JP7602368B2 - Power supply device and method for controlling the power supply device - Google Patents

Description

The present invention relates to a power supply device and a method for controlling the power supply device.

Patent document 1 describes a power conversion device that has a first operating mode in which all switching elements of the first to third switching legs are switched, and a second operating mode in which at least one of the first to third switching legs, either the upper or lower switching element, is always on, and the other switching element is always off.

JP 2016-173961 A

In a power supply device in which multiple current resonant converters are connected in series, a large inrush current flows when the power is turned on.

The present invention aims to provide a power supply device and a method for controlling the power supply device that can suppress inrush current.

A power supply device according to one aspect of the present invention comprises:
A plurality of converters;
a rectifier circuit including a plurality of rectifier arms that rectify the winding voltages of the plurality of converters and output the rectified voltages to a load;
A control circuit for controlling the plurality of converters;
Equipped with
one output terminal of each of the plurality of converters is electrically connected to the other output terminal of each adjacent converter and is electrically connected to one rectifier arm of the plurality of rectifier arms;
The control circuit includes:
When the power supply is turned on, the plurality of converters are controlled to start operating one by one.
It is characterized by:

In the power supply device,
The control circuit includes:
a control unit that controls a next converter to start operating when a predetermined threshold time has elapsed since one converter of the plurality of converters started operating;
It is characterized by:

In the power supply device,
The control circuit includes:
One of the plurality of converters is started to operate, and when an output current of the one converter becomes equal to or lower than a predetermined threshold current, a control is performed to start the operation of the next converter.
It is characterized by:

In the power supply device,
Each of the plurality of converters is a current resonant converter.
It is characterized by:

A method for controlling a power supply device according to one aspect of the present invention includes:
A control method for a power supply device comprising: a rectifier circuit including a plurality of converters; a plurality of rectifier arms that rectify winding voltages of the plurality of converters and output the rectified voltages to a load; and a control circuit that controls the plurality of converters, wherein one output terminal of each of the plurality of converters is electrically connected to the other output terminal of an adjacent converter and is also electrically connected to one rectifier arm of the plurality of rectifier arms,
When power is turned on, the plurality of converters are started to operate one by one.
It is characterized by:

The power supply device and the method for controlling the power supply device according to one aspect of the present invention have the effect of suppressing inrush current.

FIG. 1 is a diagram showing a circuit configuration of a power supply device according to a first embodiment. FIG. 2 is a diagram showing a circuit configuration of a full-bridge circuit of the power supply device according to the first embodiment. FIG. 3 is a diagram illustrating modes of the power supply device according to the first embodiment. FIG. 4 is a diagram showing the direction of voltage (current) on the secondary winding side of the power supply device according to the first embodiment. FIG. 5 is a diagram showing the output voltage and the output current of the power supply device of the comparative example. FIG. 6 is a flow chart showing the operation of the control circuit of the power supply device according to the first embodiment when the power supply is turned on. FIG. 7 is a diagram illustrating an output voltage and an output current of the power supply device according to the first embodiment.

Below, an embodiment of the power supply device and the method for controlling the power supply device of the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to this embodiment.

First embodiment and comparative example
(Overall composition)
1 is a diagram showing a circuit configuration of a power supply device according to a first embodiment. The power supply device 1 receives a DC voltage Vin that is output from a DC power supply 21 and smoothed by a capacitor 22, and outputs an output voltage Vout to a load 23.

The power supply device 1 includes a first current resonant converter 2-1 to a fourth current resonant converter 2-4, a rectifier circuit 3, a control circuit 4, a capacitor 5, a voltage sensor 6, and a current sensor 7.

In the first embodiment, the number of current resonant converters is an even number (four as a representative even number), but the present disclosure is not limited to this. The number of current resonant converters may be an odd number. In the first embodiment, the number of current resonant converters is four, but the number of current resonant converters may be two, or six or more.

In addition, each converter is not limited to a current resonant converter.

Each of the first current resonant converter 2-1 to the fourth current resonant converter 2-4 is a current resonant converter (LLC converter) that uses LLC resonance. Each of the first current resonant converter 2-1 to the fourth current resonant converter 2-4 is electrically connected to a capacitor 22. A DC voltage Vin that is output from a DC power source 21 and smoothed by the capacitor 22 is input to each of the first current resonant converter 2-1 to the fourth current resonant converter 2-4.

The first current resonant converter 2-1 includes a first full-bridge circuit FB1 and a first transformer T1. The first current resonant converter 2-1 includes a leakage inductance 14-1 and a capacitor 15-1 between the first full-bridge circuit FB1 and the first transformer T1. The leakage inductance 14-1 may be included in the first transformer T1.

The second current resonant converter 2-2 includes a second full-bridge circuit FB2 and a second transformer T2. The second current resonant converter 2-2 includes a leakage inductance 14-2 and a capacitor 15-2 between the second full-bridge circuit FB2 and the second transformer T2. The leakage inductance 14-2 may be included in the second transformer T2.

The third current resonant converter 2-3 includes a third full-bridge circuit FB3 and a third transformer T3. The third current resonant converter 2-3 includes a leakage inductance 14-3 and a capacitor 15-3 between the third full-bridge circuit FB3 and the third transformer T3. The leakage inductance 14-3 may be included in the third transformer T3.

The fourth current resonant converter 2-4 includes a fourth full-bridge circuit FB4 and a fourth transformer T4. The fourth current resonant converter 2-4 includes a leakage inductance 14-4 and a capacitor 15-4 between the fourth full-bridge circuit FB4 and the fourth transformer T4. The leakage inductance 14-4 may be included in the fourth transformer T4.

Figure 2 is a diagram showing the circuit configuration of the full bridge circuit of the power supply device of the first embodiment. Note that while Figure 2 shows the circuit configuration of the first full bridge circuit FB1, the circuit configurations of the second full bridge circuit FB2 to the fourth full bridge circuit FB4 are similar to the circuit configuration of the first full bridge circuit FB1, and therefore illustration and description are omitted.

The first full-bridge circuit FB1 includes a first arm 30-1 and a second arm 30-2. The first arm 30-1 includes a high-side transistor Tr1-1 and a low-side transistor Tr1-2. The second arm 30-2 includes a high-side transistor Tr2-1 and a low-side transistor Tr2-2.

In this disclosure, each transistor is described as a MOSFET, but is not limited to this. Each transistor may be a silicon power device, a GaN power device, a SiC power device, an IGBT (Insulated Gate Bipolar Transistor), etc.

Each transistor has a parasitic diode (body diode). A parasitic diode is a pn junction between the back gate of a MOSFET and the source and drain. The parasitic diode can be used as a freewheeling diode to release the transient back electromotive force when the transistor is turned off.

The source of transistor Tr1-1 is electrically connected to the drain of transistor Tr1-2. The source of transistor Tr2-1 is electrically connected to the drain of transistor Tr2-2.

The drain of transistor Tr1-1 and the drain of transistor Tr2-1 are electrically connected to one end (high potential end) of capacitor 22. The source of transistor Tr1-2 and the source of transistor Tr2-2 are electrically connected to the other end (low potential end) of capacitor 22.

The connection point between the drain of transistor Tr1-1 and the drain of transistor Tr2-1 is one input terminal of the first full bridge circuit FB1. The connection point between the source of transistor Tr1-2 and the source of transistor Tr2-2 is the other input terminal of the first full bridge circuit FB1.

A DC voltage Vin is input to the two input terminals of the first full-bridge circuit FB1.

The connection point between the source of transistor Tr1-1 and the drain of transistor Tr1-2 is one output terminal of the first full bridge circuit FB1. The connection point between the source of transistor Tr1-2 and the drain of transistor Tr2-2 is the other output terminal of the first full bridge circuit FB1.

The first full-bridge circuit FB1 outputs a DC voltage Vin, a DC voltage -Vin, or zero voltage between one output terminal and the other output terminal.

For example, when transistors Tr1-1 and Tr2-2 are on and transistors Tr1-2 and Tr2-1 are off, the first full-bridge circuit FB1 outputs a DC voltage Vin between one output terminal and the other output terminal.

For example, when transistors Tr1-1 and Tr2-2 are in the off state and transistors Tr1-2 and Tr2-1 are in the on state, the first full-bridge circuit FB1 outputs a DC voltage -Vin between one output terminal and the other output terminal.

For example, when transistors Tr1-1 to Tr2-2 are in the off state, the first full-bridge circuit FB1 outputs zero voltage between one output terminal and the other output terminal.

Referring again to FIG. 1, the first transformer T1 includes a primary winding 10-1, a secondary winding 11-1, and a core 12-1. The primary winding 10-1 and the secondary winding 11-1 are wound around the core 12-1.

The primary winding 10-1 includes an excitation inductance 13-1 and a leakage inductance 14-1. One end of the primary winding 10-1 is electrically connected to one output terminal of the first full-bridge circuit FB1 via a capacitor 15-1. The other end of the primary winding 10-1 is electrically connected to the other output terminal of the first full-bridge circuit FB1. The excitation inductance 13-1, the leakage inductance 14-1, and the capacitor 15-1 form an LLC resonant circuit.

In this disclosure, the LLC resonant circuit is located on the primary winding 10-1 side, but this is not limited to the above. The LLC resonant circuit may be located on the secondary winding 11-1 side. The LLC resonant circuit may also be located on both the primary winding 10-1 side and the secondary winding 11-1 side.

The second transformer T2 includes a primary winding 10-2, a secondary winding 11-2, and a core 12-2. The primary winding 10-2 includes an excitation inductance 13-2 and a leakage inductance 14-2. The connection relationship between these elements of the second transformer T2 is similar to that of the first transformer T1, so a description is omitted.

The third transformer T3 includes a primary winding 10-3, a secondary winding 11-3, and a core 12-3. The primary winding 10-3 includes an excitation inductance 13-3 and a leakage inductance 14-3. The connection relationship between these elements of the third transformer T3 is similar to that of the first transformer T1, so a description is omitted.

The fourth transformer T4 includes a primary winding 10-4, a secondary winding 11-4, and a core 12-4. The primary winding 10-4 includes an excitation inductance 13-4 and a leakage inductance 14-4. The connection relationship between these elements of the fourth transformer T4 is similar to that of the first transformer T1, so a description is omitted.

The rectifier circuit 3 is a bridge diode. The rectifier circuit 3 includes a first rectifier arm 3-1 to a fifth rectifier arm 3-5.

The first rectifier arm 3-1 includes a high-side diode D1-1 and a low-side diode D1-2. The anode of the diode D1-1 is electrically connected to the cathode of the diode D1-2.

The connection point between the anode of diode D1-1 and the cathode of diode D1-2 is the input terminal of the first rectifier arm 3-1. The cathode of diode D1-1 is one output terminal (high potential side) of the first rectifier arm 3-1. The anode of diode D1-2 is the other output terminal (low potential side) of the first rectifier arm 3-1.

The second rectifier arm 3-2 includes a high-side diode D2-1 and a low-side diode D2-2. The anode of the diode D2-1 is electrically connected to the cathode of the diode D2-2.

The connection point between the anode of diode D2-1 and the cathode of diode D2-2 is the input terminal of the second rectifier arm 3-2. The cathode of diode D2-1 is one output terminal (high potential side) of the second rectifier arm 3-2. The anode of diode D2-2 is the other output terminal (low potential side) of the second rectifier arm 3-2.

The third rectifier arm 3-3 includes a high-side diode D3-1 and a low-side diode D3-2. The anode of the diode D3-1 is electrically connected to the cathode of the diode D3-2.

The connection point between the anode of diode D3-1 and the cathode of diode D3-2 is the input terminal of the third rectifier arm 3-3. The cathode of diode D3-1 is one output terminal (high potential side) of the third rectifier arm 3-3. The anode of diode D3-2 is the other output terminal (low potential side) of the third rectifier arm 3-3.

The fourth rectifier arm 3-4 includes a high-side diode D4-1 and a low-side diode D4-2. The anode of the diode D4-1 is electrically connected to the cathode of the diode D4-2.

The connection point between the anode of diode D4-1 and the cathode of diode D4-2 is the input terminal of the fourth rectifier arm 3-4. The cathode of diode D4-1 is one output terminal (high potential side) of the fourth rectifier arm 3-4. The anode of diode D4-2 is the other output terminal (low potential side) of the fourth rectifier arm 3-4.

The fifth rectifier arm 3-5 includes a high-side diode D5-1 and a low-side diode D5-2. The anode of the diode D5-1 is electrically connected to the cathode of the diode D5-2.

The connection point between the anode of diode D5-1 and the cathode of diode D5-2 is the input terminal of the fifth rectifier arm 3-5. The cathode of diode D5-1 is one output terminal of the fifth rectifier arm 3-5. The anode of diode D5-2 is the other output terminal of the fifth rectifier arm 3-5.

The input terminal of the first rectifier arm 3-1 is electrically connected to one end 11-1a of the secondary winding 11-1 of the first transformer T1. The input terminal of the second rectifier arm 3-2 is electrically connected to the other end 11-1b of the secondary winding 11-1 of the first transformer T1 and one end 11-2a of the secondary winding 11-2 of the second transformer T2. The input terminal of the third rectifier arm 3-3 is electrically connected to the other end 11-2b of the secondary winding 11-2 of the second transformer T2 and one end 11-3a of the secondary winding 11-3 of the third transformer T3.

The input terminal of the fourth rectifier arm 3-4 is electrically connected to the other end 11-3b of the secondary winding 11-3 of the third transformer T3 and one end 11-4a of the secondary winding 11-4 of the fourth transformer T4. The input terminal of the fifth rectifier arm 3-5 is electrically connected to the other end 11-4b of the secondary winding 11-4 of the fourth transformer T4.

That is, one output terminal of each of the first current resonant converter 2-1 to the fourth current resonant converter 2-4 is electrically connected to the other output terminal of the adjacent (one above in FIG. 1) current resonant converter, and is also electrically connected to one of the rectifier arms from the first rectifier arm 3-1 to the fifth rectifier arm 3-5. For example, one output terminal (one end 11-4a of the secondary winding 11-4) of the fourth current resonant converter 2-4 is electrically connected to the other output terminal (the other end 11-3b of the secondary winding 11-3) of the adjacent (one above in FIG. 1) third current resonant converter 2-3, and is also electrically connected to the fourth rectifier arm 3-4. Note that one output terminal (one end 11-1a of the secondary winding 11-1) of the first current resonant converter 2-1 is electrically connected alone to the first rectifier arm 3-1.

In the present disclosure, adjacent current resonant converters are not limited to being adjacent geographically, but may be adjacent electrically (in terms of wiring). For example, in FIG. 1, the first current resonant converter 2-1 and the second current resonant converter 2-2 are not limited to being adjacent geographically. However, from the standpoint of simplifying wiring, reducing wiring length, etc., it is preferable that adjacent current resonant converters are adjacent geographically and adjacent electrically (in terms of wiring).

The cathodes of diodes D1-1 to D5-1 are electrically connected and form one (high potential side) output terminal of rectifier circuit 3. The anodes of diodes D1-2 to D5-2 are electrically connected and form the other (low potential side) output terminal of rectifier circuit 3. The cathodes of diodes D1-1 to D5-1 are electrically connected to one end (high potential side end) of capacitor 5. The anodes of diodes D1-2 to D5-2 are electrically connected to the other end (low potential side end) of capacitor 5.

The rectifier circuit 3 full-wave rectifies the voltage excited in the secondary windings 11-1 to 11-4 and outputs the full-wave rectified voltage to the capacitor 5. The capacitor 5 smoothes the voltage that has been full-wave rectified by the rectifier circuit 3. The voltage of the capacitor 5 is the output voltage Vout.

One end (high potential end) of the capacitor 5 is electrically connected to one end (e.g., the positive electrode of a lithium ion battery) of the load 23. The other end (low potential end) of the capacitor 5 is electrically connected to the other end (e.g., the negative electrode of a lithium ion battery) of the load 23.

The output voltage Vout smoothed by the capacitor 5 is input to the load 23. For example, if the load 23 is a lithium ion battery, the lithium ion battery is charged by the output voltage Vout smoothed by the capacitor 5.

The voltage sensor 6 detects the output voltage Vout and outputs a voltage detection signal _S1 to the control circuit 4. The current sensor 7 detects the output current Iout flowing through the load 23 and outputs a current detection signal _S2 to the control circuit 4.

The output setting unit 24 outputs a voltage setting value signal _S3 of the output voltage Vout and a current setting value signal _S4 of the output current Iout to the control circuit 4.

For example, when the load 23 is a lithium ion battery, the output setting unit 24 outputs to the control circuit 4 a voltage set value signal _S3 and a current set value signal _S4 that change the output voltage Vout from 50 V to 1000 V while maintaining the output current Iout constant at 5 A. That is, the output setting unit 24 changes the signal value of the voltage set value signal _S3 from "50 V" to "1000 V" while maintaining the signal value of the current set value signal _S4 at "5 A". Then, when the output voltage Vout reaches 1000 V, the output setting unit 24 outputs to the control circuit 4 a voltage set value signal _S3 and a current set value signal _S4 that change the output current Iout from 5 A to 0 A while maintaining the output voltage Vout constant at 1000 V. That is, the output setting section 24 changes the signal value of the current setting value signal _S4 from "5 A" to "0 A" while maintaining the signal value of the voltage setting value signal _S3 at "1000 V".

The voltage setpoint signal _S3 and the current setpoint signal _S4 are illustrated as signals conforming to CHAdeMO™, but the present disclosure is not limited thereto.

The control circuit 4 switches the mode (the number of operating converters) based on the voltage detection signal _S1 input from the voltage sensor 6, the current detection signal _S2 input from the current sensor 7, and the voltage set value signal _S3 and current set value signal _S4 input from the output setting unit 24. Then, the control circuit 4 outputs switching control signals to the first full bridge circuit FB1 to the fourth full bridge circuit FB4 so that the output voltage Vout and the output current Iout each become the set value.

Figure 3 is a diagram showing the modes of the power supply device of the first embodiment. The power supply device 1 has four modes, from the first mode to the fourth mode.

As shown in the first column 51 of Table 50, in the first mode, all of the first current resonant converter 2-1 to the fourth current resonant converter 2-4 are on (operating). The first mode is the mode with the highest output.

As shown in the second column 52 of Table 50, in the second mode, the first current resonant converter 2-1 to the third current resonant converter 2-3 are turned on, and the fourth current resonant converter 2-4 is turned off (stopped). The second mode is the mode with the second largest output.

As shown in the third column 53 of Table 50, in the third mode, the first current resonant converter 2-1 and the second current resonant converter 2-2 are turned on, and the third current resonant converter 2-3 and the fourth current resonant converter 2-4 are turned off. The third mode is the mode with the third largest output.

As shown in the fourth column 54 of Table 50, in the fourth mode, the first current resonant converter 2-1 is turned on, and the second current resonant converter 2-2 to the fourth current resonant converter 2-4 are turned off. The fourth mode is the mode with the smallest output.

Figure 4 is a diagram showing the direction of the voltage (current) on the secondary winding side of the power supply device of the first embodiment. In detail, Figure 4 is a diagram showing the direction of the voltage (current) on the secondary winding side of the first transformer T1 and the second transformer T2 when a positive voltage 61 is applied to the primary winding 10-1 of the first transformer T1 and a positive voltage 62 is applied to the primary winding 10-2 of the second transformer T2.

In this case, a voltage is generated in the primary winding 10-1 of the first transformer T1 in the direction indicated by the arrow 63, and a voltage is generated in the primary winding 10-2 of the second transformer T2 in the direction indicated by the arrow 64. Therefore, on the secondary winding side of the first transformer T1 and the second transformer T2, as indicated by the arrow 65, a voltage is generated on the path of the diode D1-2 → one end 11-1a of the secondary winding 11-1 of the first transformer T1 → the other end 11-1b of the secondary winding 11-1 of the first transformer T1 → one end 11-2a of the secondary winding 11-2 of the second transformer T2 → the other end 11-2b of the secondary winding 11-2 of the second transformer T2 → diode D3-1.

In other words, if the output polarity of one current resonant converter is the same as that of the adjacent current resonant converter, the secondary windings are connected in series (voltage addition).

The control circuit 4 can increase the voltage while maintaining the current by controlling the output polarity of one current resonant converter to be the same as that of the adjacent current resonant converter.

Comparative Example
In the comparative example, when the power supply is turned on, the control circuit 4 simultaneously starts the operation of all of the first current resonant converter 2-1 to the fourth current resonant converter 2-4.

Figure 5 shows the output voltage and output current of a power supply device of a comparative example. Waveform 71 is the waveform of the output current Iout. Waveform 72 is the waveform of the output voltage Vout.

At timing _t0 , when all of the first current resonant converter 2-1 to the fourth current resonant converter 2-4 start operating simultaneously, the output current Iout becomes a large inrush current _I0 , as shown by a waveform 71. The output current Iout decreases as time passes and eventually converges to a current _I1 . Also, as shown by a waveform 72, the output voltage Vout increases as time passes and eventually converges to a voltage _V0 .

When such a large inrush current _I0 flows, the burden of the peak current is large on the DC power supply 21, the capacitor 22, the diodes D1-1 to D5-2, the capacitor 5, the load 23, etc. In addition, since the capacitor 22, the diodes D1-1 to D5-2, and the capacitor 5 must be made large components, the device becomes larger and more expensive.

(First embodiment)
FIG. 6 is a flow chart showing the operation of the control circuit of the power supply device according to the first embodiment when the power supply is turned on.

Referring to FIG. 6, in step S10, the control circuit 4 starts the operation of the first current resonant converter 2-1. In other words, the control circuit 4 operates the power supply device 1 in the fourth mode.

In step S12, the control circuit 4 determines whether or not a predetermined threshold time has elapsed. If the control circuit 4 determines that the threshold time has not elapsed (No in step S12), it waits in step S12. If the control circuit 4 determines that the threshold time has elapsed (Yes in step S12), it advances the process to step S14.

In step S14, the control circuit 4 starts the operation of the second current resonant converter 2-2. In other words, the control circuit 4 operates the power supply device 1 in the third mode.

In step S16, the control circuit 4 determines whether the threshold time has elapsed. If the control circuit 4 determines that the threshold time has not elapsed (No in step S16), it waits in step S16. If the control circuit 4 determines that the threshold time has elapsed (Yes in step S16), it advances the process to step S18.

In step S18, the control circuit 4 starts the operation of the third current resonant converter 2-3. In other words, the control circuit 4 operates the power supply device 1 in the second mode.

In step S20, the control circuit 4 determines whether the threshold time has elapsed. If the control circuit 4 determines that the threshold time has not elapsed (No in step S20), it waits in step S20. If the control circuit 4 determines that the threshold time has elapsed (Yes in step S20), it advances the process to step S22.

In step S22, the control circuit 4 starts the operation of the fourth current resonant converter 2-4. In other words, the control circuit 4 operates the power supply device 1 in the first mode. After that, the control circuit 4 ends the power-on processing.

In this way, the control circuit 4 of the power supply device 1 of the first embodiment starts the operation of multiple current resonant converters one by one.

Figure 7 shows the output voltage and output current of the power supply device of the first embodiment. Waveform 73 is the waveform of the output current Iout. Waveform 74 is the waveform of the output voltage Vout.

At timing _t10 , when the first current resonant converter 2-1 starts operating, the output current Iout becomes a small inrush current _I10 as shown by a waveform 73. Here, _I10 < _I0 . The output current Iout decreases as time passes and eventually converges to a current _I11 . Also, as shown by a waveform 74, the output voltage Vout increases as time passes.

When the second current resonant converter 2-2 starts operating at timing _t11 after a threshold time has elapsed since timing _t10 , the output current Iout becomes a small inrush current as shown by a waveform 73. The output current Iout decreases over time and eventually converges. Also, as shown by a waveform 74, the output voltage Vout increases over time.

When the third current resonant converter 2-3 starts operating at timing _t12 after the threshold time has elapsed since timing _t11 , the output current Iout becomes a small inrush current as shown by a waveform 73. The output current Iout decreases over time and eventually converges. Also, the output voltage Vout increases over time as shown by a waveform 74.

When the fourth current resonant converter 2-4 starts operating at timing _t13 after the threshold time has elapsed since timing _t12 , the output current Iout becomes a small inrush current as shown by a waveform 73. The output current Iout decreases over time and eventually converges. Also, as shown by a waveform 74, the output voltage Vout increases over time.

As described above, the power supply device 1 of the first embodiment can make the inrush current _I10 smaller than the inrush current _I0 , compared to the comparative example. This allows the power supply device 1 to reduce the burden of peak currents on the DC power supply 21, the capacitor 22, the diodes D1-1 to D5-2, the capacitor 5, the load 23, etc. Furthermore, the power supply device 1 does not require the capacitor 22, the diodes D1-1 to D5-2, and the capacitor 5 to be large components, making it possible to reduce the size and cost of the device.

Second Embodiment
The circuit configuration of the power supply device of the second embodiment is similar to the circuit configuration of the power supply device 1 of the first embodiment, and therefore illustration and description thereof will be omitted.

In the first embodiment, the control circuit 4 starts the operation of the next current resonant converter when a threshold time has elapsed since the start of operation of one current resonant converter.

On the other hand, in the second embodiment, the control circuit 4 starts operation of one current resonant converter, and when the output current Iout becomes equal to or lower than a predetermined threshold current, starts operation of the next current resonant converter.

In this case, the control circuit 4 only needs to determine whether the output current Iout is equal to or lower than the threshold current in each of steps S12, S16, and S20 of the flowchart in FIG. 6 described in the first embodiment.

The power supply device of the second embodiment has the same effects as the first embodiment.

Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are within the scope of the invention and its equivalents as set forth in the claims, as well as the scope and gist of the invention.

REFERENCE SIGNS LIST 1 Power supply device 2-1 First current resonant converter 2-2 Second current resonant converter 2-3 Third current resonant converter 2-4 Fourth current resonant converter 3 Rectifier circuit 4 Control circuit 5, 22 Capacitor 6 Voltage sensor 7 Current sensor 21 DC power supply 23 Load 24 Output setting unit FB1 First full bridge circuit FB2 Second full bridge circuit FB3 Third full bridge circuit FB4 Fourth full bridge circuit T1 First transformer T2 Second transformer T3 Third transformer T4 Fourth transformer

Claims (4)

A plurality of converters;
a rectifier circuit including a plurality of rectifier arms that rectify output voltages of the plurality of converters and output the rectified output voltages to a single load;
A control circuit for controlling the plurality of converters;
Equipped with
one output terminal of each of the plurality of converters is electrically connected to the other output terminal of each adjacent converter and is electrically connected to one rectifier arm of the plurality of rectifier arms;
The control circuit includes:
At a first timing, a first converter among the plurality of converters is started to operate, and an output voltage of the first converter is output to the one load;
At a second timing when the output current of the first converter becomes equal to or lower than a predetermined threshold current after the first timing, a second converter electrically adjacent to the first converter is started to operate with the same output polarity as the first converter, thereby connecting the output of the first converter and the output of the second converter in series, and outputting a voltage which is the sum of the output voltage of the first converter and the output voltage of the second converter to the one load.
A power supply device comprising: The control circuit includes:
at a third timing when the output currents of the first converter and the second converter become equal to or lower than the threshold current after the second timing, a third converter electrically adjacent to the second converter is started to operate with the same output polarity as the first converter and the second converter, thereby connecting the outputs of the first converter to the third converter in series and outputting a voltage that is the sum of the output voltages of the first converter to the third converter to the single load;
At a fourth timing when the output current from the first converter to the third converter becomes equal to or less than the threshold current after the third timing, a fourth converter electrically adjacent to the third converter is started to operate with the same output polarity as the first converter to the third converter, thereby connecting the outputs from the first converter to the fourth converter in series and outputting a voltage that is the sum of the output voltages from the first converter to the fourth converter to the single load;
The inrush current of the output current output to the one load is suppressed compared to a case where all of the first converter to the fourth converter are started to operate simultaneously.
2. The power supply device according to claim 1 . Each of the plurality of converters is a current resonant converter.
3. The power supply device according to claim 1 or 2 . A control method for a power supply device comprising: a rectifier circuit including a plurality of converters; a plurality of rectifier arms that rectify output voltages of the plurality of converters and output the rectified output voltages to a single load; and a control circuit that controls the plurality of converters, wherein one output terminal of each of the plurality of converters is electrically connected to the other output terminal of an adjacent converter and is also electrically connected to one rectifier arm of the plurality of rectifier arms,
At a first timing, a first converter among the plurality of converters is started to operate, and an output voltage of the first converter is output to the one load;
At a second timing when the output current of the first converter becomes equal to or lower than a predetermined threshold current after the first timing, a second converter electrically adjacent to the first converter is started to operate with the same output polarity as the first converter, thereby connecting the output of the first converter and the output of the second converter in series, and outputting a voltage which is the sum of the output voltage of the first converter and the output voltage of the second converter to the one load.
23. A method for controlling a power supply device comprising:

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