JP2016220483A - Resonance type power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resonance type power supply device for achieving miniaturization and low cost and also to provide a power conversion system using the same.SOLUTION: Disclosed is a resonance type power supply device which includes: a transformer: a resonant element connected to a primary side of the transformer; a primary-side semiconductor element connected to an input side of the resonant element; and a secondary-side semiconductor element connected to the secondary side of the transformer. The resonance type power supply device also includes: a peak timing detector for detecting timing in which a time derivative value of the current flowing through a primary coil of the transformer; voltage detection means for detecting the primary-side voltage of the transformer in the timing; and a power supply controller for controlling the output voltage of a secondary-side circuit based on the detection voltage.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a resonant power supply device used in an insulating power conversion system such as a solar PCS or a charger.

  In power conversion systems used in solar PCSs and chargers, there is an isolated DCDC converter that ensures insulation between the primary side circuit and the secondary side circuit by converting power through a transformer. The present invention relates to a resonance type power supply device which is a kind of an insulated DCDC converter.

  The isolated DCDC converter controls the voltage on the secondary side by switching the primary side semiconductor element. The secondary side voltage information needs to be transmitted to the primary side control circuit. On the other hand, means for transmitting information by a photocoupler or the like is known (for example, Patent Document 1).

WO12 / 105077 Publication

  By using a photocoupler, a transformer, or the like as in Patent Document 1, secondary side voltage information can be transmitted to the primary side control circuit.

    However, in a circuit in which the primary side circuit or secondary side circuit is stacked in series, the ground potential of each node becomes large, so photocouplers, transformers, etc. are required to have large insulation characteristics, resulting in an increase in size and cost. Concerned.

  The above-mentioned problems are solved by the invention described in the claims.

  By using the resonant power converter of the present invention, a small and inexpensive power converter can be obtained.

1 is a circuit diagram of a resonant power supply device according to Embodiment 1. FIG. FIG. 3 is an operation waveform diagram of the resonance type power supply device according to the first embodiment. FIG. 6 is a circuit diagram of a resonant power supply device according to a second embodiment. FIG. 6 is a circuit diagram of a resonant power supply device according to a third embodiment. FIG. 6 is a circuit diagram of a power conversion system using the resonant power supply device according to the fourth embodiment. FIG. 10 is a circuit diagram of a power conversion system using the resonant power supply device according to the fifth embodiment. 7 is a control algorithm of a power conversion system using the resonance type power supply device according to the fifth embodiment. FIG. 10 is a circuit diagram of a power conversion system using the resonant power supply device according to the sixth embodiment. FIG. 16 is an example of a circuit diagram of a primary side semiconductor element, a transformer with a gap, and a secondary side semiconductor element in Example 7. FIG. 6 is a circuit diagram of a power conversion system using the resonant power supply device according to the fourth embodiment.

Embodiments of the present invention will be described below with reference to the drawings.
The symbols used in the examples are defined as follows. Q1, Q2, Q11, Q12, Q13, and Q14 are switching elements. Rsns is a voltage detection resistor used in the voltage detection means 15, Lr is a resonance inductance, Cr is a resonance capacitance, Ll is a leakage inductance, Lm is an excitation inductance, ILr is current waveform information flowing through the resonance inductance, and Ill is a current flowing through the leakage inductance. Waveform information, ILm is the current waveform information flowing in the excitation inductance, VLm is the voltage across the excitation inductance, VLl is the voltage across the leakage inductance, Id is the current supplied from the secondary side semiconductor element to Co and the power load, and Vsns is the voltage detection Voltage waveform information detected by the means 15, Vref is a voltage command value, N is a transformer primary winding, n is a transformer secondary winding, Vg_q1 is a Q1 gate signal, Vg_q2 is a Q2 gate signal, and Vo (a) is Output voltage information of the resonance type power supply device (a), which is synonymous with the input voltage information of the inverter (a), and Vo (b) is output voltage information of the resonance type power supply device (b). Yes, synonymous with the input voltage information of the inverter (b), Vref (a) is the output voltage command value (corrected error) of the resonant power supply (a), and Vref (b) is the resonant power supply (b) Output voltage command value (value corrected for error), Vref (r) is the output voltage command value (value before error correction) of the resonance type power supply device, and Vos is the resonance type power supply obtained from the output voltage detector 20 The output voltage of the device.

  FIG. 1 shows a resonant power supply device according to the first embodiment. As shown here, the resonant power supply device 01 includes a power supply main circuit 02 and a power supply controller 03. The resonant power supply device 01 is connected to an input voltage source 04 and a power supply load 05, and converts the power supplied from the input voltage source 04 into a voltage required by the power supply load 05 and outputs it.

  The power supply main circuit 02 includes a primary circuit 06 on the input voltage source 04 side, a transformer 07 with a gap, and a secondary circuit 08 on the power supply load 05 side. The primary side circuit 06 includes an input capacitance 09, a primary side semiconductor element 10, a resonance element 11, a current detection unit 14, and a voltage detection unit 15. The transformer with gap 07 has a leakage inductance Ll and an excitation inductance Lm, and the number of turns on the primary side is N and the number of turns on the secondary side is n. The transformer gap is described as being effective for the present invention since L1 is larger when the gap is provided, but the same applies to the transformer without the gap. Further, the resonance element Lr may be omitted when the leakage inductance Ll is sufficiently large. The primary semiconductor element 10 applies a pulse voltage to the resonance element 11. The secondary side circuit 08 has the secondary side semiconductor element 12 and the output capacitance 13, and smoothes the electric power transmitted from the primary side circuit 06 through the transformer 07 with a gap. The current waveform information ILr and voltage waveform information Vsns transmitted from the current detection means 14 and the voltage detection means 15 are sent to the power supply controller 03.

  The current detection means 14 detects the current flowing through the primary winding of the transformer with gap 07. If the impedance of the voltage detection means Rsns shown in FIG. 1 is sufficiently high, the current of the resonance inductance Lr or the resonance capacitance Cr is detected. May be detected. Further, as will be described later, since a timing at which the time differential value of the current flowing through the primary winding of the gapd transformer 07 becomes 0 is necessary, any current-source waveform of the primary-side semiconductor element 10 can be used as long as the current waveform can be detected. A current flowing through the element may be used.

  The power supply controller 03 receives the current waveform information ILr, the voltage waveform information Vsns, and the voltage command value Vref, and sends a control signal for the primary side semiconductor element 10 to the power supply main circuit 02. The control signal is the gate signal of each semiconductor element. Here, the gate signal of Q1 is denoted as Vg_q1, and the gate signal of Q2 is denoted as Vg_q2. The voltage command value Vref is a value sent from the host controller or recorded in the power controller 03 in advance.

  The peak timing detector 23 of the power supply controller 03 detects the peak timing of the current waveform information ILr sent from the current detection means 14. Although the peak timing is detected here, any timing may be used as long as the time differential value of the current becomes zero. The peak timing detector is preferably a circuit using a differentiation circuit or the like so as not to cause a time delay.

  When the peak timing detector 23 is configured by a differentiating circuit, since the inflection point of the time derivative value of the current other than the peak timing is included, a filter is applied so that the detection timing generator 24 does not respond to the inflection point other than the peak timing. . For example, after detecting the first timing after the switch of Q1 is turned on, a filter is provided so as not to detect the timing until the switch of Q2 is turned on.

  The output voltage detector 20 samples the voltage waveform information sent by the voltage detection means 15 at the detection timing generated in this way. If the time differential value of the current flowing through the primary winding of the transformer with gap 07 becomes 0, the voltage applied to both ends of the leakage inductance Ll becomes 0, and both ends of the primary winding of the transformer 07 with gap at that timing. The voltage is equal to the voltage (VLm) across the excitation inductance Lm. Since VLm at this timing is conductive when a current flows through the secondary semiconductor element 12, a voltage N / n times the output voltage (Vo) is generated. Therefore, the output voltage detector 20 recognizes a value n / N times the detected signal as the output voltage Vo and sends it to the PI control calculator 21 as Vos.

  The PI control arithmetic unit 21 adjusts the gate signal of the primary side semiconductor element 10 so that the difference between the voltage command value Vref and the value Vos sent from the output voltage detector 20 becomes zero. In the case of the circuit diagram of FIG. 1, the switching frequency of Q1 and Q2 is adjusted.

  The gate signal generator 22 generates a drive signal for the primary semiconductor element 10 based on a command value such as a frequency calculated by the PI control calculator 21. In addition, a driver circuit, an insulation function, and a driver necessary for driving the semiconductor elements (Q1 to Q2) of the power supply main circuit 02 are driven by the gate signals (Vg_q1, Vg_q2) of each semiconductor element sent from the power supply controller 03. Although an auxiliary power source for the purpose is not shown, these are included in the resonance type power supply device 01.

The power supply control circuit 03 may be constituted by an analog circuit, and the functions of the output voltage detector 20, the PI control arithmetic unit 21, the gate signal generator 22, the peak timing detector 23, and the detection timing generator 24 are processor functions. Or an IC having the function of the power supply controller 03.
By operating the power supply controller 03 in this manner, the power supply main circuit 02 can control the output voltage Vo to the voltage command value Vref regardless of the load current value of the power supply load 05.

  Next, the basic operation of the resonant power supply device 01 will be described with reference to FIG.

  Vg_q1 and Vg_q2 indicate the voltages between the source and gate of Q1 and Q2, respectively. ILl and VLl are the current waveform flowing in the leakage inductance Ll and the voltage waveform at both ends.

  VLm is the voltage across the excitation inductance, and Vsns is the primary winding voltage of the transformer detected by the voltage detection means 15. Since Lm and Ll are circuit elements when the transformer is expressed by an equivalent circuit, the voltage cannot actually be measured from the outside. What can actually be detected is Vsns, which is the sum of VLm and VLl.

  The resonance type power supply device 01 shown in the first embodiment supplies power to the secondary side circuit 08 and the power supply load 05 by switching the primary side semiconductor element 10 and applying a pulsed voltage to the resonance element 11. As shown in FIG. 2, Q1 and Q2 repeat the on state and the off state for substantially the same period.

  The time when Q1 is turned on is t0. First, since ILl starts from negative, current flows to the left of the circuit diagram. At this time, a voltage substantially equal to the voltage of Ci (Vi) is applied to the resonant element 11. Therefore, if the Cr voltage is Vcr, the Vi-Vcr voltage is applied to Lr, Ll, and Lm, and the current flowing through Ll increases from the negative direction to the positive direction. Let t1 be the timing at which ILl changes from negative to positive.

  If the impedance of the voltage detection means 15 is sufficiently high and the flowing current can be almost ignored, there are two routes through which ILl flows. The first is a route related to the exciting current (ILm) flowing from Ll → Lm → Cr → Ci → Q1 → Lr → Ll. A transformer with a gap reduces the inductance of Lm, which affects the ILl waveform as shown in FIG. The second is a route for supplying power from Ll to the secondary side that passes through the secondary-side semiconductor element 12 to charge and return Co. The current waveform of the second route appears in the current (Id) supplied from the secondary side semiconductor element to Co and the power supply load, and the sum of the first route and the second route appears as ILl.

  At this time, since both routes always flow through Lr, Ll, and Cr, the resonance frequency of the resonance phenomenon of Lr and Cr is reflected in ILl that is the sum. Let t2 be the peak timing of this resonance phenomenon.

  The current flowing through the second route at time t3 becomes zero. From t3 to t4, power is not sent to the secondary side, and the ILl current flows through the first current route. Since the exciting current flows through ILl in the positive direction at time t4, the output capacity of Q1 and Q2 is charged and discharged from t4 to t5 using this current. Charging / discharging is completed at t5, and Q2 is turned on at t6. At this time, since the drain-source voltage of Q2 is 0, no switching loss occurs.

  Since the current direction is reversed after t6, the detailed operation is omitted because the operation is in reverse phase from t0.

  As described above, when ILl flows, the voltage across Ll becomes a voltage that is double the leakage inductance of the time derivative of ILl (VLl = Ll · dILl / dt). Since a sine wave current flows during the period from t1 to t3, VLl has a cosine wave voltage waveform. That is, VLl becomes zero at time t2.

  On the other hand, VLm is a value obtained by multiplying the sum of the voltage (Vo) of Co and the voltage applied to the secondary semiconductor element 12 by N / n during the period in which Id flows. Since the voltage applied to the secondary semiconductor element 12 is substantially zero when a current flows, VLm can be approximated to a voltage N / n times Vo. Here, Vsns is the sum of VLl and VLm, and from the principle that VLl is 0 at t2, it can be seen that the Vsns voltage at t2 is N / n times Vo.

  1 can detect the output voltage (Vo) on the secondary side with the voltage detection means on the primary side, so that the output voltage information is transferred between the primary side and the secondary side. There is no need to provide a means, and a small resonant power supply device 01 can be realized at low cost.

  In this case, the voltage at both ends generated in the secondary side semiconductor element 08 is approximated as zero. However, since the voltage at both ends of the secondary side semiconductor element 08 depending on Id actually exists, the current of Id is detected or the load It is also possible to predict the current of Id from the current, etc., predict the voltage generated from the characteristics of the secondary-side semiconductor element 08, and include the voltage in the calculation. Specifically, Vsns = N / n · (Vd + Vo) is calculated when the voltage generated in the secondary semiconductor element 12 is Vd.

  FIG. 3 shows a circuit diagram of the power supply main circuit 02 of the second embodiment. In this embodiment, the voltage detection means 15 of the first embodiment is changed so as to detect the voltage generated between the primary windings of the transformer 07 with gap and the voltage generated in the resonance inductance. Description of common points is omitted. To do.

  The leakage inductance Ll and the resonance inductance Lr are connected in series on the equivalent circuit diagram. In other words, since the flowing currents are equal, the voltage ratio generated according to the law of V = L · dI / dt is distributed by the values of Ll and Lr, but the waveforms are equal.

  In the present invention, since it is only necessary to detect when the time differential value of the current becomes zero, that is, when the voltage across the inductance becomes zero, the transformer primary side terminal and the transformer primary side terminal are connected as shown in FIG. The voltage detection means 15 can also detect the voltage across the resonance inductance connected in series.

  FIG. 4 shows a circuit diagram of the power supply main circuit 02 of the third embodiment. In this embodiment, Cr of the resonance element 11 of the first embodiment is connected in series with Lr, and the description of common points is omitted.

  When the positive node of the input capacitance 09 is P1 and the negative node is N1, the resonance capacitance is arranged in series with Lr as in the third embodiment, so that one end of the voltage detection means has the same potential as N1. be able to.

  When the reference potential of the power supply controller 03 is made equal to N1, detection is facilitated by connecting Lr, Cr and the voltage detection means 15 as in the third embodiment.

  FIG. 5 shows a circuit diagram of a power conversion system 40 using the resonance type power supply device according to the fourth embodiment. The resonance type power supply device (a) and the resonance type power supply device (b) having the same input of the resonance type power supply device 01 described in the first to third embodiments are connected in parallel, and an inverter (a ) And inverter (b), and the output terminal of each inverter is connected to the power load 05 in series.

  When connected as shown in Fig. 5, if the high potential side of the input node of the inverter (a) is P2 and the low potential side is N2, the potential between P2 and N2 is fixed by the output voltage of the resonant power supply (a) However, the ground voltages of P2 and N2 vary greatly depending on the switching states of Q11, Q12, Q13, and Q14. Although a two-stage configuration is shown in FIG. 5, a configuration with two or more stages is possible, and the fluctuation range of the ground voltage increases as the number of inverter stages increases.

  In this way, when the voltage difference between the primary and secondary sides is large, transmitting the secondary voltage to the primary side for each resonant power supply increases the cost and size from the standpoint of insulation distance. Connected. Therefore, the present system capable of detection on the primary side is particularly effective in such a multistage configuration.

  In Example 4, the input side is connected in parallel and the output side is connected in series. However, this power conversion system is the same both when the input side is connected in series and when the output side is connected in parallel. The effect is obtained.

  Further, in the fourth embodiment, the inverter is described in the latter stage. However, even when the output capacitor has a positive terminal and a negative terminal connected in a stacked manner as shown in FIG. Therefore, by adopting this method, an inexpensive and small multistage configuration can be realized.

  FIG. 6 shows a circuit diagram of the power conversion system 40 of the fifth embodiment. In the power conversion system 40 of the fourth embodiment, the voltage detection means 33, the inverter controller (a) 31, the inverter controller (b) 31, and the power conversion system controller 32 which is a host controller are described. Description of the points to be performed is omitted.

    Although omitted in the description of the fourth embodiment, each inverter 30 is equipped with a voltage detection means 33 for detecting each input voltage and an inverter controller 31 for controlling each switching element based on the voltage information. By stacking inverters in multiple stages, an upper power conversion system controller 32 that commands the state of each stage is necessary, and each inverter controller 31 transmits input voltage information of each inverter to the power conversion system controller 32. The power conversion system control unit 32 instructs each inverter 30 of the operating state.

  On the other hand, the voltage information Vsns sent from the voltage detection means 15 implemented in the resonance type power supply device 01 to the power supply controller 03 may cause some error due to a shift in detection timing. Thus, in the fifth embodiment, an algorithm for correcting the input voltage information Vo (a) of each inverter held by the power conversion system control unit 32 and transmitting it to the power supply controller 03 is added.

  FIG. 7 shows a specific control algorithm example. The true voltage command value is Vref (r), and the input voltage information Vo (a) of each inverter is controlled by the outer loop. A value obtained by adding a voltage corresponding to the difference to the voltage command value becomes Vref (a), and this value is sent to the power supply controller (a) 03. The power supply controller (a) 03 feedback-controls the predicted output voltage Vos (a) obtained from Vsns by an inner loop, and generates a gate signal of the primary side semiconductor element 10 from the result calculated by the PI control calculator 21. . At this time, the outer loop needs to have a sufficiently low frequency response as compared with the inner loop. By designing in this way, it is possible to construct a control system with good responsiveness due to the presence of the inner loop and less error due to the presence of the outer loop. As described above, the inverter controller (b) and the power supply controller (b) are operated, so that the control can be effectively performed even in the case of two or more stages.

  In this case, the conversion process from Vo (a) to Vref (a) is performed by the power conversion system 32. However, the conversion from Vref (a) may be performed by the inverter controller 31 or the power controller 03. You may go on.

  FIG. 8 shows a circuit diagram of the power conversion system 40 of the sixth embodiment. The communication between the inverter controller 31 and the power conversion system controller 32 and the communication between the power supply controller 03 and the power conversion system controller 32 in the fifth embodiment are changed to daisy chain connection, and the common points are explained. Is omitted.

  By changing the communication as in the sixth embodiment, the number of communication ports of the power conversion system 32 can be reduced, so that the cost and size can be reduced.

  In the fifth embodiment, the power conversion system controller 32 needs to provide an insulating means between the primary side and the secondary side of the resonant power supply device 01. Calculation ICs are provided on the primary side and the secondary side of the resonance type power supply device 01 for insulation communication, or the calculation IC of the power conversion system controller 32 is arranged on the secondary side of the resonance type power supply unit 01 to control power supply. It is necessary to prepare the same number of insulated communication means as the number of units 03. Alternatively, if the calculation IC of the power conversion system controller 32 is arranged on the primary side of the resonant power supply device 01, the same number of insulation communication means as the inverter controller 31 are required.

  On the other hand, in the sixth embodiment, if the arithmetic IC of the power conversion system controller 32 is arranged on the secondary side of the resonant power supply device 01, only one insulated communication means with the power supply controller 03 is required. Alternatively, if the calculation IC of the power conversion system controller 32 is arranged on the primary side of the resonant power supply device 01, only one isolation communication means with the inverter controller 31 is required.

  As Example 7, FIG. 9A shows a case where the primary-side semiconductor element 10 has a full bridge configuration, FIG. 9B shows a case where the primary-side semiconductor element 10 has a half-bridge configuration, and FIG. FIG. 9 (d) shows a configuration in which the secondary semiconductor element 12 is configured with a synchronous rectifier, and FIG. 9 (d) illustrates a configuration in which the gap-equipped transformer 07 is configured with a center tap.

  The power supply main circuit 02 of the resonant power supply device 01 described in the first to sixth embodiments may have a function of inputting a pulse waveform to the resonant element 11 and rectifying the secondary side semiconductor element 12. Therefore, the primary-side semiconductor element 10 may be configured as shown in FIG. 9 (a) or 9 (b), or the gap-equipped transformer 07 and the secondary transformer 10 as shown in FIG. 9 (c) or 9 (d). The side semiconductor element 12 may be configured.

  In all the figures, MOSFETs are shown as switching elements. However, these elements are not limited to MOSFETs, and any element that can switch between an on function and an off function, such as an IGBT, is effective.

  As described above, by detecting the voltage on the primary side of the transformer at the time when the time differential value of the current flowing on the primary side of the transformer is zero, a small-sized and low-cost resonant power supply device can be provided. Furthermore, in a power conversion system having an inverter in the subsequent stage of the resonance type power supply device and connecting them in series or in parallel, high-precision control can be realized at low cost, downsizing, and light weight.

01 Resonance type power supply 02 Power supply main circuit 03 Power supply controller 04 Input voltage source 05 Power supply load 06 Primary side circuit 07 Transformer with gap
08 Secondary circuit 09 Input capacitance (Ci)
DESCRIPTION OF SYMBOLS 10 Primary side semiconductor element 11 Resonance element 12 Synchronous rectification element 13 Output capacitance (Co)
DESCRIPTION OF SYMBOLS 14 Current detection means 15 Voltage detection means 20 Output voltage detector 21 PI control calculator 22 Gate signal generator 23 Peak timing detector 24 Detection timing generator 30 Inverter 31 Inverter controller 32 Power conversion system controller 33 Voltage detection means 40 Power conversion system

Claims (11)

A transformer, a resonant element connected to the primary side of the transformer, a primary semiconductor element connected to the input side of the previous resonant element, and a secondary semiconductor element connected to the secondary side of the transformer, A resonance type power supply device comprising:
Based on a peak timing detector that detects the timing when the time differential value of the current flowing through the primary winding of the transformer becomes zero, voltage detection means that detects the primary side voltage of the transformer at the timing, and the detection voltage And a power supply controller for controlling the output voltage of the secondary circuit. A transformer, a resonant element connected to the primary side of the transformer, a primary semiconductor element connected to the input side of the previous resonant element, and a secondary semiconductor element connected to the secondary side of the transformer, A resonance type power supply device comprising:
A peak timing detector that detects the timing when the time differential value of the current flowing through the primary winding of the transformer becomes zero, and the voltage of the resonance inductance of the primary side of the transformer and the resonant element at the timing are detected together A resonance type power supply device comprising: a voltage detection unit; and a power supply controller that controls an output voltage of the secondary circuit based on the detection voltage. The resonance type power supply device according to claim 1 or 2,
A resonance type power supply apparatus having an input capacitance connected to an input side of the primary side semiconductor element, wherein a negative terminal of the input capacitance is connected to one end of the voltage detecting means.   4. A power conversion system, wherein two or more input terminals or output terminals of the resonance type power supply device according to claim 1 are connected in series. It is a power conversion system which has an inverter in the back | latter stage of the resonance type power supply device of Claim 1 to 3,
A power conversion system, wherein output terminals of two or more inverters are connected in series. It is a power conversion system which has an inverter in the back | latter stage of the resonance type power supply device of Claim 1 to 3,
The voltage controller has an inner loop voltage control system using voltage information sent from the voltage detection means,
A power conversion system having an outer loop voltage control system using an input voltage of the inverter. The power conversion system according to claim 6, wherein
A power conversion system, wherein output terminals of two or more inverters are connected in series. The power conversion system according to claim 7, wherein
A power conversion system, wherein each voltage command value transmitted from a power conversion system controller, which is a host controller, to each power supply controller is configured in a daisy chain. The power conversion system according to any one of claims 6 to 8,
The power conversion system, wherein a value whose value increases or decreases according to an input voltage of each inverter is transmitted from the power conversion system controller to each power supply controller. The resonance type power supply device according to any one of claims 1 to 9,
A control IC having the function of the power supply controller. In the power conversion system according to any one of claims 1 to 10,
IC having the function of the power conversion system controller.

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