Direct-current power supply device, refrigeration cycle device, air conditioner, and refrigerator

Abstract

A direct-current power supply device (100) includes a rectification circuit (10) bridged by switching elements (3, 4, 5, 6), an electric reactor (2), a gate circuit section (11) that drives the switching elements (3, 4), and a gate circuit section (12) that drives the switching elements (5, 6). A connection point (14) of the switching element (3) and the switching element (4) is connected to an alternating-current power supply (1) via the electric reactor (2), and a connection point (15) of the switching element (5) and the switching element (6) is connected to the alternating-current power supply (1) without passing through the electric reactor (2). The gate circuit section (11) turns on the switching elements (3, 4) for a longer time than the gate circuit section (12) turns on the switching elements (5, 6).

Description

Technical Field

[0001] This disclosure relates to a DC power supply device having a diode bridge-less (DBL) rectifier circuit, a refrigeration cycle device having a DC power supply device, and an air conditioner and a refrigerator equipped with a refrigeration cycle device. Background Technology

[0002] As prior art related to DC power supply devices equipped with DBL rectifier circuits, there is the technology described in Patent Document 1. In Patent Document 1, a technology is disclosed that can protect the switching elements of the DBL rectifier circuit even when there are power supply voltage disturbances such as lightning strikes.

[0003] Patent Document 1: International Publication No. 2019 / 082246

[0004] Patent Document 1 describes a situation where a recovery current flows through the switching element due to power supply voltage disturbances. However, Patent Document 1 completely fails to consider the ringing noise generated by the recovery current. Therefore, the technology in Patent Document 1 cannot suppress this ringing noise. Summary of the Invention

[0005] This disclosure is made in view of the above circumstances, with the aim of obtaining a DC power supply device capable of suppressing ringing noise caused by recovery current.

[0006] To address the aforementioned issues and achieve the objective, the DC power supply device disclosed herein includes: a rectifier circuit formed by bridging first to fourth switching elements; and a reactor connected between an AC power supply and the rectifier circuit. Furthermore, the DC power supply device includes: a first gate circuit section that drives the first and second switching elements; and a second gate circuit section that drives the third and fourth switching elements. The connection point between the first and second switching elements is connected to the AC power supply via the reactor. The connection point between the third and fourth switching elements is connected to the AC power supply without via the reactor. The first gate circuit section turns on the first switching element for a longer period than the second gate circuit section turns on the third and fourth switching elements. Additionally, the first gate circuit section turns on the second switching element for a longer period than the second gate circuit section turns on the third and fourth switching elements.

[0007] The DC power supply device disclosed herein has the effect of suppressing ringing noise caused by the recovery current. Attached Figure Description

[0008] Figure 1 This is a diagram illustrating a structural example of the DC power supply device according to Embodiment 1.

[0009] Figure 2 It means Figure 1 A diagram showing an example of the internal structure of the gate circuit section.

[0010] Figure 3 This is a diagram showing the first current path flowing in a typical MOSFET.

[0011] Figure 4 This is a diagram showing the second current path flowing in a typical MOSFET.

[0012] Figure 5 This is a diagram showing the first current path flowing in the rectifier circuit of Embodiment 1.

[0013] Figure 6 This is a diagram showing the second current path flowing in the rectifier circuit of Embodiment 1.

[0014] Figure 7 This is a diagram showing the third current path flowing in the rectifier circuit of Embodiment 1.

[0015] Figure 8 This is a diagram showing the fourth current path flowing in the rectifier circuit of Embodiment 1.

[0016] Figure 9 This is a diagram showing the fifth current path flowing in the rectifier circuit of Embodiment 1.

[0017] Figure 10 This is a diagram showing the sixth current path flowing in the rectifier circuit of Embodiment 1.

[0018] Figure 11 This is a diagram showing the operating waveforms and operating states of the main components in the DC power supply device of Embodiment 1.

[0019] Figure 12 This is a diagram showing the path of the recovery current flowing due to the first operation in the rectifier circuit of Embodiment 1.

[0020] Figure 13 This is a diagram showing the path of the recovery current flowing due to the second operation in the rectifier circuit of Embodiment 1.

[0021] Figure 14 This is a diagram showing the waveform of the main part when the switching element in the rectifier circuit of Embodiment 1 generates ringing.

[0022] Figure 15 This is a diagram showing a structural example of the refrigeration cycle device involved in Embodiment 2. Detailed Implementation

[0023] Implementation method 1.

[0024] Figure 1This is a diagram illustrating a structural example of the DC power supply device 100 according to Embodiment 1. The DC power supply device 100 of Embodiment 1 is a power supply device that converts AC power supplied from AC power source 1 into DC power and supplies it to load 8. Figure 1 As shown, the DC power supply device 100 includes a reactor 2, a rectifier circuit 10, a smoothing capacitor 7, a gate circuit section 11 serving as a first gate circuit section, a gate circuit section 12 serving as a second gate circuit section, and a control section 9.

[0025] The rectifier circuit 10 in Embodiment 1 is a DBL rectifier circuit. A typical rectifier circuit has a structure with four diodes bridged together. In contrast, the DBL rectifier circuit has a structure with four switching elements bridged together. That is, in the DBL rectifier circuit, the four diodes are replaced with switching elements.

[0026] The rectifier circuit 10 has a first bridge arm 50 and a second bridge arm 52 connected in parallel with the first bridge arm 50. The first bridge arm 50 has a switching element 3 as a first switching element and a switching element 4 as a second switching element. Switching element 3 and switching element 4 are connected in series. The second bridge arm 52 has a switching element 5 as a third switching element and a switching element 6 as a fourth switching element. Switching element 5 and switching element 6 are connected in series.

[0027] exist Figure 1 In the diagram, switching elements 3, 4, 5, and 6 are connected in parallel with diodes. An example of switching elements 3, 4, 5, and 6 is the illustrated Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). When a MOSFET is used as switching elements 3, 4, 5, and 6, a parasitic diode exists within the element. Therefore, by using a MOSFET and employing the parasitic diode, the parallel-connected diode can be omitted.

[0028] Unlike unidirectional devices such as diodes, where current flows in only one direction, MOSFETs are generally bidirectional devices capable of bidirectional current flow. That is, if a charge is supplied to the gate of the MOSFET to turn it on, the current can also flow in the opposite direction. Furthermore, "reverse" here refers to the direction opposite to the direction of current flowing in the parasitic diode integrated within the MOSFET.

[0029] Reactor 2 is connected between AC power supply 1 and rectifier circuit 10. Specifically, one end of reactor 2 is connected to one side of AC power supply 1, and the other end of reactor 2 is connected to the connection point 14 of switching elements 3 and 4. The connection point 15 of switching elements 5 and 6 is connected to the other side of AC power supply 1. Connection points 14 and 15 constitute the input terminal of rectifier circuit 10. That is, connection point 14 is the input terminal of rectifier circuit 10 connected via reactor 2, and connection point 15 is the input terminal of rectifier circuit 10 not connected via reactor 2.

[0030] A smoothing capacitor 7 is connected between the output terminals of the rectifier circuit 10. The rectifier circuit 10 converts the power supply voltage Vs applied from the AC power supply 1 via the reactor 2 into a DC voltage. The power supply voltage Vs is the AC voltage output from the AC power supply 1.

[0031] The smoothing capacitor 7 is charged through the output of the rectifier circuit 10. The smoothing capacitor 7 smooths the DC voltage output from the rectifier circuit 10. A load 8 is connected across the smoothing capacitor 7. The load 8 includes an inverter that operates using the power of the smoothing capacitor 7, a motor driven by the inverter, and a device driven by the motor.

[0032] The control unit 9 includes a processor 9a and a memory 9b. The control unit 9 receives inputs of the detected values ​​of the power supply voltage Vs, the circuit current Is, and the capacitor voltage Vd. The circuit current Is is the current flowing through the reactor 2 to the rectifier circuit 10. The circuit current is sometimes also referred to as the "primary current." The capacitor voltage Vd is the voltage of the smoothing capacitor 7. The capacitor voltage is sometimes also referred to as the "bus voltage." The power supply voltage Vs, the circuit current Is, and the capacitor voltage Vd are respectively connected via... Figure 1 The detector is not shown in the figure.

[0033] Based on the detected values ​​of power supply voltage Vs, circuit current Is, and capacitor voltage Vd, control unit 9 generates control signals for controlling the conduction of switching elements 3 and 4, and outputs them to gate circuit unit 11. Additionally, based on the detected values ​​of power supply voltage Vs, circuit current Is, and capacitor voltage Vd, control unit 9 generates control signals for controlling the conduction of switching elements 5 and 6, and outputs them to gate circuit unit 12.

[0034] The gate circuit section 11 generates and outputs gate signals Q1 and Q2 for driving the switching elements 3 and 4 based on the control signal output from the control section 9. Gate signal Q1 is a signal that controls the conduction state of the switching element 3 from on to off or from off to on. Gate signal Q2 is a signal that controls the conduction state of the switching element 4 from on to off or from off to on.

[0035] The gate circuit section 12 generates and outputs gate signals Q3 and Q4 for driving the switching elements 5 and 6 based on the control signal output from the control section 9. Gate signal Q3 is a signal that controls the conduction state of the switching element 5 from on to off or from off to on. Gate signal Q4 is a signal that controls the conduction state of the switching element 6 from on to off or from off to on.

[0036] When driving switching elements 3, 4, 5, and 6, the gate signals Q1 to Q4 are converted into voltage levels capable of driving switching elements 3, 4, 5, and 6 for output. Gate circuit sections 11 and 12 can be implemented using level shifting circuits or the like.

[0037] In the control unit 9, the processor 9a is an arithmetic unit such as a computing device, microprocessor, microcomputer, CPU (Central Processing Unit), or DSP (Digital Signal Processor). The memory 9b is a non-volatile or volatile semiconductor memory such as RAM (Random Access Memory), ROM (Read Only Memory), flash memory, EPROM (Erasable Programmable ROM), or EEPROM (Electrically EPROM).

[0038] The memory 9b stores the program that executes the functions of the control unit 9. The processor 9a receives and sends necessary information via an interface including an analog-to-digital converter and a digital-to-analog converter (not shown). The processor 9a executes the program stored in the memory 9b, thereby performing the necessary processing. The results of the processor 9a's operations are stored in the memory 9b.

[0039] Figure 2 It means Figure 1 The diagram shows an example of the internal structure of the gate circuit section 11. The gate circuit section 12 has the same structure as the gate circuit section 11. Figure 2 In the figures, the reference numerals for the structural parts corresponding to the gate circuit section 12 are shown in brackets. Furthermore, some circuit constants differ between the gate circuit section 11 and the gate circuit section 12. These differences will be described later. The gate circuit section 11 will be described below.

[0040] like Figure 2As shown, the gate circuit section 11 includes gate on-resistors 22a and 22b, gate off-resistors 23a and 23b, resistors 25a and 25b, diodes 24a and 24b, capacitors 26a and 26b, and an HVIC (High Voltage Integrated Circuit) 21. The HVIC 21 is a high-voltage IC that outputs gate signals to drive the gates of switching elements 3 and 4 based on the input signals from the control section 9.

[0041] exist Figure 2 In this structure, when the switching element 3 is switched from off to on, charge is supplied to the gate via the gate on-resistor 22a. When the switching element 3 is switched from on to off, the charge accumulated on the gate is discharged via the gate off-resistor 23a. This function of gate on and gate off, i.e., the switching of the signal transmission path, is achieved by the diode 24a, which is a unidirectional element. The capacitor 26a, the gate on-resistor 22a, the gate off-resistor 23a, and the resistor 25a together form an RC circuit.

[0042] Furthermore, when switching element 4 is switched from off to on, charge is supplied to the gate via gate on-resistor 22b. When switching element 4 is switched from on to off, the charge accumulated on the gate is discharged via gate off-resistor 23b. This function of gate on and gate off, i.e., switching of the signal transmission path, is achieved by diode 24b, which is a unidirectional element. Capacitor 26b, gate on-resistor 22b, gate off-resistor 23b, and resistor 25b together form an RC circuit.

[0043] As described above, the gate circuit sections 11 and 12 in Embodiment 1 are configured to each have a gate on-resistance for turning on the gate of the switching element of the driven object and a gate off-resistance for turning off the gate of the switching element of the driven object.

[0044] Next, refer to Figures 3-8 The accompanying drawings illustrate the basic operation of the DC power supply device 100 according to Embodiment 1. Figure 3 This is a diagram showing the first current path flowing in a typical MOSFET. Figure 4 This is a diagram showing the second current path flowing in a typical MOSFET. Figure 5 This is a diagram showing the first current path flowing in the rectifier circuit 10 of Embodiment 1. Figure 6 This is a diagram showing the second current path flowing in the rectifier circuit 10 of Embodiment 1. Figure 7 This is a diagram showing the third current path flowing in the rectifier circuit 10 of Embodiment 1. Figure 8 This is a diagram showing the fourth current path flowing in the rectifier circuit 10 of Embodiment 1.

[0045] exist Figure 3 and Figure 4 In this case, an external voltage is applied to the MOSFET with the source side being positive. Figure 3 This indicates that the MOSFET is in the gate-off state, meaning no voltage is applied between the gate and source of the MOSFET. In this case, the current flowing through the MOSFET is as follows: Figure 3 The dashed line shows the current flowing through the parasitic diode of the MOSFET.

[0046] in addition, Figure 4 This indicates that the MOSFET is in the gate-on state, meaning that a voltage is applied between the gate and source of the MOSFET, causing it to conduct. In this on-state, when the voltage drop across the MOSFET caused by its on-resistance is lower than the forward voltage of the parasitic diode, current flows through the transistor portion of the MOSFET, i.e., the MOSFET channel. In this case, the conduction loss caused by the MOSFET's on-resistance is smaller than the conduction loss when current flows through the diode. Thus, the technique of reducing conduction losses by directing current to the transistor portion of the MOSFET instead of the diode is called "synchronous rectification."

[0047] exist Figure 1 In the circuit structure shown, if all the switching elements 3, 4, 5, and 6, which are MOSFETs, are in the gate-off state, the rectifier circuit 10 performs full-wave rectification via the parasitic diodes of the MOSFETs. In the case of full-wave rectification, diodes can also be used instead of MOSFETs. On the other hand, in Embodiment 1, MOSFETs are used instead of diodes as switching elements to reduce conduction losses during the aforementioned synchronous rectification.

[0048] In the DC power supply device 100 of Embodiment 1, synchronous rectification and boosting operations controlled by a switch are performed.

[0049] like Figures 5-8 As shown, the gate circuit section 11 includes a gate circuit 11a as a first gate circuit and a gate circuit 11b as a second gate circuit. Gate circuit 11a is the gate circuit that drives the switching element 3, and gate circuit 11b is the gate circuit that drives the switching element 4. (Refer to...) Figure 2 HVIC21, gate on-resistor 22a, gate off-resistor 23a, resistor 25a, diode 24a, and capacitor 26a constitute gate circuit 11a. Additionally, HVIC21, gate on-resistor 22b, gate off-resistor 23b, resistor 25b, diode 24b, and capacitor 26b constitute gate circuit 11b.

[0050] Additionally, the gate circuit section 12 includes a gate circuit 12a as a third gate circuit and a gate circuit 12b as a fourth gate circuit. Gate circuit 12a is the gate circuit that drives the switching element 5, and gate circuit 12b is the gate circuit that drives the switching element 6. (See reference...) Figure 2 HVIC21, gate on-resistor 22a, gate off-resistor 23a, resistor 25a, diode 24a, and capacitor 26a constitute gate circuit 12a. Additionally, HVIC21, gate on-resistor 22b, gate off-resistor 23b, resistor 25b, diode 24b, and capacitor 26b constitute gate circuit 12b.

[0051] Figure 5 This represents the circuit current Is based on full-wave rectification when the power supply voltage Vs is positive. Switching elements 3 and 6 are in the gate-on state, and switching elements 4 and 5 are in the gate-off state. In this state, the circuit current Is flows through the path of AC power supply 1, reactor 2, switching element 3, smoothing capacitor 7, switching element 6, and AC power supply 1. During this full-wave rectification, in order to reduce conduction losses, the current is controlled to flow to the transistor section instead of to the parasitic diodes of switching elements 3 and 6. This control is the aforementioned synchronous rectification.

[0052] Figure 6 This represents the circuit current Is based on full-wave rectification when the power supply voltage Vs is negative. Switching elements 4 and 5 are in the gate-on state, and switching elements 3 and 6 are in the gate-off state. In this state, the circuit current Is flows through the path of AC power supply 1, switching element 5, smoothing capacitor 7, switching element 4, reactor 2, and AC power supply 1. In this full-wave rectification, to reduce conduction losses, synchronous rectification is also performed so that the current flows to the transistor section instead of to the parasitic diodes of switching elements 4 and 5.

[0053] Next, the boost operation will be explained. In the boost operation of Embodiment 1, by controlling the switching elements 3 and 4 at a certain switching frequency, the short-circuit current flows in the rectifier circuit 10, thereby boosting the capacitor voltage Vd and improving the power factor. Furthermore, the switching elements 5 and 6 are controlled to switch at half a cycle of the power supply cycle. The power supply cycle is the cycle of the power supply voltage Vs. That is, the switching elements 3 and 4 are controlled to switch at a higher speed than the switching elements 5 and 6.

[0054] Figure 7This represents the circuit current Is based on the switching action when the power supply voltage Vs is positive. Switching elements 4 and 6 are in the gate-on state, and switching elements 3 and 5 are in the gate-off state. In this state, the circuit current Is flows through the path of AC power supply 1, reactor 2, switching elements 4 and 6, and back to AC power supply 1. The circuit current Is flows without passing through the smoothing capacitor 7, and is therefore also called the "short-circuit current." The current through this path stores energy in reactor 2. Furthermore, it is switched to positive voltage by the subsequent switching action. Figure 5 When the current path is open, the energy stored in reactor 2 is released to smoothing capacitor 7. This, in turn, boosts the capacitor voltage Vd.

[0055] Figure 8 This represents the circuit current Is based on the switching action when the power supply voltage Vs is negative. Switching elements 3 and 5 are in the gate-on state, and switching elements 4 and 6 are in the gate-off state. In this state, the circuit current Is flows through the path of AC power supply 1, switching element 5, switching element 3, reactor 2, and AC power supply 1. This circuit current Is is also called the "short-circuit current." The current through this path stores energy in reactor 2. Furthermore, it is switched to positive voltage by the subsequent switching action. Figure 6 When the current path is open, the energy stored in reactor 2 is released to smoothing capacitor 7. This, in turn, boosts the capacitor voltage Vd.

[0056] In the DC power supply device 100 of Embodiment 1, the aforementioned synchronous rectification and boosting operations are repeatedly performed as basic operations. This boosts the capacitor voltage Vd.

[0057] Next, the ringing noise generated in the DC power supply device 100 will be explained.

[0058] First, the basic operation of the DC power supply device 100 has been explained in the above description. On the other hand, in actual control, when switching elements 3, 4, 5, and 6 are switched, a dead time is provided so that switching elements on the same bridge arm are not simultaneously turned on. For example, if switching elements 3 and 4 are turned on simultaneously, the first bridge arm 50 becomes short-circuited through these switching elements, the charge accumulated in the smoothing capacitor 7 is released, and a large current flows through switching elements 3 and 4. This large current could potentially damage switching elements 3 and 4. The dead time is provided to prevent such damage. The same countermeasure is taken for switching elements 5 and 6.

[0059] Figure 9 This is a diagram showing the fifth current path flowing in the rectifier circuit 10 of Embodiment 1. Figure 9This indicates the circuit current Is flowing when the power supply voltage Vs is positive and switch element 5 is open and switch element 6 is closed, and switch elements 3 and 4 are simultaneously disconnected. The simultaneous disconnection of switch elements 3 and 4 occurs during the dead time.

[0060] exist Figure 9 In the circuit, the current path through which the circuit current Is flows is... Figure 5 The current flows in the same way, but in switching element 3, the location of the current flow is different. Specifically, the circuit current Is does not flow through the transistor section of switching element 3, but through the parasitic diode of switching element 3. In this way, since the current path through the parasitic diode can be used, the dead time that makes the two switching elements of the same bridge arm, namely switching elements 3 and 4, turn off simultaneously can be set.

[0061] Figure 10 This is a diagram showing the sixth current path flowing in the rectifier circuit 10 of Embodiment 1. Figure 10 This indicates that when the power supply voltage Vs is negative and switch element 5 is on and switch element 6 is off, the circuit current Is flowing when switches elements 3 and 4 are simultaneously disconnected. When the power supply voltage Vs is negative, the simultaneous disconnection of switches 3 and 4 also occurs during the dead time.

[0062] exist Figure 10 In the circuit, the current path through which the circuit current Is flows is... Figure 6 The current flows in the same way, but in switching element 4, the location of the current flow is different. Specifically, the circuit current Is does not flow through the transistor section of switching element 4, but through the parasitic diode of switching element 4. In this way, since the current path through the parasitic diode can be utilized, a dead time that allows the two switching elements of the same bridge arm, namely switching elements 3 and 4, to be turned off simultaneously can also be set when the power supply voltage Vs is negative.

[0063] Figure 11 This is a diagram showing the operating waveforms and operating states of the main components of the DC power supply device 100 according to Embodiment 1. Figure 11 The horizontal axis represents time.

[0064] Figure 11 This represents the waveform when the above boost operation is performed twice every half cycle of the power supply voltage Vs. From Figure 11 On the upper side, the power supply voltage Vs, circuit current Is, gate signals Q1 to Q4, and the operating state of the rectifier circuit 10 are shown in sequence. In the gate signals Q1 to Q4, the conduction period of each switching element is indicated by a cross-section line.

[0065] In addition, such as Figure 11As shown, the operating states of the rectifier circuit 10 are represented by the values ​​of (1) to (6). Specifically, (1), (2), (3), (4), (5), and (6) are respectively related to... Figure 7 , Figure 9 , Figure 5 , Figure 8 , Figure 10 , Figure 6 Correspondingly, during the period enclosed by the two corresponding dashed lines, each action is performed. In the following description, any of the values ​​in (1) to (6) represents the operating state of the rectifier circuit 10.

[0066] When the power supply voltage Vs is positive, the operation state during the boosting process proceeds in the order of (1)→(2)→(3)→(2)→(1)→(2)→(3). Ringing noise is generated during the operation state (2)→(1) in these operation states. Hereinafter, the operation state when the operation state is (2)→(1) will be appropriately referred to as the "first operation state".

[0067] Next, we will explain the principle behind the generation of ringing noise. Figure 12 This is a diagram showing the path of the recovery current flowing due to the first operation shift in the rectifier circuit 10 of Embodiment 1. As described above, the operating state of the rectifier circuit 10 shifts from (2) to (1) due to the first operation shift. (2) is the dead time period, as... Figure 9 As shown, the circuit current Is flows through the parasitic diode of switching element 3. If the state transitions from this state to state (1), the circuit current Is begins to flow to switching element 4, and the parasitic diode of switching element 3 enters the recovery time. At this time, as Figure 12 As shown, a recovery current flows from the smoothing capacitor 7 toward the parasitic diode of the switching element 3. This causes a sharp increase in the drain-source voltage Vds of the switching element 3, resulting in ringing in the switching element 3.

[0068] Furthermore, the operation state during the boosting process when the power supply voltage Vs is negative follows the sequence (4)→(5)→(6)→(5)→(4)→(5)→(6). Ringing noise is generated during the operation state (5)→(4) in these operation states. Hereinafter, the operation state when it becomes (5)→(4) will be appropriately referred to as the "second operation state".

[0069] Figure 13 This is a diagram showing the path of the recovery current flowing due to the second operation shift in the rectifier circuit 10 of Embodiment 1. As described above, the operating state of the rectifier circuit 10 shifts from (5) to (4) due to the second operation shift. (5) is the dead time period, as... Figure 10As shown, the circuit current Is flows through the parasitic diode of switching element 4. If the circuit transitions from state (4) to state (5), the circuit current Is begins to flow to switching element 3, and the parasitic diode of switching element 4 enters recovery time. At this time, as shown... Figure 13 As shown, a recovery current flows from the smoothing capacitor 7 toward the parasitic diode of the switching element 4. This causes a sharp increase in the drain-source voltage Vds of the switching element 4, resulting in ringing in the switching element 4.

[0070] Figure 14 This is a graph showing the waveform of the main portion when the switching element 3 in the rectifier circuit 10 of Embodiment 1 generates ringing. The horizontal axis represents time. Figure 14 The upper section shows the waveforms of the drain-source voltage Vds and circuit current Is of the switching element 3 during boost operation. Additionally, in Figure 11 The lower section shows an enlarged waveform of the interval enclosed by the single-dot dashed line.

[0071] like Figure 14 As shown, ringing noise appears in the drain-source voltage Vds. According to... Figure 14 and Figure 11 The comparison shows that the ringing noise is generated when the first action shifts, that is, when the action state becomes (2) → (1).

[0072] Figure 14 This is an example of a double-switch operation that repeatedly performs two boost actions. However, in the case of a high-speed switch that repeatedly performs boost actions in a faster cycle than two, the ringing noise effect is more pronounced than in a double-switch operation.

[0073] The ringing noise is generated by the switching elements on the switching side during voltage boost. In the example of Embodiment 1, the ringing noise is generated by switching elements 3 and 4. Therefore, by reducing the dV / dt of the drain-source voltage Vds of switching elements 3 and 4 when they are turned on, the ringing noise can be reduced.

[0074] In the case of the first operation, by reducing the dV / dt of the drain-source voltage Vds of the switching element 4 when it is turned on, the sharp rise of the drain-source voltage Vds of the switching element 3 can be suppressed. Furthermore, reducing the dV / dt of the drain-source voltage Vds of the switching element 3 is equivalent to making the turn-on time of the switching element 4 longer than that of the switching elements 5 and 6.

[0075] When the second operation shifts, i.e., the operation state is (5) → (4), by reducing the dV / dt of the drain-source voltage Vds of the switching element 3 when it is turned on, the sharp rise of the drain-source voltage Vds of the switching element 4 can be suppressed. Furthermore, reducing the dV / dt of the drain-source voltage Vds of the switching element 4 is equivalent to making the turn-on time of the switching element 3 longer than that of the switching elements 5 and 6.

[0076] In order to make the turn-on times of switching elements 3 and 4 longer than those of switching elements 5 and 6, in Embodiment 1, a portion of the circuit constants in the gate circuit section 11 and the gate circuit section 12 are different. Specifically, as follows.

[0077] First, to ensure that the on-time of switching element 3 is longer than that of switching elements 5 and 6, the gate on-resistor 22a of gate circuit 11a uses a resistor with a larger resistance value than the gate on-resistor 22a of gate circuit 12a and the gate on-resistor 22b of gate circuit 12b. Similarly, to ensure that the on-time of switching element 4 is longer than that of switching elements 5 and 6, the gate on-resistor 22b of gate circuit 11b uses a resistor with a larger resistance value than the gate on-resistor 22a of gate circuit 12a and the gate on-resistor 22b of gate circuit 12b.

[0078] Here, the resistance value of the gate on-resistance 22a of gate circuit 11a is set as Ra, the resistance value of the gate on-resistance 22b of gate circuit 11b is set as Rb, the resistance value of the gate on-resistance 22a of gate circuit 12a is set as Ra', and the resistance value of the gate on-resistance 22b of gate circuit 12b is set as Rb'. Thus, the relationships Ra > Ra', Ra > Rb', Rb > Ra', and Rb > Rb' hold true among Ra, Ra', Rb', and Rb'.

[0079] By setting it as described above, it is possible to reduce the ringing noise generated by the switching element on the switching side during voltage boost, i.e., the switching element on the high-speed switching side.

[0080] As described above, the DC power supply device of Embodiment 1 includes: a rectifier circuit bridging first to fourth switching elements; a first gate circuit that drives the first and second switching elements; and a second gate circuit that drives the third and fourth switching elements. The connection point between the first and second switching elements is connected to an AC power supply via a reactor, while the connection point between the third and fourth switching elements is not connected to the AC power supply via a reactor. The time for the first gate circuit to turn on the first switching element is set to be longer than the time for the second gate circuit to turn on the third and fourth switching elements. Furthermore, the time for the first gate circuit to turn on the second switching element is set to be longer than the time for the second gate circuit to turn on the third and fourth switching elements. This suppresses ringing noise generated in the first and second switching elements due to recovery current.

[0081] Furthermore, in Embodiment 1, the connection point 14 of switching elements 3 and 4 is connected to the AC power supply 1 via the reactor 2, while the connection point 15 of switching elements 5 and 6 is not connected to the AC power supply 1 via the reactor 2. However, this disclosure is not limited to this configuration. It is also possible to configure the connection point 14 of switching elements 3 and 4 to be connected to the AC power supply 1 without the reactor 2, while the connection point 15 of switching elements 5 and 6 is connected to the AC power supply 1 via the reactor 2. Furthermore, in this configuration, the switching control of switching elements 5 and 6 is performed at a higher speed than that of switching elements 3 and 4.

[0082] Implementation method 2.

[0083] Figure 15 This is a diagram showing a structural example of the refrigeration cycle device 200 according to Embodiment 2. Figure 15 The refrigeration cycle device 200 according to Embodiment 2 includes the DC power supply device 100 described in Embodiment 1 and an inverter 30 connected to the DC power supply device 100. The refrigeration cycle device 200 is configured to have a refrigeration cycle 150, which is equipped with a compressor 41 with an electric motor 40, a four-way valve 42, an outdoor heat exchanger 43, an expansion valve 44, and an indoor heat exchanger 45 via refrigerant piping 46. The electric motor 40 is driven by the inverter 30.

[0084] The compressor 41 contains a compression mechanism 47 for compressing the refrigerant and an electric motor 40 for operating the compression mechanism 47. This constitutes a refrigeration cycle 150, which circulates the refrigerant from the compressor 41 between the outdoor heat exchanger 43 and the indoor heat exchanger 45 to perform cooling and heating. Furthermore, Figure 15 The refrigeration cycle 150 shown can be applied to equipment with refrigeration cycles, such as air conditioners, refrigerators, and cold storage facilities.

[0085] The refrigeration cycle apparatus 200 according to Embodiment 2 includes the DC power supply device 100 described in Embodiment 1. As described above, the DC power supply device 100 of Embodiment 1 can suppress ringing noise caused by recovery current. Therefore, when the refrigeration cycle apparatus 200 according to Embodiment 2 is applied to, for example, air conditioners and refrigerators, it is possible to achieve the effect of reducing the emitted noise from these products compared to the past. In addition, since the emitted noise can be reduced compared to the past, it is possible to easily ensure a margin relative to the allowable value of emitted noise.

[0086] The structure shown in the above embodiments is an example, which can be combined with other known technologies, or a part of the structure can be omitted or changed without departing from the main idea.

[0087] Explanation of reference numerals in the attached figures:

[0088] 1…AC power supply; 2…reactor; 3, 4, 5, 6…switching element; 7…smoothing capacitor; 8…load; 9…control unit; 9a…processor; 9b…memory; 10…rectifier circuit; 11, 12…gate circuit unit; 11a, 11b, 12a, 12b…gate circuit; 14, 15…connection point; 21…HVIC; 22a, 22b…gate on-resistance; 23a, 23b…gate off-resistance; 24a… 24b…Diode; 25a, 25b…Rector; 26a, 26b…Capacitor; 30…Inverter; 40…Motor; 41…Compressor; 42…Four-way valve; 43…Outdoor heat exchanger; 44…Expansion valve; 45…Indoor heat exchanger; 46…Refrigerant piping; 47…Compression mechanism; 50…First bridge arm; 52…Second bridge arm; 100…DC power supply; 150…Refrigeration cycle; 200…Refrigeration cycle device.

Claims

1. A direct current power supply device characterized by comprising: Possessing: a rectifier circuit bridged by a first switch element to a fourth switch element; a reactor connected between an alternating-current power supply and the rectifier circuit; a first gate circuit section that drives the first switch element and the second switch element; and a second gate circuit section that drives the third switch element and the fourth switch element, a connection point of the first switch element and the second switch element is connected to the alternating-current power supply via the reactor, a connection point of the third switch element and the fourth switch element is connected to the alternating-current power supply without passing through the reactor, the first switch element and the second switch element are subjected to switching control at a higher speed than the third switch element and the fourth switch element, the first gate circuit section turns on the first switch element for a longer time than the second gate circuit section turns on the third switch element and the fourth switch element, the first gate circuit section turns on the second switch element for a longer time than the second gate circuit section turns on the third switch element and the fourth switch element.

2. The direct-current power supply device according to claim 1, characterized in that: the first gate circuit section has a first gate circuit that drives the first switch element, and a second gate circuit that drives the second switch element, the second gate circuit section has a third gate circuit that drives the third switch element, and a fourth gate circuit that drives the fourth switch element, the first gate circuit to the fourth gate circuit each have a gate-on resistance that makes the gate of the switch element that is the object of drive conductive, and a gate-off resistance that makes the gate of the switch element that is the object of drive non-conductive, the gate-on resistance of the first gate circuit has a resistance value that is larger than the resistance values of the gate-on resistances of the third gate circuit and the fourth gate circuit, the gate-on resistance of the second gate circuit has a resistance value that is larger than the resistance values of the gate-on resistances of the third gate circuit and the fourth gate circuit.

3. A refrigeration cycle apparatus characterized by comprising: Possessing: the direct-current power supply device according to claim 1 or 2; an inverter connected to the direct-current power supply device; and a compressor having a motor driven by the inverter.

4. An air conditioner characterized by: possessing the refrigeration cycle device according to claim 3.

5. A refrigerator characterized by: possessing the refrigeration cycle device according to claim 3.

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