JP2019220371A - Power supply and lighting system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device and a lighting system capable of reducing loss. SOLUTION: A first conversion circuit 11 that converts input power into DC power, and a first conversion circuit 11 that is connected to the output side of the first conversion circuit 11 and converts the output power of the first conversion circuit 11 into DC power that drives a load 5. The two conversion circuits 21 and the control circuits 12 and 22 for controlling the first conversion circuit 11 and the second conversion circuit 21 are provided, and the control circuits 12 and 22 have an input voltage Vin, an output voltage Vout, and an output voltage Vout of the second conversion circuit 2. The magnitude of the DC voltage output by the first conversion circuit 11 is adjusted based on a predetermined target value Vaim regarding the conversion between the input voltage Vin and the output voltage Vout. [Selection diagram] Fig. 1

Description

  The present application relates to a power supply device and a lighting system.

2. Description of the Related Art Conventionally, a power supply device for supplying power to a load, an AC-DC converter for inputting AC power and outputting DC power, and a DC power output from the AC-DC converter for driving the load. A load drive unit that outputs DC drive power, and a connection cable that connects the AC-DC converter and the load drive unit are provided, and the AC-DC converter adjusts the voltage of the DC power output by the AC-DC converter. 2. Description of the Related Art There is known a power supply device that includes a voltage adjustment unit that adjusts a voltage of DC power output from an AC-DC conversion unit in accordance with an operation voltage for operating a load.
In the power supply device, the voltage of the DC power output from the AC-DC converter is adjusted to correspond to the load having the highest operating voltage among the loads connected to the plurality of load drivers (for example, Patent Document 1).

JP-A-2006-143445 (Claims 1 and 3)

  In the conventional power supply device (for example, Patent Document 1), as described above, the output voltage of the AC-DC converter is set based on the maximum load voltage. For example, if the maximum load voltage is 200 V, the output voltage of the AC-DC converter is set to a value determined from 200 V regardless of whether the 200 V load is operating or stopped. That is, even if the load of 200 V is stopped and the maximum voltage of the operating load is 150 V, the output voltage of the AC-DC converter is set based on 200 V. As described above, conventionally, the output voltage of the AC-DC converter is not always set based on the maximum voltage of the load that is actually operating. Loss during power conversion may increase. For example, when the load driving unit is a step-down chopper, the step-down ratio (input voltage / output voltage), which is the ratio between the input voltage and the output voltage of the step-down chopper, becomes unnecessarily large, and the loss in the step-down chopper increases. Become.

  The present application discloses a technique for solving the above-described problem, and has as its object to provide a power supply device and a lighting system capable of reducing loss.

The power supply device disclosed in the present application includes:
A first conversion circuit for converting input power to DC power,
A second conversion circuit connected to an output side of the first conversion circuit and converting output power of the first conversion circuit into DC power for driving a load;
A control circuit for controlling the first conversion circuit and the second conversion circuit,
The control circuit is configured to determine an input voltage and an output voltage of the second conversion circuit, and a magnitude of a DC voltage output from the first conversion circuit based on a predetermined target value related to conversion between the input voltage and the output voltage. It is to adjust the length.

  Further, a lighting system disclosed in the present application includes the power supply device, and a light emitting unit connected to an output side of the second conversion circuit of the power supply device and illuminating an illumination target.

  According to the power supply device and the lighting system disclosed in the present application, the output of the first conversion circuit is based on the input voltage and the output voltage of the second conversion circuit, and the predetermined target value regarding the conversion between the input voltage and the output voltage. Since the magnitude of the DC voltage to be applied is adjusted, the loss can be reduced.

FIG. 2 is a configuration diagram illustrating a lighting system according to a first example of the first embodiment. FIG. 2 is a circuit diagram schematically illustrating a load of a first example of the first embodiment. FIG. 3 is a circuit diagram schematically illustrating a first conversion unit of a first example of the first embodiment. FIG. 9 is a circuit diagram schematically illustrating another example of the first conversion unit of the first example of the first embodiment. FIG. 3 is a circuit diagram schematically illustrating a second converter of the first example of the first embodiment. FIG. 6 is a diagram for explaining an operation of a first conversion unit output voltage adjustment control of the first example of the first embodiment. FIG. 6 is a diagram for explaining an operation of a first conversion unit output voltage adjustment control of the first example of the first embodiment. FIG. 6 is a diagram for explaining an operation of a first conversion unit output voltage adjustment control of the first example of the first embodiment. FIG. 6 is a diagram for explaining an operation of a first conversion unit output voltage adjustment control of the first example of the first embodiment. FIG. 2 is a configuration diagram illustrating a lighting system and a power supply device according to a second example of the first embodiment. FIG. 3 is a configuration diagram illustrating a lighting system and a power supply device according to a third example of the first embodiment. FIG. 9 is a configuration diagram illustrating a lighting system and a power supply device according to a fourth example of the first embodiment. FIG. 9 is a diagram for explaining an operation of a first converter output voltage adjustment control of a fourth example of the first embodiment. FIG. 9 is a diagram for explaining an operation of a first converter output voltage adjustment control of a fourth example of the first embodiment. FIG. 9 is a diagram for explaining an operation of a first converter output voltage adjustment control of a fourth example of the first embodiment. FIG. 9 is a diagram for explaining an operation of a first converter output voltage adjustment control of a fourth example of the first embodiment.

Embodiment 1 FIG.
Hereinafter, a plurality of examples of the first embodiment of the present application will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference characters, and description thereof will be omitted or simplified as appropriate. Further, the configuration, size, arrangement, and the like of the configurations shown in the drawings can be appropriately changed within the scope of the present application.

[Description of First Example]
FIG. 1 is a configuration diagram illustrating a lighting system and a power supply device according to a first example of the first embodiment. The lighting system 101 in the first example includes a power supply device 100 having a first conversion unit 1 and a plurality of second conversion units 2, and a load 5. The input power supply 3 is connected to the input side of the first converter 1, and the load 5 is connected to the output side of the second converter 2. The first conversion unit 1 and the second conversion unit 2 are connected by a wiring cable 4. Note that the output voltage of the input power supply 3 may be an AC voltage or a DC voltage as described later.

  In the example of FIG. 1, a plurality of second converters 2 (2a to 2n) are connected in parallel to one first converter 1, and each of the second converters 2 (2a to 2n). Are connected to a load 5 (5a to 5n). However, one second converter 2 may be connected to the output side of the first converter 1 as described later.

  FIG. 2 is a circuit diagram schematically illustrating a load 5 according to a first example of the first embodiment. As shown in the drawing, the load 5 is, for example, a light-emitting unit including a plurality of light-emitting elements 50, and receives power supplied from the second conversion unit 2 to illuminate a room to be illuminated. is there. For example, the lighting system 101 is applied to a building or the like having a plurality of rooms, and a plurality of light emitting units are installed for each room.

  FIG. 2 illustrates a light-emitting unit including a plurality of light-emitting elements 50 connected in series. However, the light-emitting unit may include a plurality of light-emitting elements 50 connected in parallel. The light emitting elements 50 connected in parallel may include those connected in parallel, or the light emitting elements 50 connected in parallel may include those connected in series. Further, the light emitting element may include one light emitting element 50. In the following description, the load 5 will be described as a light emitting unit using an LED (Light Emitting Diode) as the light emitting element 50, but a light emitting unit using an organic EL (Electro Luminescence) or the like as the light emitting element. Is also good. The load 5 may be a motor, a heater, or the like instead of the light emitting unit.

  3 and 4 are configuration diagrams illustrating the first converter 1 of the first example of the first embodiment. FIG. 3 illustrates a case where the output of the input power source 3 is AC, and FIG. The configuration in the case of direct current is shown. As shown in FIG. 1, FIG. 3, or FIG. 4, the first conversion unit 1 includes a first conversion circuit 11 and a first control circuit 12.

FIG. 3 shows a configuration example of the first converter 1 when the input power supply 3 has an AC output. When the input power supply 3 has an AC output, the first converter 1 operates as an AC / DC converter.
As shown in FIG. 3, the first conversion circuit 11 includes a first connection part P11 and a second connection part P12, a third connection part P13 and a fourth connection part P14, a rectification part 111, a voltage adjustment part 112, an input voltage detection. Unit 113, and an output voltage detection unit 114. The first connection part P11 and the second connection part P12 are input parts of the first conversion circuit 11, and receive an AC output from the input power supply 3. The third connection part P13 and the fourth connection part P14 are output parts of the first conversion circuit 11, and are connected to the second conversion part 2. The input voltage detection unit 113 detects a voltage input to the voltage adjustment unit 112, and includes, for example, a resistor R1 and a resistor R2 connected in series. The output voltage detection unit 114 detects the voltage output by the voltage adjustment unit 112, and includes, for example, a resistor R3 and a resistor R4 connected in series. The rectifier 111 includes, for example, a full-wave rectifier circuit configured by a diode bridge, and plays a role of rectifying the input AC power.

  The voltage adjustment unit 112 adjusts the voltage of the DC power output from the first conversion circuit 11, and is configured by, for example, an H-type step-up / step-down circuit as shown in FIG. The voltage adjustment unit 112 includes a first switching element Q1 and a first diode D1 forming a step-down arm, and a second switching element Q2 and a second diode D2 forming a step-up arm. A first reactor L11 is connected between a connection between the first switching element Q1 and the first diode D1 and a connection between the second switching element Q2 and the second diode D2. The first switching element Q1 and the second switching element Q2 are driven by on / off control switch signals PWM1 and PWM2 output from the first control circuit 12, and are FET (Field Effect Transistor) elements or IGBT (Insulated) elements. Gate Bipolar Transistor). Voltage regulator 112 has a function as a boost converter and a function as a step-down converter. The first control circuit 12 can cause the voltage adjustment unit 112 to function as a boost converter by constantly turning on the first switching element Q1 and performing switching operation of the second switching element Q2. In addition, the first control circuit 12 can cause the voltage adjustment unit 112 to function as a step-down converter by constantly turning off the second switching element Q2 and performing the switching operation of the first switching element Q1.

  The step-down arm composed of the first switching element Q1 and the first diode D1 is connected to the rectifier 111, and the step-up arm composed of the second switching element Q2 and the second diode D2 is connected to the first conversion circuit 11 Are connected to the third connection portion P13 and the fourth connection portion P14, which are output portions of the second connection portion. Further, voltage adjustment section 112 includes a first current detection section Cs1 that detects current IL flowing through first reactor L11, and a first smoothing capacitor C2 that smoothes the output of voltage adjustment section 112.

  The voltage adjusting unit 112 may be configured by, for example, a flyback circuit, a single-ended primary converter (SEPIC) circuit, a CUK circuit, a ZETA circuit, or the like, instead of the H-type step-up / down circuit. If the information on the output voltage of the input power supply 3 and the voltage of the load 5 is known in advance and it is known that only the function as a boost converter is required, a boost circuit may be used for the voltage adjusting unit 112. Similarly, if it is known in advance that only the function as a step-down converter is necessary, a step-down circuit may be used for the voltage adjusting unit 112.

As shown in FIG. 1, the first control circuit 12 is configured to include a minimum value selection unit 13, a deviation calculation unit 14, and a control PWM unit 15.
In the control PWM unit 15, the first control circuit 12 controls the input voltage Vi of the voltage adjustment unit 112 detected by the input voltage detection unit 113, the output voltage Vo of the voltage adjustment unit 112 detected by the output voltage detection unit 114, By using the current IL flowing through the first reactor L11 detected by the first current detection unit Cs1 to generate switch signals PWM1 and PWM2 for controlling the first switching element Q1 and the second switching element Q2 to turn on and off, the input is performed. PFC (Power Factor Correction) control is performed so that the AC input current and the AC input voltage input from the power supply 3 have the same phase and the same waveform.

  Further, the first control circuit 12 adjusts the output voltage of the first conversion unit 1 according to the information on the input voltage and the output voltage of the second conversion unit 2 sent from the second conversion unit 2. Performs output voltage adjustment control. The details of the first converter output voltage adjustment control will be described later.

FIG. 4 shows a configuration example of the first converter 1 when the input power supply 3 has a DC output. When the input power supply 3 has a DC output, the first converter 1 operates as a DC / DC converter.
As shown in FIG. 4, the first conversion circuit 11 includes a first connection portion P11 and a second connection portion P12, a third connection portion P13 and a fourth connection portion P14, a voltage adjustment portion 112, an input voltage detection portion 113, and An output voltage detection unit 114 is included. When the input power supply 3 has a DC output, the rectifier 111 of FIG. 3 can be omitted, so that the voltage regulator 112 is connected to the first connection P11 and the second connection P12. When the input power supply 3 has a DC output, the PFC control is omitted in the first control circuit 12. Except for the above, the input power supply 3 is the same as the case of the AC output, and thus the description is omitted.

  FIG. 5 is a circuit diagram schematically illustrating the second converter 2 of the first example of the first embodiment. As described in FIGS. 1 and 5, the second conversion unit 2 includes a second conversion circuit 21 and a second control circuit 22.

  The second converter 2 operates as a DC / DC converter that receives the output voltage (DC voltage) of the first converter 1 and converts it to a DC voltage for driving the load 5. The input voltage of the second converter 2 is a value obtained by subtracting the voltage effect of the wiring cable 4 from the output voltage of the first converter 1. The output voltage of the second converter 2 and the input voltage of the load 5 can be regarded as the same.

  As shown in FIG. 5, the second conversion circuit 21 includes a first connection part P21 and a second connection part P22, a third connection part P23 and a fourth connection part P24, a second voltage adjustment part 211, a second input voltage detection. Unit 212 and a second output voltage detecting unit 213. The first connection part P21 and the second connection part P22 are input parts of the second conversion circuit 21 and are connected to the first conversion part 1. The third connection part P23 and the fourth connection part P24 are output parts of the second conversion circuit 21 and are connected to the load 5. The second input voltage detection unit 212 detects a voltage input to the second voltage adjustment unit 211, and includes, for example, a resistor R21 and a resistor R22 connected in series. The second output voltage detection unit 213 detects the voltage output from the second voltage adjustment unit 211, and includes, for example, a resistor R23 and a resistor R24 connected in series.

  The second voltage adjustment unit 211 adjusts the current of the DC power output from the second conversion circuit 21, and includes a third switching element Q21, a third diode D21, a second reactor L21, a second capacitor C21, And two current detectors Cs21. The third switching element Q21 is configured by an FET element, an IGBT element, or the like. The second current detector Cs21 detects the current of the DC drive power output from the second conversion circuit 21. The second voltage adjuster 211 may be a circuit having a step-down function, and may be, for example, a flyback circuit or the like.

As shown in FIG. 1, the second control circuit 22 includes an output current control unit 23, a difference calculation unit 24, and a calculation value generation unit 25. In FIG. 1, a plurality of second converters 2a to 2n are connected to the first converter 1, and the second converters 2a to 2n include second control circuits 22a to 22n, respectively. Each of the circuits 22a to 22n has an output current control unit 23a to 23n, a difference calculation unit 24a to 24n, and a calculation value generation unit 25a to 25n. In the following, the second conversion unit 2 and the second control unit The circuit 22, the output current control unit 23, the difference calculation unit 24, and the calculation value generation unit 25 will be described with generic names.
The output current control unit 23 controls the third switching element Q21 so that a desired current flows to the load 5 using the current Io detected by the second current detection unit Cs21. The difference calculation unit 24 and the calculation value generation unit 25 generate a calculation value Cv used for a first conversion unit output voltage adjustment control described later.
In the example of the present embodiment, the load 5 is current-controlled, but the load 5 may be voltage-controlled by the second converter 2. When the second converter 2 controls the voltage of the load 5, the output voltage Vout of the second converter detected by the second output voltage detector 213 is used instead of the current Io detected by the second current detector Cs21. The control may be performed by using this.

  Next, the first converter output voltage adjustment control, which is a feature of the present embodiment, will be described. In the present embodiment, information communication is performed between the first control circuit 12 and the second control circuit 22 at predetermined timings, and the output voltage of the first conversion unit 1 is determined.

  The second converter 2 generates a calculation value Cv based on the input / output voltage information, and sends it to the first converter 1 at predetermined timing. That is, the second control circuit 22 calculates the input voltage Vin of the second conversion circuit 21 detected by the second input voltage detection unit 212 and the output voltage Vout of the second conversion circuit 21 detected by the second output voltage detection unit 213. Then, the difference calculator 24 calculates a difference (Vin−Vout) between the detected input voltage Vin of the second converter 21 and the output voltage Vout of the second converter 21. Further, the calculation value generation unit 25 generates a calculation value Cv = (Vin−Vout−Vaim) by calculating a difference between the value (Vin−Vout) calculated by the difference calculation unit 24 and the target value Vaim. The target value Vaim is a target value of the difference between the input voltage Vin and the output voltage Vout of the second converter 2, and the input voltage Vin approaches the output voltage Vout or the input voltage Vin falls below the output voltage Vout, and the second It serves to prevent the operation of the converter 2 from becoming unstable. The set value of the target value Vaim may be determined based on the output voltage Vout such as 10% of the output voltage Vout, may be determined at a fixed value such as 10 V, or the switching of the second conversion circuit 21 may be performed. The element may be set to perform a zero-voltage switching operation or a zero-current switching operation. However, the value of the target value Vaim may be set to a value as small as possible within a range where the normal operation of the second converter 2 can be confirmed. desirable.

  The first control circuit 12 of the first conversion unit 1 controls the output voltage of the first conversion circuit 11 based on the operation value Cv sent from the second conversion unit 2 at each predetermined timing. The first control circuit 12 receives the operation values Cv sent from the plurality of second conversion units 2 (2a to 2n) by the minimum value selection unit 13 and selects the minimum value Cv_min from the operation values Cv. The deviation calculation unit 14 subtracts the output voltage Vo of the first conversion circuit 11 detected by the input voltage detection unit 113 and the minimum value Cv_min of the calculation value selected by the minimum value selection unit 13 from the initial value 16. Is calculated. The control PWM unit 15 generates a PWM signal for operating the switching elements Q1 and Q2 of the first conversion circuit 11 so that the deviation calculated by the deviation calculation unit 14 becomes zero, and the switching elements Q1 and Q2 of the first conversion circuit 11 To work.

  The communication performed between the first conversion unit 1 and the second conversion unit 2 may be determined to be performed, for example, at a predetermined cycle, or may be performed from outside such as when a command signal of the second conversion circuit 21 is received. The timing may be determined as a timing at which a signal is received, or may be determined as a timing at which a state change such as a voltage drop detection of the load 5 is detected. The update timing may be determined by combining two or more of the above. Further, the communication cycle may be changed by receiving an external signal or detecting a state change.

  By applying the above-described first converter output voltage adjustment control, the output voltage of the first converter 1 is adjusted to an optimal value at any time according to the operation state of the second converter 2, so that the second converter Even when the operation of the second converter 2 is stopped or when the load voltage of the second converter 2 fluctuates due to the dimming operation of the load 5, for example, the light emitting unit, a highly efficient operation can be realized. In the control of the present embodiment, since the input voltage Vin and the output voltage Vout of the second converter 2 are detected, the voltage drop of the wiring cable 4 is large, and the output voltage of the first converter 1 and the second converter Even if a voltage difference occurs between the input voltages of the second conversion unit 2, the operation of the second conversion unit 2 due to the input voltage of the second conversion unit 2 approaching or falling below the output voltage of the second conversion unit 2 is improper. Stability can be prevented.

The operation of the first converter output voltage adjustment control will be described by taking as an example a case where three sets of second converters 2a, 2b, and 2c are connected to the first converter 1 in parallel.
FIGS. 6 to 9 illustrate the input voltage Vin (Vin_a, Vin_b, Vin_c) and the output voltage Vout () of the second converter 2 (2a, 2b, 2c) for explaining the operation of the first converter output voltage adjustment control. It is an example of Vout_a, Vout_b, Vout_c), a target value Vaim (Vaim_a, Vaim_b, Vaim_c), and a calculated value Cv (Cv_a, Cv_b, Cv_c).

  In the initial state, as shown in FIG. 6, the input voltage Vin_a of the second converter 2a is 200 V, the output voltage Vout_a is 100 V, the target value Vaim_a is 10 V, the input voltage Vin_b of the second converter 2b is 190 V, and the output voltage Vout_b. Is 80 V, the target value Vaim_b is 10 V, the input voltage Vin_c of the second converter 2 c is 200 V, the output voltage Vout_c is 60 V, and the target value Vaim_c is 10 V. Note that the input voltage Vin_b of the second converter 2b is smaller by 10 V than the input voltage Vin_a of the second converter 2a and the input voltage Vin_c of the second converter 2c, but the second converter 2b performs the second conversion. It is assumed that the distribution cable 4 between the first conversion unit 1 and the units 2a and 2c is longer and the voltage drop is larger.

  Under the conditions shown in FIG. 6, the calculated value Cv_a of the second converter 2a is 90 V, the calculated value Cv_b of the second converter 2b is 100 V, and the calculated value Cv_c of the second converter 2c is 130 V. The calculation values Cv are sent from the units 2a, 2b, 2c to the first conversion unit 1. The first control circuit 12 of the first conversion unit 1 selects 90V (Cv_a) of the second conversion unit 2a, which is the minimum value Cv_min, from the three calculated values Cv sent, and selects the selected minimum value Cv_min ( The output voltage of the first conversion circuit 11 is adjusted so that 90 V) becomes zero.

  FIG. 7 shows a state after adjusting the output voltage of the first converter 1 from the state of FIG. As a result of adjusting the output voltage of the first converter 1 to be smaller, the difference between the input voltage Vin_a (110V) of the second converter 2a and the output voltage Vout_a (100V) becomes the target value Vaim_a (10V). I have. In FIG. 7, since the input voltage Vin of each of the second converters 2a, 2b, and 2c is smaller than that of FIG. 6, the step-down ratio (output voltage / input voltage) of the second converters 2a, 2b, and 2c is smaller. As a result, the loss generated in the second converters 2a, 2b, 2c is reduced.

  FIG. 8 shows a case where the second converter 2a stops operating from the state of FIG. 7, and the output voltage of the second converter 2a is 0. In the state of FIG. 8, the calculated value Cv_a of the second converter 2a is calculated to be 100V, the calculated value Cv_b of the second converter 2b is calculated to be 10V, and the calculated value Cv_c of the second converter 2c is calculated to be 40V. The minimum value selection unit 13 of the first conversion unit 1 selects 10V of the second conversion unit 2b as the minimum value Cv_min, and sets the first conversion unit 1 so that the operation value (10V) of the second conversion unit 2b becomes zero. The output voltage is adjusted. Although the example in which the calculation of the calculation value Cv and the selection of the minimum value Cv_min are executed even when the operation of the second conversion unit 2 is stopped has been described, the calculation value is calculated when the second conversion unit 2 stops. Processing may be performed such that the calculation is not performed and the calculation is excluded from the minimum value selection.

  FIG. 9 shows a state after the output voltage of the first converter 1 has been adjusted from the state of FIG. The difference between the input voltage Vin_b (90 V) and the output voltage Vin_b (80 V) of the second converter 2 b is controlled to be the target value Vaim_b (10 V) regardless of the voltage drop due to the wiring cable 4. In FIG. 9, the input voltage Vin of each of the second converters 2a, 2b, 2c is smaller than that in the state of FIG. 7, so that the step-down ratio (output voltage / input voltage) of the second converters 2a, 2b, 2c is smaller. ) Is suppressed, and the loss generated in the second converters 2a, 2b, 2c is reduced.

[Explanation of other examples]
The configuration of the first converter output voltage adjustment control is as follows if the output voltage Vo of the first converter 1 is controlled based on information on the input voltage Vin and the output voltage Vout of the second converter 2. Optional as described. In the following description, differences from the above-described first example will be mainly described, and the other points are the same as those of the first example. Therefore, the description will be appropriately omitted or simplified.

[Explanation of the second example]
FIG. 10 is a configuration diagram illustrating a lighting system and a power supply device according to a second example of the first embodiment. In the lighting system 101 and the power supply device 100 of the second example shown in FIG. 10, the difference (Vin−Vout) between the input voltage Vin and the output voltage Vout detected by the second conversion unit 2 is calculated by the difference calculation unit 24 and the difference is calculated. (Vin−Vout) is sent to the first converter 1, and the minimum value selector 13 of the first converter 1 calculates the difference (Vin−Vout) between the input voltage Vin and the output voltage Vout sent from the second converter 2. After the minimum value is selected, the difference from the target value Vaim is calculated. Also, for example, the second converter 2 does not perform an operation on the detected input voltage Vin and output voltage Vout, and sends information on the input voltage Vin and the output voltage Vout to the first converter 1 as it is, The conversion unit 1 may be configured to perform all calculations and controls, such as calculation of the difference (Vin−Vout) between the input voltage and the output voltage, calculation of the difference and the target value Vaim, and selection of the minimum value.

[Description of Third Example]
FIG. 11 is a configuration diagram illustrating a lighting system and a power supply device according to a third example of the first embodiment. The illumination system and the power supply device of the third example shown in FIG. 11 have a configuration in which the deviation calculation unit 14 is removed from the configuration of the first control circuit 12 shown in FIG. The first control circuit 12 receives the operation values Cv sent from the plurality of second conversion units 2 (2a to 2n), and selects the minimum value Cv_min from the operation values Cv by the minimum value selection unit 13. , The minimum value Cv_min is input to the control PWM unit 15, and the control PWM unit 15 generates a PWM signal for operating the switching elements Q1 and Q2 of the first conversion circuit 11.

[Explanation of the fourth example]
FIG. 12 is a configuration diagram illustrating a lighting system and a power supply device according to a fourth example of the first embodiment. In the lighting system and the power supply device of the fourth example shown in FIG. 12, an example is shown in which one second converter 2 a is connected to the first converter 1. As shown in FIG. 12, when one second conversion unit 2a is connected, the operation value Cv calculated by the one second conversion unit 2a is selected by the minimum value selection unit 13 as the minimum value Cv_min, The first converter output voltage adjustment control is performed.

  13 to 16 are diagrams for explaining the operation of the first converter output voltage adjustment control of the fourth example. The input voltage Vin_a, the output voltage Vout_a, the target value Vaim_a, and the operation value of the second converter 2a are illustrated. 9 shows an example of Cv_a. In FIGS. 13 to 16 and the following description, the input voltage Vin_a, the output voltage Vout_a, the target value Vaim_a, and the calculated value Cv_a are represented as the input voltage Vin, the output voltage Vout, the target value Vaim, and the calculated value Cv.

  In the initial state, as shown in FIG. 13, the input voltage Vin of the second converter 2a is 200V, the output voltage Vout is 100V, and the target value Vaim is 10V. At this time, the operation value Cv of the second conversion unit 2a is calculated to be 90V, and the operation value Cv (90V) is sent from the second conversion unit 2a to the first conversion unit 1. In the first control circuit 12 of the first conversion unit 1, the operation value Cv (90V) sent from the second conversion unit 2a by the minimum value selection unit 13 is selected as the minimum value Cv_min, and the selected minimum value Cv_min ( The output voltage of the first conversion circuit 11 is adjusted so that 90 V) becomes zero.

  FIG. 14 shows a state after adjusting the output voltage of the first converter 1 from the state of FIG. As a result of adjusting the output voltage of the first converter 1 to be smaller, the difference between the input voltage Vin (110V) and the output voltage Vout (100V) of the second converter 2a becomes the target value Vaim (10V). I have. As a result, in FIG. 14, the step-down ratio (output voltage / input voltage) of the second converter 2a is suppressed as compared with the case of FIG. 13, and the loss generated in the second converter 2a is reduced.

  FIG. 15 shows a case where the operation of the second converter 2a is stopped from the state of FIG. 14, and the output voltage Vout of the second converter 2a is 0. In the state of FIG. 15, the operation value Cv of the second conversion unit 2a is calculated as 100V. The minimum value selection unit 13 of the first conversion unit 1 selects the operation value Cv (100V) of the second conversion unit 2a as the minimum value Cv_min, and sets the minimum value Cv_min (100V) of the second conversion unit 2a to zero. The output voltage of the first converter 1 is adjusted. Although the example in which the calculation of the operation value Cv and the selection of the minimum value Cv_min are executed even when the operation of the second conversion unit 2a is stopped has been described, the second conversion unit 2a may be stopped when the second conversion unit 2a stops. A process for transmitting an operation stop signal of the second conversion unit 2a from the conversion unit 2a to the first conversion unit 1 and stopping the operation of the first conversion unit 1 may be performed. FIG. 16 shows a state after the output voltage of the first converter 1 has been adjusted from the state of FIG.

  As described above, even when one second converter 2 is connected to the output side of the first converter 1, the first converter output voltage adjustment control is performed with the same configuration as that of FIG. Can be. By applying the configuration in which one second converter 2 is connected to the output side of the first converter 1 to FIGS. 10 and 11, the first converter output voltage adjustment control can be performed. .

  In the first to fourth examples, the first control circuit for controlling the first conversion circuit and the second control circuit for controlling the second conversion circuit have been separately described. The circuit and the second control circuit may be integrated into one control circuit. Alternatively, a plurality of first converters 1 may be arranged in parallel with respect to the input power source 3, and the second converter 2 may be connected to the output side of each first converter 1. In this case, information from the second converter 2 is transmitted to each of the plurality of first converters 1, and the first converter output voltage adjustment control is performed.

[Effects of Embodiment]
As described above, in the present embodiment, the first conversion circuit that converts the input power into the DC power, and the output power of the first conversion circuit that is connected to the output side of the first conversion circuit and converts the output power of the first conversion circuit into the DC power that drives the load. A second conversion circuit for converting, and a control circuit for controlling the first and second conversion circuits, wherein the control circuit is configured to control an input voltage, an output voltage, and an input voltage and an output voltage of the second conversion circuit. Since the magnitude of the DC voltage output from the first conversion circuit is adjusted based on a predetermined target value related to the conversion, the loss of the second conversion circuit can be reduced, and the second conversion circuit can be reduced. In addition, the power supply device and the lighting system can be reduced in size and cost.

  The second conversion circuit is a step-down conversion circuit connected in parallel to the output side of the first conversion circuit, and the control circuit controls the input voltage and the output voltage for each of the plurality of second conversion circuits. And calculating a calculated value obtained by subtracting a target value from the difference between the calculated values, selecting a minimum value among the plurality of calculated values, and adjusting the magnitude of the DC voltage output from the first conversion circuit based on the selected minimum value. Therefore, the output voltage of the first converter can always be adjusted to an optimum value in accordance with the operation state of the second converter, and the step-down ratio of the second converter can be prevented from increasing. The loss that occurs can be reduced.

  The second conversion circuit is a step-down conversion circuit connected to the output side of the first conversion circuit, and the control circuit subtracts a target value from a difference between an input voltage and an output voltage of the second conversion circuit. The calculated operation value is calculated, the calculated value is selected as the minimum value, and the magnitude of the DC voltage output from the first conversion circuit is adjusted based on the selected minimum value. Accordingly, the output voltage of the first converter can be constantly adjusted to an optimum value, the step-down ratio of the second converter can be prevented from increasing, and the loss generated in the second converter can be reduced.

  The control circuit includes a first control circuit that controls the first conversion circuit, and a plurality of second control circuits that respectively control the second conversion circuits. Since the information communication is performed at a predetermined timing, even if the first conversion circuit and the first control circuit and the second conversion circuit and the second control circuit are installed in remote places, the communication can be appropriately performed. The control of the present embodiment can be achieved.

  Further, even when the first conversion circuit and the second conversion circuit are connected by a wiring cable, the output voltage of the first conversion circuit is adjusted using the input / output voltage information of the second conversion circuit. , The input voltage of the second conversion circuit can be prevented from approaching or falling below the output voltage of the second conversion circuit, and a stable operation of the second conversion circuit can be realized. .

  Further, since the output voltage of the first conversion circuit is determined regardless of the magnitude of the voltage input from the input power supply, the withstand voltage characteristic of the connection cable connecting the first conversion circuit and the second conversion circuit is determined by the load. Of the operating voltage. As a result, the connection cable can be reduced in size and cost, and thus the power supply device and the lighting system can be reduced in size and cost.

Although this application describes various exemplary embodiments, the various features, aspects, and functions described in one or more embodiments are not limited to the application of a particular embodiment. , Alone or in various combinations.
Accordingly, innumerable modifications not illustrated are envisioned within the scope of the technology disclosed herein. For example, a case where at least one component is deformed, added or omitted, and a case where at least one component is extracted and combined with a component of another embodiment are included.

1 first conversion unit, 2 second conversion unit, 3 input power, 4 wiring cable, 5 load,
11 first conversion circuit, 12 first control circuit, 13 minimum value selection unit, 14 deviation calculation unit,
15 control PWM unit, 21 second conversion circuit, 22 second control circuit,
23 output current control unit, 24 difference operation unit, 25 operation value generation unit, 50 light emitting element,
100 power supply device, 101 lighting system, 111 rectifier, 112 voltage adjuster,
113 input voltage detection unit, 114 output voltage detection unit, 211 second voltage adjustment unit,
212 second input voltage detector, 213 second output voltage detector,
Q1 first switching element, Q2 second switching element, D1 first diode,
D2 second diode, L11 first reactor, Cs1 first current detector,
Q21 third switching element, D21 third diode, L21 second reactor,
Cs21 Second current detector.

Claims (11)

A first conversion circuit for converting input power to DC power,
A second conversion circuit connected to an output side of the first conversion circuit and converting output power of the first conversion circuit into DC power for driving a load;
A control circuit for controlling the first conversion circuit and the second conversion circuit,
The control circuit is configured to control an input voltage and an output voltage of the second conversion circuit, and a magnitude of a DC voltage output from the first conversion circuit based on a predetermined target value related to conversion between the input voltage and the output voltage. Power supply to adjust the power. The second conversion circuit is a step-down conversion circuit connected in parallel to an output side of the first conversion circuit,
The control circuit calculates a calculation value obtained by subtracting the target value from a difference between an input voltage and an output voltage for each of the plurality of second conversion circuits, and selects a minimum value among the plurality of calculation values, The power supply device according to claim 1, wherein the magnitude of the DC voltage output from the first conversion circuit is adjusted based on the selected minimum value. The second conversion circuit is a step-down conversion circuit connected to one output side of the first conversion circuit,
The control circuit calculates an operation value obtained by subtracting the target value from the difference between the input voltage and the output voltage of the second conversion circuit, selects the operation value as a minimum value, and sets the operation value based on the selected minimum value. The power supply device according to claim 1, wherein the magnitude of the DC voltage output from the first conversion circuit is adjusted. The control circuit includes a first control circuit that controls the first conversion circuit, and a plurality of second control circuits that control the second conversion circuit, respectively.
The second control circuit calculates a calculated value obtained by subtracting the target value from a difference between an input voltage and an output voltage of the second conversion circuit, and transmits the calculated value to the first control circuit,
The first control circuit selects a minimum value among the plurality of operation values transmitted from the second control circuit, and controls a DC voltage output from the first conversion circuit based on the selected minimum value. The power supply device according to claim 2, wherein the size is adjusted. The control circuit includes a first control circuit that controls the first conversion circuit, and a plurality of second control circuits that control the second conversion circuit, respectively.
The second control circuit calculates a difference between an input voltage and an output voltage of the second conversion circuit and transmits the difference to the first control circuit,
The first control circuit selects a minimum value among the plurality of differences transmitted from the second control circuit, and performs the first conversion based on a value obtained by subtracting the target value from the selected minimum value. 3. The power supply according to claim 2, wherein the magnitude of the DC voltage output from the circuit is adjusted. The control circuit includes a first control circuit that controls the first conversion circuit, and a second control circuit that controls the second conversion circuit,
The second control circuit calculates a calculation value obtained by subtracting the target value from a difference between an input voltage and an output voltage of the second conversion circuit, and transmits the calculated value to the first control circuit,
The first control circuit selects the operation value transmitted from the second control circuit as a minimum value, and adjusts the magnitude of the DC voltage output from the first conversion circuit based on the selected minimum value. The power supply device according to claim 3. The power supply device according to any one of claims 1 to 6, wherein communication between the first conversion circuit and the second conversion circuit is performed at a predetermined timing. The power supply device according to claim 7, wherein the timing is determined based on at least one of a specific cycle, a voltage fluctuation of the load, and a command signal received by the second conversion circuit. 9. The power supply device according to claim 1, wherein an input voltage of the first conversion circuit is an AC voltage, and the first conversion circuit is an AC / DC conversion circuit having a PFC function. The power supply device according to any one of claims 1 to 8, wherein an input voltage of the first conversion circuit is a DC voltage, and the first conversion circuit is a DC / DC conversion circuit. An illumination system comprising: the power supply device according to any one of claims 1 to 10; and a light emitting unit connected to an output side of the second conversion circuit of the power supply device and configured to illuminate an object to be illuminated. .

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