Power converter and method for adjusting the same

Abstract

To reduce variations in a power converter having a plurality of power conversion units.SOLUTION: A power converter includes power conversion units of a first group and a second group connected in parallel. The power converter includes a delay time adjustment unit that adjusts turn-on timing or turn-off timing of a switching element. The delay time adjustment unit gives an alternating delay time difference command for alternately and repeatedly delaying the turn-on timing or the turn-off timing of the switching element of the first group and the switching element of the second group, estimates delay time variations of turn-on or turn-off based on a relation between an alternating delay time difference of the alternating delay time difference command and temperature change in the vicinity of the switching element of one group, and sets the turn-on timing or the turn-off timing of the switching element so as to compensate for influence of the delay time variations using a non-alternating delay time difference command based on the delay time variations.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power conversion device. [Background technology]

[0002] To reduce global energy consumption, there is a demand for high efficiency in power conversion devices that use semiconductor switching elements, such as inverters that drive motors, converters that supply power to inverters, charge / discharge devices for electric vehicles, etc. These power conversion devices are sometimes configured with multiple power conversion units equipped with switching elements connected in parallel.

[0003] In a plurality of power conversion units connected in parallel, if variations in the switching timing occur due to variations in the characteristics of the switching elements or signal delays in the gate drive circuit, the loss in the switching elements may be biased towards one of the elements.

[0004] Furthermore, to improve the efficiency of power conversion equipment, it is necessary to reduce the energy loss in switching elements. Losses in switching elements include conduction loss that occurs when current flows through the switching element, and switching loss that occurs when the switching element is switched between the on and off states.

[0005] The following Patent Documents 1 and 2 describe techniques for reducing switching loss in parallel-connected power conversion devices or techniques for equalizing loss in switching elements.

[0006] Patent Document 1 discloses a power conversion method that can reduce switching loss by alternately and repeatedly delaying the turn-on timing between units in parallel-connected power conversion devices.

[0007] Patent Document 2 discloses a technology that includes a temperature measurement circuit that measures the temperature of a plurality of switching elements, and that equalizes the losses of the switching elements by changing the switching timing of the switching elements so as to equalize the temperatures of the switching elements. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2022-191597 [Patent Document 2] Patent Publication No. 2021-185725 Summary of the Invention [Problem to be solved by the invention]

[0009] In the technology described in Patent Document 1, when the switching timing of the elements in response to a turn-on command varies between units due to characteristic variations in the switching elements or signal delays in the gate drive circuit, even if a command is given to repeatedly delay the turn-on commands between units, the turn-on of the switching elements does not alternate between units, and there is a risk that the switching loss of the switching elements cannot be sufficiently reduced.

[0010] The technology described in Patent Document 2 may not be able to equalize the temperatures of the switching elements when there is variation in the characteristics of the multiple temperature measurement circuits. Also, when the relationship between the loss of the switching elements and the temperatures detected by the temperature measurement circuits is uneven among multiple units due to the influence of the thermal resistance of the cooler, there is a risk that the temperatures of the switching elements may not be equalized.

[0011] The present invention has been made in view of the above circumstances, and aims to reduce variations in a power converter having a plurality of power conversion units. [Means for solving the problem]

[0012] An example of how to solve the above problem is as follows. A power conversion device including a plurality of power conversion units connected in parallel via inductance components, each of the plurality of power conversion units belongs to a first group or a second group; Each of the power conversion units includes a switching element, the power conversion device includes a delay time adjustment unit that adjusts the turn-on timing or the turn-off timing of the switching element; the delay time adjustment unit provides an alternating delay time difference command that alternately and repeatedly delays the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the first group and the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the second group, estimating a turn-on or turn-off delay time variation of one of the switching elements based on a relationship between the alternating delay time difference of the alternating delay time difference command and a temperature change in the vicinity of the switching element of the one group; The delay time adjustment unit sets the turn-on timing or turn-off timing of the switching element so as to compensate for the effect of the turn-on or turn-off delay time variation using a non-alternating delay time difference command based on the turn-on or turn-off delay time variation. [Effects of the Invention]

[0013] According to the present invention, it is possible to appropriately detect variations in turn-on delay times of switching elements in a plurality of power conversion units connected in parallel. Further means and advantages of the present invention will become apparent throughout the entire specification below. [Brief explanation of the drawings]

[0014] [Figure 1] 1 is a circuit configuration diagram of a power conversion device according to an embodiment of the present invention. [Figure 2A]1 is a schematic diagram of an operating mode for reducing turn-on losses, where no alternating delay is applied, tD=0. [Figure 2B] 1 is a schematic diagram of an operating mode for reducing turn-on losses when applying an alternating delay, tD>0. [Figure 3A] 10 shows an example of the turn-on delay times of the switching elements Q1 and Q2, where tON1=tON2 and ΔtON12=0 ns. [Figure 3B] 10 is a schematic diagram showing the relationship between the alternating delay time difference command tD, the turn-on delay time variation ΔtON12, and the actual turn-on sequence, in the case of tD=0. [Figure 3C] 10 is a schematic diagram showing the relationship between the alternating delay time difference command tD, the turn-on delay time variation ΔtON12, and the actual turn-on sequence, in the case of tD>0. [Figure 4A] This is an example of the turn-on delay times of the switching elements Q1 and Q2, where tON1>tON2 and ΔtON12>0 ns. [Figure 4B] 10 is a schematic diagram showing the relationship between the alternating delay time difference command tD, the turn-on delay time variation ΔtON12, and the actual turn-on sequence, in the case of tD=0. [Figure 4C] 10 is a schematic diagram showing the relationship between the alternating delay time difference command tD, the turn-on delay time variation ΔtON12, and the actual turn-on sequence, in the case of tD>0. [Figure 5] FIG. 1 is a flowchart according to an embodiment of the present invention. [Figure 6A] This is an example of diagnosis when the turn-on delay time variation of the element ΔtON12=0. [Figure 6B] This is an example when N=1 and tD_1=0. [Figure 6C] This is an example when N=2 and tD_2=△tstep. [Figure 6D] This is an example when N=3 and tD_3=2×△tstep. [Figure 7A]This is an example of diagnosis when the turn-on delay time variation of the element is ΔtON12=2×Δtstep. [Figure 7B] This is an example when N=1 and tD_1=0. [Figure 7C] This is an example when N=2 and tD_2=△tstep. [Figure 7D] This is an example when N=3 and tD_3=2×△tstep. [Figure 7E] This is an example when N=4 and tD_3=3×△tstep. [Figure 7F] This is an example when N=5 and tD_3=4×△tstep. [Figure 8A] This is an example of diagnosis when the turn-on delay time variation of the element is ΔtON12=0.5×Δtstep. [Figure 8B] This is an example when N=1 and tD_1=0. [Figure 8C] This is an example when N=2 and tD_2=△tstep. [Figure 8D] This is an example when N=3 and tD_3=2×△tstep. [Figure 9A] This is an example of diagnosis when the turn-on delay time variation of the element is ΔtON12=2.5×Δtstep. [Figure 9B] This is an example when N=1 and tD_1=0. [Figure 9C] This is an example when N=2 and tD_2=△tstep. [Figure 9D] This is an example when N=3 and tD_3=2×△tstep. [Figure 9E] This is an example when N=4 and tD_3=3×△tstep. [Figure 9F] This is an example when N=5 and tD_3=4×△tstep. [Figure 10A] 10 is a diagram showing a method for determining the sign of ΔtON12 when ΔtON12>0 ns. [Figure 10B] FIG. [Figure 10C] This is a diagram for direction 1 of non-alternating delay. [Figure 10D]This is a diagram for non-alternating delay direction 2. [Figure 11A] 10 is a diagram showing a delay time difference ΔtON12 when ΔtON12>0 ns. [Figure 11B] FIG. [Figure 11C] FIG. [Figure 12A] 10 is a diagram showing a delay time difference ΔtON12 when ΔtON12>0 ns. [Figure 12B] FIG. [Figure 12C] FIG. [Figure 13] 1 is an explanatory diagram of an example of a power conversion device of the present invention. [Figure 14] 1 is an explanatory diagram of an example of a power conversion device of the present invention. [Figure 15] 1 is an explanatory diagram of an example of a power conversion device of the present invention. [Figure 16] 1 is an explanatory diagram of an example of a power conversion device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings as needed. Note that the triangle (△) in the specification is intended to represent the Greek letter delta. [Example]

[0016] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments are examples for explaining the present invention, and appropriate omissions and simplifications have been made for clarity of explanation. Furthermore, not all of the elements and combinations thereof described in the embodiments are necessarily essential to the solution of the invention. When there are multiple components having the same or similar functions, they may be described using the same reference numeral with different subscripts. Furthermore, when it is not necessary to distinguish between these multiple components, the subscripts may be omitted in the description.

[0017] FIG. 1 is a diagram showing an example of a circuit configuration diagram of a power conversion device 100 according to the first embodiment. 1, the power conversion device 100 includes power conversion units 10 and 20, current sensors 11 and 21, a voltage sensor 3, inductors L0, L11, and L21, switching elements Q1 and Q2, diodes D11 and D21, a capacitor C0, and a control unit 30. The control unit 30 includes a delay time adjustment unit 31, a turn-on delay time variation estimation unit 32, and a storage unit 33. When, for example, turn-off is used as the time or timing to be adjusted, 32 is interpreted as a turn-off delay time variation estimation unit. When both turn-on and turn-off are used, 32 is interpreted as a turn-off and turn-off delay time variation estimation unit. In this specification, 32 is used in this broad sense.

[0018] The adjustment by delay time adjustment unit 31 includes adjustment of the turn-on time, adjustment of the turn-off time, or adjustment of both. In the following explanation, in order to avoid repeated explanations, an example of adjustment of the turn-on time or turn-on timing will be described. However, within the scope of application of the same technical concept, adjustment of the turn-off time or turn-off timing, or adjustment of both the turn-on time and turn-off time, or adjustment of both the turn-on timing and turn-off timing, is also included in the scope of the technical concept disclosed in the present invention.

[0019] The illustrated power conversion device 100 is connected between a DC power supply 1 and a load 2 (for example, a motor), receives power from the DC power supply 1, and supplies DC power to the load 2.

[0020] This power conversion device 100 includes a power conversion unit 10, a power conversion unit 20, inductors L0, L11, and L21, current sensors 11 and 21 that detect currents I1 and I2, and a control unit 30 that controls the load voltage by controlling the on / off of switching elements included in the power conversion units 10 and 20. T11 is a temperature sensor. 70 is information, examples of which include measurements from various sensors. 71 is an instruction.

[0021] Before explaining the invention, the principle of turn-on loss reduction by alternate delay will be explained.

[0022] FIG. 2 is a schematic diagram regarding an operation mode for reducing turn-on loss. FIG. 2A is a schematic diagram when alternate delay is not applied, and FIG. 2B is a schematic diagram when alternate delay is applied (alternate delay time difference command: tD). The principle of reducing turn-on loss in FIG. 2B where turn-on alternate delay of switching elements Q1 and Q2 is applied will be explained using FIG. 2B as compared with FIG. 2A. At time (0) < t1, the gate commands of Q1 and Q2 are off, and the reactor currents I1 and I2 flow through diodes D1 and D2. At time (1) = t1, the gate command of Q2 changes from off to on, and the gate command of Q1 remains off. In the subsequent time t1 to t2, with the conduction of switching element Q2, a current flows between the drain and source of Q2, and current I2 increases. On the other hand, since the total current I1 + I2 does not change abruptly due to inductor L0, current I1 decreases as current I2 increases. At time (2) = t2, the gate command of Q1 changes from off to on, and the gate command of Q2 remains on. Since current I1 decreased at time t1 to t2, the turn-on current of Q1 becomes smaller compared to FIG. 2A, and the turn-on loss of Q1 also becomes smaller. At time (3) = t3, switching elements Q1 and Q2 turn off. At time (4) = t4, the gate signal of Q1 changes from off to on. Since I1 decreased in the previous cycle (time t1 to t2), the turn-on current of Q1 becomes smaller compared to FIG. 2A, and the turn-on loss of Q1 becomes smaller. In the subsequent time t4 to t5, with the conduction of switching element Q1, a current flows between the drain and source of Q1, and current I1 increases. On the other hand, since the total current I1 + I2 does not change abruptly due to inductor L0, current I2 decreases as current I1 increases. (5) At time t5, the gate command for Q2 changes from off to on, while the gate command for Q1 remains on. Because the current I2 decreases between t4 and t5, the turn-on current of Q2 becomes smaller than in Figure 2A, and the turn-on loss of Q2 also becomes smaller. (6) At time t6, switching elements Q1 and Q2 are turned off, and reactor currents I1 and I2 flow through diodes D1 and D2. (7) At time t7, the gate command for Q2 changes from off to on, while the gate command for Q1 remains off. From time t7 to t8, as switching element Q2 becomes conductive, current flows between the drain and source of Q2, increasing current I2. Meanwhile, inductor L0 prevents a sudden change in the total current I1 + I2, so current I1 decreases as current I2 increases. (8) At time t8, the gate command for Q1 changes from off to on, while the gate command for Q2 remains on. Because the current I1 decreases between t7 and t8, the turn-on current of Q1 becomes smaller than in Figure 2A, and the turn-on loss of Q1 also becomes smaller.

[0023] As described above, by alternately delaying the turn-on timing of switching elements Q1 and Q2, the turn-on order of the switching elements alternates every period, thereby reducing both the turn-on current of Q1 (I1 at time t2, I1 at time t4, I1 at time t8) and the turn-on current of Q2 (I2 at time t1, I2 at time t5, I2 at time t7).

[0024] The delay times of the turn-on timings of the switching elements included in the power conversion units 10 and 20 of the above-described power conversion device 100 are relative. Therefore, a configuration may be adopted in which the turn-on timings of the switching elements included in one power conversion unit are fixed, while the turn-on timings of the switching elements included in the other power conversion unit are alternately delayed / advanced. 3A shows an example of the turn-on delay time of the switching elements Q1 and Q2. As shown in FIG. 3A, the turn-on delay time of the switching element Q1 (the turn-on delay time from the ON command of Q1) is set to t ON1The turn-on delay time of the switching element Q2 (the turn-on delay time from the ON command of Q2) is defined as t ON2 Figure 3 is a schematic diagram showing an example of the turn-on delay time. DS1 , V DS2 ) changes in a step-like manner, but in reality the drain-source voltage decreases over time due to the physical phenomena of the gate circuit and semiconductor.

[0025] 3A and 4A show examples of individual differences in the turn-on delay times of the switching elements Q1 and Q2. ON1 =t ON2 This is an example of the case where t ON1 >t ON2 This is an example of the case.

[0026] Turn-on delay time variation △t between switching elements Q1 and Q2 ON12 △t ON12 =t ON1 -t ON2 In Figure 3A, △t ON12 = 0 ns, and in Figure 3B, △t ON12 >0ns.

[0027] In this embodiment, the turn-on delay time variation Δt ON12 Estimate.

[0028] Figures 3B and 3C show the ON1 =t ON2 The alternating delay time difference command tD and turn-on delay time variation △t ON12 3B is a schematic diagram showing the relationship between the alternating delay time difference command t D Since the alternating delay time difference command t D By setting the turn-on order alternates every cycle.

[0029] Figures 4B and 4C show the ON1 >t ON2 In the case of (△tON12 >0 ns) D and turn-on delay time variation △t ON12 10 is a schematic diagram showing the relationship between the actual turn-on order and the order in which the switches are turned on.

[0030] FIG. 4B shows the alternate delay time difference command t D Even though the turn-on delay time variation △t ON12 Therefore, the switching elements Q1 and Q2 are not turned on at the same time, but are always turned on in the order Q2 → Q1. In Figure 4C, the turn-on delay time variation Δt ON12 is the alternating delay time difference command t D Since it is larger than the alternating delay time difference command t D Regardless of the setting, the turn-on order does not alternate, and always turns on in the order Q2 → Q1.

[0031] In this way, the turn-on delay time variation △t ON12 If there is a turn-on delay time variance △t, even if a command to turn on the switching elements Q1 and Q2 simultaneously is given, they will not actually turn on at the same time, causing an imbalance between the currents I1 and I2 and increasing the loss in the circuit. ON12 When there is an alternating delay time difference command t D Even if the order is given, the actual turn-on order will not alternate, and the switching loss cannot be reduced sufficiently.

[0032] In this embodiment, the turn-on delay time variation Δt ON12 Estimate the turn-on delay time variation △t ON12 The purpose is to compensate for the impact of

[0033] FIG. 5 is a flowchart of the inventive method according to the first embodiment.

[0034] The operations in steps 101 to 112 (S101 to S112) will be explained below. In steps S101 and S102, the variable N relating to the number of trials is set to N=1, and the alternating delay time difference command tD_N is set to 0 and the process proceeds to S103. In S103 and S104, the process waits until the temperature of the temperature sensor falls within a predetermined temperature range, and once the temperature falls within the predetermined temperature range, the temperature of the temperature sensor is stored and the process proceeds to S105. In steps S105 to S107, the alternating delay time difference command t D_N Set the temperature change △T before and after operation by operating the circuit under the specified load conditions for a specified time. N Calculate the temperature change △T N The alternating delay time difference command t D_N and store it in association with the above, and proceed to S108. In S108, it is determined whether N is equal to or greater than 3. If S108 is Yes, the process proceeds to S111, and if S108 is No, the process proceeds to S109. In steps S109 to S110, the value of N is updated (added) from N to N+1, and the alternating delay time difference command t D_N A D_N-1 +△t step and proceed to S103. In S111, the difference in temperature change △t N-2 -△t N-1 and △T N-1 -△T N Each of these is compared with a threshold value TH. If S111 is Yes, proceed to S112. If No, proceed to S109. S112 is △T N-2 , △T N-1 , △T N , t D_Nー2 , t D_Nー1 , t D_N Based on △T Non12 A specific estimation method will be described below using a diagnostic example with reference to FIGS.

[0035] Figure 6 shows the turn-on delay time variation △t on12 But, △t on12 This is a diagnostic example when N=0. First, when N=1, the alternating delay time difference command t D_1 = 0. At this time, as shown in FIG. 6B, the turn-on order is simultaneous in each period. Next, when N=2, the alternating delay time difference command t D_2 =△t STEPAt this time, as shown in Figure 6C, the turn-on order alternates between Q2 → Q1 and Q1 → Q2. Therefore, due to the loss reduction effect of alternate turn-on, the temperature rise becomes △T1 > △T2. Next, when N = 3, the alternate delay time difference command t D_3 =2×△t STEP In this case, as shown in Figure 6D, the turn-on order alternates in each cycle. When N=3, the effect of reducing turn-on loss due to the alternating delay is greater than when N=2, so the temperature rise is △T1>△T2>△T3. From Figure 6A, △t ON12 =tD _1 =0.

[0036] Figure 7 shows the turn-on delay time variation △t ON12 △t ON12 =2×△t STEP This is a diagnosis example when N=1 to 2, and the alternating delay time difference command t D_N (N=1~2) Turn-on delay time variation △t ON12 , the turn-on order is Q2 → Q1 in each period as shown in Figures 7B and 7C. When N=3, the alternating delay time difference command t D_3 and turn-on delay time variation △t ON12 , the turn-on order in each period is Q2 → Q1, and they are turned on simultaneously, as shown in FIG. 7D. When N=4 to 5, the alternating delay time difference command t D_N (N=4~5) is the turn-on delay time variation △t ON12 Since the turn-on order in each cycle is larger than that of N=4, as shown in Figures 7E and 7F, Q2 → Q1 and Q1 → Q2 are alternately repeated. When N=5, the effect of reducing turn-on loss due to the alternating delay is greater than when N=4, so the temperature rise is △T1 ≒ △T2 ≒ △T3 > △T4 > △T5. From Figure 7A, △t ON12 =t D_3 =2×△t STEP It can be estimated that: Figure 8 shows the turn-on delay time variation △t ON12 △t ON12 =0.5×△t STEPFirst, when N=1, the alternating delay time difference command t D_1 = 0. At this time, as shown in Figure 8B, the turn-on delay time variation Δt ON12 =t ON1 -t ON2 =0.5×△t STEP Therefore, the turn-on order is Q2 → Q1 in each cycle. Next, when N=2, the alternating delay time difference command t D_2 =△t STEP At this time, as shown in FIG. 8C, the alternating delay time difference command t D_2 is the turn-on delay time variation △t ON12 Since N is larger than 3, the turn-on order is Q2 → Q1 and Q1 → Q2, which are repeated alternately. Therefore, the temperature rise becomes △T1 > △T2 due to the loss reduction effect of alternate turn-on. Next, when N=3, the alternating delay time difference command t D_3 =2×△t STEP In this case, as shown in Figure 8D, the turn-on order alternates in each cycle. When N=3, the effect of reducing turn-on loss due to the alternating delay is greater than when N=2, so the temperature rise is △T1>△T2>△T3. From Figure 8A, t D_1 <△t ON12 <t D_2 and by linear approximation, △t ON12 =0.5×△t STEP It can be estimated that:

[0037] Figure 9 shows the turn-on delay time variation △t ON12 △t ON12 =2.5×△t STEP This is a diagnosis example when N=1 to 3, and the alternating delay time difference command t D_N (N=1~3) Turn-on delay time variation △t ON12 , the turn-on order is Q2 → Q1 in each period as shown in Figures 9B to 9D. When N = 4 to 5, the alternating delay time difference command t D_N (N=4~5) is the turn-on delay time variation △t ON12Since the turn-on order in each cycle is larger than that of N=4, as shown in Figures 9E and 9F, the turn-on order in each cycle is alternating, with Q2 → Q1 and Q1 → Q2 being repeated. When N=5, the effect of reducing turn-on loss due to the alternating delay is greater than when N=4, so the temperature rise is △T1 ≒ △T2 ≒ △T3 > △T4 > △T5. From Figure 9A, t D_3 <△t ON12 <t D_4 and by linear approximation, △t ON12 =2.5×△t STEP It can be estimated that:

[0038] Figure 10 shows the relationship between △t ON12 10A is a diagram showing a method for determining the sign of t. A non-alternating delay time is applied to either the power conversion units of the first group or the power conversion units of the second group, and a determination is made as to whether the currents of the power conversion units of the first group and the power conversion units of the second group are balanced when a non-alternating delay time is applied compared to when a non-alternating delay time is not applied. In the example of FIG. 10A, t ON1 >t ON2 Therefore, without any control to balance I1 and I2, I1 <I2となる。

[0039] In FIG. 10C, a non-alternating delay is applied so that the Q1 command is delayed relative to the Q2 command. The current is unbalanced compared to FIG. 10B before compensation. When the current is unbalanced in this way, the estimated result Δt for the non-alternating delay time difference is calculated so that the Q2 command is delayed relative to the Q1 command in the opposite direction to FIG. 10C. ON12C Just give it the following.

[0040] In FIG. 10D, a non-alternating delay is applied so that the Q1 command is delayed relative to the Q2 command. The current is now balanced compared to before compensation. When the current is balanced in this way, the estimated result Δt for the non-alternating delay time difference is shown in FIG. 10D, so that the Q2 command is delayed relative to the Q1 command in the same direction as FIG. ON12C Just give it the following.

[0041] As described above, by providing a non-alternating delay time to either the power conversion units of the first group or the power conversion units of the second group, and providing a non-alternating delay time compared to when no non-alternating delay time is provided, if the currents of the power conversion units of the first group and the power conversion units of the second group change in a direction that balances them, the non-alternating delay time is provided to the power conversion units of that group, and if the currents change in a direction that disbalances them, the non-alternating delay time is provided to the power conversion units of a group different from that group, thereby making it possible to reduce the loss of switching elements associated with implementing a non-alternating delay time.

[0042] In FIG. 1, one of the first group of power conversion units and the second group of power conversion units is shown as power conversion unit 10, and the other is shown as power conversion unit 20.

[0043] Figure 11 shows the turn-on delay time variation △t ON12 The first example of a method for compensating for the effect of

[0044] The delay time difference Δt shown in Fig. 11A ON12 is estimated using the method shown in the flowchart of Figure 5, and the estimated result △t ON12C The waveform before compensation is shown in FIG. 11B, and the waveform after compensation is shown in FIG. 11C. ON12 By compensating for the influence of the command, the actual turn-on can be performed at the same time, and the current can be balanced.

[0045] Figure 12 shows the turn-on delay time variation Δt when the alternating delay time difference command tD is set. ON12 This shows a second example of how to compensate for the effect of

[0046] The delay time difference Δt shown in Fig. 12A ON12 is estimated using the method shown in the flowchart of Figure 5, and the estimated result △t ON12C The turn-on delay time variation Δt ON1212C is a schematic diagram of the waveform when the alternating delay time difference command tD is set without compensating for the D After setting the turn-on delay time variation △t ON12 12B is a schematic diagram of the waveform when the turn-on delay time variation Δt ON12 By setting the alternating delay time difference command tD after compensating for the effect of the above in the command, the actual turn-on order can be alternated. Compared to Figure 12B, Figure 12C allows the actual turn-on order to be alternated, which reduces turn-on loss.

[0047] The technical concept of the present invention is a method for adjusting a power conversion device to reduce variations in a power conversion device having multiple power conversion units. Therefore, as long as the above-described various explanations and technical concepts are used, the adjustment method for a power conversion device is also included within the scope of the present invention. Furthermore, as long as the above-described various explanations and technical concepts are used, the diagnostic method for a power conversion device is also included within the scope of the present invention. Furthermore, power conversion devices using these methods are naturally also included within the scope of the present invention.

[0048] One example of how this method can be applied is to adjust the delay time before shipping the equipment. By setting a non-alternating delay time for each device, it is possible to diagnose the device even when there are individual differences in the switching elements of each device, and switching loss can be reduced.

[0049] Another example of the adjustment method of this method is a diagnostic method that can be performed at any time after the shipment of the device, to diagnose the deterioration of elements involved in switching that accompanies product use.

[0050] As another example of the adjustment method of this technique, for example, the diagnosis method of this technique may be performed remotely after the device is shipped. The turn-on delay time is changed and diagnosed from outside the power conversion device using wired or wireless communication means. In this case, a diagnostic signal is provided from outside to perform the diagnosis.

[0051] Such adjustments can be performed at various times, for example, before shipment of the device, at any time after shipment, or periodically. Furthermore, adjustments can be performed using various methods, such as adjustments made directly to the device, adjustments made from a control room or the like within a factory, or remote adjustments made via a wired or wireless connection to an external device. Alternatively, adjustments made by a diagnostic service, maintenance management service, or the like deployed on the cloud are also included in the scope of the present invention.

[0052] Next, an example of the power conversion device of the present invention will be described from another perspective.

[0053] 13 is an explanatory diagram of an example of a power conversion device of the present invention. The technology used therein is the same as that already described. It corresponds to an example of a configuration diagram using the circuit configuration of FIG.

[0054] The power conversion device 100 has a power conversion unit 10 and a power conversion unit 20. In the figure, there are two power conversion units, but there may be any number as long as there are multiple power conversion units, and the case of three or more units is also included.

[0055] Each power conversion unit, for example, has a diode module 53 and a power module 54. 11 and 21 are current sensors. They have a capacitor C0 and a voltage sensor 3. Information from each sensor is transmitted to the control unit 30 at 70. T11 is a temperature sensor.

[0056] The control unit 30 uses the transmitted information to control one or both of the power conversion units 10 and 20 according to instructions 71 so as to reduce the variation in the entire power conversion device 100 .

[0057] An example of receiving instructions or input from outside will be explained next.

[0058] 14 differs from FIG. 13 in that the power conversion device 100 is configured to have a communication unit 65. The communication unit 65 performs communication 61 with the control unit 30. Note that this communication is not limited to so-called public communication, but also includes communication methods, transmission methods, wiring methods, etc. specific to the power conversion device 100.

[0059] The communication unit 65 establishes wired or wireless communication with an external terminal 60, thereby realizing communication 61.

[0060] For example, in the case of wireless communication, various lines such as a mobile phone line, a Wi-Fi line, an internet line, etc. can be used as appropriate.

[0061] The external terminal 60 is used to check the status of the power conversion device 100 and to give instructions such as adjustments to the power conversion device 100. The external terminal 60 can be implemented using various types of hardware, such as a PC, a tablet device, or a smartphone as a terminal device. A function for instructing adjustments to the power conversion device 100 is implemented on such hardware as a browser destination function or as an application.

[0062] FIG. 15 is a diagram illustrating a situation in which communication is performed via the cloud 62, in contrast to FIG.

[0063] This embodiment naturally includes a case where the terminal 60 and the power conversion device 100 communicate with each other via the cloud 62. Furthermore, it also includes a case where various services such as a monitoring service, a maintenance management service, and a maintenance service for the power conversion device 100 are provided on the cloud 62. For example, if a user who operates the power conversion device 100 has a contract for an optimal operation service or the like with a supplier of the power conversion device 100, the supplier of the power conversion device 100 will deploy an operation management service for the power conversion device 100 on the cloud 62, monitor the state of the power conversion device 100, and adjust variations in the power conversion device as necessary.

[0064] In addition, when such a service on the cloud is the subject of operation and management, the terminal 60 may not be present.

[0065] As a modification of FIG. 15, as shown in FIG. 16, a case in which a cloud 62 performs processing in cooperation with another server 63 is also included in the scope of the present invention.

[0066] The above examples illustrate the ideas and concepts of the present invention. Of course, examples realized by combining the examples are also included within the scope of the present invention. Furthermore, as long as the disclosed ideas and concepts are used, modifications and similar examples are also included within the scope of the present invention.

[0067] Furthermore, one example of the present invention described using the above embodiments can also be expressed as follows.

[0068] <Part 1> A power conversion device including a plurality of power conversion units connected in parallel via inductance components, each of the plurality of power conversion units belongs to a first group or a second group; Each of the power conversion units includes a switching element, the power conversion device includes a delay time adjustment unit that adjusts the turn-on timing or the turn-off timing of the switching element; the delay time adjustment unit provides an alternating delay time difference command that alternately and repeatedly delays the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the first group and the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the second group, estimating a turn-on or turn-off delay time variation of one of the switching elements based on a relationship between the alternating delay time difference of the alternating delay time difference command and a temperature change in the vicinity of the switching element of the one group; The delay time adjustment unit sets the turn-on timing or turn-off timing of the switching element so as to compensate for the effect of the turn-on or turn-off delay time variation using a non-alternating delay time difference command based on the turn-on or turn-off delay time variation.

[0069] <Part 2> In the power conversion device according to <Item 1>, The delay time adjustment unit sets the turn-on timing or turn-off timing of the switching elements of the power conversion units of the first group and the power conversion units of the second group based on the non-alternating delay time difference command and the alternating delay time difference command.

[0070] <Part 3> In the power conversion device according to <Item 1> or <Item 2>, A power conversion device that calculates a slope of a switching element temperature change with respect to the alternating delay time difference, estimates the alternating delay time difference at a point where the slope changes by calculation, and estimates a delay time variation for turning on or off the switching element.

[0071] <Part 4> In the power conversion device according to <Item 1> or <Item 2>, providing a non-alternating delay time to one of the power conversion units of the first group and the power conversion units of the second group, and if providing the non-alternating delay time causes the currents of the power conversion units of the first group and the power conversion units of the second group to change in a direction that balances the currents, providing the non-alternating delay time to the one of the power conversion units; A power conversion device that applies a non-alternating delay time to the other power conversion unit when the power changes in an unbalanced direction.

[0072] <Part 5> In the power conversion device according to <Item 1>, A power conversion device that performs a diagnostic operation before starting use of the power conversion device and sets a delay time of the power conversion device.

[0073] <Part 6> In the power conversion device according to <Item 1>, A power conversion device that adjusts delay time by applying an external diagnostic signal.

[0074] <Part 7> 1. A method for adjusting a power conversion apparatus including a plurality of power conversion units connected in parallel via inductance components, comprising: each of the plurality of power conversion units belongs to a first group or a second group; Each of the power conversion units includes a switching element, the power conversion device includes a delay time adjustment unit that adjusts the turn-on timing or the turn-off timing of the switching element; the delay time adjustment unit provides an alternating delay time difference command that alternately and repeatedly delays the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the first group and the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the second group, estimating a turn-on or turn-off delay time variation of one of the switching elements based on a relationship between the alternating delay time difference of the alternating delay time difference command and a temperature change in the vicinity of the switching element of the one group; The delay time adjustment unit uses a non-alternating delay time difference command based on the turn-on or turn-off delay time variation to set the turn-on timing or turn-off timing of the switching element so as to compensate for the effect of the turn-on or turn-off delay time variation.

[0075] <Part 8> In the method for adjusting a power conversion device according to <Item 7>, The delay time adjustment unit sets the turn-on timing or turn-off timing of the switching elements of the power conversion units of the first group and the power conversion units of the second group based on the non-alternating delay time difference command and the alternating delay time difference command.

[0076] <No. 9> In the method for adjusting a power conversion device according to <No. 7> or <No. 8>, A method for adjusting a power conversion device, which calculates a slope of a switching element temperature change with respect to the alternating delay time difference, estimates the alternating delay time difference at a point where the slope changes by calculation, and estimates a delay time variation for turn-on or turn-off of the switching element.

[0077] <Part 10> In the method for adjusting a power conversion device according to <No. 7> or <No. 8>, providing a non-alternating delay time to one of the power conversion units of the first group and the power conversion units of the second group, and if providing the non-alternating delay time causes the currents of the power conversion units of the first group and the power conversion units of the second group to change in a direction that balances the currents, providing the non-alternating delay time to the one of the power conversion units; A method for adjusting a power conversion device that applies a non-alternating delay time to the other power conversion unit when the power conversion unit changes in an unbalanced direction.

[0078] <Part 11> In the method for adjusting a power conversion device according to <Item 7>, A method for adjusting a power conversion device, comprising: performing a diagnostic operation before starting use of the power conversion device; and setting a delay time of the power conversion device.

[0079] <Part 12> In the method for adjusting a power conversion device according to <Item 7>, A method for adjusting a power conversion device by applying an external diagnostic signal and adjusting a delay time.

[0080] <Part 13> A power conversion device using the method for adjusting a power conversion device according to any one of <No. 7>, <No. 8>, <No. 11> and <No. 12>.

[0081] <Part 14> A power conversion device using the power conversion device adjustment method described in <Item 9>.

[0082] <Part 15> A power conversion device using the power conversion device adjustment method described in <Item 10>. [Explanation of symbols]

[0083] 1:DC power supply 2: Load 10: Power conversion unit 11: Current sensor 20: Power conversion unit 21: Current sensor 30: Control unit 31: Delay time adjustment section 32: Turn-on delay time variation estimation unit 33: Storage part L0, L11, L21: inductors Q1, Q2: switching elements D11, D21: Diodes C0: Capacitor 53: Diode module 54: Power module 60: Terminal 61: Communication 62: Cloud 63: Server 65:Communication unit 70: Information 71: Instructions 100: Power conversion device

Claims

1. A power conversion device including a plurality of power conversion units connected in parallel via inductance components, each of the plurality of power conversion units belongs to a first group or a second group; Each of the power conversion units includes a switching element, the power conversion device includes a delay time adjustment unit that adjusts the turn-on timing or the turn-off timing of the switching element; the delay time adjustment unit provides an alternating delay time difference command that alternately and repeatedly delays the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the first group and the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the second group, estimating a turn-on or turn-off delay time variation of one of the switching elements based on a relationship between the alternating delay time difference of the alternating delay time difference command and a temperature change in the vicinity of the switching element of the one group; The delay time adjustment unit sets the turn-on timing or turn-off timing of the switching element so as to compensate for the effect of the turn-on or turn-off delay time variation using a non-alternating delay time difference command based on the turn-on or turn-off delay time variation.

2. 2. The power conversion device according to claim 1, The delay time adjustment unit sets the turn-on timing or turn-off timing of the switching elements of the power conversion units of the first group and the power conversion units of the second group based on the non-alternating delay time difference command and the alternating delay time difference command.

3. The power conversion device according to claim 1 or 2, A power conversion device that calculates a slope of a switching element temperature change with respect to the alternating delay time difference, estimates the alternating delay time difference at a point where the slope changes by calculation, and estimates a delay time variation for turning on or off the switching element.

4. The power conversion device according to claim 1 or 2, providing a non-alternating delay time to one of the power conversion units of the first group and the power conversion units of the second group, and if providing the non-alternating delay time causes the currents of the power conversion units of the first group and the power conversion units of the second group to change in a direction that balances the currents of the power conversion units of the first group and the power conversion units of the second group, providing the non-alternating delay time to the one of the power conversion units; A power conversion device that applies a non-alternating delay time to the other power conversion unit when the power changes in an unbalanced direction.

5. 2. The power conversion device according to claim 1, A power conversion device that performs a diagnostic operation before starting use of the power conversion device and sets a delay time of the power conversion device.

6. 2. The power conversion device according to claim 1, A power conversion device that adjusts delay time by applying an external diagnostic signal.

7. 1. A method for adjusting a power conversion apparatus including a plurality of power conversion units connected in parallel via inductance components, comprising: each of the plurality of power conversion units belongs to a first group or a second group; Each of the power conversion units includes a switching element, the power conversion device includes a delay time adjustment unit that adjusts the turn-on timing or the turn-off timing of the switching element; the delay time adjustment unit provides an alternating delay time difference command that alternately and repeatedly delays the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the first group and the turn-on timing or the turn-off timing of the switching element included in the power conversion unit of the second group, estimating a turn-on or turn-off delay time variation of one of the switching elements based on a relationship between the alternating delay time difference of the alternating delay time difference command and a temperature change in the vicinity of the switching element of the one group; The delay time adjustment unit uses a non-alternating delay time difference command based on the turn-on or turn-off delay time variation to set the turn-on timing or turn-off timing of the switching element so as to compensate for the effect of the turn-on or turn-off delay time variation.

8. The method for adjusting a power conversion device according to claim 7, The delay time adjustment unit sets the turn-on timing or turn-off timing of the switching elements of the power conversion units of the first group and the power conversion units of the second group based on the non-alternating delay time difference command and the alternating delay time difference command.

9. The method for adjusting a power conversion device according to claim 7 or 8, A method for adjusting a power conversion device, which calculates a slope of a switching element temperature change with respect to the alternating delay time difference, estimates the alternating delay time difference at a point where the slope changes by calculation, and estimates a delay time variation of the turn-on or turn-off of the switching element.

10. The method for adjusting a power conversion device according to claim 7 or 8, providing a non-alternating delay time to one of the power conversion units of the first group and the power conversion units of the second group, and if providing the non-alternating delay time causes the currents of the power conversion units of the first group and the power conversion units of the second group to change in a direction that balances the currents of the power conversion units of the first group and the power conversion units of the second group, providing the non-alternating delay time to the one of the power conversion units; A method for adjusting a power conversion device that applies a non-alternating delay time to the other power conversion unit when the power conversion unit changes in an unbalanced direction.

11. The method for adjusting a power conversion device according to claim 7, A method for adjusting a power conversion device, comprising: performing a diagnostic operation before starting use of the power conversion device; and setting a delay time of the power conversion device.

12. The method for adjusting a power conversion device according to claim 7, A method for adjusting a power conversion device by applying an external diagnostic signal and adjusting a delay time.

13. A power conversion device using the method for adjusting a power conversion device according to any one of claims 7, 8, 11 and 12.

14. A power converter using the method for adjusting a power converter according to claim 9.

15. A power converter using the method for adjusting a power converter according to claim 10.

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