Signal generation device and power conversion system

Abstract

To provide a signal generation device capable of generating a switching control signal by correcting synchronization deviation of a plurality of signal generation devices while suppressing an increase in the number of times of switching.SOLUTION: The signal generation device 12 includes a triangular wave signal output unit 1221 that outputs a triangular wave signal, a vertex timing detection unit 1222 that detects a timing of a vertex of the triangular wave signal, a delay time detection unit 1223 that detects a delay time, and a signal correction unit 1224 that corrects the triangular wave signal. When the delay time from the first vertex timing to the timing of receiving the first synchronization signal, which is the synchronization signal SYNC, is detected, the signal corrector 1224 corrects the triangular wave signal so as to continue the signal value at the next vertex for the delay time at the second vertex timing, which is the timing of the next vertex of the first vertex timing.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a signal generating device that generates a switching control signal for a power conversion device, and a power conversion system. [Background technology]

[0002] There is known a technique for controlling the output of a power conversion device using a switching control signal based on a PWM (Pulse Width Modulation) method, etc. When driving a motor or the like using the power conversion device, there is also known a technique for synchronizing the motor rotation timing with a switching circuit that generates a switching control signal.

[0003] For example, Patent Document 1 discloses a drive signal generation circuit that corrects the phase shift of a triangular wave chopping signal relative to the rotational position of a motor. The drive signal generation circuit in Patent Document 1 is a circuit that outputs a PWM signal using a triangular wave signal generated by a triangular wave chopping signal based on a counter value.

[0004] The drive signal generation circuit of Patent Document 1 includes a register that latches a counter value at a predetermined timing. After the counter value is latched, the drive signal generation circuit of Patent Document 1 corrects the counter value according to the register value when the triangular wave signal reaches a predetermined phase value. In this way, the drive signal generation circuit of Patent Document 1 reduces unevenness in motor torque strength. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-291277 Summary of the Invention [Problem to be solved by the invention]

[0006] The PWM signal described above is generated, for example, by comparing the magnitude of the signal value of a triangular wave signal with a command value. For example, if the signal value of the triangular wave signal is smaller than the command value, a "1" is output, and if the signal value of the triangular wave signal is larger than the command value, a "0" is output. In this way, when the signal value of the triangular wave signal intersects with the command value, the PWM signal switches between "0" and "1."

[0007] In order to synchronize switching control signals such as PWM signals among multiple control boards, in a configuration in which a master board and a slave board are connected to each other via an optical communication cable or the like so that they can communicate with each other and transmit and receive synchronization signals, it is necessary to correct the discrepancy in the operating clock of each control board based on the synchronization signal.

[0008] The deviation of the operating clock is corrected, for example, as follows, depending on the period of the synchronization signal: If the period of the synchronization signal is shorter than the period from one peak to the next peak of the triangular wave signal, the signal value of the triangular wave signal is corrected to the signal value of the next peak at the timing when the synchronization signal is received.

[0009] Furthermore, if the period of the synchronization signal is longer than the period from one peak to the next peak of the triangular wave signal, the signal value of the triangular wave signal is corrected to the signal value of the peak at the timing when the synchronization signal is received. In this case, if the signal value of the triangular wave signal has crossed the command value before the synchronization signal is received, the signal value of the triangular wave signal will again cross the command value after the signal value has been corrected.

[0010] As described above, when the period of the synchronization signal is long, the number of times that the switching control signal, such as the PWM signal, switches may increase. Therefore, it is desired to suppress the increase in the number of times that the switching control signal switches.

[0011] An object of the present invention is to provide a signal generating device that can generate switching control signals by correcting the synchronization error of a plurality of signal generating devices while suppressing an increase in the number of switching operations. [Means for solving the problem]

[0012] A signal generating device according to one embodiment of the present invention is a signal generating device that generates switching control signals for a power conversion device based on a command value and a triangular wave signal serving as a carrier wave, while synchronizing with a synchronization signal that synchronizes multiple signal generating devices. The signal generating device includes: a triangular wave signal output unit that outputs a triangular wave signal in which vertices at which the signal value repeatedly reaches maximum or minimum values ​​appear; a vertex timing detection unit that detects the timing of the vertices of the triangular wave signal; a delay time detection unit that detects a delay time from the vertex timing detected by the vertex timing detection unit to a timing at which the synchronization signal is received; and a signal correction unit that corrects the triangular wave signal based on the delay time detected by the delay time detection unit. When the delay time detection unit detects a first delay time that is the delay time from a first vertex timing, which is the timing of the first vertex detected by the vertex timing detection unit, to a timing at which the first synchronization signal is received, the signal correction unit corrects the triangular wave signal at a second vertex timing, which is the timing of a second vertex following the first vertex, by the first delay time (first configuration).

[0013] In the above configuration, the delay time occurs when the period of the synchronization signal is longer than the period of the peaks, which is the period at which peaks repeatedly appear. The period of the peaks is half the period of the triangular wave signal. Therefore, the delay time occurs when the period of the synchronization signal is longer than half the period of the triangular wave signal.

[0014] Furthermore, in the above configuration, when the delay time is detected, the signal correction unit corrects the triangular wave signal so that the signal value at the next peak is maintained for the delay time. Therefore, even when the delay time occurs, the signal value of the triangular wave signal can be prevented from crossing the command value. This prevents an increase in the number of times the switching control signal, which is generated based on the command value and the triangular wave signal, switches. This prevents an increase in power consumption due to an increase in the number of times the switching control signal switches.

[0015] Therefore, it is possible to generate a switching control signal by correcting the synchronization error of a plurality of signal generating devices while suppressing an increase in the number of switching operations.

[0016] In the first configuration, when the delay time detection unit detects a second delay time, which is the delay time from the timing at which the continuation of the signal value at the second vertex is completed to the timing at which a second synchronization signal, which is the synchronization signal subsequent to the first synchronization signal, is received, the signal correction unit corrects the triangular wave signal so that the signal value at the third vertex is continued for the second delay time at a third vertex timing, which is the timing of a third vertex subsequent to the second vertex timing (second configuration).

[0017] In the above configuration, the triangular wave signal is corrected at the third vertex by using the second delay time after the signal value is maintained at the second vertex, thereby correcting the synchronization error of the multiple signal generators while suppressing an increase in the number of switching times, even at the third vertex.

[0018] In the first configuration, if the synchronization signal is received while the signal value is continuing at the second peak, the signal correction unit changes the signal value at the timing when the synchronization signal is received (third configuration).

[0019] In the above configuration, the synchronization signal can be processed with priority over the continuation of the signal value at the second peak of the triangular wave signal. A synchronization signal may be received while the signal value at the second peak of the triangular wave signal is continuing, for example, if a synchronization error has been alleviated or eliminated. In such a case, the synchronization signal can be given priority, and the synchronization error of the multiple signal generating devices can be corrected to generate a switching control signal.

[0020] In the first configuration, when the first delay time is equal to or longer than half the period of the cycle in which the signal value of the triangular wave signal is at its maximum value and is equal to or shorter than the period, the signal correction unit corrects the signal value of the triangular wave signal to the signal value of the second peak at the timing when the first synchronization signal is received, thereby changing the signal value (fourth configuration).

[0021] If the delay time is half the length of the peak period, it is possible that the synchronization signal that should have been received was not received for some reason. Therefore, in the above case, the delay time may have been detected by receiving the synchronization signal next to the synchronization signal that should have been received.

[0022] In the above-described configuration, when there is a possibility that the synchronization signal following the synchronization signal that should have been received has been received, the signal value of the triangular wave signal is corrected to the signal value of the second peak, thereby changing the signal value.

[0023] This allows for appropriate correction to be made so that the synchronization signal that should have been received can be ignored and synchronization based on the synchronization signal can be recovered.

[0024] A fifth configuration includes a plurality of signal generating devices according to any one of the first to fourth configurations and a plurality of the power conversion devices, wherein one of the plurality of signal generating devices outputs the synchronization signal to another of the plurality of signal generating devices, and the plurality of power conversion devices convert power based on the switching control signal generated by the one of the signal generating devices or the other of the signal generating devices based on the synchronization signal.

[0025] According to the above-described configuration, it is possible to easily realize a power conversion system that can generate switching control signals by correcting the synchronization error of a plurality of signal generating devices. [Effects of the Invention]

[0026] A signal generating device according to one embodiment of the present invention includes a triangular wave signal output unit that outputs a triangular wave signal in which vertices at which the signal value reaches a maximum or minimum repeatedly appear, a vertex timing detection unit that detects the timing of the vertices of the triangular wave signal, a delay time detection unit that detects a delay time from the vertex timing detected by the vertex timing detection unit to a timing at which a synchronization signal is received, and a signal correction unit that corrects the triangular wave signal based on the delay time detected by the delay time detection unit. When the delay time detection unit detects a first delay time that is the delay time from a first vertex timing that is the timing of the vertex detected by the vertex timing detection unit to a timing at which a first synchronization signal that is the synchronization signal is received, the signal correction unit corrects the triangular wave signal at a second vertex timing that is the timing of a second vertex that is the next vertex after the first vertex by the first delay time.

[0027] In the above-described configuration, by correcting the triangular wave signal, it is possible to suppress an increase in the number of switching operations, while correcting the synchronization error of a plurality of signal generating devices to generate a switching control signal. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a block diagram showing a schematic configuration of a power conversion system including a signal generating device according to an embodiment. [Figure 2] FIG. 2 is a functional block diagram showing a schematic configuration of a signal generating device operating as a master. [Figure 3] FIG. 3 is a timing chart of the signal generating device operating as a master. [Figure 4]FIG. 4 is a functional block diagram showing a schematic configuration of a signal generating device operating as a slave. [Figure 5] FIG. 5 is a timing chart in which the period of the synchronization signal is shorter than the period of the peaks. [Figure 6] FIG. 6 is a timing chart showing a case where the signal value is not continuously processed at a given vertex when the period of the synchronization signal is longer than the period of the vertex. [Figure 7] FIG. 7 is a timing chart showing a case where the signal value is continuously processed at a predetermined vertex when the period of the synchronization signal is longer than the period of the vertex. [Figure 8] FIG. 8 is a timing chart of signal correction by the signal generating device according to the first modification. [Figure 9] FIG. 9 is a timing chart of signal correction by the signal generating device according to the second modification. DETAILED DESCRIPTION OF THE INVENTION

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals and the description thereof will not be repeated.

[0030] (Overall composition) FIG. 1 is a block diagram showing a schematic configuration of a power conversion system SYS1 including signal generation devices 11, 12, and 13 according to an embodiment.

[0031] Referring to FIG. 1, a power conversion system SYS1 includes a plurality of signal generating devices 11, 12, and 13, and a plurality of power conversion devices 21, 22, and .

[0032] The signal generating device 11 generates a PWM signal, which is a switching control signal for controlling the drive of the power conversion device 21, and outputs the PWM signal to the power conversion device 21. The signal generating device 12 outputs the PWM signal to the power conversion device 22. The signal generating device 13 outputs the PWM signal to the power conversion device 23.

[0033] Of the multiple signal generators 11, 12, and 13, the signal generator 11 operates as a master. The signal generators 12 and 13 operate as slaves. The signal generators 11, 12, and 13 are connected in series so as to be able to communicate with each other via a synchronization signal transmission cable 31 such as an optical communication cable. That is, the signal generator 11 outputs a synchronization signal SYNC to the signal generator 12, and the signal generator 12 outputs a synchronization signal SYNC to the signal generator 13.

[0034] The multiple power electronics devices 21, 22, and 23 are connected so as to be able to receive signals from the multiple signal generators 11, 12, and 13, respectively. The multiple power electronics devices 21, 22, and 23 convert power based on the PWM signals generated by the multiple signal generators 11, 12, and 13, respectively.

[0035] (Details of the signal generator) (Signal generator acting as master) Fig. 2 is a functional block diagram showing a schematic configuration of the signal generating device 11 operating as a master, and Fig. 3 is a timing chart of the signal generating device 11 operating as a master.

[0036] 2 and 3, the signal generating device 11 operating as a master has a clock signal output unit 111, a carrier wave signal output unit 112, and a switching control signal output unit 113.

[0037] The clock signal output unit 111 generates a clock signal CK1 of a predetermined frequency and outputs it to the carrier signal output unit 112.

[0038] The carrier wave signal output unit 112 outputs a triangular wave signal TR1 based on the clock signal CK1. In detail, the carrier wave signal output unit 112 includes a triangular wave signal output unit 1121 and a synchronization signal output unit 1122.

[0039] The triangular wave signal output unit 1121 generates the triangular wave signal TR1 using a counter value that repeatedly counts up or down at a predetermined cycle based on the clock signal CK1. As shown in Fig. 3, in the triangular wave signal TR1, vertices (X1, X2, X3, ...) where the signal value reaches a maximum or minimum value repeatedly appear at a vertex cycle TX1. Note that the vertex cycle TX1 is half the cycle TTR of the triangular wave signal TR1.

[0040] The synchronization signal output unit 1122 generates synchronization signals SYN11, SYN12, and SYN13 in sequence, for example, in a period TX1 in which vertices appear in the order of vertices X1, X2, and X3. Therefore, in the signal generating device 11, the period TSYN of the synchronization signal SYNC is the same as the period TX1 of the vertices. In the following description, when there is no need to distinguish between the synchronization signals SYN11, SYN12, and SYN13, they will be collectively referred to as the synchronization signal SYNC.

[0041] The synchronization signal output unit 1122 outputs the generated synchronization signal SYNC to another signal generating device 12 that is a slave.

[0042] (Signal generator acting as a slave) 4 is a functional block diagram showing a schematic configuration of signal generating device 12 operating as a slave. Signal generating device 12 operating as a slave differs from signal generating device 11 operating as a master in that carrier signal output unit 122 performs signal correction. In the following, components similar to those of signal generating device 11 are given the same reference numerals and description thereof will be omitted, and only components different from signal generating device 11 will be described. Furthermore, the configuration of signal generating device 13 operating as a slave is similar to that of signal generating device 12, and therefore description thereof will not be repeated.

[0043] Referring to FIG. 4, signal generating device 12 operating as a slave has clock signal output unit 121, carrier wave signal output unit 122, and switching control signal output unit 113.

[0044] The clock signal output unit 121 generates a clock signal CK2 of a predetermined frequency and outputs it to the carrier signal output unit 122.

[0045] The carrier wave signal output unit 122 outputs the corrected triangular wave signal TR2 or TR11 synchronized based on the synchronization signal SYNC. In detail, the carrier wave signal output unit 122 has a triangular wave signal output unit 1221, a peak timing detection unit 1222, a delay time detection unit 1223, a signal correction unit 1224, and a synchronization signal output unit 1225.

[0046] In an ideal case where there is no synchronization error, the triangular wave signal output unit 1221 generates a triangular wave signal TR1 as shown in Fig. 3 based on the clock signal CK2. "No synchronization error" means that the period TX1 of the peaks is the same as the period TSYN of the synchronization signal SYNC, and the timing at which the peaks (X1, X2, X3, ...) appear is the same as the timing at which the synchronization signal SYNC is received.

[0047] However, in reality, due to clock misalignment or the like, the period TX1 of the peaks may differ from the period TSYN of the synchronization signal SYNC, and the timing at which the peaks (X1, X2, X3, ...) appear may differ from the timing at which the synchronization signal SYNC is received. The triangular wave signal output unit 1221 outputs the corrected triangular wave signal TR2 or TR11 corrected by the signal corrector 1224 in accordance with such synchronization misalignment. Such synchronization misalignment will be described in detail later.

[0048] The peak timing detector 1222 detects the timing of the peaks (X1, X2, X3, . . . ) of the triangular wave signal TR1.

[0049] The delay time detector 1223 detects a delay time t1 from the timing of the apex (X1, X2, X3, . . . ) detected by the apex timing detector 1222 to the timing of receiving the synchronization signal SYNC (see also FIG. 6).

[0050] The signal corrector 1224 corrects the triangular wave signal TR1 based on the delay time t1 detected by the delay time detector 1223. The signal corrector 1224 also corrects the triangular wave signal TR1 based on the synchronization signal SYNC.

[0051] The synchronization signal output unit 1225 outputs the received synchronization signal SYNC to another signal generating device 13 .

[0052] (Details of sync loss) The case where the period TSYN of the synchronization signal SYNC is shorter than the period TX1 of the peaks and the case where the period TSYN of the synchronization signal SYNC is longer than the period TX1 of the peaks will be described in turn.

[0053] (When the period of the synchronization signal is shorter than the period of the peak) 5 is a timing chart showing a case where the period TSYN of the synchronization signal SYNC is shorter than the peak period TX1. Referring to FIG. 5, when the period TSYN of the synchronization signal SYNC is shorter than the peak period TX1, the signal corrector 1224 corrects the signal value of the triangular wave signal to the signal value of the peak X following the timing at which the synchronization signal SYNC is received. This results in a corrected triangular wave signal TR11 as shown in the lower part of FIG.

[0054] (When the period of the synchronization signal is longer than the period of the peak) Fig. 6 is a timing chart showing a case where signal values ​​are not continuously processed at a predetermined vertex when the period TSYN of the synchronization signal SYNC is longer than the period TX1 of the vertices. Fig. 7 is a timing chart showing a case where signal values ​​are continuously processed at a predetermined vertex when the period TSYN of the synchronization signal SYNC is longer than the period TX1 of the vertices. Signal correction when the period TSYN of the synchronization signal SYNC is longer than the period TX1 of the vertices will be described below.

[0055] If the signal value is not continuously processed at a given vertex, a switch occurs as shown in Figure 6. Specifically, the switch occurs in the following stages.

[0056] First, when the signal value is decreasing from the peak X101, which is the maximum value of the triangular wave signal, the synchronization signal SYN11 is received with a delay time t1. If the signal value has already decreased to a value below the command value when the synchronization signal SYN11 is received, the PWM signal switches at the timing P1 when the command value and the signal value intersect.

[0057] Next, upon reception of the synchronization signal SYN11, the signal value returns to the signal value at vertex X101. This causes the command value and the signal value to intersect again. Furthermore, the signal value of the triangular wave signal decreases again from the signal value at vertex X101. In this case, the decrease in the signal value causes the command value and the signal value to intersect again. Therefore, switching of the PWM signal occurs at timing P2 of vertex RX101 and timing P3 where the command value and the signal value intersect again.

[0058] It should be noted that the same switching of the PWM signal as described above may occur at the vertex where the triangular wave signal has its minimum value.

[0059] In order to prevent the above-described switching from occurring, the signal generating device 12 performs signal processing as follows. Referring to Fig. 7 in addition to Fig. 4, in the signal generating device 12, the carrier wave signal output unit 122 generates a triangular wave signal based on the clock signal CK2 generated by the clock signal output unit 121. In detail, the triangular wave signal generated by the triangular wave signal output unit 1221 reaches a maximum value at the vertex X11 (first vertex).

[0060] Furthermore, the triangular wave signal output unit 1221 decreases the signal value of the triangular wave signal, causing the command value and the signal value to intersect at timing P11. At a subsequent timing P12, the carrier wave signal output unit 122 receives a synchronization signal SYN11 (first synchronization signal). The delay time detection unit 1223 detects a delay time t1 (first delay time) relative to the timing of the vertex X11 (first vertex timing).

[0061] The triangular wave signal output unit 1221 decreases the signal value of the triangular wave signal from the timing of the vertex X11 for the period of the vertex cycle TX1. At the vertex X21 (second vertex) next to the vertex X11, the triangular wave signal reaches its minimum value.

[0062] The signal corrector 1224 corrects the triangular wave signal at the timing of the vertex X21 (second vertex timing) so that the signal value of the vertex X21 is maintained for the delay time t1. In other words, the signal corrector 1224 stops counting up the signal value for the delay time t1 from the timing of the vertex X21.

[0063] After the delay time t1 has elapsed, the triangular wave signal output unit 1221 changes the signal value at the timing of the corrected peak RX21. In other words, the triangular wave signal output unit 1221 resumes counting up the signal value at the corrected peak RX21.

[0064] Thereafter, when the carrier wave signal output unit 122 receives the synchronization signal SYN12 (second synchronization signal), the delay time detection unit 1223 detects the delay time t2 (second delay time) relative to the timing of the vertex RX21.

[0065] The triangular wave signal output unit 1221 increases the signal value of the triangular wave signal for the period of the vertex TX1. After the command value and the signal value intersect at timing P13, the triangular wave signal reaches its maximum value at vertex X31 (third vertex) next to vertex RX21.

[0066] The signal corrector 1224 corrects the triangular wave signal at the timing of the vertex X31 (third vertex timing) so that the signal value of the vertex X31 is maintained for the delay time t2.

[0067] The triangular wave signal output unit 1221 decreases the signal value at the timing of the corrected vertex RX31 after delay time t2 has elapsed from the timing of the vertex X31. After the command value and the signal value intersect at timing P14, the triangular wave signal output unit 1221 receives the synchronization signal SYN11 with a delay of delay time t3 from the timing of the corrected vertex RX31, and then repeats the signal correction described above.

[0068] As described above, the signal generating device 12 includes a triangular wave signal output unit 1221 that outputs a triangular wave signal in which vertices (X1, X2, X3, ...) where the signal value reaches a maximum or minimum value repeatedly appear, a vertex timing detection unit 1222 that detects the timing of the vertices (X1, X2, X3, ...) of the triangular wave signal, a delay time detection unit 1223 that detects the delay time t1 from the timing of the vertex detected by the vertex timing detection unit 1222 to the timing of receiving the synchronization signal SYNC, and a signal correction unit 1224 that corrects the triangular wave signal based on the delay time t1 detected by the delay time detection unit 1223. When a delay time t1 is detected from the first vertex timing, which is the timing of the first vertex detected by the vertex timing detection unit 1222, to the timing at which the first synchronization signal SYN11, which is the synchronization signal SYNC, is received, the signal correction unit 1224 corrects the triangular wave signal at the second vertex timing, which is the timing of the second vertex that is the vertex next to the first vertex timing, by the delay time t1.

[0069] In the above configuration, delay time t1 occurs when the period TSYN of the synchronization signal SYNC is longer than the vertex period TX1, which is the period during which the vertices (X1, X2, X3, ...) repeatedly appear. The vertex period TX1 is half the period of the triangular wave signal. Therefore, delay time t1 occurs when the period TSYN of the synchronization signal SYNC is longer than half the period of the triangular wave signal.

[0070] In the above configuration, when a delay time t1 is detected, the signal corrector 1224 corrects the triangular wave signal so that the signal value at the next vertex X21 is maintained for the duration of the delay time t1. Therefore, even when a delay time t1 occurs, the signal value of the triangular wave signal can be prevented from intersecting with the command value. This prevents an increase in the number of times the switching control signal, which is generated based on the command value and the triangular wave signal, switches. This prevents an increase in power consumption due to an increase in the number of times the switching control signal switches.

[0071] Therefore, it is possible to correct the missynchronization of the plurality of signal generators 11, 12, and 13 and generate switching control signals for the power converters 21, 22, and 23 while suppressing an increase in the number of switching operations.

[0072] Furthermore, as described above, when a delay time t2 is detected from the timing at which the continuation of the signal value at the next vertex X21 is completed to the timing at which the second synchronization signal SYN12, which is the synchronization signal subsequent to the first synchronization signal SYN11, the signal correction unit 1224 corrects the triangular wave signal so that the signal value at the vertex X31 is continued for the delay time t2 at the third vertex timing, which is the vertex timing subsequent to the second vertex timing.

[0073] In the above configuration, the triangular wave signal is corrected at the third vertex by using the delay time t2 after the signal value is maintained at the second vertex, thereby correcting the synchronization error of the multiple signal generators 11, 12, and 13 while suppressing an increase in the number of switching times, even at the third vertex.

[0074] Furthermore, in the above-described power conversion system SYS1, a system capable of correcting the synchronization deviation of the plurality of signal generation devices 11, 12, and 13 and generating switching control signals for the power conversion devices 21, 22, and 23 can be easily realized.

[0075] (Variation 1) Fig. 8 is a timing chart of signal correction by the signal generating device 12 according to Modification 1. The signal generating device 12 according to Modification 1 will be described with reference to Fig. 8 in addition to Fig. 4. If the signal correcting unit 1224 receives a synchronization signal SYN12 while the signal value of the triangular signal wave is maintained at vertex X21 (second vertex) for delay time t1, the signal correcting unit 1224 changes the signal value at timing P21 when the synchronization signal SYN12 is received.

[0076] The delay time detector 1223 may detect the time t21 from the timing of the vertex X21 to the timing P21 at which the synchronization signal SYN12 is received.

[0077] In this case, the period TSYN of the synchronization signal SYNC may be shorter than the period TX1 of the peak. Therefore, the delay time detection unit 1223 may perform the signal correction shown in FIG.

[0078] In the above-described configuration, the synchronization signal SYN12 can be processed with priority over the continuation of the signal value at the peak X21 of the triangular wave signal. A case in which the synchronization signal SYN12 is received while the signal value at the peak X21 of the triangular wave signal is continuing may occur, for example, when a synchronization error is alleviated or eliminated. In such a case, the synchronization signal SYN12 is given priority, and the synchronization error of the multiple signal generators 11, 12, and 13 can be corrected to generate switching control signals for the power converters 21, 22, and 23.

[0079] (Variation 2) Fig. 9 is a timing chart of signal correction by the signal generating device 12 according to Modification 2. The signal generating device 12 according to Modification 2 will be described with reference to Fig. 9 in addition to Fig. 4. If the delay time t12 (first delay time) relative to the timing of vertex X21 (first vertex) is equal to or longer than half the vertex period TX1 and is equal to or shorter than the vertex period TX1, the signal correcting unit 1224 recognizes that the next synchronization signal SYN13 (first synchronization signal) to be received is the synchronization signal following the synchronization signal SYN12 that was originally supposed to be received.

[0080] Specifically, the triangular wave signal generated by the triangular wave signal output unit 1221 reaches a maximum value at vertex X11. In the example shown in Fig. 9, the carrier wave signal output unit 122 receives the synchronization signal SYN11 at the timing of vertex X11. The signal generating device 12 is synchronized by the synchronization signal SYNC at the timing of vertex X11.

[0081] The triangular wave signal output unit 1221 decreases the signal value of the triangular wave signal from the timing of vertex X11 to the timing of vertex X21, where the signal value is the minimum. The carrier wave signal output unit 122 does not receive a synchronization signal from the timing of vertex X11 to the timing of vertex X21. Furthermore, the triangular wave signal output unit 1221 increases the signal value of the triangular wave signal at the timing of vertex X21.

[0082] At timing P32 after vertex X21, the carrier signal output unit 122 receives the synchronization signal SYN13. The delay time detection unit 1223 detects a delay time t12 relative to the timing of vertex X21. The delay time t12 is equal to or longer than half the period of the vertex cycle TX1, but is equal to or shorter than the vertex cycle TX1.

[0083] Because the delay time t12 is a predetermined length, the signal corrector 1224 corrects the signal value of the triangular wave signal to the next vertex RX32 at timing P32 when the synchronization signal SYNC13 is received. The signal corrector 1224 changes the signal value from the maximum value of the triangular wave signal at vertex RX32. In other words, when the signal corrector 1224 receives the synchronization signal SYNC13, it reduces the signal value of the triangular wave signal from its maximum value.

[0084] If the delay time t12 is longer than half the peak period TX1, it is possible that the synchronization signal SYN12 that should have been received was not received for some reason. Therefore, in the above case, the delay time t12 may have been detected by receiving the synchronization signal SYN13 that follows the synchronization signal SYN12 that should have been received.

[0085] In other words, the time TSYN13 between synchronization signals SYN11 and SYN13 is not the period of synchronization signal SYNC, but the period of two synchronization signals. It is also possible that synchronization signal SYN13 arrived earlier than its intended period. Note that the difference between the master and slave clock signals is small compared to the period of the triangular wave signal, and it is generally unlikely that a control signal would be received beyond the peak period TX1.

[0086] In the above-described configuration, when there is a possibility that this has been detected by receiving the synchronization signal SYNC13 that follows the synchronization signal SYN12 that should have been received, the signal correction unit 1224 corrects the signal value of the triangular wave signal to the signal value of the next vertex RX32.

[0087] As a result, if the synchronization signal SYN12 cannot be received, the synchronization signal SYN12 that should have been received can be ignored, and appropriate correction can be made to recover synchronization using the synchronization signal SYNC.

[0088] (Other embodiments) Although the embodiments of the present invention have been described above, the above-described embodiments are merely examples for carrying out the present invention. Therefore, the present invention is not limited to the above-described embodiments, and it is possible to appropriately modify the above-described embodiments within the scope of the spirit of the present invention.

[0089] In the above-described embodiment and each modified example (hereinafter referred to as "embodiments, etc."), three signal generators 11, 12, and 13 are connected to three power electronics devices 21, 22, and 23. However, the number of signal generators or power electronics devices may be two, or may be four or more. Furthermore, the inputs or outputs of the power electronics devices may be connected in series or in parallel.

[0090] In the above-described embodiment, the signal generating devices 11, 12, and 13 are connected in series by a synchronization signal transmission cable 31 such as an optical communication cable. However, a plurality of signal generating devices acting as slaves may be connected in parallel to one signal generating device acting as a master.

[0091] In the above-described embodiment, the signal generating device 11 is the master. However, the signal generating device may be changeable between master and slave.

[0092] In the above-described embodiment, the slave signal generating devices 12 and 13 are electrically connected to the power conversion devices 22 and 23. However, the control board of the power conversion device may have the signal generating device. [Industrial Applicability]

[0093] The present invention can be used in a signal generating device that generates a switching control signal for a power conversion device. [Explanation of symbols]

[0094] 11, 12, 13: Signal generation device 21, 22, 23: Power conversion device 31: Synchronization signal transmission cable 111: Clock signal output section 112: Carrier signal output unit 1121: Triangular wave signal output section 1122: Synchronization signal output section 113: Switching control signal output section 121: Clock signal output section 122: Carrier signal output section 1221: Triangular wave signal output section 1222: Vertex timing detector 1223: Delay time detection unit 1224: Signal correction unit 1225: Synchronization signal output section SYS1: Power conversion system

Claims

1. A signal generating device that generates a switching control signal for a power conversion device based on a command value and a triangular wave signal that is a carrier wave while synchronizing with a synchronization signal that synchronizes a plurality of signal generating devices, a triangular wave signal output unit that outputs a triangular wave signal in which peaks at which the signal value reaches a maximum or minimum value repeatedly appear; a peak timing detection unit that detects the timing of the peak of the triangular wave signal; a delay time detection unit that detects a delay time from the timing of the apex detected by the apex timing detection unit to the timing of receiving the synchronization signal; a signal correction unit that corrects the triangular wave signal based on the delay time detected by the delay time detection unit; and The signal correction unit when the delay time detection unit detects a first delay time, which is the delay time from a first vertex timing as the timing of the first vertex that is the vertex detected by the vertex timing detection unit to a timing of receiving the first synchronization signal that is the synchronization signal, the triangular wave signal is corrected at a second vertex timing as the timing of a second vertex that is the vertex next to the first vertex, by the first delay time. Signal generation device.

2. 2. The signal generating device according to claim 1, when the delay time detection unit detects a second delay time, which is the delay time from the timing at which the continuation of the signal value at the second apex is completed to the timing at which a second synchronization signal, which is the synchronization signal next to the first synchronization signal, is received, the signal correction unit corrects the triangular wave signal so that the signal value at the third apex is continued for the second delay time at a third apex timing, which is the timing of a third apex subsequent to the second apex timing. Signal generation device.

3. 2. The signal generating device according to claim 1, When the synchronization signal is received while the signal value is maintained at the second vertex, the signal correction unit changes the signal value at the timing when the synchronization signal is received. Signal generation device.

4. 2. The signal generating device according to claim 1, When the first delay time is equal to or longer than half the period of the cycle in which the signal value of the triangular wave signal reaches a maximum value and is equal to or shorter than the period, the signal correction unit corrects the signal value of the triangular wave signal to the signal value of the second peak at a timing when the first synchronization signal is received, thereby changing the signal value. Signal generation device.

5. A plurality of signal generating devices according to any one of claims 1 to 4; A plurality of the power conversion devices; and one signal generator among the plurality of signal generators outputs the synchronization signal to another signal generator; the plurality of power conversion devices convert power based on the switching control signal generated by the one signal generation device or the other signal generation device based on the synchronization signal; Power conversion systems.

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