Multi-phase converter

Abstract

To provide a multi-phase converter having an EMC filter that is affected by external magnetic flux, and reduces influence of leakage magnetic flux of a reactor on the EMC filter.SOLUTION: A multiphase converter includes at least five voltage converter circuits connected in parallel, each having a reactor, and an EMC filter connected to the plurality of voltage converter circuits. When a required output is equal to or less than the total maximum output of the two voltage converter circuits, the multi-phase converter stops the voltage converter circuit including the reactor disposed closest to the EMC filter, and sequentially operates a plurality of sets of the remaining voltage converter circuits with a pair of the voltage converter circuits in which the reactors are adjacent to each other as one set.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The technology disclosed in this specification relates to a multi-phase converter in which a plurality of voltage converter circuits are connected in parallel. [Background technology]

[0002] The voltage converter circuit includes a reactor. Because magnetic flux leaks from the reactor, care must be taken when placing electrical components (especially electrical components that are affected by the magnetic flux) around the reactor. Patent Document 1 discloses a technology for reducing the effect of leakage magnetic flux from the reactor on a current sensor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-145486 Summary of the Invention [Problem to be solved by the invention]

[0004] A multi-phase converter includes multiple voltage converter circuits, each of which includes a reactor. Because a multi-phase converter includes multiple reactors, particular attention must be paid to their influence on other electrical components. This specification relates to a multi-phase converter including an EMC filter that is affected by external magnetic flux, and provides a technology for reducing the influence of leakage magnetic flux from the reactor on the EMC filter. [Means for solving the problem]

[0005] The multi-phase converter disclosed in this specification includes at least five voltage converter circuits connected in parallel and an EMC filter connected to the voltage converter circuits. Each voltage converter circuit has a reactor. In the multi-phase converter disclosed in this specification, when the output required of the multi-phase converter is less than or equal to the total maximum output of two voltage converter circuits, the voltage converter circuit including the reactor located closest to the EMC filter is stopped, and the remaining voltage converter circuits are operated sequentially, with each pair of voltage converter circuits having adjacent reactors as one set. Note that an EMC (Electro Magnetic Compatibility) filter is a type of noise filter that suppresses electromagnetic interference, and its filtering performance is affected by external magnetic flux.

[0006] In the multi-phase converter disclosed in this specification, if the required output can be met by the combined output of two voltage converter circuits, (N-2) of the N voltage converter circuits are deactivated. N is an integer greater than or equal to 5. One of the voltage converter circuits to be deactivated is the voltage converter circuit with the reactor located closest to the EMC filter. Since the voltage converter circuit closest to the EMC filter remains deactivated, no leakage magnetic flux is emitted from the reactor of that voltage converter circuit, thereby not affecting the EMC filter. Of the remaining (N-3) voltage converter circuits, only the voltage converter circuit pair with adjacent reactors operates, while the other voltage converter circuits do not operate, thereby preventing leakage magnetic flux from spreading over a wide area. The multi-phase converter disclosed in this specification can reduce the impact of reactor leakage magnetic flux on the EMC filter. Furthermore, since multiple pairs of voltage converter circuits are operated in sequence, no load is concentrated on a specific voltage converter circuit. Note that "operating a plurality of paired voltage converter circuits sequentially" is another way of saying "operating a plurality of paired voltage converter circuits in turn." This can also be expressed as "operating a plurality of paired voltage converter circuits in rotation."

[0007] Details and further improvements of the technology disclosed in this specification are described in the following "Description of Embodiments of the Invention." [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a circuit diagram of a multi-phase converter according to an embodiment. [Figure 2] FIG. 2 is a plan view of the power supply circuit multi-phase converter. [Figure 3] 10 is an example of a map for determining the number of voltage converter circuits to be operated. DETAILED DESCRIPTION OF THE INVENTION

[0009] A multi-phase converter 2 according to an embodiment will be described with reference to the drawings. FIG. 1 shows a circuit diagram of the multi-phase converter 2. The multi-phase converter 2 is a boost converter that boosts the voltage input to its input terminals (input terminal positive terminal 2a and input terminal negative terminal 2b) and outputs it from its output terminals (output terminal positive terminal 2c and output terminal negative terminal 2d). The multi-phase converter 2 includes five voltage converter circuits 10a-10e. The five voltage converter circuits 10a-10e are connected in parallel between the input terminals and output terminals of the multi-phase converter 2.

[0010] The five voltage converter circuits 10a-10e have the same circuit structure. Therefore, in Fig. 1, only the specific circuit of the voltage converter circuit 10a is shown, and the circuits of the other voltage converter circuits 10b-10e are not shown. However, only the reactors 12a-12e included in each of the five voltage converter circuits 10a-10e are shown.

[0011] The voltage converter circuit 10a will be described. The voltage converter circuit 10a is a boost converter circuit. The voltage converter circuit 10a includes a reactor 12a, a switching element 11a, and diodes 13a and 14a. One end of the reactor 12a is connected to the input terminal positive electrode 2a of the multi-phase converter 2, and the other end is connected to the anode of the diode 13a. The cathode of the diode 13a is connected to the output terminal positive electrode 2c of the multi-phase converter 2. The input terminal negative electrode 2b and the output terminal negative electrode 2d of the multi-phase converter 2 are directly connected to the ground G.

[0012] The switching element 11a is connected between the other end of the reactor 12a and ground G. The diode 14a is connected in antiparallel to the switching element 11a. In other words, the anode of the diode 14a is connected to ground G, and the cathode is connected to the other end of the reactor 12a.

[0013] When the switching element 11a is appropriately turned on and off, the voltage applied to the input terminal is boosted and output from the output terminal. The structure and operation of the voltage converter circuit 10a of Figure 1 are well known.

[0014] Voltage converter circuits 10b-10e are also boost converter circuits. The configurations of voltage converter circuits 10b-10e are the same as those of voltage converter circuit 10a, so illustrations and explanations of the circuits are omitted. Voltage converter circuit 10a has reactor 12a, and voltage converter circuit 10b (10c-10e) has reactor 12b (12c-12e).

[0015] An EMC (Electro Magnetic Compatibility) filter 3 is connected between the voltage converter circuits 10a-10e and the output terminal positive electrode 2c of the multi-phase converter 2. In addition, an output smoothing capacitor 4 is connected between the output terminal positive electrode 2c of the multi-phase converter 2 and the output terminal negative electrode 2d (ground G).

[0016] An EMC filter is a type of noise filter that suppresses electromagnetic interference. EMC filter 3 suppresses differential mode noise and common mode noise that occur in the output paths of voltage converter circuits 10a-10e. The structure and function of EMC filters are well known, so a detailed explanation of the structure will be omitted, but it is known that the filtering performance of EMC filters is affected when they receive magnetic flux from outside.

[0017] Figure 2 shows a plan view of the multi-phase converter 2. Figure 2 shows the state in which the top cover of the housing 9 of the multi-phase converter 2 is open. In other words, Figure 2 shows the layout of the components of the multi-phase converter 2. Five reactors 12a-12e are arranged in a row inside the housing 9. The EMC filter 3 is located above the reactor 12e on the far right, and the circuit board 5 is located to the left of the EMC filter 3. The switching elements and diodes of all the voltage converter circuits are mounted on the circuit board 5. The output smoothing capacitor 4 is located on the circuit board 5. The terminal of the input terminal negative electrode 2b is located below the reactor 12c, and the input terminal positive electrode 2a is located above the EMC filter 3. The output terminal positive electrode 2c is located to the right of the EMC filter 3, and the output terminal negative electrode 2d is located below that. All components are located at the same height inside the housing 9. In other words, the components shown in Figure 2 are located on the same plane parallel to the plane of the drawing.

[0018] The dashed line in Figure 2 represents the leakage magnetic flux of the reactor 12e. When the voltage converter circuit 10e is operating, current flows through the reactor 12e, resulting in leakage magnetic flux in the reactor 12e. As shown in Figure 2, the leakage magnetic flux of the reactor 12e interlinks with the EMC filter 3. The filtering performance of the EMC filter 3 is affected by external magnetic flux. Therefore, it is desirable to prevent the leakage magnetic flux of the reactor from reaching the EMC filter 3 as much as possible. Therefore, if the required output power can be met by the total output power of the four voltage converter circuits, the multi-phase converter 2 disables the voltage converter circuit 10e that includes the reactor 12e closest to the EMC filter 3. The multi-phase converter 2 then realizes the required output power using the remaining voltage converter circuits 10a-10d. The leakage magnetic flux of reactor 12d adjacent to reactor 12e also links with EMC filter 3, but the amount of leakage magnetic flux generated by reactor 12d that links with EMC filter 3 is much smaller than the amount of leakage magnetic flux of reactor 12e that links with EMC filter 3, and the influence of the leakage magnetic flux of reactor 12d on EMC filter 3 is small.

[0019] Figure 3 shows a graph with the required output current (required output current) of multi-phase converter 2 plotted on the vertical axis and the required output voltage (required output voltage) plotted on the vertical axis. The numbers in the graph indicate the number of voltage converter circuits to be operated. In range A, where both the required output current and required output voltage are high (i.e., the range where the required output power is high), five voltage converter circuits (all voltage converter circuits) must be operated to achieve the required output power. In range B, where the required output voltage is high but the required output current is somewhat low (i.e., the range where the required output power is somewhat low), four voltage converter circuits must be operated. Furthermore, in range C, where the required output current is low, three voltage converter circuits must be operated. In range D, where both the required output voltage and required output current are low, two voltage converter circuits must be operated. Note that Figure 3 shows the case where a fuel cell is connected to the input terminal of multi-phase converter 2. In this case, range E, where the required output current is high and the required output voltage is low, is outside the range where multi-phase converter 2 operates. This is because fuel cells, due to their characteristics, cannot output a high current at a low voltage.

[0020] When the required output power cannot be achieved without operating all five voltage converter circuits 10a-10e, the multi-phase converter 2 operates the five voltage converter circuits 10a-10e. When the required output power is equal to or less than the total maximum output power of the four voltage converter circuits (i.e., in the case of ranges B, C, and D in FIG. 3), the multi-phase converter 2 suspends operation of the voltage converter circuit 10e that includes the reactor 12e closest to the EMC filter 3. The multi-phase converter 2 then operates at least one of the remaining voltage converter circuits 10a-10d to achieve the required output power. Note that the "total maximum output power of the N voltage converter circuits" means "the sum of the respective maximum output powers of the N voltage converter circuits."

[0021] When the required output is less than the total maximum output power of the four voltage converter circuits and exceeds the total maximum output power of the three voltage converter circuits (range B in Figure 3), the multi-phase converter 2 stops the voltage converter circuit 10e, which includes the reactor 12e located closest to the EMC filter 3, and operates the remaining four voltage converter circuits 10a-10d.

[0022] When the required output is less than the total maximum output power of the three voltage converter circuits but more than the total maximum output power of two voltage converter circuits (range C in Figure 3), the multi-phase converter 2 stops the voltage converter circuit 10e, which includes the reactor 12e located closest to the EMC filter 3, and one other voltage converter circuit, and operates the remaining three voltage converter circuits. At this time, the multi-phase converter 2 sequentially stops one of the four voltage converter circuits 10a-10d, excluding the voltage converter circuit 10e, and operates the remaining three voltage converter circuits. By sequentially switching the voltage converter circuits to be stopped other than the voltage converter circuit 10e, the load on the voltage converter circuits can be leveled. The voltage converter circuit 10e, which includes the reactor 12e located closest to the EMC filter 3, is always in a stopped state, does not generate leakage magnetic flux, and does not affect the EMC filter 3.

[0023] When the required output is equal to or less than the total maximum output power of the two voltage converter circuits (range D in FIG. 3 ), the multi-phase converter 2 stops voltage converter circuit 10e, which includes reactor 12e located closest to EMC filter 3, and two other voltage converter circuits, and operates the remaining two voltage converter circuits. At this time, the multi-phase converter 2 sequentially operates the remaining voltage converter circuits, with each set consisting of a pair of voltage converter circuits with adjacent reactors. Specifically, the multi-phase converter 2 stops voltage converter circuit 10e. The multi-phase converter 2 defines voltage converter circuits 10a and 10b, which include adjacent reactors 12a and 12b, respectively, as a first pair of voltage converter circuits, and defines voltage converter circuits 10c and 10d, which include other adjacent reactors 12c and 12d, respectively, as a second pair of voltage converter circuits. The multi-phase converter 2 alternately operates the first pair of voltage converter circuits and the second pair of converter circuits while keeping the voltage converter circuit 10e stopped.

[0024] As a result of the above processing, when the required output power is equal to or less than the total maximum output of the four voltage converter circuits, the voltage converter circuit 10e closest to the EMC filter 3 remains stopped. Therefore, the reactor 12e of the voltage converter circuit 10e does not generate leakage magnetic flux and does not affect the EMC filter 3. Of the remaining four voltage converter circuits, the voltage converter circuit pair with adjacent reactors operates, and the other voltage converter circuits do not operate, preventing leakage magnetic flux from spreading over a wide area. Note that a controller (not shown) included in the multi-phase converter 2 controls each voltage converter circuit and switches which voltage converter circuit to operate.

[0025] The multi-phase converter 2 of the embodiment includes five voltage converter circuits. The technology disclosed in this specification can be applied to a multi-phase converter including N (N>4) voltage converter circuits. The configuration when the technology disclosed in this specification is applied to a multi-phase converter including N voltage converter circuits is described below.

[0026] N voltage converter circuits are connected in parallel between the input and output terminals of the multi-phase converter. An EMC filter is connected between the N voltage converter circuits and the positive output terminal of the multi-phase converter. The N voltage converter circuits have the same circuit configuration, and each voltage converter circuit has a reactor. The N reactors are arranged in a row, and an EMC filter is placed near the reactor at the end of the row.

[0027] When the output required of the multi-phase converter is equal to or less than the total maximum output of the two voltage converter circuits, the voltage converter circuit including the reactor located closest to the EMC filter is stopped, and the remaining voltage converter circuits are operated in sequence as multiple sets of voltage converter circuits, with a pair of voltage converter circuits whose reactors are adjacent to each other forming one set.

[0028] Specifically, (N-1) voltage converter circuits are divided into sets of pairs of voltage converter circuits each having adjacent reactors. When N=6, two sets of paired voltage converter circuits are also defined. When N=5, two sets of paired voltage converter circuits are defined. When N=7, three sets of paired voltage converter circuits are defined. The multi-phase converter divides the (N-1) voltage converter circuits into sets of paired voltage converter circuits each having adjacent reactors. The multi-phase converter then operates the multiple paired voltage converter circuits sequentially. In other words, the multiple paired voltage converter circuits are operated in an alternating sequence. This prevents leakage flux from the reactors from reaching the EMC filter and distributes the load on the remaining reactors (remaining voltage converter circuits). In other words, it is possible to avoid concentrating the load on a specific reactor (specific voltage converter circuit).

[0029] The following points should be noted regarding the technology described in the embodiments: The multiple voltage converter circuits provided in the multi-phase converter may be either step-up converter circuits or step-down converter circuits, as long as they include reactors for voltage conversion.

[0030] The multi-phase converter circuit may include at least five voltage converter circuits, and may include six or more voltage converter circuits.

[0031] When a multi-phase converter includes N voltage converter circuits and the required output power for the multi-phase converter is equal to or less than the total maximum output power of the (NM) (N>M) voltage converter circuits, the multi-phase converter may stop the voltage converter circuits corresponding to the M reactors closest to the EMC filter, and cover the required output power with the remaining (NM) voltage converter circuits.

[0032] Although specific examples of the present invention have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and variations of the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical utility alone or in various combinations, and are not limited to the combinations described in the claims at the time of filing. Furthermore, the technology exemplified in this specification or drawings can achieve multiple objectives simultaneously, and achieving one of these objectives alone is technically useful. [Explanation of symbols]

[0033] 2: Multiphase converter 3: EMC filter 4: Output smoothing capacitor 5: Circuit board 9: Housing 10a-10e: Voltage converter circuit 11a: Switching element 12a-12e: Reactor 13a, 13b: Diode

Claims

[Claim 1] 1. A multi-phase converter, comprising: at least five voltage converter circuits connected in parallel, each voltage converter circuit having a reactor; an EMC filter connected to a plurality of the voltage converter circuits; It is equipped with a multi-phase converter that, when an output required of the multi-phase converter is equal to or less than a total maximum output of two of the voltage converter circuits, stops the voltage converter circuit including the reactor that is arranged closest to the EMC filter, and sequentially operates a plurality of sets of the remaining voltage converter circuits, with a pair of the voltage converter circuits having adjacent reactors as one set.

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