Switching power supply and control device

Abstract

To disclose a technology capable of stabilizing output voltage of a switching power supply device.SOLUTION: A switching power supply device has a switching circuit transforming input power by switching according to a pulse drive signal, a smoothing circuit arranging parallel capacitors at least on an output side of the switching circuit, and a control device generating the pulse drive signal so that output voltage of the smoothing circuit may become predetermined output target voltage. The control device has a voltage compensation unit generating a control value changing a time ratio of the pulse drive signal so as to suppress a difference of the output voltage for the output target voltage, a current compensation unit correcting the control value based on detection current in a predetermined position of the smoothing circuit, and a virtual capacitance unit calculating a current correction amount by a virtual capacitance generated by virtual parallel elements parallel to the capacitors from the output voltage and correcting the control value input to the current compensation unit.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a switching power supply and a control device. [Background technology]

[0002] In recent years, various types of switching power supplies have been proposed (see, for example, Patent Documents 1-3 and Non-Patent Document 1). [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2011-254645 [Patent Document 2] Japanese Patent Publication No. 2017-200419 [Patent Document 3] Japanese Patent Publication No. 2022-91189 [Non-patent literature]

[0004] [Non-Patent Document 1] Masashi Yokoo, Keiichiro Kondo, "Design Method for Damping Control Systems of Vector-Controlled Induction Motor Drive Systems in DC Electric Railway Vehicles," Transactions of the Institute of Electrical Engineers of Japan, June 1, 2015, Vol. 135, No. 6, pp. 622-631. [Overview of the project] [Problems that the invention aims to solve]

[0005] When aiming to miniaturize and improve the efficiency of switching power supplies, one possible approach is to use small, low-loss components in the circuit. However, using such components in the smoothing circuit of a switching power supply can lead to a decrease in damping ability, which can cause the output voltage waveform to become oscillating, for example, during load fluctuations.

[0006] Accordingly, the present application discloses a technique capable of stabilizing the output voltage of a switching power supply device. Means for Solving the Problem

[0007] In order to solve the above problem, in the present invention, when a virtual parallel element is provided in a smoothing circuit, a current correction amount based on a virtual capacitance generated by the virtual parallel element is calculated from an output voltage, and a control value that changes a duty ratio of a pulse drive signal is corrected.

[0008] Specifically, the present invention is a switching power supply device, comprising: a switch circuit that transforms input power by switching in accordance with a pulse drive signal; a smoothing circuit in which a parallel capacitor is arranged at least on the output side of the switch circuit; and a control device that generates the pulse drive signal such that an output voltage of the smoothing circuit reaches a predetermined output target voltage, wherein the control device includes: a voltage compensation unit that generates a control value for changing a duty ratio of the pulse drive signal so as to suppress a difference between the output voltage and the output target voltage; a current compensation unit that corrects the control value based on a detection current at a predetermined position of the smoothing circuit; and a virtual capacitance unit that calculates, from the output voltage, a current correction amount based on a virtual capacitance generated by a virtual parallel element parallel to the capacitor, and corrects the control value input to the current compensation unit.

[0009] With such a switching power supply device, the control value for changing the duty ratio of the pulse drive signal is corrected so as to include the virtual capacitance generated by the virtual parallel element that does not actually exist in the smoothing circuit. Therefore, even when a small-sized low-loss capacitor is used as the actual capacitor in the smoothing circuit, the output voltage can be stabilized without lowering the attenuation capability.

[0010] Note that the virtual parallel element may include a virtual capacitor and a virtual resistor that are parallel to the capacitor. If the current correction amount based on the virtual capacitance generated by such a virtual parallel element is calculated from the output voltage, and the control value input to the current compensation unit is corrected, the output voltage can be stabilized.

[0011] Furthermore, the virtual admittance used by the virtual capacitance section to correct the control value may include a filter that reduces the gain in the high-frequency range. Including such a filter makes it possible to properly correct the control value.

[0012] Furthermore, the smoothing circuit may include an inductor connected to the switch circuit, and the control device may further have a virtual inductance section that calculates the voltage correction amount due to the virtual inductance generated by a virtual series element in series with the inductor from the detected current, and corrects the output target voltage input to the voltage compensation section. In such a switching power supply device, the control value that changes the time ratio of the pulse drive signal is corrected to include the virtual inductance generated by a virtual series element that does not actually exist in the smoothing circuit. Therefore, even if a small, low-loss inductor is used in the smoothing circuit, the output voltage can be stabilized without reducing the attenuation capacity.

[0013] Furthermore, the virtual series elements may include a virtual inductor and a virtual resistor in series with the inductor. By calculating the voltage correction amount due to the virtual inductance generated by such virtual parallel elements from the output voltage and correcting the target output voltage input to the voltage compensation unit, the output voltage can be stabilized.

[0014] Furthermore, the virtual impedance used by the virtual inductance section to correct the control value may include a filter that reduces the gain in the high-frequency range. Including such a filter makes it possible to properly correct the control value.

[0015] Furthermore, the current compensation unit may correct the control value based on the detected current averaged by a filter that averages the current. Such a current compensation unit improves the noise immunity of the detected current.

[0016] Furthermore, the switch circuit and smoothing circuit may form a single-phase or three-phase inverter circuit. If the switch circuit and smoothing circuit form such an inverter circuit in the switching power supply device, the output voltage output to the load can be stabilized.

[0017] Furthermore, the present invention can also be viewed from the perspective of a control device for a switching power supply. The present invention may be a control device for a switching power supply having, for example, a switch circuit that transforms input power by switching in response to a pulse drive signal, and a smoothing circuit that arranges an inductor in series and a capacitor in parallel on the output side of the switch circuit, wherein the control device comprises a control unit that generates a pulse drive signal so that the output voltage of the smoothing circuit becomes a predetermined output target voltage, and the control unit comprises a voltage compensation unit that generates a control value that changes the time ratio of the pulse drive signal so as to suppress the difference in the output voltage with respect to the output target voltage, a current compensation unit that corrects the control value based on the detected current at a predetermined location of the smoothing circuit, and a virtual capacitance unit that calculates the amount of current correction by virtual capacitance generated by a virtual parallel element in parallel with the capacitor from the output voltage and corrects the control value input to the current compensation unit. [Effects of the Invention]

[0018] With the above-mentioned switching power supply and control device, it is possible to stabilize the output voltage of the switching power supply. [Brief explanation of the drawing]

[0019] [Figure 1] Figure 1 is an illustrative diagram of the circuit configuration realized in a switching power supply device according to an application example. [Figure 2] Figure 2 is a block diagram of the control system of a switching power supply. [Figure 3] Figure 3 is a circuit diagram of a three-phase inverter. [Figure 4] Figure 4 shows a typical plant model after dq conversion in a three-phase inverter. [Figure 5] Figure 5 shows a plant model when a load is connected to a three-phase inverter. [Figure 6] Figure 6 shows a small-signal model of the d-axis in a three-phase inverter. [Figure 7]Figure 7 is a block diagram of a control system in which the virtual capacitance section of the embodiment is applied to the basic configuration of current mode control. [Figure 8] Figure 8 shows the verification results for a three-phase inverter. [Figure 9] Figure 9 shows the verification results for a single-phase inverter. [Modes for carrying out the invention]

[0020] <Examples of application> Figure 1 is an illustrative diagram of the circuit configuration realized in the switching power supply device according to the application example. The switching power supply device 1 according to this application example is a converter equipped with a switch circuit 2, a smoothing circuit 3, and a control device 6, and converts the voltage of the input power of the switching power supply device 1 to output. The switch circuit 2 transforms the input power by switching in accordance with the pulse drive signal generated by the control device 6. The smoothing circuit 3 is a circuit in which an inductor 4 and a capacitor 5 are placed in series on the output side of the switch circuit 2, and smooths the output current of the switch circuit 2 with the inductor 4 and capacitor 5 to remove harmonic components contained in the output current of the switch circuit 2.

[0021] Furthermore, in the switching power supply device of this application example, the control device 6 performs calculations to virtually create a virtual resistance V1, virtual inductor V2, virtual capacitor V3, virtual ESRV4 (ESR: equivalent series resistance), and virtual dummy resistance V5, as shown in Figure 1. While inductor 4 and capacitor 5 are elements of real components, virtual resistance V1, virtual inductor V2, virtual capacitor V3, virtual ESRV4, and virtual dummy resistance V5 are not elements of real components. Virtual resistance V1, virtual inductor V2, virtual capacitor V3, and virtual ESRV4 are elements that are virtually realized in the calculations of the control device 6 that controls the switching of the switch circuit 2. Therefore, in order to easily distinguish between real and non-real components, in Figure 1, the part composed of inductor 4 and capacitor 5 is designated as the real component RP, the part composed of virtual resistance V1 and virtual inductor V2 is designated as virtual inductance VLR, and the part composed of virtual capacitor V3, virtual ESRV4, and virtual dummy resistance V5 is designated as virtual capacitance VCR.

[0022] Figure 2 is a block diagram of the control system of the switching power supply unit 1. The block diagram shown in Figure 2 is realized by the control operation of the control device 6. The controlled object B1 represents the entire switch circuit 2 and smoothing circuit 3. The control device 6 generates a pulse drive signal for the switch circuit 2 so that the output voltage of the switching power supply unit 1 becomes a predetermined output target voltage. In addition, the control system of the switching power supply unit 1 realizes current mode control by using the current flowing through the smoothing circuit 3.

[0023] Furthermore, the control system of the switching power supply 1 is provided with a virtual inductance section B9 to realize the virtual inductance VLR shown in Figure 1. The virtual inductance section B9 has a filter B4 and a subtractor B6. Because the control system of the switching power supply 1 is provided with such a virtual inductance section B9, the control system makes it appear as if the virtual inductance VLR, which is formed by a virtual resistance V1 and a virtual inductor V2, actually exists, even though it does not. The value is calculated and reflected in the change in the time ratio of the pulse drive signal. Therefore, even if a relatively small capacitance element is used as the inductor 4 implemented in the smoothing circuit 3, the resulting decrease in attenuation ability can be compensated for by the virtual inductance section B9.

[0024] Furthermore, the control system of the switching power supply 1 is provided with a virtual capacitance section B10 to realize the virtual capacitance VCR shown in Figure 1. The virtual capacitance section B10 includes a filter B5 and a subtractor B8. Because the control system of the switching power supply 1 is provided with such a virtual capacitance section B10, control values ​​are calculated as if the virtual capacitance VCR, which is formed by the virtual capacitor V3, virtual ESRV4, and virtual dummy resistor V5, were real, even though they do not actually exist, and these values ​​are reflected in the change in the time ratio of the pulse drive signal. Therefore, even if a relatively small capacitance element is used as the capacitor 5 implemented in the smoothing circuit 3, the resulting decrease in attenuation ability can be compensated for by the virtual capacitance section B10.

[0025] According to the switching power supply device 1 in this application example, even if small and low-loss components are used for the elements implemented in the smoothing circuit 3, the control device 6 calculates control values ​​as if virtual inductance VLR and virtual capacitance VCR actually exist in the smoothing circuit 3, and these are reflected in the change in the time ratio of the pulse drive signal of the switch circuit 2. Therefore, even if small and low-loss components are used for the inductors 4 and capacitors 5 that make up the smoothing circuit 3 in order to miniaturize and improve the efficiency of the switching power supply device 1, the output voltage e o This suppresses the oscillation of the waveform. Therefore, it is possible to prevent high-frequency oscillations superimposed on the output voltage waveform.

[0026] In this application example, a configuration in which a virtual inductance section B9 and a virtual capacitance section B10 are provided in the control system and the smoothing circuit 3 reproduces the virtual inductance VLR and virtual capacitance VCR is illustrated. However, the switching power supply 1 is not limited to this configuration. For example, the switching power supply 1 may omit the virtual inductance section B9 from the control system and reproduce only the virtual capacitance VCR in the smoothing circuit 3 without reproducing the virtual inductance VLR.

[0027] <Embodiment> The embodiments described below are one aspect of the present application and do not limit the technical scope of the present application.

[0028] The circuit configuration of the switching power supply device according to this embodiment will be described with reference to Figure 1, which was used in the description of the application example above. The switching power supply device 1 according to this embodiment is a converter equipped with a switch circuit 2, a smoothing circuit 3, and a control device 6, as described in the application example above, and converts the voltage of the input power of the switching power supply device 1 to output. The switch circuit 2 transforms the input power by switching in accordance with the pulse drive signal generated by the control device 6. The smoothing circuit 3 is a circuit in which an inductor 4 in series and a capacitor 5 in parallel are arranged on the output side of the switch circuit 2, and by smoothing the output current of the switch circuit 2 with the inductor 4 and the capacitor 5, harmonic components and the like contained in the output current of the switch circuit 2 are removed. In the switching power supply device of this embodiment, as described in the application example, a virtual resistance V1, a virtual inductor V2, a virtual capacitor V3, a virtual ESRV4, and a virtual dummy resistance V5 are virtually formed.

[0029] Next, the control system of the switching power supply 1 according to this embodiment will be described with reference to Figure 2 used in the description of the application example above. In the switching power supply 1 according to this embodiment, the control device 6 controls the output voltage e of the switching power supply 1. o The predetermined output target voltage e orefA pulse drive signal for the switch circuit 2 is generated such that the above condition is satisfied. That is, the control device 6 obtains an output vol tage e o and a predetermined output target voltage e oref by a subtractor B7 that calculates a difference therebetween. Then, the control device 6 processes the difference calculated by the subtractor B7 in a voltage compensator B2 to correct the difference. The corrected difference is used to generate the pulse drive signal for the switch circuit 2, whereby a basic control system that adjusts the output voltage e o of the switching power supply device 1 to the predetermined output target voltage e oref is implemented.

[0030] Furthermore, in the control system of the switching power supply device 1 according to the present embodiment, current mode control is implemented by using an output current i o obtained by an ammeter that detects a current flowing through a smoothing circuit 3. Specifically, a difference between the difference output from the voltage compensator B2 and the output current i o is calculated by a subtractor B8. Then, the control device 6 processes the difference calculated by the subtractor B8 in a current compensator B3 to correct the difference. The corrected difference is used as a control value for changing a duty ratio of the pulse drive signal, whereby current mode control using the output current i o is implemented. This implements a control system that is excellent in line regulation and facilitates phase compensation. Note that, although the output current i o of the switching power supply device 1 is exemplified here as the current used for current mode control, the current of an inductor 4 may be used instead of the output current of the switching power supply device 1, for example.

[0031] Furthermore, as described in the application example, the control system of the switching power supply device 1 according to the present embodiment is provided with a virtual inductance unit B9 for implementing the virtual inductance VLR shown in FIG. 1. The virtual inductance unit B9 includes a filter B4 and a subtractor B6. The filter B4 receives the output current i oThis corrects the following. Filter B4 reproduces the virtual inductance VLR connected in series with the output of switch circuit 2, so the virtual impedance of the virtual inductance VLR is Z vl The virtual inductor V2 of the virtual inductance VLR is inductance L V and ESRr vl The virtual resistance V1 of the virtual inductance VLR is R dp Letting this, it can be expressed by the following equation 1. In the following equation 1, f vl This is a filter intended to reduce gain in the high-frequency range, and R dp This is a voltage drop.

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[0032] Subtractor B6 outputs target voltage e oref The difference between this and the output of filter B4 is calculated, and correction information e drp This generates the output voltage e. For the sake of understanding, subtractor B7 is used above. o and a predetermined output target voltage e oref Although it was explained that the difference is calculated, more precisely, subtractor B7 calculates the output voltage e o and correction information e drp The difference between the two is calculated. The difference calculated by the subtractor B7 is then input to the voltage compensator B2. Because the control system of the switching power supply 1 is equipped with such a virtual inductance section B9, a control value is calculated as if a virtual inductance VLR, which is formed by the virtual resistance V1 and virtual inductor V2, actually exists, even though it does not, and this is reflected in the change in the time ratio of the pulse drive signal. Therefore, even if an element with a relatively small capacitance is used as the inductor 4 implemented in the smoothing circuit 3, the resulting decrease in attenuation ability can be compensated for by the virtual inductance section B9.

[0033] Furthermore, the control system of the switching power supply device 1 according to this embodiment is provided with a virtual capacitance unit B10 for realizing the virtual capacitance VCR shown in Figure 1, as explained in the application example. The virtual capacitance unit B10 has a filter B5 and a subtractor B8. The filter B5 controls the output voltage e o This corrects the following. Filter B5 reproduces the virtual capacitance VCR connected in parallel to the output of switch circuit 2, so the virtual admittance of the virtual capacitance VCR is Y VC The virtual capacitor V3 of the virtual capacitance VCR is Passitance C V The virtual ESRV4 of the virtual capacitance VCR is r vc The virtual dummy resistor V5 of the virtual capacitance VCR is R dm If we let f, then it can be expressed by the following equation 2. In the following equation 2, f vc This is a filter intended to reduce gain in the high-frequency range, and R dm This improves the dumping factor.

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[0034] Subtractor B8 outputs an output current i from the output of voltage compensator B2. o The difference is calculated by subtracting the output of filter B5. The difference calculated by subtractor B8 is then input to current compensator B3. Because the control system of switching power supply 1 is equipped with such a virtual capacitance section B10, even though it does not actually exist, a control value is calculated as if a virtual capacitance VCR consisting of a virtual capacitor V3, a virtual ESRV4, and a virtual dummy resistor V5 were real, and this is reflected in the change in the time ratio of the pulse drive signal. Therefore, even if a relatively small capacitance element is used as the capacitor 5 implemented in the smoothing circuit 3, the resulting decrease in attenuation ability can be compensated for by the virtual capacitance section B10.

[0035] According to the switching power supply device 1 of this embodiment, even if small and low-loss elements are used for the elements implemented in the smoothing circuit 3, the control device 6 calculates control values ​​as if virtual inductance VLR and virtual capacitance VCR actually exist in the smoothing circuit 3, and these are reflected in the change in the time ratio of the pulse drive signal of the switch circuit 2. Therefore, even if small and low-loss inductors 4 and capacitors 5 that constitute the smoothing circuit 3 are used to miniaturize and improve the efficiency of the switching power supply device 1, the output voltage e o The waveform does not tend to become oscillatory. Therefore, high-frequency vibrations superimposed on the output voltage waveform can be suppressed.

[0036] Furthermore, as explained in the application example, the switching power supply device 1 according to this embodiment may, for example, omit the virtual inductance section B9 from the control system and reproduce only the virtual capacitance VCR in the smoothing circuit 3 without reproducing the virtual inductance VLR.

[0037] <Example 1> The following describes an example in which the virtual capacitance VCR in the above embodiment is applied to the voltage control of a three-phase inverter.

[0038] Figure 3 is a circuit diagram of a three-phase inverter. The application of the above embodiment to the three-phase inverter shown in Figure 3 will be considered below. As shown in Figure 3, the three-phase inverter has a switch circuit with a total of six switches for switching each of the U, V, and W phases, and a smoothing circuit provided for each phase. Resistor R is the load. Figure 4 is a general plant model after dq conversion in a three-phase inverter. As shown in Figure 4, the general plant model after dq conversion in a three-phase inverter is voltage mode control, and the above embodiment cannot be applied to this plant model. Therefore, in order to apply the above embodiment to a three-phase inverter, current mode control of the three-phase inverter will be considered.

[0039] Figure 5 shows a plant model when a load is connected to a three-phase inverter. The plant model shown in Figure 5 is represented using the concept of a motor. The plant model shown in Figure 5 is unsuitable for a current-mode control model, so it will be modified to be suitable for a current-mode control model. In the plant model shown in Figure 5, V cd , V cq i d and i q The state equation with respect to the state variable is expressed by the following equation 3.

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[0040] In this case, the characteristic equation becomes a quartic function of s, making analysis difficult. Therefore, we decoupling the dq axis in this equation 3 using the same approach as for motors. That is, we transform equation 3 into the following equation 4.

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[0041] If we consider the third term on the right-hand side of equation 4 as a disturbance and cancel it out with feedforward, the dq axis becomes decoupled, as shown in the following two equations, 5 and 6.

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[0042] Furthermore, the output equation is expressed by the following equation 7.

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[0043] By the way, if α is the control input, the input-output relationship is defined by the following equation 8.

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[0044] The third term on the right-hand side of both equations 5 and 6 is a term that is canceled out by feedforward and is considered a disturbance. Except for this disturbance term, the state equations are the same as those for a buck converter. Therefore, deriving the small-signal model for the d-axis from equations 5 and 7 yields equations 9 and 10 below.

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[0045] However, the coefficients of the above formula are as follows:

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[0046] Similarly, deriving the small-signal model for the q-axis yields the following equations 12 and 13.

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[0047] As can be seen by comparing equations 9 and 10, and equations 12 and 13, if the subscripts d and q are swapped, the two equations become the same, and naturally the configuration of the control system becomes the same. Therefore, focusing only on the d axis... We will now present a small-signal model of the three-phase inverter. Figure 6 shows the small-signal model of the d-axis in a three-phase inverter.

[0048] In this embodiment 1, a virtual capacitance unit B10 that reproduces the virtual capacitance VCR in the above embodiment is applied to a control system of such a model, which has current mode control as its basic configuration. Figure 7 is a block diagram of a control system in which the virtual capacitance unit B10 in the embodiment is applied to the basic configuration of current mode control. The basic configuration is the same as in Figure 2, but in this embodiment 1, since average current mode control is used in accordance with the actual system, a current averaging filter Fi is provided. This improves the immunity of the detected current to noise. In Figure 7, C v This corresponds to the voltage compensator B2 in the above embodiment, and C i This corresponds to the current compensator B3 in the above embodiment, and Y VC This corresponds to filter B5 in the above embodiment. The current averaging filter Fi is expressed by the following equation 14, C i This is expressed by the following formula 15, C v This is expressed by the following formula 16.

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[0049] Figure 8 shows the verification results for a three-phase inverter. In this verification, in addition to this embodiment 1, which combines current mode control with virtual capacitance VCR as the control method for the three-phase inverter, comparative examples were prepared: Comparative Example 1 using voltage mode control and Comparative Example 2 using current mode control. Simulations were performed on the behavior when the resistive load was abruptly changed from 100% to 1% and when a rectifier load was used. The specifications of the three-phase inverter are 200Vac / 10kVA (rated load resistance R rate The impedance is 4.08Ω, and the circuit parameters for each symbol shown in Figure 3 are as follows. Input voltage: 400V Output line voltage: 200Vrms Switching frequency fsw: 20kHz Reference frequency f: 50Hz L = 250 [μH] rl = 50 [mΩ] C = 36 [μF] (star connection) rc = 10 [mΩ] Sampling frequency: 40kHz

[0050] As can be seen by comparing the waveforms in Figure 8, in this embodiment 1, vibrations are quickly dampened when the load changes abruptly, and the output is stable, compared to comparative examples 1 and 2. Furthermore, the output is stable even when a rectifier is loaded. Therefore, from these verification results, it can be seen that when the above embodiment is applied to a three-phase inverter, even if small, low-loss elements are used to constitute the smoothing circuit, the output voltage can be stabilized compared to general voltage mode control or current mode control. Accordingly, if this embodiment 1 is used in the electrical equipment on a customer's premises, for example, in the event of a power outage in the power grid and the loss of external power, and during self-sustaining operation where power is supplied to the premises by a storage battery, power can be continuously supplied to the premises at a stable voltage even if the electrical load on the premises changes abruptly.

[0051] <Example 2> Figure 9 shows the verification results for a single-phase inverter. The above embodiment can be applied not only to the three-phase inverter shown as Example 1, but also to, for example, a single-phase inverter. Details such as the plant model study and simulation conditions are omitted, but in this verification, Example 2 was created by applying the virtual capacitance VCR from the above embodiment to the voltage control of a single-phase inverter, and Comparative Example 3 was created by using a single-phase inverter with normal current mode control without applying the above embodiment, and simulations were performed.

[0052] As can be seen by comparing the waveforms in Figure 9, in this embodiment 2, vibrations are quickly dampened when the load changes abruptly, and the output is more stable compared to comparative example 3. Furthermore, the output is stable even when a rectifier is loaded. Therefore, from these verification results, it can be seen that applying the above embodiment to a single-phase inverter makes it possible to stabilize the output voltage, similar to embodiment 1. Accordingly, in this embodiment 2, as in embodiment 1, even if the electrical load on the premises changes abruptly during self-sustaining operation, for example, when external power is lost due to a power grid outage and power is supplied to the premises by a storage battery, power can continue to be supplied to the premises at a stable voltage.

[0053] <Other variations> The above embodiments can be applied to a wide variety of power supply devices, including not only the three-phase inverter of Embodiment 1 and the single-phase inverter of Embodiment 2, but also DC-DC converters incorporated into various electronic devices and inverters that control various drive sources.

[0054] Furthermore, the above embodiments can be modified as appropriate without changing the gist of what is disclosed herein. For example, the above examples illustrate a buck converter circuit configuration having a smoothing circuit 3 in which an inductor 4 in series and a capacitor 5 in parallel are arranged on the output side of the switch circuit 2. However, the above embodiments may be modified to, for example, a buck-boost converter having a smoothing circuit in which an inductor and a capacitor in parallel are arranged on the output side of the switch circuit, or a boost converter having a smoothing circuit in which an inductor is arranged on the power supply side of the switch element of the switch circuit and a capacitor is arranged in parallel on the output side of the switch circuit.

[0055] Furthermore, this application includes the following supplementary matters. <Note 1> A switch circuit (2) that transforms the input power by switching in accordance with a pulse drive signal, A smoothing circuit (3) having a capacitor in parallel with at least the output side of the switch circuit, The pulse drive signal is generated such that the output voltage of the smoothing circuit becomes a predetermined output target voltage. A control device (6) and a control device (6) are provided, The control device is A voltage compensation unit (B2) generates a control value that changes the time ratio of the pulse drive signal in order to suppress the difference in output voltage with respect to the output voltage, A current compensation unit (B3) corrects the control value based on the detected current at a predetermined location in the smoothing circuit, The system includes a virtual capacitance unit (B10) that calculates a current correction amount based on the virtual capacitance generated by a virtual parallel element in parallel with the capacitor from the output voltage, and corrects the control value input to the current compensation unit. Switching power supply. [Explanation of Symbols]

[0056] 1. Switching power supply 2. Switch Circuit 3...Smoothing circuit 4. Inductor 5. Capacitor 6. Control device B1 ··Controlled object B2 Voltage Compensator B3...Current compensator B4 Filter B5 Filter B6 Subtractor B7 Subtractor B8 Subtractor B9...Virtual Inductance Section B10...Virtual capacitance section V1...Virtual Resistance V2...Virtual Inductor V3...Virtual Capacitor V4...Virtual ESR V5... Virtual dummy resistor RP... Actual parts VLR (Virtual Inductance) VCR (Virtual Capacitance)

Claims

1. A switch circuit that transforms the input power by switching in response to a pulse drive signal, A smoothing circuit that includes a capacitor in parallel with at least the output side of the switch circuit, The system includes a control device that generates the pulse drive signal such that the output voltage of the smoothing circuit becomes a predetermined output target voltage, The control device is A voltage compensation unit that generates a control value that changes the time ratio of the pulse drive signal in order to suppress the difference in output voltage with respect to the output voltage target voltage, A current compensation unit that corrects the control value based on the detected current at a predetermined location in the smoothing circuit, The system includes a virtual capacitance unit that calculates a current correction amount based on the virtual capacitance generated by a virtual parallel element in parallel with the capacitor, from the output voltage, and corrects the control value input to the current compensation unit. Switching power supply.

2. The virtual parallel element includes a virtual capacitor and a virtual resistor in parallel with the capacitor. A switching power supply device according to claim 1.

3. The virtual admittance used by the virtual capacitance section to correct the control value includes a filter that reduces the gain in the high-frequency range. A switching power supply device according to claim 1 or 2.

4. The smoothing circuit includes an inductor connected to the switch circuit. The control device further includes a virtual inductance unit that calculates a voltage correction amount due to the virtual inductance generated by a virtual series element in series with the inductor from the detected current, and corrects the output target voltage input to the voltage compensation unit. A switching power supply device according to claim 1.

5. The aforementioned virtual series element includes a virtual inductor and a virtual resistor in series with the inductor. The switching power supply device according to claim 4.

6. The virtual impedance used by the virtual inductance section to correct the control value includes a filter that reduces the gain in the high-frequency range. A switching power supply device according to claim 4 or 5.

7. The current compensation unit corrects the control value based on the detected current averaged by a filter that averages the current. A switching power supply device according to claim 1.

8. The switch circuit and the smoothing circuit form a single-phase or three-phase inverter circuit. A switching power supply device according to claim 1.

9. A control device for a switching power supply, comprising a switch circuit that transforms input power by switching in accordance with a pulse drive signal, and a smoothing circuit that has a capacitor in parallel with at least the output side of the switch circuit, The system includes a control unit that generates the pulse drive signal such that the output voltage of the smoothing circuit becomes a predetermined output target voltage, The control unit, The pulse drive signal suppresses the difference in output voltage with respect to the output target voltage. A voltage compensation unit that generates a control value that changes the ratio of the numbers, A current compensation unit that corrects the control value based on the detected current at a predetermined location in the smoothing circuit, The system includes a virtual capacitance unit that calculates a current correction amount based on the virtual capacitance generated by a virtual parallel element in parallel with the capacitor, from the output voltage, and corrects the control value input to the current compensation unit. A control device for switching power supplies.

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