JP2009232587A - Power supply device and control method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent instability occurring when changing the number of voltage conversion circuits to be operated in a power supply device configured by connecting a plurality of voltage conversion circuits in parallel. <P>SOLUTION: The power supply device is provided with: voltage conversion circuits of a plurality of channels that synthesize output currents so as to supply the synthesized current to a common load; a load-state calculation means for calculating a value of a current or power supplied to the load; an operating channel number setting means for setting the number of channels of the voltage conversion circuits to be operated; and a signal generating means that controls the voltage conversion circuits in accordance with the number of channels to be set, newly starts at least one voltage conversion circuit and reduces the output currents of the other voltage conversion circuits that are started when increasing the number of channels of the voltage conversion circuits to be operated, and also, stops at least one voltage conversion circuit and increases the output currents of the other voltage conversion circuits that are started when reducing the number of channels of the voltage conversion circuits to be operated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply device that performs voltage conversion by a switching operation, and more particularly to a power supply device that is configured by connecting in parallel a plurality of channels of voltage conversion circuits that perform voltage conversion by a switching operation. Furthermore, the present invention relates to a method for controlling such a power supply device.

  In recent years, switching power supplies such as DC / DC converters, which are small and light and can efficiently extract power, have been widely used. For example, in an insulated DC / DC converter using a transformer, an AC voltage is generated on the secondary side of the transformer by performing a switching operation on the primary side of the transformer, and this AC voltage is rectified and smoothed by a diode and a capacitor. By doing so, a DC voltage is obtained. A non-insulated switching power supply using a choke coil instead of a transformer is also used.

  However, in a switching power supply, in order to obtain large output power, components such as a transformer, a choke coil, and a capacitor are increased in size. In addition, output voltage ripple generated by switching also increases. Therefore, a multi-phase power supply device has been developed in which a plurality of voltage conversion circuits operating in different phases are connected in parallel. According to the multi-phase power supply apparatus, it is possible to reduce the size of the components and reduce the ripple of the output voltage.

  As a related technique, Patent Document 1 discloses a DC / DC converter of a switching control system aiming at obtaining a high-quality conversion output with little ripple in a wide dynamic range from a small current to a large current with high efficiency. ing. The DC / DC converter synthesizes and smoothes a plurality of switching circuits that perform on / off control of input currents supplied from a common input power supply and currents that are on / off controlled in each switching circuit, and supplies them to a load. A multi-phase circuit that allows a smoothing circuit and a plurality of switching circuits to be turned on / off in the same cycle and different phases, and that the on-time width of each switching circuit is feedback-controlled so that the output voltage of the smoothing circuit becomes a predetermined target value. It is characterized by comprising an operation control means that has a PWM control circuit and reduces a switching circuit that forms an ON / OFF energization path for an input current at the time of low current output.

  Patent Document 2 discloses a multi-phase DC / DC converter circuit for the purpose of obtaining high efficiency in a wide load range from low load to high load. This DC / DC converter circuit has a plurality of operation phases and is provided with a phase switching circuit capable of switching the number of operations in the operation phase depending on the magnitude of the output load of the DC / DC converter circuit.

FIG. 7 is a diagram schematically showing the DC / DC converter described in Patent Document 1. As shown in FIG. This DC / DC converter includes voltage conversion circuits 101 and 102 configured by a plurality of switching circuits, a voltage detection circuit 103, and a control circuit that controls the voltage conversion circuits 101 and 102 based on the detection result of the voltage detection circuit 103. 104. The output current of the voltage conversion circuit 101 and 102 are combined via the connected Intakutansu elements respectively, is smoothed by the capacitor is supplied to a load Z _L as power P _L.

FIG. 8 is a diagram for explaining the operation of the DC / DC converter shown in FIG. 8, the horizontal axis represents time (t), and the vertical axis represents the output power _{P 1} and _{P 2} of the voltage conversion circuit 101 and 102, the power _{P L} supplied to the load _{Z L} . As shown in FIG. 8, in the power P _L is smaller period supplied to the load Z _L, but only the voltage conversion circuit 101 is operated, the power P _L is greater period supplied to the load Z _L is Both of the voltage conversion circuits 101 and 102 operate.

The control circuit 104 feedback-controls the voltage conversion circuits 101 and 102 based on the detection result of the voltage detection circuit 103, but the output voltage of the DC / DC converter fluctuates transiently due to a delay in response in the feedback control. as a result, hunting of the voltage supplied to the load Z _L (the control response result vibrates) occurs. Patent Documents 1 and 2 do not disclose solving such a transient output voltage hunting.
JP 2002-44941 A (page 1-2, FIG. 1) JP 2007-116834 A (page 2-3, FIG. 1)

  Accordingly, in view of the above points, the present invention provides a power supply device configured by connecting in parallel a plurality of voltage conversion circuits that perform voltage conversion by switching operation, when changing the number of channels of the voltage conversion circuit to be operated. The purpose is to prevent instability such as hunting of the transient output voltage that occurs.

  In order to solve the above-described problem, a power supply device according to one aspect of the present invention performs a voltage conversion operation by performing a switching operation according to a pulsed drive signal, combines output currents, and supplies them to a common load. A voltage conversion circuit for the channel, a detection means for detecting an output current supplied to the load, a load state calculation means for calculating a value of a current or power supplied to the load based on a detection result of the detection means, and a load Based on the current or power value calculated by the state calculation means, the operation channel number setting means for setting the number of channels of the voltage conversion circuit to be operated in the plurality of voltage conversion circuits, and the operation channel number setting means. By controlling the voltage converter circuit of multiple channels according to the number of channels to be operated and increasing the number of channels of the voltage converter circuit to be operated In addition, when at least one voltage conversion circuit is newly activated, the output current of another activated voltage conversion circuit is decreased, and the number of channels of the voltage conversion circuit to be operated is decreased, at least one voltage conversion circuit Signal generation means for stopping the circuit and increasing the output current of another activated voltage conversion circuit.

  In addition, a control method for a power supply apparatus according to one aspect of the present invention performs a voltage conversion operation by performing a switching operation in accordance with a pulsed drive signal, combines output currents, and supplies a plurality of channels to a common load. A method for controlling a power supply apparatus having a voltage conversion circuit, the step (a) of detecting an output current supplied to a load, and the current or power supplied to the load based on the detection result in step (a) A step (b) for calculating a value, and a step (c) for setting the number of channels of the voltage conversion circuit to be operated in the voltage conversion circuit of a plurality of channels based on the current or power value calculated in step (b). ) And a channel of the voltage conversion circuit for controlling and operating the voltage conversion circuit of a plurality of channels according to the number of channels set in step (c). When the number is increased, at least one voltage conversion circuit is newly activated, and the output current of another activated voltage conversion circuit is decreased to reduce the number of channels of the voltage conversion circuit to be operated. A step (d) of stopping at least one voltage conversion circuit and increasing an output current of another activated voltage conversion circuit.

  According to the present invention, when changing the amount of output current of at least one voltage conversion circuit, the amount of output current of another activated voltage conversion circuit is changed in the opposite direction, so that the voltage conversion circuit that operates The transient characteristics can be improved, for example, by suppressing the hunting of the transient output voltage that occurs when the number of signals is changed.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The same constituent elements are denoted by the same reference numerals, and the description thereof is omitted.
FIG. 1 is a diagram showing a configuration of a power supply device according to the first embodiment of the present invention. This power supply apparatus includes AC power supply voltage input terminals 1 and 2, DC power supply voltage output terminals 3 and 4, a rectifying and smoothing circuit 10 that rectifies and smoothes an input AC power supply voltage, and a rectifying and smoothing circuit 10. And a voltage conversion circuit of a plurality of channels that performs voltage conversion by supplying a smoothed voltage and performing a switching operation (in FIG. 1, the voltage conversion circuit 11 of the channel 1 to the voltage conversion circuit 14 of the channel 4 are shown). The output synthesis circuit 30 synthesizes the output currents (output power) of the voltage conversion circuits 11 to 14, and the control unit 40 that controls the voltage conversion circuits 11 to 14.

  Further, the power supply device includes an input voltage detection circuit 50 that detects a common input voltage of the voltage conversion circuits 11 to 14, an output voltage detection circuit 60 that detects an output voltage of the output synthesis circuit 30, and the voltage conversion circuits 11 to 11. Input current detection circuits 71 to 74 for detecting the 14 input currents, and output current detection circuits 81 to 84 for detecting the output currents of the voltage conversion circuits 11 to 14, respectively. Note that the type and number of detection circuits can be changed as needed. For example, instead of the input current detection circuits 71 to 74, an input current detection circuit that detects a common input current of the voltage conversion circuits 11 to 14 is provided, and instead of the output current detection circuits 81 to 84, An output current detection circuit for detecting the output current may be provided.

  The rectifying / smoothing circuit 10 includes, for example, a diode bridge and a capacitor. The AC voltage applied between the input terminal 1 and the input terminal 2 is full-wave rectified by the diode bridge and smoothed by the capacitor.

  The voltage conversion circuit 11 of the channel 1 is connected in series to a transformer 20 that boosts or steps down an AC voltage on the primary side and outputs the boosted voltage to the secondary side, and a primary winding 21 of the transformer. And a drive circuit 25 that generates a drive signal for driving the switching element 24 based on the drive signal supplied from the control unit 40 and the switching element 24 such as a MOSFET that supplies current to the primary winding 21 of the transformer. And a diode 26 for half-wave rectifying the voltage generated in the secondary winding 22 of the transformer, and a capacitor 27 for smoothing the rectified voltage. Here, the diode 26 and the capacitor 27 constitute an output circuit.

  The transformer 20 includes a magnetic core 23, and a primary side winding 21 and a secondary side winding 22 that are wound around the core 23. Assuming that the number of turns of the primary winding 21 is N1 and the number of turns of the secondary winding 22 is N2, when there is no loss, the step-up ratio between the primary side and the secondary side is N2 / N1. A dot symbol attached to the transformer 20 indicates the polarity of the winding.

  Generally, in a switching power supply, as a power transmission method from the primary side to the secondary side of the transformer, a forward method in which power is transmitted from the primary side to the secondary side when the switching element is turned on, and the switching element is turned off. Sometimes there is a flyback system that transmits power from the primary side to the secondary side. In this embodiment, a flyback method is adopted. The flyback method has the advantage that a choke coil is unnecessary, the number of parts is small, and the circuit is simple. Note that the number of switching elements is not limited to one, and a plurality of switching elements may be used to form a bridge configuration.

  The circuit connected to the primary winding 21 of the transformer and the circuit connected to the secondary winding 22 of the transformer are isolated from each other by using an optical signal transmission element such as a photocoupler. For example, when the control unit 40 is connected to the primary winding 21 of the transformer, an optical signal transmission element is provided in a part of the signal path from the output voltage detection circuit 60 and the output current detection circuits 81 to 84 to the control unit 40. Is used.

  On the other hand, when the control unit 40 is connected to the secondary winding 22 of the transformer, an optical signal transmission element is provided in a part of the signal path from the input voltage detection circuit 50 and the input current detection circuits 71 to 74 to the control unit 40. Is used, and an optical signal transmission element is used in a part of a signal path from the control unit 40 to the voltage conversion circuits 11 to 14. Note that it is not necessary to provide an isolation element for a current detection circuit that detects current based on electromotive force generated by electromagnetic induction.

  In the flyback voltage conversion circuit 11 as shown in FIG. 1, the primary side winding 21 and the secondary side winding 22 of the transformer have a reverse polarity relationship, and the switching element 24 is turned on. While the transformer 20 is on, the primary side current of the transformer 20 increases, but the secondary side of the transformer 20 is reverse-biased by the diode 26, so the secondary side current does not flow. The transformer 20 stores energy in the core 24 when the switching element 24 is on.

  Next, when the switching element 24 is turned off, the magnetic field tries to maintain a current, so that the voltage polarity of the transformer 20 is reversed and a current flows on the secondary side of the transformer 20. The secondary current of the transformer 20 is charged to the capacitor 27 via the diode 26 connected in series to the secondary winding 22 of the transformer, so that a DC output voltage is generated between the output terminal 3 and the output terminal 4. Is generated.

  The first voltage conversion circuit 11 has been described above, but the same applies to the second to fourth voltage conversion circuits 12 to 14. The output synthesis circuit 30 includes a plurality of diodes 31 to 34. The anodes of the diodes 31 to 34 are connected to the outputs of the voltage conversion circuits 11 to 14, respectively, and the cathodes of the diodes 31 to 34 are connected to the output terminal 3 of the power supply device. The diodes 31 to 34 synthesize the output currents of the voltage conversion circuits 11 to 14 and prevent backflow of the output current. However, since a voltage drop occurs in the diodes 31 to 34, the outputs of the voltage conversion circuits 11 to 14 may be connected to each other directly or via an inductance element or the like.

  The control unit 40 includes a DSP (digital signal processor) in which a control block that generates a control signal such as a drive signal is integrated, and software (control program) inside or outside the DSP. And a storage unit 41 such as a nonvolatile memory for storing data. The DSP operates by being supplied with a clock signal having a frequency of about 40 MHz to 1 GHz, and can switch the switching element 24 at a high frequency of about 10 kHz to 500 kHz. The storage unit 41 has an LUT (Look Up Table), and various setting values used for controlling the operation of the power supply apparatus are stored in the LUT. The control unit 40 also includes a plurality of D / A converters that convert analog detection signals output from various detection circuits into digital detection signals.

  FIG. 2 is a block diagram for explaining the operation of the control unit shown in FIG. As shown in FIG. 2, the control unit 40 includes a load state calculation unit 42, an operation channel number setting unit 43, and a control signal generation unit 44 as functional blocks. These functional blocks are configured using a DSP and software (control program), but may be configured using a digital circuit or an analog circuit.

Load condition calculation unit 42, based on an output voltage value which is the detection result of the output voltage detection circuit 60, the output current value is a detection result of the output current detection circuit 81 to 84, the power supplied to a load Z _L Is calculated. The operation channel number setting unit 43 sets the number of channels of the voltage conversion circuit to be operated in the plurality of voltage conversion circuits 11 to 14 based on the power value calculated by the load state calculation unit 42.

  The control signal generation unit 44 generates a drive signal that is individually supplied to each of the voltage conversion circuits 11 to 14 as a control signal in accordance with the number of channels set by the operation channel number setting unit 43, whereby the voltage conversion circuit 11 to 14 are controlled. When the voltage conversion circuits of a plurality of channels are operated simultaneously, the phases of the drive signals supplied to these voltage conversion circuits may be different from each other (multi-phase method) or may be aligned. When the output voltage ripple is relatively large, the output voltage ripple can be reduced by adopting the multi-phase method.

  For example, the control signal generation unit 44 converts the voltage conversion circuits 11 to 14 of a plurality of channels into the voltage conversion circuit 11 of the channel 1, the voltage conversion circuit 12 of the channel 2, the voltage conversion circuit 13 of the channel 3, and the voltage conversion circuit of the channel 4. Operate with priority in the order of 14. Here, when increasing the number of channels of the voltage conversion circuit to be operated, the control signal generation unit 44 newly activates at least one voltage conversion circuit and outputs the output current of the other voltage conversion circuits that are activated. When reducing the number of channels of the voltage conversion circuit to be operated, at least one voltage conversion circuit is stopped and the output current of the other voltage conversion circuits that are activated is increased. This control is performed by feedforward control in which the duty of the drive signal is set based on the set value stored in the storage unit 41 when the number of channels of the voltage conversion circuit to be operated is changed. Thereby, when the number of channels of the voltage conversion circuit to be operated is switched, fluctuations in the output voltage are suppressed.

  Further, the control signal generation unit 44 uses the input voltage value that is the detection result of the input voltage detection circuit 50, the output voltage value that is the detection result of the output voltage detection circuit 60, and the detection results of the input current detection circuits 71 to 74. The duty of the drive signal is feedback controlled based on at least one of a certain input current value and an output current value that is a detection result of the output current detection circuits 81 to 84. For example, the control signal generation unit 44 adjusts the duty of the drive signal supplied to the voltage conversion circuit to be operated based on the output voltage value that is the detection result of the output voltage detection circuit 60.

  When the switching frequency is 50 kHz, the switching period is 20 μs, and the response characteristic of the feedback control system is considered to be about 200 μs, which is generally about 10 times the switching period, considering filter characteristics and the like. That is, during this time, feedback control does not function normally, and instability due to response delay occurs. Therefore, in the present embodiment, when switching the number of channels, the feedback control is once canceled, and the duty of the drive signal is predicted and controlled by feedforward control. After switching the number of channels, the control may be immediately returned to the feedback control, or the control referring to the set value stored in the storage unit 41 may be continued with the predetermined period as a transition period.

  In the above, instead of controlling the duty, or while controlling the duty, feedforward control or feedback control for controlling the frequency (switching frequency) of the drive signal may be performed.

Next, a method for controlling a power supply apparatus according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a flowchart illustrating a method for controlling the power supply apparatus according to an embodiment of the present invention, and FIG. 4 is a diagram illustrating an example of a change in output power of a voltage conversion circuit having a plurality of channels. In FIG. 4, the horizontal axis represents the output power of the power supply apparatus, and the vertical axis represents the load factors U _{1 to} U ₄ of the voltage conversion circuits 11 to 14. The load factor U of the voltage conversion circuit of each channel is expressed by the following equation.
U = {P (t) / P _MAX } × 100 (%)
Here, P _MAX represents the maximum power load set for the voltage conversion circuit of each channel, and P (t) represents the power load actually loaded by the voltage conversion circuit of each channel at time t. .

  First, in step S11 of FIG. 3, the operation channel number setting unit 43 sets an initial value of the number of channels of the voltage conversion circuit to be operated. For example, the operation channel number setting unit 43 sets the number of channels of the voltage conversion circuit to be operated to “1”. Accordingly, in step S12, the control signal generation unit 44 activates the voltage conversion circuit having the set number of channels. For example, the control signal generation unit 44 activates the voltage conversion circuit 11 of channel 1.

  As the output voltage of the power supply device increases, the power supplied to the load increases. When the output voltage of the power supply device reaches a predetermined value, if the impedance of the load is constant, the output power of the power supply device becomes a constant value. When the load becomes heavier, the output power of the power supply device also gradually increases. When only the output power of the voltage conversion circuit 11 of the channel 1 is insufficient, the voltage conversion circuits 12, 13, and 14 of the channels 2, 3, and 4 are sequentially activated as shown in FIG.

In step S13, the output voltage detecting circuit 60 and the output current detection circuit 81 to 84, detects the output voltage and output current supplied to the load Z _L, respectively. In step S14, the load state calculation unit 42, based on the output voltage detecting circuit 60 and the output current detection circuit 81 to 84 of the detection result in step S13, calculates the value of the power supplied to the load Z _L. In this example, since only the voltage conversion circuit 11 of the channel 1 is operating, the load state calculation unit 42 is based on the detection results of the output voltage detection circuit 60 and the output current detection circuit 81. May be calculated. In step S <b> 15, the operation channel number setting unit 43 sets the number of channels of the voltage conversion circuit to be operated in the voltage conversion circuits 11 to 14 of the plurality of channels based on the power value calculated in step 14.

  When the number of channels of the voltage conversion circuit to be operated increases in step S16, the control signal generation unit 44 newly activates at least one voltage conversion circuit in step S17 and activates another in step S18. Reduce the output current of the voltage converter circuit.

For example, as shown in FIG. 4, when the load factor U ₁ of the voltage conversion circuit 11 reaches about 100%, the number of operation channels setting unit 43 sets the number of channels of the voltage conversion circuit for operating to "2". Accordingly, the control signal generation unit 44 activates the voltage conversion circuit 12 of the channel 2. Here, the control signal generating unit 44 based on the setting value stored in the storage unit 41, along with increasing the load factor U ₂ of the voltage converter circuit 12 about 50%, the load factor of the voltage converting circuit 11 U so as to lower the ₁ to about 50%, generating a driving signal of the channel 1 and 2. By doing so, when the number of channels is increased, fluctuations in the output voltage of the power supply device are suppressed, and the load factors U ₁ and U _{2 of} the voltage conversion circuits 11 and 12 become substantially equal. Is stable.

  That is, in the output synthesis circuit 30 shown in FIG. 1, when the outputs of the voltage conversion circuits 11 to 14 are directly connected without using the diodes 31 to 34, the output currents of the plurality of voltage conversion circuits are significantly different. A so-called “cross current” in which the output current of one voltage conversion circuit flows into another voltage conversion circuit occurs, and the voltage conversion efficiency of the power supply device also decreases. Therefore, by making the output currents of the plurality of voltage conversion circuits substantially equal, the operation of the power supply device can be stabilized and the voltage conversion efficiency can be improved.

Further, when the load factors U ₁ and U _{2 of} the voltage conversion circuits 11 and 12 reach about 100%, the operation channel number setting unit 43 sets the number of channels of the voltage conversion circuit to be operated to “3”. Accordingly, the control signal generation unit 44 activates the voltage conversion circuit 13 of the channel 3.

Here, the control signal generating unit 44 based on the setting value stored in the storage unit 41, along with increasing the load factor U ₃ of the voltage converter circuit 13 about 66%, the load of the voltage conversion circuit 11 and 12 The drive signals of channels 1 to 3 are generated so that the rates U ₁ and U ₂ are lowered to about 66%. By doing so, when the number of channels is increased, fluctuations in the output voltage of the power supply device are suppressed, and the load factors U _{1 to} U _{3 of the} voltage conversion circuits 11 to 13 are substantially equal, so that the operation of the power supply device is performed. Stabilize.

Further, when the load factors U _{1 to} U ₃ of the voltage conversion circuits 11 to 13 reach about 100%, the operation channel number setting unit 43 sets the number of channels of the voltage conversion circuit to be operated to “4”. Accordingly, the control signal generation unit 44 activates the voltage conversion circuit 14 of the channel 4.

Here, the control signal generating unit 44 based on the setting value stored in the storage unit 41, along with increasing the load factor U ₄ of the voltage conversion circuit 14 to about 75%, the load of the voltage conversion circuit 11 to 13 The drive signals of channels 1 to 4 are generated so that the rates U _{1 to} U ₃ are lowered to about 75%. By doing so, fluctuations in the output voltage of the power supply device can be suppressed when increasing the number of channels, and the load factors U _{1 to} U _{4 of the} voltage conversion circuits 11 to 14 become substantially equal, so that the operation of the power supply device can be performed. Stabilize.

  Referring to FIG. 3 again, when the number of channels of the voltage conversion circuit to be operated decreases in step S16, the control signal generation unit 44 stops at least one voltage conversion circuit in step S19, and in step S20. Increase the output current of other activated voltage converters.

For example, as shown in FIG. 4, when the load factors U _{1 to} U ₄ of the voltage conversion circuits 11 to 14 are lower than about 75%, the operation channel number setting unit 43 sets the number of channels of the voltage conversion circuit to be operated to “ 3 ”. Accordingly, the control signal generation unit 44 stops the voltage conversion circuit 14 of the channel 4.

Here, the control signal generating unit 44 based on the setting value stored in the storage unit 41, along with lowering the load factor U ₄ of the voltage conversion circuit 14 to 0%, the load factor of the voltage converting circuit 11 to 13 The drive signals for channels 1 to 3 are generated so that U _{1 to} U ₃ are raised to about 100%. By doing so, fluctuations in the output voltage of the power supply device can be suppressed when the number of channels is reduced, and the load factors U _{1 to} U _{3 of the} voltage conversion circuits 11 to 13 become substantially equal, so that the operation of the power supply device can be performed. Stabilize.

Further, when the load factors U _{1 to} U ₃ of the voltage conversion circuits 11 to 13 are lower than about 66%, the operation channel number setting unit 43 sets the number of channels of the voltage conversion circuit to be operated to “2”. Accordingly, the control signal generation unit 44 stops the voltage conversion circuit 13 of the channel 3.

Here, the control signal generating unit 44 based on the setting value stored in the storage unit 41, along with lowering the load factor U ₃ of the voltage converter circuit 13 to 0%, the load factor of the voltage conversion circuit 11 and 12 The drive signals for channels 1 and 2 are generated so that U ₁ and U ₂ are raised to about 100%. By doing so, fluctuations in the output voltage of the power supply device can be suppressed when the number of channels is reduced, and the load factors U ₁ and U _{2 of} the voltage conversion circuits 11 and 12 become substantially equal, so that the operation of the power supply device can be performed. Stabilize.

Further, when the load factors U ₁ and U _{2 of} the voltage conversion circuits 11 and 12 are lower than about 50%, the operation channel number setting unit 43 sets the number of channels of the voltage conversion circuit to be operated to “1”. Accordingly, the control signal generation unit 44 stops the voltage conversion circuit 12 of the channel 2.

Here, control signal generating unit 44 based on the setting value stored in the storage unit 41, along with lowering the load factor U ₂ of the voltage converter circuit 12 to 0%, the load factor U ₁ of the voltage conversion circuit 11 The drive signal of channel 1 is generated so as to increase the signal to about 100%. By so doing, fluctuations in the output voltage of the power supply device can be suppressed when the number of channels is reduced.

  In the example shown in FIG. 4, when the voltage conversion circuits of a plurality of channels are operated simultaneously, the output power (load factor) of these voltage conversion circuits is made substantially equal, but the present invention is limited to this. The output powers (load factors) of the voltage conversion circuits of a plurality of channels to be operated may be different from each other. For example, when the number of channels of the voltage conversion circuit to be operated is changed from “1” to “2”, the load factor of the voltage conversion circuit of channel 1 is lowered from about 100% to about 80% and the voltage of channel 2 The load factor of the conversion circuit may be increased from 0% to about 20%.

Next, a second embodiment of the present invention will be described.
FIG. 5 is a block diagram for explaining the operation of the control unit of the power supply device according to the second embodiment of the present invention. In the second embodiment, as illustrated in FIG. 5, the control signal generation unit 44 uses a common drive signal for the multiple-channel voltage conversion circuits 11 to 14 and the multiple-channel voltage conversion circuits 11 to 11 as control signals. The voltage conversion circuits 11 to 14 are controlled by supplying an individual enable signal to each of 14. Other points are the same as those of the first embodiment shown in FIG. The drive circuit 25 shown in FIG. 1 supplies a drive signal to the switching element 24 such as a MOSFET when the enable signal is activated, and fixes the drive signal at a low level when the enable signal is deactivated. . An example of such a drive circuit is shown in FIG.

  The drive circuit shown in FIG. 6 includes a level shifter 91 that shifts the level of the drive signal supplied from the control unit 40, two inversion circuits (inverters) 92 and 93 that buffer the output signal of the level shifter 91, and these inversion circuits. And a switch circuit 94 connected to the power supply lines 92 and 93.

The level shifter 91 is supplied with power supply potentials V _DD and V _SS and a high power supply potential V _H used for driving the switching element 24. The level shifter 91 converts the voltage range of the drive signal from the range of the power supply voltage (V _DD −V _SS ) to the range of the power supply voltage (V _H −V _SS ). Here, for example, the power supply voltage (V _DD −V _SS ) is 5V, and the power supply voltage (V _H −V _SS ) is 15V.

The inverting circuits 92 and 93 operate by being supplied with the power supply potentials V _H and V _SS . Here, the switch circuit 94 is turned on / off supply of the power supply potential V _H accordance with the enable signal. For example, the switch circuit 94 includes a P channel transistor connected between the power supply potential V _H and the power supply lines of the inverting circuits 92 and 93, a resistor for applying the power supply potential V _H to the gate of the P channel transistor, And an N-channel transistor for controlling the gate potential of the channel transistor. The drain of the N-channel transistor is connected to the gate of the P-channel transistor, the source is connected to the power supply potential _VSS , and an enable signal is supplied to the gate. Hereinafter, the drive signal supplied to the switching element 24 is referred to as a “gate signal”.

When the enable signal is inactivated to the low level, the switch circuit 94 is turned off and the power supply potential _VH is not supplied to the inverting circuits 92 and 93, so that the gate signal output from the inverting circuit 93 is at the low level. . Accordingly, the switching element 24 maintains the off state. When the enable signal is activated to a high level, the switch circuit 94 is turned on and the power supply potential _VH is supplied to the inverting circuits 92 and 93, so that a pulsed gate signal is generated from the inverting circuit 93 based on the drive signal. Is output. The switching element 24 shown in FIG. 1 performs a switching operation when a drive signal is applied from the drive circuit 25.

  Referring to FIG. 5 again, the control signal generation unit 44 activates the enable signal supplied to the voltage conversion circuit to be operated, and deactivates the enable signal supplied to the voltage conversion circuit not to be operated. In the case where the output power is made substantially equal in the voltage conversion circuits of a plurality of channels to be operated, the control signal generation unit 44 supplies the same drive signal to these voltage conversion circuits, so that the same as shown in FIG. Operation can be realized.

  In the above description, an insulating switching power supply circuit using a transformer has been described as an example of the voltage conversion circuit. However, a non-insulated switching power supply circuit using a choke coil may be used instead of the transformer. Moreover, the power supply device according to the present invention can be applied not only to the switching power supply device as shown in FIG. 1 but also to a front stage portion of a commercial inverter using a solar cell or a fuel cell as a DC input.

  The present invention can be used in a power supply device that performs voltage conversion by a switching operation.

It is a figure which shows the structure of the power supply device which concerns on the 1st Embodiment of this invention. It is a block diagram for demonstrating operation | movement of the control part shown in FIG. It is a flowchart which shows the control method of the power supply device which concerns on one Embodiment of this invention. It is a figure which shows the example of a change of the output electric power of the voltage conversion circuit of multiple channels. It is a block diagram for demonstrating operation | movement of the control part of the power supply device which concerns on the 2nd Embodiment of this invention. It is a figure which shows the example of the drive circuit shown in FIG. It is a figure which shows typically the DC / DC converter described in patent document 1. FIG. It is a figure for demonstrating operation | movement of the DC / DC converter shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Input terminal 3, 4 Output terminal 10 Rectification smoothing circuit 11-14 Voltage conversion circuit 20 Transformer 21 Primary side winding 22 Secondary side winding 23 Core 24 Switching element 25 Drive circuit 26 Diode 27 Capacitor 30 Output composition circuit 31-34 Diode 40 Control unit 41 Storage unit 50 Input voltage detection circuit 60 Output voltage detection circuit 71-74 Input current detection circuit 81-84 Output current detection circuit 91 Level shifter 92, 93 Inversion circuit 94 Switch circuit

Claims (8)

A voltage conversion circuit that performs a voltage conversion operation by performing a switching operation according to a pulsed drive signal, synthesizes an output current, and supplies it to a common load; and
Detecting means for detecting an output current supplied to the load;
Load state calculation means for calculating a value of current or power supplied to the load based on a detection result of the detection means;
Operation channel number setting means for setting the number of channels of the voltage conversion circuit to be operated in the voltage conversion circuit of the plurality of channels based on the current or power value calculated by the load state calculation means;
When the number of channels of the voltage conversion circuit to be operated is increased by controlling the voltage conversion circuits of the plurality of channels according to the number of channels set by the operation channel number setting means, at least one voltage conversion circuit is newly activated. When the output current of the other voltage conversion circuit is decreased and the number of channels of the voltage conversion circuit to be operated is decreased, at least one voltage conversion circuit is stopped and the other voltage conversion circuit is activated. Signal generating means for increasing the output current of the circuit;
A power supply apparatus comprising:   The power supply apparatus according to claim 1, wherein the signal generation unit performs feedforward control that sets a duty and / or frequency of a drive signal based on a set value when the number of channels of the voltage conversion circuit to be operated is changed.   3. The power supply device according to claim 1, wherein the signal generation unit feedback-controls the duty and / or frequency of the drive signal supplied to the voltage conversion circuit to be operated based on the output voltage detected by the detection unit. . The detecting means;
An output voltage detection circuit for detecting an output voltage supplied to the load;
At least one output current detection circuit for detecting an output current supplied to the load;
The power supply device according to claim 1, comprising:   5. The power supply device according to claim 1, wherein the load state calculation unit, the operation channel number setting unit, and the signal generation unit are configured using a DSP (digital signal processing device). . A method for controlling a power supply apparatus having a voltage conversion circuit of a plurality of channels that performs a voltage conversion operation by performing a switching operation according to a pulsed drive signal, synthesizes an output current, and supplies the output current to a common load,
Detecting an output current supplied to the load (a);
Calculating the value of the current or power supplied to the load based on the detection result in step (a) (b);
Setting the number of channels of the voltage conversion circuit to be operated in the voltage conversion circuit of the plurality of channels based on the current or power value calculated in step (b);
When the number of channels of the voltage conversion circuit to be operated is increased by controlling the voltage conversion circuit of the plurality of channels according to the number of channels set in step (c), at least one voltage conversion circuit is newly activated, When the output current of the activated voltage conversion circuit is decreased and the number of channels of the voltage conversion circuit to be operated is decreased, at least one voltage conversion circuit is stopped and other voltage conversion circuits Increasing the output current (d);
A method for controlling a power supply apparatus comprising:   The step (d) includes performing feedforward control for setting the duty and / or frequency of the drive signal based on the set value when changing the number of channels of the voltage conversion circuit to be operated. Control method of power supply.   The step (d) includes feedback control of the duty and / or frequency of the drive signal supplied to the voltage conversion circuit to be operated based on the output voltage detected in the step (a). The power supply device control method according to claim.

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