.
Can be periodically switched between the power running mode and the regenerative mode, but if the gain K is excessively increased, excessive negative torque is generated and the compressor motor Therefore, in the inverter control apparatus according to the third embodiment, the power running regeneration ratio output from the power running regeneration ratio calculation unit 12f described later is equal to or less than a predetermined value set in advance. Thus, a function for adjusting the gain K is provided.

  As an outline of the operation of the current command generation unit 12 in the defrosting operation mode, the torque control unit 12b performs powering based on the preset initial gain K1 (> 1) at the first processing timing (every predetermined time Ta). A current command value Is for periodically switching between the mode and the regeneration mode is derived, and the power running regeneration ratio calculation unit 12f derives a power running regeneration ratio based on the current command value Is.

  Next, at the second processing timing, the torque control unit 12b determines the powering regeneration ratio derived at the first processing timing based on a predetermined value (for example, an actual machine test result, a simulation analysis result, etc., and preferably Is less than 1/3), and when the power running regeneration ratio exceeds a predetermined value, a gain K2 (= K1−ΔK) obtained by reducing the gain K by an amount of change ΔK from the initial gain K1. ) To cause the negative torque in the regeneration mode to decrease. Conversely, when the power running regeneration ratio is equal to or less than a predetermined value set in advance, the gain K is set to a gain K2 (= K1 + ΔK) that is increased from the initial gain K1 by a change amount ΔK, thereby increasing the negative torque in the regeneration mode. Act in the direction. The current command value Is is derived based on the gain K2, and the power running regeneration ratio is derived by the power running regeneration ratio calculation unit 12f.

In the subsequent processing timing, by performing the same operation as the second processing timing, it is possible to maintain the drive of the compressor motor by suppressing excessive negative torque due to the regeneration mode. The compressor motor 5 in the regenerative mode with respect to the drive control amount of the compressor motor 5 in the power running mode is determined based on the operation mode information output from the operation mode switching unit 12e and the current command value Is output from the torque control unit 12b. The ratio of the drive control amount (hereinafter referred to as the power regeneration ratio) is derived. Here, in order to obtain the output torque information indirectly, the drive control amount is an absolute value of the cumulative value of the current command value Is.

  First, when the operation mode output from the operation mode switching unit 12e is the defrosting operation mode, the compressor motor 5 is operated by periodically switching between the power running mode and the regeneration mode. Cumulative value (ΣIsm) of current command value Is in power running mode (current command value Is is zero or more) and current command in regenerative mode (current command value is is negative) A cumulative value (ΣIsg) of the value Is is derived.

  FIG. 11 is a diagram for explaining the operation of the power running regeneration ratio calculation unit 12f. FIG. 11A shows the current command value Is, FIG. 11B shows the accumulated value of the current command value Is, and the current command value at a predetermined time Ta (in this example, three rotation cycles of the compressor motor 5). A value obtained by sequentially accumulating Is when Is is equal to or greater than zero is ΣIsm, and a value obtained by sequentially accumulating Is when the current command value Is is negative is ΣIsg.

  From the power running mode Is cumulative value (ΣIsm) and the regeneration mode Is cumulative value (ΣIsg) derived as described above, the power running regeneration ratio is derived as shown in the following equation.

Power regeneration ratio = | ΣIsg / ΣIsm | (13)
In addition, when the operation mode output from the operation mode switching unit 12e is normal operation, the compressor motor 5 is operated only in the power running mode, so that the power running regeneration ratio is zero (calculation by a microcomputer, a system LSI, or the like). In order to reduce the processing burden on the apparatus, the process of deriving the Is cumulative value and the power regeneration ratio is omitted).

  In this way, by providing the regeneration mode in which the output torque of the compressor motor is negative, the fluctuation range of the output torque is expanded, and in the power running mode, the operation is performed by shifting the current phase of the compressor motor from the optimum point. Sometimes, by generating the maximum negative torque, the motor heat generation effect can be maximized and the refrigerant temperature and lubricating oil temperature inside the compressor can be increased more rapidly. In particular, during defrosting of an air conditioner or the like, the defrosting time can be shortened by increasing the refrigerant temperature, and the heating operation can be switched more rapidly.

  Furthermore, a function of adjusting the gain K by the torque control unit 12b so that the power running regeneration ratio (absolute value of the ratio of the Is cumulative value of the regeneration mode to the Is cumulative value of the power running mode) at a predetermined time is 1/3 or less. By providing, the excessive negative torque by regeneration mode can be suppressed and the drive of a compressor motor can be maintained.

  As described above, the inverter control device according to the present invention can maximize the motor heat generation effect and quickly increase the refrigerant temperature and the lubricating oil temperature inside the compressor. Therefore, the air conditioner, the refrigerator, The present invention can be applied to an application for driving a compressor motor such as a refrigerator or a heat pump water heater.

DESCRIPTION OF SYMBOLS 1 AC power supply 2 Rectification means 3 Smoothing means 3a Reactor 3b Capacitor 4 Orthogonal transformation means 5 Compressor motor 6 Inverter control means 7 Current detection means 10 Base driver 11 PWM signal generation part 12 Current command generation part 12a Speed control part 12b Torque control part 12c Rotating coordinate system current command calculation unit 12d Current phase adjustment unit 12e Operation mode switching unit 12f Powering regeneration ratio calculation unit 31 Compressor 32 Four-way valve 33 Outdoor heat exchanger 34 Throttle device 35 Indoor heat exchanger 36 Accumulator 37 Outdoor fan 38 Indoor Fan 41 Indoor unit 42 Outdoor unit 43 Liquid side connection pipe 44 Gas side connection pipe

Claims (2)

A compressor that compresses refrigerant; a motor that drives the compressor; an inverter that converts DC power into AC power and supplies the motor; and current detection means that detects a current value that drives the motor. In the inverter control device for controlling the current value for driving the motor so that the output torque of the motor becomes a required torque, in the defrosting operation mode, the power running mode in which the output torque of the motor is positive including zero The regeneration mode in which the output torque is negative is periodically switched , and the absolute value of the ratio of the cumulative value of the output torque in the regeneration mode to the cumulative value of the output torque in the powering mode in a predetermined time is 1/3 or less. An inverter control device characterized in that a regeneration mode is provided . Current phase adjusting means for adjusting the current phase of the motor is further provided, and in the defrosting operation mode, the current phase adjusting means is configured to change the current phase of the motor from the phase where the output torque is maximum in the power running mode. 2. The inverter control device according to claim 1, wherein the phase of the motor is adjusted in a forward direction within a positive range, and the current phase of the motor is adjusted to a phase that minimizes the output torque in the regeneration mode.