Power converter

Abstract

To provide a power conversion device capable of effectively using high-voltage, high-frequency electrical energy generated by a resonant operation of a resonant circuit.SOLUTION: A power conversion device includes: a switching element Q1; and a resonant circuit 1 which is connected to an output side of the switching element Q1 and in which an inductor L3 and a plasma actuator PA10 are connected in series.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a power conversion device.

Background Art

[0002] Patent Document 1 discloses a power conversion device using a Class E circuit that includes a switching element, and a resonant circuit composed of an inductor and a capacitor connected to the output side of the switching element.

[0003] This power conversion device performs a low-loss switching operation by zero-voltage switching that turns on when the voltage across both ends of the switching element is zero. As a result, the drive frequency of the switching element can be increased to miniaturize passive components such as inductors and capacitors.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problem to be Solved by the Invention

[0005] However, in the power conversion device, since the resonant circuit performs a resonant operation, a high-voltage high-frequency voltage is generated inside the power conversion device. For this reason, the generated high-voltage, high-frequency electrical energy cannot be effectively utilized.

[0006] An object of the present invention is to provide a power conversion device capable of effectively utilizing high-voltage, high-frequency electrical energy generated by the resonant operation of a resonant circuit.

Means for Solving the Problem

[0007] The power conversion device according to the present invention comprises a switching element and a first resonant circuit connected to the output side of the switching element, in which a first inductor and a first plasma actuator are connected in series. [Effects of the Invention]

[0008] According to the present invention, it is possible to provide a power conversion device that can effectively utilize high-voltage, high-frequency electrical energy generated by the resonant operation of a resonant circuit. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1(a) is a circuit diagram of a power converter according to the first embodiment of the present invention. Figure 1(b) is a diagram showing the voltage waveform applied to the plasma actuator of the power converter according to the first embodiment. [Figure 2] Figure 2 is a circuit diagram of a power conversion device according to a second embodiment of the present invention. [Figure 3] Figure 3 is a circuit diagram of a power conversion device according to a third embodiment of the present invention. [Figure 4] Figure 4 is a circuit diagram of a power conversion device according to the fourth embodiment of the present invention. [Figure 5] Figure 5 is a circuit diagram of a power conversion device according to a fifth embodiment of the present invention. [Figure 6] Figure 6 is a circuit diagram of a power conversion device according to the sixth embodiment of the present invention. [Modes for carrying out the invention]

[0010] Hereinafter, several embodiments of the power conversion device of the present invention will be described in detail with reference to the drawings. In the drawings of the power conversion device according to each embodiment, the same or corresponding parts are denoted by the same reference numerals and their descriptions are omitted.

[0011] (First Embodiment) FIG. 1(a) is a circuit diagram of the power conversion device according to the first embodiment of the present invention. The power conversion device according to the first embodiment converts power supplied from an input power supply connected to the input side into predetermined power by turning on and off a switching element Q1, and supplies the converted power to a load connected to the output side.

[0012] The power conversion device is a Class E power converter, and includes a Class E inverter circuit and a rectifier circuit not shown in the drawings. Here, a voltage resonant type Class E inverter circuit will be described. The Class E inverter circuit includes choke coils L1 and L2, a switching element Q1, a capacitor C1 connected in parallel with the switching element Q1, and a resonant circuit 1.

[0013] In the Class E inverter circuit, the switching element Q1 repeatedly turns on and off at high frequency and high voltage to generate a high-frequency alternating current. The rectifier circuit rectifies the high-frequency current generated by the Class E inverter circuit.

[0014] A choke coil L1 is connected between the input positive terminal P of the input power supply formed of a DC power supply and one end of the switching element Q1. A choke coil L2 is connected between the input negative terminal N of the input power supply and the other end of the switching element Q1.

[0015] The switching element Q1 has one end connected to one end of the choke coil L1, and the other end connected to one end of the choke coil L2. The switching element Q1 is configured by, for example, a unipolar transistor such as a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). The switching element Q1 switches between an on operation and an off operation in response to an on / off control signal from a control unit 5.

[0016] As for the capacitor C1, a capacitor as a single component may be disposed, or the capacitor C1 may not be disposed as an individual component by utilizing the parasitic capacitance of the MOSFET used as the switching element Q1.

[0017] The rectifier circuit may be provided with a so-called Class E rectifier including a diode, a rectification-side shunt capacitor connected in parallel with the diode, and an output choke inductor, or may be provided with a so-called Class D rectifier composed of four diodes connected in a bridge configuration.

[0018] The higher the operating frequency of the power conversion device, the smaller the inductance value and capacitance value required for passive components such as inductors and capacitors used therein, and the power conversion device can be miniaturized.

[0019] The Class E power conversion device achieves zero turn-on loss by turning on the switching element Q1 after making the voltage across the switching element Q1 zero using the current of the resonant circuit 1 during the off period of the switching element Q1. Since so-called zero-voltage switching can be performed, loss can be reduced even when the operating frequency is increased, and there is potential for miniaturizing the power conversion device.

[0020] However, since a high voltage is generated between capacitor elements in the resonant circuit due to voltage resonance, the generated high-voltage, high-frequency electrical energy cannot be effectively utilized.

[0021] Therefore, in the power conversion device according to the first embodiment shown in Fig. 1(a), a resonant circuit 1 is provided which is formed by connecting an inductor L3 and a plasma actuator PA10 (first plasma actuator) having a capacitor component in series. The resonant circuit 1 constitutes a first resonant circuit. The resonant frequency formed by the inductor L3 and the plasma actuator PA10 is substantially the same as the driving frequency of the switching element Q1.

[0022] As will be described later, the plasma actuator PA10 is configured to have an upper electrode, a lower electrode, and a dielectric between the upper electrode and the lower electrode, and includes a capacitor.

[0023] In other words, by replacing the capacitor that generates resonance with the plasma actuator PA10, the voltage applied to the plasma actuator PA10 increases due to the resonant operation between the inductor L3 and the plasma actuator PA10. This is used to drive the plasma actuator PA10.

[0024] As shown in Figure 1(b), the resonant operation generates a sinusoidal high voltage with a voltage difference of, for example, 2.2kV between its maximum and minimum values. This sinusoidal high voltage allows the plasma actuator PA10 to generate plasma. This enables effective utilization of the high voltage and high frequency electrical energy generated by the resonant operation of the resonant circuit.

[0025] Furthermore, since the power converter can supply the power necessary for plasma generation to the plasma actuator PA10, it eliminates the need for an additional power supply required for plasma generation.

[0026] The airflow generated by the plasma actuator PA10 can cool components such as the inductor L3, allowing for a smaller cooling system.

[0027] Furthermore, the power conversion device is not limited to a Class E inverter circuit, but may also be a resonant power conversion device including an LLC converter composed of an inductor L, a leakage inductance L, and a capacitor C. This resonant power conversion device can also obtain effects similar to those of the power conversion device according to the aforementioned embodiment.

[0028] (Second embodiment) Figure 2 is a circuit diagram of a power converter according to a second embodiment of the present invention. In the power converter according to the second embodiment shown in Figure 2, at least some of the components in the resonant power converter, such as the inductor L3, are positioned to face the wind generated by the plasma actuator PA10, compared to the power converter according to the first embodiment shown in Figure 1.

[0029] The plasma actuator PA10 accelerates positive ions or electrons from the low-temperature plasma generated by atmospheric pressure barrier discharge using an electric field. When these ions or electrons collide with surrounding air molecules, their momentum is transferred to the air molecules, generating wind (induced flow).

[0030] As shown in Figure 2, the plasma actuator PA10 comprises a dielectric 11, an upper electrode 12 exposed on the surface of the dielectric 11, and a lower electrode 13 covered by the dielectric 11. The lower electrode 13 is offset from the upper electrode 12 in the in-plane direction of the dielectric 11.

[0031] One end of inductor L3 is connected to the lower electrode 13, and the other end of inductor L3 is connected to one end of capacitor C1, one end of switching element Q1, and one end of choke coil L1. One end of load R is connected to the upper electrode 12, and the other end of load R is connected to the other end of capacitor C1, the other end of switching element Q1, and one end of choke coil L2.

[0032] Because the electric field generated between the electrodes on the surface of the dielectric 11 is biased, positive ions or electrons are easily accelerated in the in-plane direction of the dielectric 11 from the upper electrode 12 to the lower electrode 13, and an induced flow is generated in one direction, resulting in a high efficiency of induced flow generation relative to power consumption. For this reason, the inductor L3 is positioned opposite to the wind (induced flow) generated in the in-plane direction of the dielectric 11 from the upper electrode 12 to the lower electrode 13.

[0033] As described above, in the power conversion device according to the second embodiment, the inductor L3 and the like are positioned opposite to the wind (induced flow) generated in the in-plane direction of the dielectric 11 of the plasma actuator PA10 from the upper electrode 12 to the lower electrode 13. Therefore, the heat generated in the inductor L3 and the like is dissipated by the wind generated by the plasma actuator PA10.

[0034] In other words, by utilizing the airflow generated from the plasma actuator PA10, components such as the inductor L3 in the circuit, or the heat sink, can be cooled, thus improving heat dissipation efficiency and allowing for miniaturization of the power conversion device, including the cooler.

[0035] (Third embodiment) Figure 3 is a circuit diagram of a power conversion device according to a third embodiment of the present invention. The power conversion device according to the third embodiment shown in Figure 3 has a resonant circuit 1a formed by a parallel circuit in which a capacitor C2 is connected in parallel with the plasma actuator PA10 and an inductor L3, compared to the power conversion device according to the first embodiment shown in Figure 1.

[0036] If the resonant frequency of the inductor L3 and the plasma actuator PA10 does not reach the desired resonant frequency, for example, the driving frequency of the switching element Q1, a capacitor C2 is connected in parallel to the plasma actuator PA10. The desired resonant frequency can be adjusted by combining the capacitance value of the plasma actuator PA10 and the capacitance value of capacitor C2 with the inductance value of the inductor L3.

[0037] Furthermore, the other effects of the power converter according to the third embodiment are the same as those of the power converter according to the first embodiment.

[0038] (Fourth embodiment) Figure 4 is a circuit diagram of a power converter according to the fourth embodiment of the present invention. The power converter according to the fourth embodiment is a voltage-resonant high-frequency Class E PFC (power factor correction) power converter circuit. The input power supply outputs AC to the power converter. The high-frequency Class E PFC power converter is characterized in that, compared to Figure 1, it consists of at least two series-connected switch groups Q1 and Q2.

[0039] Since the other configurations are the same as those shown in Figure 1, only the configuration and operation of switch groups Q1 and Q2 will be explained here.

[0040] The switch group Q1, Q2 consists of a series circuit of switching element Q1 and switching element Q2. One end of switching element Q1 is connected to one end of choke coil L1, and one end of switching element Q2 is connected to one end of choke coil L2. The on and off operations of switching elements Q1 and Q2 are controlled by a control signal from the control unit 5.

[0041] The voltage input to the Class E PFC power converter is an AC voltage. Depending on the polarity of the AC voltage, the control unit 5 switches one of the switching elements Q1 and Q2, while making the other conductive. This enables PFC operation and improves the power factor.

[0042] Although the input voltage is AC and the operation of the two switching elements Q1 and Q2 differs from the power conversion circuit according to the first embodiment, the effects are the same as those of the power conversion device according to the first embodiment.

[0043] (Fifth embodiment) Figure 5 is a circuit diagram of a power converter according to a fifth embodiment of the present invention. In the power converter according to the fifth embodiment, a peak voltage suppression resonant circuit 2 is provided in parallel with the switching element Q1 to suppress the peak voltage of the switching element Q1. The peak voltage suppression resonant circuit 2 consists of a resonant circuit in which an inductor L4 and a plasma actuator PA20 (second plasma actuator) are connected in series.

[0044] In the peak voltage suppression resonant circuit 2 between inductor L4 and plasma actuator PA20, one end of inductor L4 is connected to one end of choke coil L1 and one end of switching element Q1. One end of plasma actuator PA20 is connected to the other end of inductor L4. The other end of plasma actuator PA20 is connected to one end of inductor L2 and the other end of switching element Q1. The peak voltage suppression resonant circuit 2 between inductor L4 and plasma actuator PA20 constitutes a second resonant circuit.

[0045] The resonant frequency f between inductor L4 and plasma actuator PA20 LC This is expressed by equation (1), where C is the capacitance value of the plasma actuator PA20.

[0046] f LC = 1 / {2π(LC)} 1 / 2}…(1)

[0047] resonance frequency f LC The driving frequency f is used to turn the switching element Q1 on / off. SW It has a higher frequency than that.

[0048] Although high voltage is generated in the switching element Q1 due to voltage resonance, the peak voltage can be suppressed by adding a peak voltage suppression resonant circuit 2, which has a resonant frequency higher than the drive frequency (switching frequency), in parallel with the switching element Q1. This makes it possible to reduce the voltage withstand capability of the switching element Q1, resulting in lower costs and reduced conduction losses.

[0049] By replacing the capacitor element of the peak voltage suppression resonant circuit 2 with the plasma actuator PA20, the voltage applied to the plasma actuator PA20 increases due to resonance, allowing plasma to be generated by the voltage change. This makes it possible to effectively utilize the high-voltage, high-frequency electrical energy generated by the resonant operation of the resonant circuit.

[0050] Furthermore, since the power converter can supply the power necessary for plasma generation, it eliminates the need for an additional power supply required for plasma generation.

[0051] Furthermore, as shown in Figure 2, the plasma actuator PA20 comprises a dielectric 11, an upper electrode 12 exposed on the surface of the dielectric 11, and a lower electrode 13 covered by the dielectric 11. The lower electrode 13 is offset from the upper electrode 12 in the in-plane direction of the dielectric 11, and an inductor L4 is positioned to face the wind generated from the upper electrode 12 toward the lower electrode 13 in the in-plane direction of the dielectric 11.

[0052] The airflow generated from the plasma actuator PA20 of the peak voltage suppression resonant circuit 2 can be used to cool the inductor L4 or the heat sink, thereby improving heat dissipation efficiency and allowing for miniaturization of the power conversion device, including the cooler.

[0053] (Sixth embodiment) Figure 6 is a circuit diagram of a power conversion device according to the sixth embodiment of the present invention. The power conversion device according to the sixth embodiment is a current-resonant LLC power conversion circuit, in which the capacitor element of the resonant circuit 1b is replaced with a plasma actuator PA10.

[0054] In the current-resonant LLC power conversion circuit, a series circuit of switching elements Q1 and Q2 is connected between the input positive terminal P and the input negative terminal N of the input power supply. A plasma actuator PA10, a leakage inductance Lr, and the excitation inductance Lm of the primary winding Pr of the transformer Tr are connected to both ends of switching element Q2.

[0055] The primary winding Pr and secondary winding S of the transformer Tr are magnetically coupled and have a leakage inductance Lr. A load R is connected to both ends of the secondary winding S.

[0056] What are switching elements Q1 and Q2? They switch on and off alternately. When switching element Q1 is turned on, current flows through the path P→Q1→PA10→Lr→Lm→N. When switching element Q2 is turned on, current flows through the path Lm→Q2→PA10→Lr→Lm.

[0057] At this time, resonance occurs between the plasma actuator PA10, the leakage inductance Lr, and the excitation inductance Lm, and between the plasma actuator PA10 and the leakage inductance Lr.

[0058] In other words, by replacing the capacitor in the resonant circuit 1b with the plasma actuator PA10, the voltage applied to the plasma actuator PA10 within the resonant circuit 1b increases due to resonance, and plasma can be generated by the change in voltage. This makes it possible to effectively utilize the high-voltage, high-frequency electrical energy generated by the resonant operation of the resonant circuit.

[0059] Furthermore, since the power converter can supply the power necessary for plasma generation, it eliminates the need for an additional power supply required for plasma generation.

[0060] The airflow generated from the plasma actuator PA10 can be used to cool components such as the excitation inductance Lm of the primary winding Pr in the circuit, or a heat sink. This improves heat dissipation efficiency and allows for miniaturization of the power conversion device, including the cooler.

[0061] Furthermore, by connecting a capacitor C2 in parallel with the plasma actuator PA10, as shown in Figure 3, the resonant frequency can be adjusted to a desired resonant frequency.

[0062] Furthermore, the present invention is not limited to the power conversion devices according to the first to sixth embodiments, and any number of power conversion devices according to the first to sixth embodiments may be used in combination. [Explanation of symbols]

[0063] 1,1a,1b resonant circuit 2. Peak voltage suppression resonant circuit 5. Control Unit 10,20 Plasma Actuator PA 11 Dielectrics 12 Upper electrode 13 Lower electrode Q1, Q2 switching elements L1, L2 choke coils L3, L4 Inductors C1, C2 Capacitors Tr transformer Pr Primary winding S Secondary winding Lm Excitation Inductance Lr leakage inductance P Input positive terminal N Input negative terminal T1, T2 Input Terminals R load

Claims

1. Input terminals, A switching element connected to the input terminal, The system comprises a first resonant circuit connected to the output side of the switching element, In a power conversion device that converts power input from the input terminal into a predetermined power by turning the switching element on and off at a driving frequency approximately the same as the resonant frequency of the first resonant circuit, and supplies the converted power to a load connected to the first resonant circuit, A capacitor connected in parallel to the switching element, It has multiple input terminals and at least one choke coil connected to the switching element, At least one end of the switching element has a high-frequency Class E circuit connected to the choke coil and the first resonant circuit. The first resonant circuit includes a first plasma actuator, A power conversion device in which the upper and lower electrodes of the first plasma actuator are connected to other elements that constitute the first resonant circuit, separate from the first plasma actuator.

2. The power conversion device according to claim 1, wherein the other element comprises a first capacitor connected in parallel with the first plasma actuator.

3. Input terminals, A switching element connected to the input terminal, The system comprises a first resonant circuit connected to the output side of the switching element, In a power conversion device that converts power input from the input terminal into a predetermined power by turning the switching element on and off at a driving frequency approximately the same as the resonant frequency of the first resonant circuit, and supplies the converted power to a load connected to the first resonant circuit, A first switch group in which at least two of the switching elements are connected in series, A capacitor connected in parallel to the first switch group, It has multiple input terminals and at least one choke coil connected to the switching element, At least one end of the switching element has a high-frequency Class E power factor correction circuit connected to the choke coil and the first resonant circuit. The first resonant circuit includes a first plasma actuator, A power conversion device in which the upper and lower electrodes of the first plasma actuator are connected to other elements that constitute the first resonant circuit, separate from the first plasma actuator.

4. The power conversion device according to claim 1 or 3, wherein the other element comprises a first inductor connected in series with the first plasma actuator.

5. The switching element has a peak voltage suppression resonant circuit connected in parallel, The aforementioned peak voltage suppression resonant circuit consists of a second resonant circuit in which a second inductor and a second plasma actuator are connected in series. The power conversion device according to claim 1 or 3, wherein the resonant frequency of the second inductor and the second plasma actuator is higher than the drive frequency of the switching element.

6. The system has a second switch group in which at least two of the switching elements are connected in series, The power conversion device according to claim 1 or 3, wherein the first resonant circuit is connected in parallel to one of the switching elements of the second switch group.

7. A transformer having a primary winding and a secondary winding that is magnetically coupled to the primary winding, The power conversion device according to claim 6, wherein the other element comprises the excitation inductance and leakage inductance of the primary winding connected in series with the first plasma actuator.

8. The power conversion device according to claim 4, wherein the first plasma actuator comprises a dielectric, an upper electrode exposed on the surface of the dielectric, and a lower electrode covered by the dielectric, the lower electrode being offset from the upper electrode in the in-plane direction of the dielectric, and the first inductor being positioned to face the wind generated from the upper electrode toward the lower electrode in the in-plane direction of the dielectric.

9. The power conversion device according to claim 5, wherein the second plasma actuator comprises a dielectric, an upper electrode exposed on the surface of the dielectric, and a lower electrode covered by the dielectric, the lower electrode being offset from the upper electrode in the in-plane direction of the dielectric, and the second inductor being positioned to face the wind generated from the upper electrode toward the lower electrode in the in-plane direction of the dielectric.

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