Ac / DC conversion device, rotary machine drive device, and refrigeration cycle application device

Abstract

An AC / DC conversion device (2) comprises: a rectifier circuit (20) that has a switching element (215) and rectifies a power supply voltage applied from an AC power supply (1); a capacitor (216) that is connected to DC buses (9a, 9b) and smooths the output voltage of the rectifier circuit (20); a reactor (212) that is disposed further on the AC power supply (1) side than the capacitor (216); and a control unit (6) that generates a switching signal for controlling the switching element (215). The control unit (6) generates the switching signal such that a harmonic component included in the power supply current flowing between the AC power supply (1) and the rectifier circuit (20) conforms to the harmonic standard value of the power supply current.

Description

AC / DC converters, rotating machine drives, and refrigeration cycle application equipment

[0001] The present disclosure relates to an AC / DC converter that converts AC power into desired DC power, and to a rotating machine drive device and refrigeration cycle equipment that are equipped with the AC / DC converter.

[0002] A power factor correction circuit is typically used to obtain DC voltage from an AC power source. A power factor correction circuit maintains a constant bus voltage and controls the power supply current to comply with harmonic standards. A power factor correction circuit and its control method, the "simple switching method" (also known as the "partial switching method"), performs switching at least once per half cycle of the power supply voltage, which is the voltage of the AC power supply. This method has the advantage of being able to control the bus voltage lower than the peak value of the power supply voltage. However, when the bus voltage is set lower than the peak value of the AC power supply using the simple switching method, the operating circuit switches from a boost chopper to a capacitor-input diode rectifier, which can distort the power supply current.

[0003] To address this issue, the prior art disclosed in Patent Document 1 below determines whether a combination of reactor capacity and switching timing complies with harmonic standards by repeating the design for each load power.

[0004] Japanese Patent Application Laid-Open No. 2000-125545

[0005] However, the conventional technology described in Patent Document 1 involves a method of checking whether compliance with harmonic standards can be achieved through repeated trials, which has the problem that the number of trials increases exponentially as the number of pulses increases. Furthermore, there is no clear guideline for quantitatively and uniquely designing control gains, which has the problem that it takes a long time to complete the design.

[0006] The present disclosure has been made in consideration of the above, and aims to shorten the time required for design by obtaining an AC-DC conversion device that can comply with harmonic standards without relying on trial-and-error adjustments.

[0007] In order to solve the above-mentioned problems and achieve the object, an AC-DC converter according to the present disclosure includes a rectifier circuit, a smoothing capacitor, a reactor, and a control unit. The rectifier circuit has at least one switching element and rectifies a power supply voltage applied from an AC power supply. The capacitor is connected to a DC bus and smooths the output voltage of the rectifier circuit. The reactor is arranged closer to the AC power supply than the capacitor. When generating a switching signal to control the switching element arranged closer to the AC power supply than the capacitor, the control unit generates the switching signal so that harmonic components contained in the power supply current flowing between the AC power supply and the rectifier circuit comply with the harmonic standard value for the power supply current.

[0008] The AC-DC converter according to the present disclosure can comply with harmonic standards without relying on trial-and-error adjustments, thereby achieving the effect of reducing the time required for design.

[0009] 6A and 6B are block diagrams illustrating an example of the configuration of a rotary machine drive device according to a first embodiment; a circuit diagram illustrating an example of the configuration of an AC / DC converter according to a first embodiment; a block diagram illustrating an example of the configuration of a control unit according to a first embodiment; a block diagram illustrating an example of the configuration of a voltage control unit according to a first embodiment; a block diagram illustrating an example of the configuration of a current control unit according to a first embodiment; a block diagram illustrating an example of the configuration when a target value filter is introduced into the current control unit shown in FIG. 5; a block diagram for explaining the transfer function of a current control system in an AC / DC converter including the current control unit shown in FIG. 6; a diagram illustrating an example of the operating waveforms of a power supply voltage, a bus voltage, and a power supply current when PI control is applied to the current controller shown in FIG. 6; a diagram illustrating an example of the operating waveforms of a power supply voltage, a bus voltage, and a power supply current when PS control is applied to the current controller shown in FIG. 6; a diagram illustrating an example of current harmonic characteristics when PS control is applied to the current controller shown in FIG. 6; a relationship between the ratio of the sum of harmonic components and operating power when PS control is applied to the current controller shown in FIG. FIG. 11 shows an example of a configuration of an AC / DC converter according to embodiment 12. FIG. 12 shows an example of a configuration of an AC / DC converter according to embodiment 13. FIG. 13 shows an example of a configuration of an AC / DC converter according to embodiment 14. FIG. 14 shows an example of a configuration of an AC / DC converter according to embodiment 15. FIG. 15 shows an example of a configuration of a refrigeration cycle application device according to embodiment 16.

[0010] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An AC-DC converter, a rotary machine drive device, and a refrigeration cycle application device according to embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0011] Embodiment 1. Fig. 1 is a block diagram showing an example of the configuration of a rotating machine driving device 8 according to Embodiment 1. The rotating machine driving device 8 is connected to an AC power source 1 and a load 4 including a motor 41. The rotating machine driving device 8 includes an AC-DC converter 2 and a DC-AC converter 3. When the rotating machine driving device 8 is used in an air conditioner, the load 4 is a compressor or a fan, and the motor 41 is a compressor motor or a fan motor.

[0012] 2 is a circuit diagram showing an example of the configuration of the AC-DC converter 2 according to the first embodiment. The AC-DC converter 2 according to the first embodiment mainly includes a control unit 6, a rectifier circuit 20, a reactor 212, and a capacitor 216. The AC-DC converter 2 also includes a current detection unit 211 and voltage detection units 217a and 217b as means for detecting voltage or current. In this document, when the voltage detection units 217a and 217b are distinguished from each other without reference numerals, the voltage detection unit 217b will be referred to as a "first voltage detection unit" and the voltage detection unit 217a will be referred to as a "second voltage detection unit."

[0013] The rectifier circuit 20 includes single-phase diode bridge cells 213a and 213b, each of which has four diodes bridge-connected, and a switching element 215 connected in parallel across the single-phase diode bridge cell 213b. The single-phase diode bridge cells 213a and 213b are connected in parallel to each other across the AC power supply 1. The rectifier circuit 20 shown in FIG. 2 is called a "simple switching circuit." The single-phase diode bridge cell 213b and the switching element 215 constitute a switching cell 225. The switching element 215 performs a switching operation at least once per half cycle of the power supply voltage.

[0014] The capacitor 216 is connected between the DC bus 9a and the DC bus 9b. The reactor 212 is arranged closer to the AC power supply than the capacitor 216. The rectifier circuit 20 receives the power supply voltage applied from the AC power supply 1 via the reactor 212 and rectifies the received power supply voltage. The capacitor 216 smoothes the output voltage of the rectifier circuit 20.

[0015] The voltage detector 217b detects a bus voltage, which is the voltage of a DC bus to which the capacitor is connected. The voltage detector 217a detects a power supply voltage. The current detector 211 detects a power supply current flowing between the AC power supply 1 and the rectifier circuit 20.

[0016] The control unit 6 receives the detection values ​​of the voltage detection units 217a and 217b and the current detection unit 211. The control unit 6 generates a switching signal for controlling the on / off of the switching element 215 based on the detection values.

[0017] An example of the switching element 215 is an insulated gate bipolar transistor (IGBT) as shown in the figure, but is not limited to an IGBT. Any element capable of switching operation may be used as the switching element 215. Another example of the switching element 215 is a metal-oxide-semiconductor field-effect transistor (MOSFET).

[0018] 2 is configured as a closed loop using the detected values ​​of the voltage detectors 217a, 217b and the current detector 211, but may be configured as an open loop using a target value, an estimated value, etc. When the AC-DC converter 2 is configured as an open loop, it is also possible to control the switching element 215 without using the detected values ​​of the voltage detectors 217a, 217b and the current detector 211.

[0019] 3 is a block diagram showing an example configuration of the control unit 6 according to the first embodiment. The control unit 6 includes a voltage control unit 61, a current control unit 62, and a switching signal generation unit 63. The voltage control unit 61 generates a first current command value using a first voltage command value. The current control unit 62 generates a second voltage command value using the first current command value. The switching signal generation unit 63 generates a switching signal using the second voltage command value.

[0020] 4 is a block diagram showing an example configuration of the voltage control unit 61 according to the first embodiment. The voltage control unit 61 includes a voltage controller 611 and a subtractor 612. The voltage control unit 61 generates a first current command value using a first voltage command value that is a command value for the bus voltage. More specifically, the subtractor 612 generates a voltage deviation that is the difference between the first voltage command value and the voltage detected by the voltage detection unit 217b. The voltage controller 611 generates the first current command value using the voltage deviation output from the subtractor 612. The voltage controller 611 can be configured as, for example, a proportional integral (PI) controller.

[0021] The transfer function G when the voltage controller 611 is configured as a PI controller ＡＶＲ（ｓ） can be expressed by the following equation (1).

[0022]

[0023] Here, the transfer function G ＡＶＲ（ｓ） "AVR" in the above is an abbreviation for "Automatic Voltage Regulator." Also, in the above formula (1), K ｐＡＶＲ is the proportional gain, and K ｉＡＶＲ is the integral gain and s is the Laplace operator. In the PI controller, the proportional gain K ｐＡＶＲ and integral gain K ｉＡＶＲ can be determined arbitrarily. ｐＡＶＲ may be set to zero and configured as an I controller, or the integral gain K ｉＡＶＲ may be set to zero and configured as a P controller.

[0024] FIG. 5 is a block diagram showing an example configuration of the current control unit 62 according to the first embodiment. The current control unit 62 includes a current controller 621, a subtractor 622, and a multiplier 623. The current control unit 62 generates a second voltage command value using a second current command value obtained by causing the first current command value to follow a sine wave. More specifically, the multiplier 623 multiplies the first current command value by an excitation signal. The excitation signal is a sine wave synchronized with the phase of the power supply voltage. The sine wave is generated based on the voltage phase, which is the phase of the detected voltage detected by the voltage detection unit 217a. The output of the multiplier 623 is input to the subtractor 622 as a second current command value. The subtractor 622 generates a current deviation, which is the difference between the second current command value and the detected current detected by the current detection unit 211. The current controller 621 generates the second voltage command value using the current deviation output from the subtractor 622. The current controller 621 can be configured, for example, as a PS (Proportional Sinusoidal) controller.

[0025] The transfer function G when the current controller 621 is configured as a PS controller ＡＣＲ（ｓ） can be expressed by the following equation (2).

[0026]

[0027] Here, the transfer function G ＡＣＲ（ｓ） "ACR" in the above expression is an abbreviation for "Automatic Current Regulator." ｐＡＣＲ is the proportional gain, and K ｓＡＣＲ is the S control gain, and ω ｎ is the angular frequency and s is the Laplace operator. In the PS controller, the proportional gain K ｐＡＣＲ , S control gain K ｓＡＣＲ and angular frequency ω ｎ can be determined arbitrarily.

[0028] The PS controller is a controller in which an S controller, which is a Laplace transform expression of a sine wave function or a cosine wave function, is inserted in parallel with a P controller. ｎ This controller has improved tracking performance for a sinusoidal input of angular frequency ω. ｎThe reason why the tracking performance improves for a pulsating input can be explained by the internal model principle. The internal model principle states that if the controller's denominator has the same factors as the denominator polynomial of the command value expressed in Laplace transform, the command value can be tracked without deviation. Note that the current controller 621 may be configured as a PIS controller by inserting an I controller in parallel with the PS controller.

[0029] Fig. 6 is a block diagram showing a configuration example in which a target value filter 624 is introduced into the current control unit 62 shown in Fig. 5. Fig. 7 is a block diagram used to explain the transfer function of the current control system 7 in the AC-DC converter 2 including the current control unit 62 shown in Fig. 6.

[0030] In Fig. 6, a target value filter 624 is inserted in the preceding stage of the current control unit 62 shown in Fig. 5. The target value filter 624 is inserted to adjust the response of the transfer function of the current control unit 62 shown in Fig. 5. Specifically, the response of the transfer function of the current control unit 62 is adjusted by ensuring that the zero points of the transfer function of the current control unit 62 are canceled by the poles of the target value filter 624.

[0031] Here, the closed loop transfer function G in the current control system 7 of FIG. ｃｌｏｓｅ（ｓ） can be expressed by the following equation (3).

[0032]

[0033] In the above formula (3), G ｃ is the transfer function of any controller 72, and G Ｐ is the transfer function of an arbitrary controlled plant 73. If the above equation (3) has a zero point, the closed-loop response cannot be determined by the poles alone. Therefore, the closed-loop transfer function G ｃｌｏｓｅ（ｓ） A target value filter 74 having the same pole as the zero point of is inserted in the front stage of the closed loop. Then, the transfer function G Ｆ（ｓ） and the closed loop transfer function G ｃｌｏｓｅ（ｓ） The desired response is realized by canceling out the influence of the zero point between the target value filter 74 and the transfer function G′. ｃｌｏｓｅ（ｓ） can be expressed by the following equation (4).

[0034]

[0035] In the above formula (4), G Ｘ is an arbitrary transfer function. Ｘ is the transfer function G' ｃｌｏｓｅ（ｓ） The transfer function G may be set to the value of the zeroth power of the Laplace operator s in the denominator polynomial of the above equation, or may have any zero point. Ｆ（ｓ） The controller response can be adjusted by applying a setpoint filter 74 having:

[0036] Next, the operating characteristics when PS control is applied to the current controller 621 will be clarified by comparing with the conditions when a PI controller is applied to the current controller 621.

[0037] Fig. 8 is a diagram showing example operating waveforms of the power supply voltage, bus voltage, and power supply current when PI control is applied to the current controller 621 shown in Fig. 6. The upper part of Fig. 8 shows waveforms of the absolute values ​​of the bus voltage and power supply voltage. The lower part of Fig. 8 shows waveforms of the detected power supply current, the fundamental wave component of the detected power supply current, and the power supply current command value. The detected power supply current is the detected waveform of the power supply current detected by the current detection unit 211.

[0038] The operating conditions in Fig. 8 are those in which the bus voltage is equal to or less than the peak absolute value of the power supply voltage, as shown in the upper part of Fig. 8. Under these conditions, the rectifier circuit 20 operates as a capacitor-input diode rectifier circuit rather than as a boost circuit, making it impossible to control the bus voltage. In this case, an excessive value accumulates in the PI control integrator, causing a windup phenomenon, and the detected power supply current cannot follow the power supply current command value.

[0039] In contrast, Fig. 9 is a diagram showing example operating waveforms of the power supply voltage, bus voltage, and power supply current when PS control is applied to the current controller 621 shown in Fig. 6. As with Fig. 8, the upper part of Fig. 9 shows waveforms of the absolute values ​​of the bus voltage and power supply voltage, and the middle part of Fig. 9 shows waveforms of the detected power supply current, the fundamental wave component of the detected power supply current, and the power supply current command value. The lower part of Fig. 9 shows a switching signal for controlling the switching element 215.

[0040] As shown in the middle part of Figure 9, the fundamental wave component of the detected power supply current is nearly identical to the power supply current command value. This shows that if PS control, which has high tracking performance for a sinusoidal input, is applied to the current controller 621, the fundamental wave of the detected power supply current can track the power supply current command value even under conditions in which the bus voltage is equal to or less than the peak absolute value of the power supply voltage. Note that Figure 9 shows the results for operating conditions in which the bus voltage is equal to or less than the peak absolute value of the power supply voltage, but it goes without saying that the fundamental wave of the detected power supply current will track the power supply current command value even under operating conditions in which the bus voltage exceeds the peak absolute value of the power supply voltage.

[0041] Fig. 10 is a diagram showing an example of current harmonic characteristics when PS control is applied to the current controller 621 shown in Fig. 6. The current harmonic standard used in Fig. 10 is IEC 61000-3-2 Class A. Note that IEC 61000-3-2 Class A is an example of a current harmonic standard, and is not limited to this standard.

[0042] In Figure 10, the solid lines indicate the standard values ​​for current harmonics from the second to the fortieth order as specified in IEC 61000-3-2 Class A. Also in Figure 10, the dashed lines indicate the effective values ​​of the second to the fortieth order harmonic components during rated operation. The harmonic components during rated operation represent the components remaining after subtracting the fundamental component of the power supply current from the power supply current that flows when the AC-DC converter 2 is operated at rated power. In this paper, the second to the fortieth order harmonics are defined as "low-order harmonics."

[0043] 10, the waveforms of the dashed lines are lower than the waveforms of the solid lines for the 2nd to 40th orders. This shows that if PS control, which has high tracking performance for sine wave input, is applied to the current controller 621, the low-order harmonics contained in the power supply current will comply with the harmonic standard values ​​for the power supply current. Note that while FIG. 10 shows the harmonic components during rated operation as an example, it goes without saying that the effect of PS control on suppressing harmonic components can be obtained even during times other than rated operation.

[0044] Fig. 11 is a diagram showing an example of the relationship between the ratio of the sum of harmonic components and operating power when PS control is applied to the current controller 621 shown in Fig. 6. The ratio of the sum of harmonic components here means the ratio of the sum of second-order and higher harmonic components to the fundamental wave of the power supply current.

[0045] It can be seen from Fig. 11 that the proportion of the sum of harmonic components is 10% or more in all operating regions shown in Fig. 11. The fact that the proportion of the sum of harmonic components is 10% or more is unique to the technique of embodiment 1, in which PS control is applied to current controller 621 to control switching element 215. When the operating power is low, the proportion of the sum of harmonic components increases, but the harmonic standard value when the operating power is low also increases, and as shown in Fig. 10, the effective value of the current harmonics does not exceed the harmonic standard value of the power supply current.

[0046] The control method of the first embodiment is characterized in that a current controller 621 is applied to the control unit 6, and PS control, which has high tracking performance for a sine wave input, is further applied to the current controller 621. While the application of PS control to improve tracking performance for a sine wave input is considered to be a relatively common practice, the application of PS control to comply with harmonic standards is considered to be a novel method that has never been used before.

[0047] As described above, the AC-DC converter according to the first embodiment includes a rectifier circuit that rectifies a power supply voltage applied from an AC power supply, a capacitor that smooths the output voltage of the rectifier circuit, and a reactor that is located closer to the AC power supply than the capacitor. The rectifier circuit has at least one switching element that is located closer to the AC power supply than the capacitor. When generating a switching signal to control the switching element, the control unit generates the switching signal so that harmonic components contained in the power supply current flowing between the AC power supply and the rectifier circuit comply with the harmonic standard value of the power supply current. The AC-DC converter according to the first embodiment enables compliance with the harmonic standard without relying on a trial-and-error adjustment method that repeatedly checks whether compliance with the harmonic standard is achieved. Furthermore, the AC-DC converter according to the first embodiment enables compliance with the harmonic standard while improving the input power factor, even under operating conditions in which the bus voltage exceeds the peak absolute value of the power supply voltage.

[0048] To achieve the above functions, the control unit according to the first embodiment is configured to include a voltage control unit that generates a first current command value using a first voltage command value that is a command value for a bus voltage, a current control unit that generates a second voltage command value using a second current command value that causes the first current command value to follow a sine wave, and a switching signal generation unit that generates a switching signal using the second voltage command value. The current control unit has a current controller, and PS control is applied to the current controller. The input stage of the current control unit is also configured to include a filter that manipulates the zero point of a feedback loop that feeds back the second voltage command value output by the current control unit to the input stage of the second current command value. Using a control unit configured in this manner eliminates the need to repeatedly design a combination of reactor capacity and switching timing for each load power to determine whether it complies with harmonic standards. This eliminates the need for trial-and-error adjustment work and shortens the time required for design work and the time required to complete the design.

[0049] When the switching element is controlled using the control unit configured as described above, low-order harmonics are superimposed on the power supply current flowing between the AC power supply and the AC-DC converter. The total of the harmonic components of the power supply current is 10% or more of the fundamental wave of the power supply current.

[0050] Furthermore, when the control system of the AC-DC converter is configured as a closed loop, it is configured to include a current detection unit that detects a power supply current flowing between the AC power supply and the rectifier circuit, a first voltage detection unit that detects a bus voltage, and a second voltage detection unit that detects a power supply voltage. When the control system of the AC-DC converter is configured as a closed loop, the first current command value may be generated using a voltage deviation that is the difference between the first voltage command value and the detected voltage detected by the first voltage detection unit, and the sine wave that excites the first current command value may be generated based on the voltage phase detected by the second voltage detection unit. Furthermore, the second voltage command value may be generated using a current deviation that is the difference between the second current command value and the detected current detected by the current detection unit.

[0051] Embodiment 2 In the first embodiment, a configuration was described in which PS control was applied to the current controller 621 of the current control unit 62 for the purpose of improving the follow-up performance to a sinusoidal command. In the second embodiment, a configuration will be described in which PIR (Proportional Integral Resonant) control is applied to the current controller 621 of the current control unit 62 for the same purpose.

[0052] Fig. 12 is a diagram showing a configuration example of an AC-DC converter 2 according to embodiment 2. Components having the same or equivalent functions as those in Fig. 2 are denoted by the same reference numerals. Note that descriptions of content that overlaps with embodiment 1 will be omitted as appropriate.

[0053] 12 has a configuration called a full PAM (Pulse Amplitude Modulation) circuit. The rectifier circuit 20 includes a single-phase diode bridge cell 213a, a switching element 215, and a diode 218. In the single-phase diode bridge cell 213a, the switching element 215 performs a switching operation at least once per half cycle of the power supply voltage.

[0054] 2 is disposed between the single-phase diode bridge cell 213a and the diode 218. The switching element 215 is disposed between the single-phase diode bridge cell 213a and the capacitor 216 and is connected in parallel to the single-phase diode bridge cell 213a and the capacitor 216. The current detection unit 211 is disposed between the single-phase diode bridge cell 213a and the diode 218.

[0055] 2 and 12, the positions and connection forms of the switching element 215 and the reactor 212 are different, but in both configurations, the switching element 215 and the reactor 212 are arranged closer to the AC power source 1 than the capacitor 216. This arrangement relationship is similar in other embodiments described later.

[0056] 12, the switching element 215 is shown as an IGBT, but any element capable of switching operation may be used. Furthermore, although the AC-DC converter 2 shown in FIG. 12 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 217a and 217b and the current detector 211 do not need to be used.

[0057] 12 may be used in the first embodiment, and the simple switching circuit of Fig. 2 may be used in the second embodiment. That is, when the AC-DC converter 2 has a step-up function or a step-down function, the rectifier circuit 20 includes at least one switching element, but the control method described in this paper is applicable even if the control method for controlling the switching element is different.

[0058] Next, the transfer function of the PIR controller will be described. First, the transfer function G ＰＩＲ（ｓ） can be expressed by the following equation (5).

[0059]

[0060] In the above formula (5), K ｐ is the proportional gain, K ｉ is the integral gain, K ｒ is the resonance control gain, ω １ is the angular frequency of the current control response, ω ２ is the angular frequency of the sine wave command to be followed. ＰＩＲ（ｓ） A PIR controller having the following formula may be applied to the current controller 621 in Fig. 5 or 6. The use of a PIR controller can also provide the same effect as the PS control.

[0061] As described above, PIR control is applied to the current controller provided in the current controller in the controller according to embodiment 2. Even when PIR control is applied instead of PS control, the same effects as those of embodiment 1 can be obtained.

[0062] Embodiment 3 In embodiment 3, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as those of the AC-DC converter 2 described in embodiments 1 and 2 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0063] Fig. 13 is a diagram showing a configuration example of an AC-DC converter 2 according to embodiment 3. In the AC-DC converter 2 shown in Fig. 13, a rectifier circuit 20 is configured with a single-phase H-bridge cell including four switching elements 220a, 220b, 220c, and 220d. Note that the configuration and operation of the rectifier circuit 20 shown in Fig. 13 are publicly known, and further description thereof will be omitted here.

[0064] The control unit 6 generates switching signals to drive the four switching elements 220a, 220b, 220c, and 220d using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in FIG. 13 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0065] 13, the switching elements 220a, 220b, 220c, and 220d are shown as IGBTs, but any elements capable of switching operation may be used. Furthermore, although the AC-DC converter 2 shown in FIG. 13 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 217a and 217b and the current detector 211 do not need to be used.

[0066] Embodiment 4 In embodiment 4, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC-DC converter 2 described in embodiments 1 and 2 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0067] FIG. 14 is a diagram illustrating a configuration example of an AC-DC converter 2 according to a fourth embodiment. In the AC-DC converter 2 of FIG. 14, a rectifier circuit 20 is configured with a single-phase H-bridge cell including two diodes 218a and 218b and two switching elements 220c and 220d. In the rectifier circuit 20 illustrated in FIG. 14, one leg is configured with a series circuit of the diodes 218a and 218b, and the other leg is configured with a series circuit of the switching elements 220c and 220d. The configuration and operation of the rectifier circuit 20 illustrated in FIG. 14 are publicly known, and therefore further description thereof will be omitted here.

[0068] The control unit 6 generates switching signals to drive the two switching elements 220c and 220d using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in Fig. 14 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0069] 14, the switching elements 220c and 220d are shown as IGBTs, but any elements capable of switching operation may be used. Furthermore, although the AC-DC converter 2 shown in FIG. 14 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 217a and 217b and the current detector 211 do not need to be used.

[0070] Embodiment 5 In embodiment 5, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC-DC converter 2 described in embodiments 1 and 2 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0071] FIG. 15 is a diagram illustrating a configuration example of an AC-DC converter 2 according to a fifth embodiment. In the AC-DC converter 2 of FIG. 15, a rectifier circuit 20 is configured with a single-phase H-bridge cell including two diodes 218a and 218c and two switching elements 220b and 220d. In the rectifier circuit 20 illustrated in FIG. 15, the diodes 218a and 218c are arranged in the upper arms of the two legs, and the switching elements 220b and 220d are arranged in the lower arms of the two legs. The configuration and operation of the rectifier circuit 20 illustrated in FIG. 15 are publicly known, and therefore further description thereof will be omitted here.

[0072] The control unit 6 generates switching signals to drive the two switching elements 220b and 220d using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in Fig. 15 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0073] 15, the switching elements 220b and 220d are shown as IGBTs, but any elements capable of switching operation may be used. Furthermore, although the AC-DC converter 2 shown in FIG. 15 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 217a and 217b and the current detector 211 do not need to be used.

[0074] Sixth Embodiment In a sixth embodiment, a different example of the AC-DC converter 2 including the control unit 6 described in the first or second embodiment will be described. Components having the same or equivalent functions as those of the AC-DC converter 2 described in the first or second embodiment will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0075] 16 is a diagram showing a configuration example of an AC-DC converter 2 according to a sixth embodiment. In the AC-DC converter 2 shown in FIG. 16, the rectifier circuit 20 is configured with a single-phase H-bridge cell including two diodes 218a and 218b, four switching elements 220a, 220b, 220c, and 220d, a capacitor 216b, and a voltage detector 217c. The voltage detector 217c may be provided outside the rectifier circuit 20.

[0076] In the rectifier circuit 20 shown in FIG. 16 , one leg is configured with a series circuit of diodes 218a and 218b, and the other leg is configured with a series circuit of switching elements 220a, 220b, 220c, and 220d. Capacitor 216b is connected between the connection point of switching elements 220a and 220b and the connection point of switching elements 220c and 220d. Voltage detection unit 217c detects the voltage of capacitor 216b and outputs the detected value to control unit 6. Based on the detected values ​​of voltage detection units 217a, 217b, and 217c and current detection unit 211, control unit 6 generates switching signals for controlling switching elements 220a, 220b, 220c, and 220d. Note that the configuration and operation of the rectifier circuit 20 shown in FIG. 16 are publicly known, and further description thereof will be omitted here.

[0077] The control unit 6 generates switching signals to drive the four switching elements 220a, 220b, 220c, and 220d using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in FIG. 16 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0078] 16, the switching elements 220a, 220b, 220c, and 220d are shown as IGBTs, but any elements capable of switching operation may be used. Furthermore, although the AC-DC converter 2 shown in FIG. 16 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 217a, 217b, and 217c and the current detector 211 do not need to be used.

[0079] Embodiment 7 In embodiment 7, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC-DC converter 2 described in embodiments 1 and 2 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0080] 17 is a diagram illustrating a configuration example of an AC-DC converter 2 according to a seventh embodiment. In the AC-DC converter 2 of FIG. 17 , a rectifier circuit 20 includes a single-phase H-bridge cell 221 and a switching cell 222. The single-phase H-bridge cell 221 includes two diodes 218a and 218c and two switching elements 220b and 220d. The switching cell 222 includes four switching elements 220e, 220f, 220g, and 220h, a capacitor 216c, and a voltage detection unit 217c. The voltage detection unit 217c may be provided outside the switching cell 222.

[0081] In a single-phase H-bridge cell 221 shown in Fig. 17, diodes 218a and 218c are arranged in the upper arms of two legs, and switching elements 220b and 220d are arranged in the lower arms of two legs. In a switching cell 222 shown in Fig. 17, four switching elements 220e, 220f, 220g, and 220h are bridge-connected. A capacitor 216c is connected in parallel to a first leg consisting of switching elements 220e and 220f and a second leg consisting of switching elements 220g and 220h.

[0082] The voltage detection unit 217c detects the voltage of the capacitor 216c and outputs the detected value to the control unit 6. The control unit 6 generates switching signals for controlling the switching elements 220b, 220d, 220e, 220f, 220g, and 220h based on the detected values ​​of the voltage detection units 217a, 217b, and 217c and the current detection unit 211. The configuration and operation of the rectifier circuit 20 shown in FIG. 17 are publicly known, and further description thereof will be omitted here.

[0083] The control unit 6 generates switching signals to drive the six switching elements 220b, 220d, 220e, 220f, 220g, and 220h using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in FIG. 17 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0084] 17, the switching elements 220b, 220d, 220e, 220f, 220g, and 220h are shown as IGBTs, but any elements capable of switching operation may be used. Furthermore, although the AC-DC converter 2 shown in FIG. 17 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 217a, 217b, and 217c and the current detector 211 do not need to be used.

[0085] Embodiment 8 In embodiment 8, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC-DC converter 2 described in embodiments 1 and 2 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0086] FIG. 18 is a diagram illustrating a configuration example of an AC-DC converter 2 according to an eighth embodiment. In the AC-DC converter 2 of FIG. 18, the rectifier circuit 20 is composed of a single-phase diode bridge cell 213a and a switching cell 225. The switching cell 225 includes a single-phase diode bridge cell 213b and a series circuit formed by two switching elements 220a and 220b. The series circuit is connected in parallel to the single-phase diode bridge cell 213b. In FIG. 18, the capacitor 216 in FIG. 2 is replaced with two capacitors 216a and 216b connected in series. The series-connected capacitors 216a and 216b are connected between the DC buses 9a and 9b.

[0087] The control unit 6 generates switching signals for controlling the switching elements 220a and 220b based on the detection values ​​of the voltage detection units 217a and 217b and the current detection unit 211. The configuration and operation of the rectifier circuit 20 shown in Fig. 18 are publicly known, and further description thereof will be omitted here.

[0088] The control unit 6 generates switching signals to drive the two switching elements 220a and 220b using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in Fig. 18 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0089] 18, the switching elements 220a and 220b are shown as IGBTs, but any elements capable of switching operation may be used. Furthermore, although the AC-DC converter 2 shown in FIG. 18 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 217a and 217b and the current detector 211 do not need to be used.

[0090] Embodiment 9 In embodiment 9, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC-DC converter 2 described in embodiments 1 and 2 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0091] Fig. 19 is a diagram showing a configuration example of an AC-DC converter 2 according to a ninth embodiment. While the AC-DC converter 2 of Fig. 13 shows a single-phase AC power supply 1, Fig. 19 shows this changed to a three-phase AC power supply 5. As a result, in the AC-DC converter 2 of Fig. 19, the rectifier circuit 20 is configured with a three-phase full-bridge cell 226 including six switching elements 220a, 220b, 220c, 220d, 220e, and 220f. Reactors 212a, 212b, and 212c are inserted in each phase between the three-phase AC power supply 5 and the rectifier circuit 20, and current detectors 211a and 211b are arranged in any two of the three phases.

[0092] The voltage detection unit 227 detects the voltage of each phase of the three-phase AC power supply 5 and outputs the detected value to the control unit 6. The current detection units 211a and 211b detect the currents flowing in any two of the three phases and output the detected values ​​to the control unit 6. The current in the remaining phase can be determined by calculation within the control unit 6, taking advantage of the fact that the currents in the phases are three-phase balanced.

[0093] The control unit 6 generates switching signals for controlling the switching elements 220a, 220b, 220c, 220d, 220e, and 220f based on the detection values ​​of the voltage detection units 227 and 217b and the current detection units 211a and 211b. Note that the configuration and operation of the rectifier circuit 20 shown in Fig. 19 are publicly known, and further description thereof will be omitted here.

[0094] The control unit 6 generates switching signals to drive the six switching elements 220a, 220b, 220c, 220d, 220e, and 220f using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in FIG. 19 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0095] Although the switching elements 220a, 220b, 220c, 220d, 220e, and 220f are shown as IGBTs in FIG. 19 , any elements capable of switching may be used. Although the AC-DC converter 2 shown in FIG. 19 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 227 and 217b and the current detectors 211a and 211b do not need to be used. Furthermore, the control according to the ninth embodiment may be performed on an αβ coordinate system or a three-phase coordinate system.

[0096] Embodiment 10 In embodiment 10, a different example of the AC / DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC / DC converter 2 described in embodiments 1, 2, and 9 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0097] FIG. 20 is a diagram illustrating a configuration example of an AC-DC converter 2 according to a tenth embodiment. In the AC-DC converter 2 illustrated in FIG. 20, the rectifier circuit 20 includes a three-phase diode bridge cell 228 and a three-phase simplified PAM cell 229. The three-phase diode bridge cell 228 includes six diodes connected in a full bridge configuration. The three-phase simplified PAM cell 229 includes single-phase diode bridge cells 213a, 213b, and 213c, and switching elements 215a, 215b, and 215c connected in parallel to the single-phase diode bridge cells 213a, 213b, and 213c, respectively. The single-phase diode bridge cells 213a, 213b, and 213c are connected between the three-phase lines and the reactors 212a, 212b, and 212c and the three-phase diode bridge cell 228. The three-phase simple PAM cell 229 also includes a capacitor 216d, one end of which is connected to the single-phase diode bridge cells 213a, 213b, and 213c, and the other end of which is connected to the DC bus 9b. The capacitor 216d may be provided outside the three-phase simple PAM cell 229.

[0098] The control unit 6 generates switching signals for controlling the switching elements 215a, 215b, and 215c based on the detection values ​​of the voltage detection units 227 and 227b and the current detection units 211a and 211b. Note that the configuration and operation of the rectifier circuit 20 shown in Fig. 20 are publicly known, and further description thereof will be omitted here.

[0099] The control unit 6 generates switching signals to drive the three switching elements 215a, 215b, and 215c using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in Fig. 20 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0100] Although the switching elements 215a, 215b, and 215c are shown as IGBTs in FIG. 20 , any elements capable of switching operation may be used. Although the AC-DC converter 2 shown in FIG. 20 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 227 and 217b and the current detectors 211a and 211b do not need to be used. Furthermore, the control according to the tenth embodiment may be performed on an αβ coordinate system or a three-phase coordinate system.

[0101] Embodiment 11 In embodiment 11, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC-DC converter 2 described in embodiments 1, 2, 9, and 10 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0102] Fig. 21 is a diagram showing a configuration example of an AC-DC converter 2 according to embodiment 11. In the AC-DC converter 2 of Fig. 21, the capacitor 216d is removed from the configuration of the AC-DC converter 2 of Fig. 20. Other configurations are the same as or equivalent to those of Fig. 20.

[0103] The control unit 6 generates switching signals for controlling the switching elements 215a, 215b, and 215c based on the detection values ​​of the voltage detection units 227 and 217b and the current detection units 211a and 211b. Note that the configuration and operation of the rectifier circuit 20 shown in Fig. 21 are publicly known, and further description thereof will be omitted here.

[0104] The control unit 6 generates switching signals to drive the three switching elements 215a, 215b, and 215c using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in Fig. 21 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0105] Although the switching elements 215a, 215b, and 215c are shown as IGBTs in FIG. 21 , any elements capable of switching operation may be used. Although the AC-DC converter 2 shown in FIG. 21 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 227 and 217b and the current detectors 211a and 211b do not need to be used. Furthermore, the control according to the eleventh embodiment may be performed on an αβ coordinate system or a three-phase coordinate system.

[0106] Embodiment 12 In embodiment 12, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC-DC converter 2 described in embodiments 1, 2, and 9 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0107] Fig. 22 is a diagram showing a configuration example of an AC-DC converter 2 according to embodiment 12. In the AC-DC converter 2 shown in Fig. 22, the rectifier circuit 20 has a configuration called a full PAM circuit. The rectifier circuit 20 includes a three-phase diode bridge cell 228, a switching element 215, and a diode 218.

[0108] The control unit 6 generates a switching signal for controlling the switching element 215 based on the detection values ​​of the voltage detection units 227, 217b and the current detection unit 211. The configuration and operation of the rectifier circuit 20 shown in Fig. 22 are well known, and further description thereof will be omitted here.

[0109] The control unit 6 generates a switching signal for driving the switching element 215 using the control method described in the first or second embodiment. As a result, the AC-DC converter 2 shown in Fig. 22 can also achieve the same effects as those of the first or second embodiment.

[0110] Although the switching element 215 is shown as an IGBT in FIG. 22 , any element capable of switching operation may be used. Although the AC-DC converter 2 shown in FIG. 22 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 227 and 217 b and the current detector 211 do not need to be used. Furthermore, the control according to the twelfth embodiment may be performed on an αβ coordinate system or a three-phase coordinate system.

[0111] Embodiment 13 In embodiment 13, a different example of the AC / DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC / DC converter 2 described in embodiments 1, 2, 9, and 12 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0112] Fig. 23 is a diagram showing a configuration example of an AC-DC converter 2 according to embodiment 13. In the AC-DC converter 2 of Fig. 23, the reactors 212a, 212b, and 212c that were arranged between the three-phase AC power supply 5 and the three-phase diode bridge cell 228 in the configuration of the AC-DC converter 2 of Fig. 22 are replaced with a reactor 212. In Fig. 23, the reactor 212 is arranged between the three-phase diode bridge cell 228 and the diode 218. The rest is the same as or equivalent to Fig. 22.

[0113] The control unit 6 generates a switching signal for controlling the switching element 215 based on the detection values ​​of the voltage detection units 227, 217b and the current detection unit 211. The configuration and operation of the rectifier circuit 20 shown in Fig. 23 are publicly known, and further description thereof will be omitted here.

[0114] The control unit 6 generates a switching signal for driving the switching element 215 using the control method described in the first or second embodiment. As a result, the AC-DC converter 2 shown in Fig. 23 can also achieve the same effects as those of the first or second embodiment.

[0115] Although the switching element 215 is shown as an IGBT in FIG. 23 , any element capable of switching operation may be used. Furthermore, although the AC-DC converter 2 shown in FIG. 23 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 227 and 217 b and the current detector 211 do not need to be used. Furthermore, the control according to the thirteenth embodiment may be performed on an αβ coordinate system or a three-phase coordinate system.

[0116] Embodiment 14 In embodiment 14, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC-DC converter 2 described in embodiments 1, 2, and 9 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0117] FIG. 24 is a diagram illustrating a configuration example of an AC-DC converter 2 according to a fourteenth embodiment. In the AC-DC converter 2 of FIG. 24 , the rectifier circuit 20 is configured with a three-phase diode bridge cell 228 and a three-phase bidirectional switching cell 231. The three-phase bidirectional switching cell 231 includes six switching elements 231a, 231b, 231c, 231d, 231e, and 231f. Also, in FIG. 24 , the capacitor 216 of FIG. 19 is replaced with two capacitors 216a and 216b connected in series. The series-connected capacitors 216a and 216b are connected between the DC buses 9a and 9b. In the three-phase bidirectional switching cell 231, the switching elements 231a and 231b, the switching elements 231c and 231d, and the switching elements 231e and 231f are connected in series in pairs. Each series-connected pair is arranged for each phase between the three-phase diode bridge cell 228 and the connection point of the capacitors 216 a, 216 b. Note that the configuration and operation of the rectifier circuit 20 shown in FIG. 24 are well known, and further description thereof will be omitted here.

[0118] The control unit 6 generates switching signals to drive the six switching elements 231a, 231b, 231c, 231d, 231e, and 231f using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in Fig. 24 can also achieve the same effects as those of embodiment 1 or embodiment 2.

[0119] Although the switching elements 231a, 231b, 231c, 231d, 231e, and 231f are shown as IGBTs in FIG. 24 , any elements capable of switching operation may be used. Although the AC-DC converter 2 shown in FIG. 24 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 227 and 217b and the current detectors 211a and 211b do not need to be used. Furthermore, the control according to the fourteenth embodiment may be performed on an αβ coordinate system or a three-phase coordinate system.

[0120] Embodiment 15 In embodiment 15, a different example of the AC-DC converter 2 including the control unit 6 described in embodiment 1 or embodiment 2 will be described. Note that components having the same or equivalent functions as components of the AC-DC converter 2 described in embodiments 1 and 2 will be denoted by the same reference numerals, and overlapping descriptions will be omitted.

[0121] FIG. 25 is a diagram illustrating a configuration example of an AC-DC converter 2 according to a fifteenth embodiment. In the AC-DC converter 2 of FIG. 25, a rectifier circuit 20 is configured with a single-phase diode bridge cell 213a and an interleaved cell 219. The interleaved cell 219 is configured by combining two sets of a reactor 212, a switching element 215, and a diode 218 in the full-PAM circuit configuration described in FIG. 12. Specifically, the interleaved cell 219 includes reactors 2191a and 2191b, diodes 2192a and 2192b, and switching elements 2193a and 2193b. The configuration and operation of the rectifier circuit 20 illustrated in FIG. 25 are publicly known, and further description thereof will be omitted here.

[0122] The control unit 6 generates switching signals to drive the two switching elements 2193a and 2193b using the control method described in embodiment 1 or embodiment 2. As a result, the AC-DC converter 2 shown in Fig. 25 can also achieve the same effects as those in embodiment 1 or embodiment 2.

[0123] Although the switching elements 2193a and 2193b are shown as IGBTs in FIG. 25 , any elements capable of switching may be used. Furthermore, although the AC-DC converter 2 shown in FIG. 25 is configured as a closed loop, it may also be configured as an open loop. When the AC-DC converter 2 is configured as an open loop, the detection values ​​of the voltage detectors 217a and 217b and the current detector 211 do not need to be used. Furthermore, although FIG. 25 shows an example in which the interleaved cells 219 are configured in two stages, the interleaved cells 219 may also be configured in three or more stages. Furthermore, the rectifier circuits 20 shown in the first to fourteenth embodiments may also be configured in an interleaved configuration.

[0124] Sixteenth Embodiment Fig. 26 is a diagram showing a configuration example of a refrigeration cycle-applied device 900 according to a sixteenth embodiment. The refrigeration cycle-applied device 900 according to the sixteenth embodiment includes the rotating machine drive device 8 described in the first embodiment. The refrigeration cycle-applied device 900 according to the sixteenth embodiment can be applied to products equipped with a refrigeration cycle, such as air conditioners, refrigerators, freezers, and heat pump water heaters.

[0125] The refrigeration cycle device 900 includes a compressor 42 incorporating the motor 41 of the first embodiment, a four-way valve 902, an indoor heat exchanger 906, an expansion valve 908, and an outdoor heat exchanger 910, all of which are attached via refrigerant piping 912. Inside the compressor 42, there are provided a compression mechanism 904 that compresses the refrigerant, and a motor 41 that operates the compression mechanism 904. The refrigeration cycle device 900 can perform heating or cooling operation by switching the four-way valve 902.

[0126] The compression mechanism 904 is driven by a variable-speed controlled motor 41. During heating operation, as indicated by the solid arrows, the refrigerant is pressurized by the compression mechanism 904 and discharged, passes through the four-way valve 902, the indoor heat exchanger 906, the expansion valve 908, the outdoor heat exchanger 910, and the four-way valve 902, and returns to the compression mechanism 904. During cooling operation, as indicated by the dashed arrows, the refrigerant is pressurized by the compression mechanism 904 and discharged, passes through the four-way valve 902, the outdoor heat exchanger 910, the expansion valve 908, the indoor heat exchanger 906, and the four-way valve 902, and returns to the compression mechanism 904. During heating operation, the indoor heat exchanger 906 acts as a condenser to release heat, and the outdoor heat exchanger 910 acts as an evaporator to absorb heat. During cooling operation, the outdoor heat exchanger 910 acts as a condenser to release heat, and the indoor heat exchanger 906 acts as an evaporator to absorb heat. The expansion valve 908 reduces the pressure of the refrigerant and causes it to expand.

[0127] The refrigeration cycle applied device 900 according to the sixteenth embodiment has been described as including the rotating machine driving device 8 described in the first embodiment, but is not limited to this. The refrigeration cycle applied device 900 may include the rotating machine driving device 8 including the rectifier circuit 20 described in any of the second to fifteenth embodiments. Furthermore, the refrigeration cycle applied device 900 may include a rectifier circuit other than the rectifier circuit 20 described in any of the first to fifteenth embodiments, as long as the control method of the first or second embodiment can be applied.

[0128] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies, or the embodiments may be combined with each other, or part of the configuration may be omitted or modified without departing from the spirit of the invention. For example, the above-described control method may also be applied to a DC-AC converter.

[0129] 1 AC power supply, 2 AC / DC converter, 3 DC / AC converter, 4 Load, 5 Three-phase AC power supply, 6 Control unit, 7 Current control system, 8 Rotating machine drive unit, 9a, 9b DC bus, 20 Rectifier circuit, 41 Motor, 42 Compressor, 61 Voltage control unit, 62 Current control unit, 63 Switching signal generation unit, 72 Controller, 73 Control target plant, 74, 624 Target value filter, 211, 211a, 211b Current detection unit, 212, 212a, 212b, 212c, 2191a, 2191b Reactor, 213a, 213b, 213c Single-phase diode bridge cells, 215, 215a, 215b, 215c, 220a, 220b, 220c, 220d, 220e, 220f, 220g, 220h, 231a, 231b, 231c, 231d, 231e, 231f, 2193a, 2193b Switching elements, 216, 216a, 216b, 216c, 216d Capacitors, 217a, 217b, 217c, 227 Voltage detection units, 218, 218a, 218b, 218c, 2192a, 2192b Diodes, 219 Interleaved cells, 221 Single-phase H-bridge cells, 222, 225 Switching cells, 226 Three-phase full-bridge cells, 228 Three-phase diode bridge cells, 229 Three-phase simple PAM cell, 231 Three-phase bidirectional switching cell, 611 Voltage controller, 612, 622 Subtractor, 621 Current controller, 623 Multiplier, 900 Refrigeration cycle application equipment, 902 Four-way valve, 904 Compression mechanism, 906 Indoor heat exchanger, 908 Expansion valve, 910 Outdoor heat exchanger, 912 Refrigerant piping.

Claims

1. An AC / DC conversion device comprising: a rectifier circuit having at least one switching element for rectifying a power supply voltage applied from an AC power supply; a capacitor connected to a DC bus for smoothing the output voltage of the rectifier circuit; a reactor located on the AC power supply side of the capacitor; and a control unit for generating a switching signal for controlling the switching element, wherein the switching element is located on the AC power supply side of the capacitor, and the control unit generates the switching signal so that harmonic components contained in the power supply current flowing between the AC power supply and the rectifier circuit comply with the harmonic standard value of the power supply current.

2. The AC-DC conversion device according to claim 1, characterized in that the control unit comprises: a voltage control unit that generates a first current command value using a first voltage command value which is a command value for a bus voltage which is the voltage of the DC bus; a current control unit that generates a second voltage command value using a second current command value which causes the first current command value to follow a sine wave; and a switching signal generation unit that generates the switching signal using the second voltage command value.

3. The AC / DC converter according to claim 2, comprising: a current detection unit that detects the power supply current; a first voltage detection unit that detects the bus voltage; and a second voltage detection unit that detects the power supply voltage, wherein the first current command value is generated using a voltage deviation that is the difference between the first voltage command value and the detected voltage detected by the first voltage detection unit, the sine wave is generated based on the voltage phase detected by the second voltage detection unit, and the second voltage command value is generated using a current deviation that is the difference between the second current command value and the detected current detected by the current detection unit.

4. An AC / DC converter as claimed in claim 2 or 3, characterized in that low-order harmonics are superimposed on the power supply current.

5. An AC / DC converter as claimed in claim 2 or 3, characterized in that the sum of the harmonic components of the power supply current is 10% or more of the fundamental wave of the power supply current.

6. An AC / DC converter as described in claim 2 or 3, characterized in that the current control unit is provided with a filter that operates a zero point of a feedback loop that feeds back the second voltage command value output by the current control unit to an input stage of the second current command value.

7. A rotary machine drive device comprising an AC / DC converter according to any one of claims 1 to 6.

8. A refrigeration cycle device comprising an AC / DC converter as claimed in any one of claims 1 to 6.

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