TW201918013A - Air conditioner - Google Patents

Abstract

This air conditioner is provided with an electric motor (1), and a power conversion device (1) which uses a vector control method to perform power conversion. The power conversion device (1) is provided with: a pulse control unit (7) for outputting a pulse signal; a power conversion circuit (41) which uses the pulse signal to convert DC power into AC power; a current detection unit (6) which detects the current of the power conversion circuit (41); a vector control unit (8) for generating a command voltage for the pulse control unit (7); and a pulse stopping control unit (9) which generates a pulse stopping control signal for stopping the pulse signal in an interval determined using the current phase as a reference, and outputs the pulse stopping control signal to the pulse control unit (7). The vector control unit (8) starts operation of the pulse stopping control unit (9) if the motor current of the electric motor (1) is within a prescribed range of the motor current at the present rotational speed when there is no load.

Description

Air conditioner

[0001] The present invention relates to an air conditioner.

[0002] Various techniques have been developed for motor drive devices of air conditioners to achieve high efficiency and high output. For example, a technology of “180-degree energization” in which a current flowing from a motor drive device to a motor is switched in a sinusoidal waveform (Pulse Width Modulation) control has been disclosed. In addition, a technique has been disclosed in which the “120-degree energization” of the PWM control is switched so that the current flowing to the motor is intermittent based on the phase of the induced voltage generated by the motor as a reference. [0003] For example, it is described in Patent Document 1 that the PWM output is stopped for a certain period of time based on the vector control 180-degree energization method and the motor current phase during motor drive as a reference, thereby satisfying the specifications of the gate and driver. The switching loss during PWM control is reduced, and a highly efficient power conversion device can be provided. PRIOR ART DOCUMENT Patent Document [0004] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-115955

(Problems to be Solved by the Invention) [0005] The invention described in Patent Document 1 uses a motor current phase during motor driving as a reference to stop PWM output for a certain period of time, thereby reducing switching loss during PWM control. However, the invention described in Patent Document 1 is not a technology that achieves high efficiency in a wide range by being limited to a specific condition (below rotation speed / motor average current or less). In addition, if the PWM output is stopped by DC fan control, the influence of external interference such as wind, which is different from the compressor, must be considered. If the PWM output is stopped irrespective of the operating state, vibration may deteriorate or stop. [0006] Therefore, an object of the present invention is to provide an air conditioner that can reduce deterioration of motor driving and reduce copper loss while avoiding deterioration of motor vibration or motor stop. (Means for Solving the Problems) [0007] In order to solve the foregoing problems, the air conditioner system of the present invention includes: a motor; and a power conversion device that uses a vector control method to drive the aforementioned motors by PWM control. Power conversion. The power conversion device includes: a pulse control unit that outputs a pulse signal for performing the PWM control; and a power conversion circuit that includes a three-phase switching element and uses the output from the pulse control unit. The pulse signal converts DC power to AC power; a current detection unit detects a current flowing to the power conversion circuit; a vector control unit performs vector control based on the current detected by the current detection unit, Generating a command voltage to the pulse control section; and a pulse stop control section for stopping switching elements on the positive side and the negative side of a predetermined phase of the power conversion circuit, generating the reference voltage based on the current phase of the power conversion circuit A pulse stop control signal that stops the pulse signal in the set interval, and outputs the pulse stop control signal to the pulse control unit. The vector control unit is within a predetermined range if the motor current of the electric motor is within a predetermined range with no load relative to the current rotation speed, even if the operation of the pulse stop control unit is started. [0008] Other means will be described in a form for implementing the invention. [Effects of the Invention] [0009] According to the present invention, it is possible to achieve reduction in switching loss associated with motor driving and reduction in motor copper loss while avoiding deterioration of motor vibration or motor stop.

[0011] Hereinafter, embodiments for implementing the present invention will be described in detail with reference to the drawings. [Overview] The power conversion device of this embodiment includes a power conversion circuit (inverter) that converts DC power to AC power using a pulse signal controlled by PWM, and detects flow-to-power conversion A vector control unit that performs vector control on the power conversion circuit based on the current of the circuit. [0013] The power conversion device is additionally provided with an open phase section that stops a pulse signal in a section set based on a zero-cross point of a current phase flowing to the power conversion circuit as a reference, and stops switching elements of upper and lower arms of the same phase. Thereby, the power conversion device can reduce the number of switching times in the PWM control and reduce the switching loss. In addition, the power conversion device can obtain the correct position information of the magnet position of the motor by setting an open phase interval and the zero crossing point of the current phase. As a result, stable vector control can be performed, and the efficiency of the power conversion circuit (converter) and the motor can be improved. [0014] Hereinafter, an embodiment of a power conversion device according to the present invention will be described in detail with reference to the drawings. It should be noted that in all the drawings for explaining the embodiments, the same constituent elements are denoted by the same symbols in principle, and repeated descriptions thereof are omitted. [0015] FIG. 1 shows a circuit configuration of a power conversion device 1 of a PWM control method according to this embodiment. In the power conversion device 1 of this embodiment, as shown in FIG. 1, if a power conversion circuit 4 composed of a three-phase converter driven by PWM control is used, a vector control drive as a permanent magnet synchronous motor will be described In the case of the AC motor 3, a control method when a phase pulse stop interval (that is, an open phase interval) is set in the pulse signal of the power conversion circuit 4 is used. [0016] "Circuit Configuration of Power Conversion Device" As shown in FIG. 1, the power conversion device 1 is configured to include a power conversion circuit 4, a phase current detection unit 6, and a control device 5. The power conversion circuit 4 is configured to include a three-phase converter that converts DC power to AC power. The phase current detection unit 6 detects a motor current flowing to an AC motor (motor) 3 connected to the power conversion circuit 4. The control device 5 performs vector control based on the phase current information (current) α detected by the phase current detection unit 6 using a pulse signal for performing PWM control. A DC voltage Vd is applied to the power conversion circuit 4 by a power source 2. [0017] The power conversion circuit 4 is configured to include a power conversion main circuit 41 and a gate driver 42. The gate driver 42 generates a gate signal of an IGBT (Insulated Gate Bipolar Transistor) supplied to the power conversion main circuit 41 based on a pulse signal γ from the pulse control unit 7. The power conversion main circuit 41 is constituted by three-phase switching elements Q1 to Q6 each having an IGBT and a diode connected in parallel in opposite directions. This power conversion main circuit 41 has U-phase, V-phase, and W-phase switching pins, and uses a pulse signal γ output from the pulse control unit 7 to convert DC power to AC power. [0018] The U-phase switching pin is configured by connecting switching elements Q1 and Q2 in series between a positive electrode and a negative electrode. The collector of the switching element Q1 is connected to the positive electrode, and the emitter of the switching element Q2 is connected to the collector of the switching element Q2. The emitter of the switching element Q2 is connected to the negative electrode. The connection node between the emitter of the switching element Q1 and the collector of the switching element Q2 is connected to the U-phase coil of the AC motor 3. However, in this embodiment, the voltage at the connection node between the emitter of the switching element Q1 and the collector of the switching element Q2 is formed as the voltage Vu. The electricity flowing to the U-phase coil of the AC motor 3 is referred to as a U-phase AC current Iu. [0019] A pulse signal GPU + output from the gate driver 42 is applied to the gate of the switching element Q1. The gate of the switching element Q2 is applied with a pulse signal GPU- output from the gate driver 42. [0020] The V-phase switching pin is configured by connecting switching elements Q3 and Q4 in series between a positive electrode and a negative electrode. The collector of the switching element Q3 is connected to the positive electrode, and the emitter of the switching element Q3 is connected to the collector of the switching element Q4. The emitter of the switching element Q4 is connected to the negative electrode. The connection node between the emitter of the switching element Q3 and the collector of the switching element Q4 is connected to the V-phase coil of the AC motor 3. [0021] The gates of the switching elements Q3 and Q4 are each applied with a pulse signal output from the gate driver 42. [0022] The W-phase switching pin is configured by connecting switching elements Q5 and Q6 in series between a positive electrode and a negative electrode. The collector of the switching element Q5 is connected to the positive electrode, and the emitter of the switching element Q5 is connected to the collector of the switching element Q6. The emitter of the switching element Q6 is connected to the negative electrode. The connection node between the emitter of the switching element Q5 and the collector of the switching element Q6 is connected to the W-phase coil of the AC motor 3. [0023] The gates of the switching elements Q5 and Q6 are each applied with a pulse signal output from the gate driver 42. [0024] The control device 5 is configured to include a pulse control unit 7, a vector control unit 8, and a pulse stop control unit 9. The pulse control unit 7 supplies the pulse signal γ controlled by the applied voltage command (command voltage) V ^* to the gate driver 42 to perform PWM control. The vector control unit 8 performs vector control using the phase current information α detected by the phase current detection unit 6 and calculates an applied voltage command V ^* . The pulse stop control unit 9 outputs a pulse signal γ to the pulse control unit 7 to stop the phase pulse stop interval (open phase interval) δ in the vicinity of the current zero crossing based on the phase information (current phase) of the current calculated by the vector control. Phase pulse stop control signal (pulse stop control signal) β. The phase pulse stop control signal (pulse stop control signal) β stops the switching elements on the positive and negative sides of a predetermined phase of the power conversion circuit 4. [0025] Here, the vector control unit 8 is, for example, Non-Patent Document 1 (Sakamoto et al., "Simple Vector Control of a Permanent Magnet Synchronous Motor Without Position Sensor Suitable for Home Appliances", Electrical Theory D, Vol. 124 Vol. 2004) pp.1133-1140) or Non-Patent Document 2 (Tohoku et al., "Review of New Vector Control Methods for Permanent Magnet Synchronous Motors for High Speed" Electrical Theory D, Vol. 129 Vol. 1 (2009) pp. 36-45), it can be driven by detecting the output current of the converter to perform 3 phase-2 phase conversion (dq conversion; direct-quadrature conversion), feedback to the control system, and then perform 2 phase-3 phase conversion to drive The general vector control of the converter is implemented, and the control method is not specific. Therefore, since the operation of the vector control unit 8 is a well-known technique, detailed description is omitted. 2 is a front view of the indoor unit 100, the outdoor unit 200, and the remote controller Re of the air conditioner A in this embodiment. [0027] As shown in FIG. 2, the air conditioner A is called a so-called room air conditioner. The air conditioner A includes an indoor unit 100, an outdoor unit 200, a remote controller Re, and a power conversion device 1 (not shown in FIG. 2) shown in FIG. The indoor unit 100 and the outdoor unit 200 are connected by a refrigerant pipe 300, and the room in which the indoor unit 100 is installed is air-conditioned by a known refrigerant cycle. In addition, the indoor unit 100 and the outdoor unit 200 receive and transmit information to each other through a communication cable (not shown). In addition, the outdoor unit 200 is connected by wiring (not shown), and an AC voltage is supplied through the indoor unit 100. The power conversion device 1 (see FIG. 1) is provided in the outdoor unit 200 and converts AC power supplied from the indoor unit 100 side into DC power. [0028] The remote controller Re is operated by a user, and transmits an infrared signal to the remote controller transmitting and receiving unit Q of the indoor unit 100. The contents of the infrared signal are instructions such as operation request, setting temperature change, timer, operation mode change, and stop request. The air conditioner A performs air-conditioning operations such as a cold room mode, a warm room mode, and a dehumidification mode according to the instructions of the infrared signals. In addition, the indoor unit 100 sends data such as room temperature information, humidity information, and electricity bill information to the remote controller Re by the remote control receiving and transmitting unit Q. [0029] The operation of the power conversion device 1 mounted on the air conditioner A will be described below. The power conversion device 1 converts the DC voltage Vd supplied from the power source 2 into AC again, and drives the AC motor 3 (not shown in FIG. 2). The AC motor 3 (not shown) is a DC fan motor, but it can also be applied to a compressor motor. [Waveforms in Normal Operation] Here, in order to clarify the PWM control during intermittent energization operation by the power conversion device 1, the PWM control during normal operation will be described using FIG. 3. FIG. 3 is a waveform diagram showing the relationship between the AC voltage, the AC current, and the pulse signal flowing to the AC motor 3 in the comparative example. The voltage phase is displayed on the horizontal axis, and the voltage, current, and pulse signals are displayed on the vertical axis. [0031] The control device 5 generates a PWM pulse signal (pulse signal γ) by comparing the PWM carrier signal with the applied voltage command V ^* as shown in the first graph of FIG. 3 in the pulse control unit 7. The command value of the applied voltage command V ^* is calculated by the vector control unit 8 based on the phase current information α detected by the phase current detection unit 6. Here, the acquisition of the phase current information α by the phase current detection unit 6 may also be disclosed in, for example, FIG. 1 of Japanese Patent Application Laid-Open No. 2004-48886, and the AC output current may be directly detected by the CT (Current Transformer). As disclosed in FIG. 12 of the publication, it is possible to obtain the current information of the DC bus by a shunt resistor, and reproduce the phase current based on the current information. [0032] Next, the relationship between the AC voltage, the AC current, and the pulse signal supplied from the power conversion device 1 to the AC motor 3 during normal operation will be described in detail using FIG. 3. The first graph in FIG. 3 shows the PWM carrier signal and the applied voltage command V ^* , and shows the U-phase applied voltage command Vu ^* as a representative. Here, θv represents a voltage phase based on the U-phase. [0033] In the PWM control method, as shown in the first chart of FIG. 3, the pulse control unit 7 generates the third chart of FIG. 3 based on the U-phase applied voltage command Vu ^* and the triangular wave carrier signal (PWM carrier signal). The pulse signals GPU + and GPU- shown below are output to the gate driver 42 to drive the power conversion main circuit 41. The pulse signal GPU + is voltage-converted by the gate driver 42 and is applied to the gate of the switching element Q1 on the upper side of the U-phase. The pulse signal GPU- is voltage converted by the gate driver 42 and is applied to the gate of the switching element Q2 on the lower side of the U-phase. That is, the pulse signals GPU + and GPU- are formed to be positive and negative (1, 0) as opposite signals. [0034] With the pulse signals GPU + and GPU-, the power conversion main circuit 41 performs PWM control, so that the U-phase AC current Iu shown in the second chart of FIG. 3 flows in the AC motor 3 series. Here, the φ system indicates a phase difference between a voltage and a current. [0035] In addition, the vector control unit 8 performs vector control based on the phase current information α including the U-phase AC current Iu, thereby controlling the amplitude of the voltage and the phase difference φ between the voltage and the current. [0036] As shown in FIG. 3, in the PWM control during normal operation, the switching operation is often performed during one cycle of voltage and current for 180 degrees of conduction, which is more than the 120 degree conduction method or the period during which the switching operation stops. The 150-degree energization method has more switching times. Therefore, the 180-degree energization method increases the switching loss. [Waveforms During Intermittent Power-On Operation] In the following description, the operation of the pulse-stop control unit 9 (refer to FIG. 1) that temporarily stops the switching operation of the pulse signals for PWM control will be described using FIGS. 1 and 4. [0038] FIG. 4 is a waveform diagram showing the relationship between the AC voltage, the AC current, and the pulse signal flowing to the AC motor 3 and the phase pulse stop control signal in this embodiment. The voltage phase is displayed on the horizontal axis and the vertical axis is displayed. Voltage, current, pulse signal and open phase control signal (phase pulse stop control signal) are all accurate. That is, FIG. 4 is a waveform chart in the intermittent energizing operation shown in FIG. 4 compared with the waveform chart in the normal operation of FIG. 3. [0039] As shown in the fourth graph of FIG. 4, the pulse stop control unit 9 is based on the zero-crossing point φ of the current phase controlled by the vector control. The phase φ and the phase φ + π are as follows: (1) As shown in the phase pulse stop interval (open phase interval) δ, the pulse control unit 7 outputs a phase pulse stop control signal (open phase control signal) β that stops switching together with the pulse signals GPU + and GPU-. This phase pulse stop control signal β outputs "0" if switching is stopped together with the pulse signals GPU + and GPU-. If the PWM control mode is switched without stopping the switching, it outputs "1". [0040] That is, from Equation (1), when φ is set as the phase difference between voltage and current, and δ is set as the phase pulse stop interval (open phase interval), the voltage phase θv based on the U-phase is φ When -δ / 2 <θv <φ + δ / 2 and φ + π-δ / 2 <θv <φ + π + δ / 2, the switching is stopped by the pulse signals GPU + and GPU-. Then, in addition to this, switching is performed by pulse signals GPU + and GPU-. [0042] Therefore, the output state from the pulse control unit 7 is in the phase pulse stop interval δ of the phase pulse stop control signal β, and both the pulse signals GPU + and GPU- are turned OFF. Therefore, as shown in the third graph of FIG. 4, the pulse control unit 7 outputs a signal sequence of pulse signals that are stopped in the phase pulse stop interval δ. In other words, the phase pulse stop interval (open phase interval) δ is set twice between one cycle of voltage and current. Among them, if the configuration of this embodiment is adopted, the modulation method of the target PWM control is not only a sine wave PWM control method, but also a two-phase modulation PWM control method or a third harmonic addition type PWM control method. The same phase pulse stop interval δ. [0043] As shown above, the pulse signals GPU + and GPU- are provided during the period during which the switching operation is stopped by the pulse stop control unit 9. In the switching stop interval and the switching operation interval, the pulse signals are The shape is set based on the induced voltage phase. That is, the switching stop interval and switching operation interval of the pulse signals GPU + and GPU- are set based on the zero crossing point of the current phase as a reference. [0044] In other words, during normal operation, the pulse signal is based on the voltage phase of the induced voltage as a reference. Therefore, as shown in the third graph of FIG. OFF duty becomes symmetrical shape. However, during the intermittent energizing operation, the phase pulse stop interval δ is set based on the current phase (that is, it is not a pulse signal based on the voltage phase). Therefore, as shown in the third graph of FIG. Before and after the zero crossing point, the ON / OFF operation of the pulse signal train is not formed symmetrically. That is, in this embodiment, the ON / OFF operation of the pulse signal train is asymmetrical before and after the zero crossing point of the current. [0045] As described above, during the intermittent energizing operation, since the phase pulse stop interval δ is provided in the interval including the zero crossing point of the current, the phase pulse stop interval δ is centered as shown in the third graph of FIG. 4. The pulse signal lines A and B before and after are formed into an asymmetric shape. Therefore, if a phase pulse stop interval δ is provided in the interval including the zero crossing point of the current, and by observing whether the pulse signals before and after the phase pulse stop interval δ are asymmetric, it is easy to determine whether the intermittent power supply of this embodiment is applicable. action. [0046] "Waveforms when Driven by Real Machine" Fig. 5 is a waveform diagram showing the relationship between U-phase voltage, U-phase current, and pulse signals when a real machine equipped with the power conversion device 1 according to this embodiment is driven. The horizontal axis shows the voltage phase, and the vertical axis shows the voltage, current, and pulse signals. That is, FIG. 5 shows a method of setting a phase pulse stop section near the zero-cross point including the current caused by the intermittent energizing operation of the present embodiment. The phase pulse stop is set in the two-phase modulation PWM control method. The voltage, current and pulse signal when driving the real machine within the interval. [0047] The first graph of FIG. 5 shows the U-phase terminal voltage Vun of the power conversion main circuit 41, and the second graph of the same graph shows the U-phase AC current Iu flowing to the AC motor 3. In the third graph of the same graph, Display pulse signals GPU +, GPU-. [0048] As shown in the third graph of FIG. 5, in the interval (shown as δ) sandwiched by a one-dot chain line, the pulse signal GPU + and GPU- switching signals are both OFF, and it can be confirmed that the phase pulse stop interval δ is set. . In addition, since the phase pulse stop interval δ is set, it is also possible to confirm that the U-phase AC current Iu becomes zero in a section sandwiched by a one-point chain line. [0049] "Effects of Intermittent Energizing Operation" Fig. 6 shows the power conversion circuit loss, the motor loss of the phase pulse stop interval (open phase interval) δ caused by the power conversion device 1 of this embodiment, and the total thereof. The characteristic diagram of the relationship of the subsequent comprehensive loss shows the phase pulse stop interval (open phase interval) δ on the horizontal axis and the loss on the vertical axis. That is, FIG. 6 shows the characteristics of the phase pulse stop interval δ set by the pulse stop control section 9, the loss of the power conversion circuit 4, the loss of the AC motor 3, and the combined loss of these two losses. [0050] As shown in FIG. 6, the loss (power conversion circuit loss) of the power conversion circuit 4 according to this embodiment is reduced as the number of switching times decreases as the phase pulse stop interval δ is increased. In addition, the loss (motor loss) of the AC motor 3 is increased by setting the phase pulse stop interval δ, and the higher harmonic components of the current are increased. In addition, as the phase pulse stop interval δ becomes larger, the increase of the high harmonic components of the current becomes significant, and therefore the increase in the loss (motor loss) of the AC motor 3 becomes significant. Therefore, as shown in FIG. 6, there is a phase pulse stop interval δ _opt in which the total loss after adding these two losses (power conversion circuit loss and motor loss) is minimized. By setting the phase pulse stop interval δ to the phase pulse stop interval δ _opt , the overall loss of the power conversion device 1 can be reduced. [0051] As described above, by using the pulse stop control unit 9, the number of switching of pulse signals for performing PWM control can be reduced. In other words, if the pulse-stop control unit 9 performed by microcomputer control is configured by software, the configuration of the power conversion circuit 4 of the comparative example is not changed, and it is possible to achieve high efficiency of the power conversion device 1 without adding new hardware. In addition, since the switching operation is stopped near the zero-crossing of the current of the AC motor 3, it is possible to suppress an increase in torque ripple in the 150-degree energization method. [0052] However, the vector control method of this embodiment is a simple vector control without a position sensor, which is simplified based on a conventional vector control. This simple sensorless vector control can provide performance equivalent to ideal vector control, except for transient states where speed or load torque changes. In other words, the simple vector control without position sensor can not expect the performance like ideal vector control in a transient state where speed or load torque changes. In the transient state shown above, if the PWM output is stopped by the intermittent energizing operation, there is a possibility that the vibration may deteriorate or stop. [0053] The present invention executes an intermittent energizing operation only when it is determined that the motor is stably driven, thereby avoiding deterioration of motor vibration or a stopper of the motor. 7 is a graph showing an execution area and a hysteresis area of an intermittent energization operation when applied to a DC fan. The horizontal axis of the graph shows the number of rotations per minute, which is the rotation speed. The vertical axis of the graph shows the current flowing to the AC motor 3. The I _m reference value is a current value that becomes a high-domain rotation number at no load. The motor current I _m can be calculated by the following formula (2). [0055] [0056] The solid line graph shows the relationship between the actual rotation number N and the motor current I _m when no load is applied. The medium-dotted line graph shows the relationship between the actual number of rotations N and the motor current I _m when a predetermined positive load is applied to the AC motor 3, and the value is higher than the current I _r2 with respect to the solid line graph. The thin dotted line graph shows the relationship between the actual number of rotations N and the motor current I _m when a larger positive load is applied to the AC motor 3, and the relatively moderate dotted line graph is a value higher than the current I _h2 . For example, if a DC fan is blown against the wind, a positive load is applied to the AC motor 3, and it deviates in the direction of a medium dotted line graph or a thin dotted line graph. [0057] The graph of the one-dot chain line shows the relationship between the actual rotation number N and the motor current I _m when a predetermined negative load is applied to the AC motor 3, and the value of the current I _r1 is lower than that of the solid line graph. The thick dotted line graph shows the relationship between the actual number of rotations N and the motor current I _m when a larger negative load is applied to the AC motor 3, and the relatively moderate dotted line graph is a value lower than the current I _h1 . For example, if a DC fan is blown downwind, a negative load is applied to the AC motor 3, and the motor is deflected in the direction of a one-dot chain line graph or a thick dotted line graph. [0058] execution area Z ₁ represents a region-based dark hatched region, intermittent energization begin operation. This execution area Z ₁ is an area between a dotted line graph and a one-dot chain line graph. That is, a state in which a load within a predetermined range is applied to the motor. At this time, the control device 5 starts the intermittent power-on operation. Among them, since FIG. 7 is applied to a case of a DC fan, it is considered that the positive and negative loads of the AC motor 3 are approximately the same. Therefore, the current I _r1 and the current I _r2 are set to be equal. [0059] The execution region Z ₁ is formed as a region in which the value of the current I _h1 or more is added to the lower limit value of 1 _m . The phase current detection unit 6 of this embodiment detects a current through a shunt resistor (not shown). Therefore, there is a detectable lower limit of I _m . Therefore, a lower limit is also set in the execution area Z ₁ . [0060] The hysteresis area Z ₂ is a light shaded area, and displays an area where the intermittent power-on operation is performed and the execution is continued. The hysteresis region Z ₂ is a region between a thin dotted line graph and a thick dotted line graph. The control device 5 stops the intermittent energization operation if the hysteresis is shifted by more than the hysteresis from the execution area Z ₁ . By setting the hysteresis, chattering at the boundary of the execution area Z ₁ can be prevented. [0061] Among them, since FIG. 7 is applied to a case of a DC fan, it is considered that the positive and negative loads of the AC motor 3 are approximately the same. Therefore, the current I _h1 and the current I _h2 are set to be equal. The hysteresis region Z ₂ is formed as a region above the I _m lower limiter. [0062] The execution area Z ₁ and the hysteresis area Z ₂ are areas that are set to be equal to or lower than the number of high-domain rotations. [0063] FIG. 8 is a graph showing an execution area and a hysteresis area of an intermittent energizing operation when applied to a compressor. The solid line shows the relationship between the actual rotation number N and the motor current I _m at no load. [0064] The medium-dotted dotted line shows the relationship between the actual number of rotations N and the motor current I _m when a predetermined positive load is applied to the AC motor 3, and the value is higher than the current I _r4 with respect to the solid line. The thin dotted line shows the relationship between the actual number of rotations N and the motor current I _m when a larger positive load is applied to the AC motor 3, and the relatively medium dotted line is a value higher than the current I _h4 . When the compressor in a non-loaded state is rotated, in most cases, a positive load is applied to the AC motor 3, and therefore, it deviates in a direction of a medium dotted line or a thin dotted line. [0065] The one-dot chain line shows the relationship between the actual number of rotations N and the motor current I _m when a predetermined negative load is applied to the AC motor 3, and the value is a value lower than the solid line I _r3 relative to the solid line. The thick dotted line indicates the relationship between the actual number of rotations N and the motor current I _m when a larger negative load is applied to the AC motor 3, and the relatively medium-dotted dotted line is a value lower than the current I _h3 . When the compressor is rotated, a negative load is hardly applied to the AC motor 3. Therefore, the current I _r3 is set to be smaller than the current I _r4 , and the current I _h3 is set to be less than the current I _h4 . [0066] The execution area Z ₃ is a dark shaded area, and displays an area where the intermittent power-on operation is started. This execution area Z ₃ is an area between a dotted line and a dot chain line. That is, a state in which a load within a predetermined range is applied to the motor. At this time, the control device 5 starts the intermittent power-on operation. Among them, FIG. 8 is a case where the compressor is applied. Therefore, it is considered that the load applied to the AC motor 3 is mostly positive. Therefore, the current I _r2 is set to be larger than the current I _r1 . [0067] The execution region Z ₃ is formed as a region in which the value of the current I _h3 or more is added to the I _m lower limit limiter. The phase current detection unit 6 of this embodiment detects a current by a shunt resistor (not shown). Therefore, there is a detectable lower limit of I _m . Therefore, a lower limit is also set in the execution area Z ₃ . [0068] The hysteresis region Z ₄ is a region of light-colored hatching. It shows an area where the intermittent power-on operation is performed and the execution is continued. The hysteresis region Z ₄ is a region between a thin dotted line and a thick dotted line. When the control device 5 shifts the hysteresis by more than the execution area Z ₃ , the intermittent power-on operation is stopped. Among them, FIG. 8 is a case where the compressor is applied, and therefore it is considered that most of the cases are applied to the AC motor 3 in the positive case. Therefore, the current I _h4 is set to be larger than the current I _h3 . [0069] The hysteresis region Z ₂ is formed as a region that is equal to or larger than the lower limit of 1 _m . The execution region Z ₁ and the hysteresis region Z ₂ are separately formed as regions having a high-domain rotation number or less. 9 is a diagram showing an execution area and a hysteresis area of an intermittent energization operation defined by a modulation rate. When the modulation rate exceeds M ₁ , the intermittent energizing operation starts. After the modulation rate exceeds M ₁ , if it is less than (M ₁ -M _h ), the intermittent energizing operation will stop. [0071] In the intermittent energizing operation, when the modulation rate exceeds M ₂ , the intermittent energizing operation is stopped. After the modulation rate exceeds M ₂ , when it is less than (M ₂ -M _h ), the intermittent energizing operation starts. As shown above, if the modulation rate is in the middle region, the intermittent power-on operation is performed, and when the predetermined hysteresis is exceeded, the intermittent power-on operation is stopped. This makes it possible to more accurately determine that the motor is driving stably. 10 is a diagram showing an execution area and a hysteresis area of an intermittent energization operation defined by a rotation speed. When the rotation speed exceeds R ₁ , the intermittent energization operation starts. After the rotation speed exceeds R ₁ , if it is less than (R ₁ -R _h ), the intermittent energizing operation will stop. [0073] In the intermittent energization operation, when the rotation speed exceeds M ₂ , the intermittent energization operation is stopped. After the rotation speed exceeds R ₂ and is less than (R ₂ -R _h ), the intermittent energizing operation starts. As shown above, if the rotation speed is in the middle region, the intermittent energizing operation is performed, and when the predetermined hysteresis is exceeded, the intermittent energizing operation is stopped. This makes it possible to more accurately determine that the motor is driving stably. 11 is a diagram showing an execution area and a hysteresis area of an intermittent energization operation defined by an outside air temperature. When the outside temperature exceeds T ₁ , the intermittent energizing operation starts. After the outside air temperature exceeds T ₁ , when it is less than (T ₁ -T _h ), the intermittent energizing operation will stop. [0075] In the intermittent energizing operation, when the outside air temperature exceeds T ₂ , the intermittent energizing operation is stopped. When the outside air temperature exceeds T ₂ and is less than (T ₂ -T _h ), the intermittent energizing operation starts. As shown above, if the outside air temperature is in the middle region, the intermittent power-on operation is performed, and if the predetermined hysteresis is exceeded, and the power is not in the middle region, the intermittent power-on operation is stopped. This makes it possible to more accurately determine that the motor is driving stably. [0076] FIG. 12 is a graph showing a phase adjustment method when the intermittent power supply is stopped and when it is permitted. Before time t0, the intermittent power-on operation is permitted. At this time, the control device 5 causes the power conversion circuit 4 to perform an intermittent energization operation at an intermittent phase θ. [0077] At time t0, the control device 5 determines that the intermittent energization operation is stopped. From then on, until time t1, the control device 5 gradually reduces the intermittent phase, and stops the intermittent energizing operation at time t1. At time t2, the control device 5 determines that the intermittent energization operation is started. From then on, until time t3, the control device 5 gradually increases the intermittent phase, and performs intermittent energizing operation at the intermittent phase θ at time t3. As described above, since the intermittent phase is gradually changed, it is possible to alleviate the switching shock wave accompanying the start or stop of the intermittent energizing operation. [0078] (Modifications) The present invention includes various modifications, and is not limited to the embodiments described above. For example, the above embodiments are described in detail for easy understanding of the present invention, and are not necessarily limited to those having all the components described. A part of the structure of one embodiment may be replaced with a structure of another embodiment, or a structure of another embodiment may be added to the structure of one embodiment. A part of the configuration of each embodiment may be added, deleted, or replaced with another configuration. [0079] Each of the above-mentioned structures, functions, processing units, processing means, and the like may be implemented by a piece of hardware such as an integrated circuit to realize a part or all of these. The above-mentioned various structures, functions, etc. can also be interpreted by the processor to implement the programs for each function to be executed, thereby being implemented by software. Information such as programs, tables, and files that implement various functions can be placed in memory, hard disks, SSD (Solid State Drive, solid state drive) and other recording devices, or flash memory cards, DVD (Digital Versatile Disk, digital Versatile Disc) and other recording media. [0080] In each embodiment, the control line or information line is shown as being necessary in the description, and it is not necessarily the entire control line or information line on the product. In fact, almost all of them can be considered to be connected to each other. Examples of the modification of the present invention include the following (a) to (e). [0081] (a) It is also applicable to any motor, and is not limited to a motor of a DC fan or a compressor. (B) The execution area may not be formed below the high-domain rotation number. (C) It can be determined that the stable driving may be a region indicated by torque and a number of revolutions per minute instead of being limited to a region indicated by a motor current I _m and a number of revolutions per minute. Here, the torque value is calculated by the sum of the calculated value of the torque theoretical formula and the offset value as shown in Equation (3). [0082] In addition, the calculated value of the theoretical torque formula is calculated by Expression (4). [0083] That is, a torque by the motor current I _m is based and unambiguously calculated, it can be substituted with a torque motor current I _m, it is determined whether the driving stability. (D) It can be determined that the stable driving may be a region indicated by a modulation rate and a rotation number per minute, instead of being limited to a region indicated by a motor current I _m and a rotation number per minute. Among them, if the applied voltage is constant, the modulation rate can be calculated from the motor current I _m univocally. (E) In addition to detecting the motor current flowing to the AC motor (motor), it is also possible to detect the current flowing to the power conversion circuit to form this as a motor current.

[0084]

1‧‧‧Power Conversion Device

2‧‧‧ Power

3‧‧‧AC motor (motor)

4‧‧‧Power Conversion Circuit

41‧‧‧Power Conversion Main Circuit

42‧‧‧Gate driver

5‧‧‧control device

6‧‧‧phase current detection section

7‧‧‧Pulse control department

8‧‧‧ Vector Control Department

9‧‧‧Pulse stop control section

Q1 ～ Q6‧‧‧Switching element

Vd‧‧‧DC voltage

A‧‧‧Air conditioner

100‧‧‧ indoor unit

200‧‧‧ outdoor unit

Re‧‧‧Remote Control

Q‧‧‧Receiving and sending department of remote control

300‧‧‧Refrigerant piping

α‧‧‧ Phase Current Information (Current)

β‧‧‧ phase pulse stop control signal (pulse stop control signal)

γ‧‧‧Pulse signal (PWM pulse signal)

ζ‧‧‧ Phase Information

δ‧‧‧ phase pulse stop interval (open phase interval)

GPU + ‧‧‧ Pulse signal

GPU-‧‧‧Pulse signal

Iu‧‧‧U-phase AC current

φ‧‧‧phase difference

Vu‧‧‧Voltage

V ^* ‧‧‧ voltage command

[0010] FIG. 1 is a block diagram showing a circuit configuration of a power conversion device of a PWM control method in this embodiment. FIG. 2 is a front view of an indoor unit, an outdoor unit, and a remote controller of the air conditioner in this embodiment. Figure 3 is a waveform diagram showing the relationship between the AC voltage, AC current, and pulse signal flowing to the motor during normal operation. Figure 4 is a waveform diagram showing the relationship between the AC voltage, AC current, and pulse signals flowing to the motor and the phase pulse stop control signals during the intermittent energizing operation. FIG. 5 is a waveform diagram showing the relationship between the U-phase voltage, the U-phase current, and the pulse signal when a real machine including a power conversion device is driven. FIG. 6 is a characteristic diagram showing the relationship between the power conversion circuit loss, the motor loss, and the total loss of the phase pulse stop interval (open phase interval) caused by the power conversion device of this embodiment. FIG. 7 is a graph showing an execution area and a hysteresis area of an intermittent energization operation when applied to a DC fan. FIG. 8 is a graph showing an execution area and a hysteresis area of an intermittent energization operation when applied to a compressor. FIG. 9 is a diagram showing an execution area and a hysteresis area of an intermittent energization operation defined by a modulation rate. FIG. 10 is a diagram showing an execution area and a hysteresis area of an intermittent energization operation defined by a rotation speed. FIG. 11 is a diagram showing an execution area and a hysteresis area of an intermittent energization operation defined by an outside temperature. FIG. 12 is a graph showing a phase adjustment method when the intermittent power supply is stopped and when it is permitted.

Claims (8)

An air conditioner is characterized in that: is equipped with: an electric motor; and a power conversion device that uses a vector control method to perform power conversion for driving the motor by PWM control; the power conversion device is provided with: pulse The control unit outputs pulse signals for performing the aforementioned PWM control. The power conversion circuit is configured by including three-phase switching elements and uses the pulse signals output by the pulse control unit to convert DC power into AC power; a current detection unit that detects the current flowing to the power conversion circuit; a vector control unit that performs vector control based on the current detected by the current detection unit to generate a command voltage to the pulse control unit And a pulse stop control unit for stopping the positive and negative switching elements of a predetermined phase of the power conversion circuit, and generating the pulse signal to stop in a section set based on the current phase of the power conversion circuit Pulse stop The control signal outputs the pulse stop control signal to the pulse control unit. The vector control unit is within a predetermined range if the motor current of the motor is at no load to the current rotation speed, even if the pulse stop control unit The action begins. For example, the air conditioner of the first scope of the patent application, in which the vector control unit starts the operation of the pulse stop control unit, and gradually increases the interval for generating the pulse stop control signal from zero to the previously set interval. . For example, the air conditioner of the first scope of the application for a patent, wherein if the vector control unit operates the pulse stop control unit, if the motor current of the electric motor exceeds a predetermined hysteresis amount and is not within the range with respect to the predetermined range, Even if the operation of the aforementioned pulse stop control section is stopped. For example, the air conditioner of the third scope of the patent application, wherein if the vector control unit stops the operation of the pulse stop control unit, the interval for generating the pulse stop control signal is gradually reduced from the previously set interval to zero. . An air conditioner is characterized in that: is equipped with: an electric motor; and a power conversion device that uses a vector control method to perform power conversion for driving the motor by PWM control; the power conversion device is provided with: pulse The control unit outputs pulse signals for performing the aforementioned PWM control. The power conversion circuit is configured by including three-phase switching elements and uses the pulse signals output by the pulse control unit to convert DC power into AC power; a current detection unit that detects the current of the power conversion circuit; a vector control unit that performs vector control based on the current detected by the current detection unit to generate a command voltage to the pulse control unit; and The pulse stop control unit generates a pulse to stop the pulse signal in a section set based on a current phase of the power conversion circuit in order to stop the positive and negative switching elements of a predetermined phase of the power conversion circuit. Stop control The pulse stop control signal is output to the pulse control unit. The vector control unit is within a predetermined range if the torque of the motor is within a predetermined range when the torque of the motor relative to the current rotation speed is not loaded, even if the pulse stop control unit operates. Start. For example, in the air conditioner of the fifth item of the patent application, if the vector control unit makes the pulse stop control unit operate, the torque of the motor exceeds a predetermined hysteresis and is not within the range with respect to the predetermined range, even if the foregoing The operation of the pulse stop control section is stopped. An air conditioner is characterized in that: is equipped with: an electric motor; and a power conversion device that uses a vector control method to perform power conversion for driving the motor by PWM control; the power conversion device is provided with: pulse The control unit outputs pulse signals for performing the aforementioned PWM control. The power conversion circuit is configured by including three-phase switching elements and uses the pulse signals output by the pulse control unit to convert DC power into AC power; a current detection unit that detects the current of the power conversion circuit; a vector control unit that performs vector control based on the current detected by the current detection unit to generate a command voltage to the pulse control unit; and The pulse stop control unit generates a pulse to stop the pulse signal in a section set based on a current phase of the power conversion circuit in order to stop the positive and negative switching elements of a predetermined phase of the power conversion circuit. Stop control The pulse stop control signal is output to the pulse control unit. ， The vector control unit is within a predetermined range if the modulation rate of the electric motor is within a predetermined range when the modulation rate of the electric motor is relative to the current rotation speed without load. The action begins. For example, the air conditioner of the seventh scope of the application for a patent, wherein if the vector control unit makes the pulse stop control unit operate, the modulation rate of the motor exceeds a predetermined hysteresis and is not within the range with respect to the predetermined range, even if The operation of the pulse stop control unit is stopped.