Power Supply System

Abstract

In a non-contact power supply system 110, a main power supply device and a sub power supply device are each equipped with a timer counter 25 that counts at a predetermined cycle and generate AC current on the basis of the count value of the timer counter 25. The main power supply device transmits a rectangular wave to the sub power supply device. The sub power supply device generates interrupt processing at a timing in which the value of the rectangular wave transmitted from the main power supply device changes and compares the count value of the timer counter 25 at said timing with a determination value. When the count value is smaller than the determination value in the comparison result, the sub power supply device makes the carrier cycle of the timer counter 25 shorter than the predetermined cycle. When the count value is greater than the determination value in the comparison result, the sub power supply device makes the cycle of the timer counter longer than the predetermined cycle.

Description

[Technical Field]

[0001] The present invention relates to a power supply system. [Background technology]

[0002] A known conventional power supply system is described in, for example, Patent Document 1. The power supply system described in Patent Document 1 includes one main power conversion device and one or more sub power conversion devices. Each power conversion device includes a time counter and a carrier wave generation unit that generates a carrier wave in synchronization with the time counter. The main power conversion device includes a synchronization data generation unit that generates synchronization data for synchronizing the value of the sub time counter with the main time counter when the time counter reaches a predetermined value, and a communication unit that transmits the synchronization data to the sub. The sub power conversion device includes a communication unit that receives the synchronization data, a time counter correction processing unit that corrects the value of the time counter based on the synchronization data, a current sensor that detects the output current of the sub power conversion device, and a gate timing adjustment unit that advances or delays the phase of the gate signal of the sub power conversion device based on a reflux current component. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 5901861 Summary of the Invention [Problem to be solved by the invention]

[0004] In conventional power supply systems, the synchronization data generated by the synchronization data generator of the main power conversion device includes a communication time. When the synchronization data includes a communication time, it takes time to generate the synchronization data and also time to receive the synchronization data. Therefore, when the system is used as a high-frequency power source, for example, and synchronization control is required in a shorter time, appropriate synchronization control may not be achieved.

[0005] An object of one aspect of the present invention is to provide a power supply system that can speed up synchronous control between a plurality of power supply devices. [Means for solving the problem]

[0006] A power supply system according to one aspect of the present invention is a power supply system comprising a first power supply device that generates an AC current, and one or more second power supply devices that generate an AC current synchronized in phase with the AC current of the first power supply device, wherein each of the first power supply device and the second power supply device has a timer counter that counts at a predetermined period and generates the AC current based on the count value of the timer counter, the first power supply device transmits a rectangular wave to the second power supply device that has a first value when the count value of the timer counter is less than a threshold value, and a second value when the count value is equal to or greater than the threshold value, the second power supply device generates an interrupt process at a timing when the value of the rectangular wave transmitted from the first power supply device changes, compares the count value of the timer counter at that timing with a judgment value, and if the comparison result shows that the count value is smaller than the judgment value, shortens the period of the timer counter than the predetermined period, and if the comparison result shows that the count value is greater than the judgment value, lengthens the period of the timer counter than the predetermined period.

[0007] In a power supply system according to one aspect of the present invention, the second power supply device generates an interrupt process when the value of a square wave transmitted from the first power supply device changes, and compares the count value of a timer counter at that time with a determination value. If the comparison result indicates that the count value is smaller than the determination value, the second power supply device shortens the period of the timer counter to a predetermined period, and if the comparison result indicates that the count value is greater than the determination value, the second power supply device lengthens the period of the timer counter to a predetermined period. In this way, in the power supply system, the information (data, signals) transmitted from the first power supply device to the second power supply device is a square wave, thereby reducing the time required for the first power supply device to generate information related to synchronization control and reducing the time required for the second power supply device to receive information. Furthermore, in the power supply system, the time required from when the timer counter reaches a threshold value to when the interrupt process is generated can be shortened, thereby enabling the first power supply device and the second power supply device to synchronize in a short time (high speed). Therefore, the power supply system can achieve high-speed synchronization control between multiple power supply devices.

[0008] In one embodiment, the determination value may be set based on a communication time required for communication between the first power supply device and the second power supply device and a threshold value. In this configuration, the determination value is set taking into consideration delays that occur in communication between the first power supply device and the second power supply device. Therefore, in the power supply system, the first power supply device and the second power supply device can be appropriately synchronized.

[0009] In one embodiment, each of the first value and the second value may be one bit of information. In this configuration, a change in the value of the square wave can be determined by one bit, so that interrupt processing can be generated at high speed.

[0010] In one embodiment, the second power supply device may shorten the period of the timer counter by a predetermined amount when the comparison result indicates that the count value is smaller than the determination value, lengthen the period of the timer counter by a predetermined amount when the comparison result indicates that the count value is greater than the determination value, and return the period of the timer counter to the predetermined period when the comparison result indicates that the count value is equal to the determination value after changing the period of the timer counter. In this configuration, the change in the period of the timer counter is limited to the predetermined amount, thereby preventing large changes in the period.

[0011] In one embodiment, each of the first power supply device and the second power supply device may supply power in a contactless manner.

[0012] In one embodiment, the first power supply device and the second power supply device are set by performing switching control in each of the plurality of power supply devices, and a number is assigned to each of the plurality of power supply devices, and switching to the first power supply device or the second power supply device may be performed based on the presence or absence of power supply and the number. With this configuration, the first power supply device and the second power supply device can be appropriately set in the plurality of power supply devices. [Effects of the Invention]

[0013] According to one aspect of the present invention, it is possible to increase the speed of synchronous control among a plurality of power supply devices. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a diagram schematically illustrating a track of a transportation system including a power supply system according to an embodiment. [Figure 2] FIG. 2 is a diagram showing the configuration of the contactless power supply device. [Figure 3] FIG. 3 is a diagram showing communication between contactless power supply devices in the power supply system. [Figure 4] FIG. 4 is a diagram illustrating the configuration of the control device. [Figure 5]FIG. 5 is a diagram showing the relationship between the operation of the power supply device and the state of the contactless power supply device. [Figure 6] FIG. 6 is a diagram showing a carrier period and a synchronization signal. [Figure 7] 7(a) and 7(b) are diagrams showing examples of judgment values ​​in a carrier cycle. [Figure 8] FIG. 8 is a diagram for explaining the synchronization process. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same or corresponding elements are designated by the same reference numerals, and redundant description will be omitted.

[0016] As shown in Fig. 1, the conveying system 100 is a system for conveying articles using an overhead transport vehicle 120 that is movable along a track rail T. The track rail T is a member that allows the overhead transport vehicle 120 to travel, and is suspended from the ceiling.

[0017] The conveyance system 100 includes a contactless power supply system (power supply system) 110 and an overhead transport vehicle 120. In the conveyance system 100, power is supplied to the overhead transport vehicle 120 in a contactless manner from power supply lines 12A and 12B provided on the track rail T. The overhead transport vehicle 120 travels using the power supplied from the power supply lines 12A and 12B. The overhead transport vehicle 120 drives various devices provided on the overhead transport vehicle 120 using the power supplied from the power supply lines 12A and 12B.

[0018] The overhead transport vehicle 120 includes, for example, a ceiling-suspended crane, an OHT (Overhead Hoist Transfer), etc. The goods include, for example, a container for storing multiple semiconductor wafers, a container for storing glass substrates, a reticle pod, general parts, etc.

[0019] The track rail T is, for example, a circular track. The overhead transport vehicle 120 travels clockwise on the track rail T. Power is supplied to the power feeders 12A and 12B from the non-contact power feeders 1A, 1B, 1C, and 1D. The power feeders 12A and 12B are arranged below the track rail T in the traveling direction of the overhead transport vehicle 120, on at least one of the right and left sides of the track center. Note that the power feeder 12B is arranged below the power feeder 12A, and therefore overlaps below the power feeder 12A in FIG. 1 .

[0020] The arrangement of the power feeders 12A and 12B with respect to the track rail T is changed by the switching unit 30. In the initial area where the power feeders 12A and 12B are connected to the contactless power feeders 1A, 1B, 1C, and 1D, the power feeders 12A and 12B are arranged on the left side of the track rail T. When the overhead transport vehicle 120 travels on the track rail T in the traveling direction, the arrangement of the power feeders 12A and 12B is switched from the left side to the right side of the track rail T by the switching unit 30.

[0021] The contactless power supply system 110 includes contactless power supply devices 1A, 1B, 1C, and 1D. The contactless power supply devices 1A, 1B, 1C, and 1D supply power to an overhead transport vehicle 120 in a contactless manner. The contactless power supply devices 1A, 1B, 1C, and 1D supply high-frequency current. The high frequency is, for example, 9 kHz.

[0022] 2, contactless power supply devices 1A, 1B, 1C, and 1D include a power supply 2, a molded case circuit breaker 3, a noise filter 4, a power factor correction device 5, a rectifier 6, a smoother 7, an inverter 8, a filter circuit 9, a first current sensor 10, a second current sensor 11, power supply lines 12A and 12B, and a control device 13. The noise filter 4, the power factor correction device 5, the rectifier 6, and the smoother 7 configure a power converter 16.

[0023] The power source 2 is a facility that supplies AC power such as a commercial power source, and supplies AC power (three-phase 200V). The frequency of the AC power is, for example, 50 Hz or 60 Hz. The molded case circuit breaker 3 opens the electrical circuit when an overcurrent flows. The noise filter 4 removes noise from the AC power. The noise filter 4 is made up of, for example, a capacitor. The power factor correction device 5 improves the power factor by making the input current closer to a sine wave. The power factor correction device 5 is made up of, for example, a reactor.

[0024] The rectifier 6 converts AC power supplied from the power source 2 (power factor correction device 5) into DC power. The rectifier 6 is formed of a rectifying element such as a diode, for example. The rectifier 6 may be formed of a switching element such as a transistor. The smoother 7 smoothes the DC power converted by the rectifier 6. The smoother 7 is formed of an electrolytic capacitor, for example. The voltage converter may further have a step-up / step-down function.

[0025] The inverter 8 converts the DC power output from the smoother 7 into AC power and outputs it to the filter circuit 9. The inverter 8 changes the magnitude of the AC power output to the filter circuit 9 by changing the switching frequency based on a control signal output from the control device 13. The inverter 8 has a plurality of switching elements 14. The switching elements 14 are elements that can be electrically switched between open and closed. Examples of the switching elements 14 that can be used include MOSFETs (Metal Oxide Semiconductor Field Effect Transistors), IGBTs (Insulated Gate Bipolar Transistors), and bipolar transistors.

[0026] The filter circuit 9 is provided between the inverter 8 and the power supply lines 12A and 12B. The filter circuit 9 suppresses harmonic noise. The filter circuit 9 includes a reactor RT1, a capacitor C0, a capacitor C1, a reactor RT2, and a capacitor C2.

[0027] The capacitor C0 and the reactor RT1 are connected in series to form a first resonant circuit RC1. The reactor RT1 includes a coil L11 and a coil L12. The reactor RT2 and the capacitor C2 are connected in series to form a second resonant circuit RC2. The first resonant circuit RC1 and the second resonant circuit RC2 are connected in series.

[0028] The first current sensor 10 detects a current I1 (inverter current) output from the inverter 8, i.e., flowing through the inverter 8. The first current sensor 10 outputs a first current signal indicating the detected current I1 to the control device 13. The second current sensor 11 detects a current I2 (supply current) of the AC power passing through the second resonant circuit RC2. The second current sensor 11 outputs a second current signal indicating the detected current I2 to the control device 13.

[0029] The control device 13 controls the operation of the inverter 8. The control device 13 is a computer system or processor implemented in an integrated circuit. The control device 13 is composed of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and an input / output interface, etc. Various programs and data are stored in the ROM.

[0030] The control device 13 is connected to the first current sensor 10 and the second current sensor 11 of the filter circuit 9. The control device 13 receives the first current signal and the second current signal output from the first current sensor 10 and the second current sensor 11, respectively.

[0031] The control device 13 controls the inverter 8 to control the magnitude of the AC power (AC current) supplied to the power feeders 12A and 12B, and thereby controls the magnitude of the power supplied to the overhead transport vehicle 120. In this embodiment, the power control is performed using, for example, phase shift control. In the phase shift control, a power control parameter for controlling the magnitude of the AC power is changed. The control unit 15 performs phase shift control to change the magnitude (frequency) of the AC power by changing the on-period of the inverter 8. The control device 13 adjusts the switching frequency of each switching element 14 using drive signals to the multiple switching elements 14 of the inverter 8, and changes the on-period of each switching element 14. The power control parameter in the phase shift control is the on-period of each switching element 14 of the inverter 8.

[0032] The control device 13 performs power control based on the first current signal and the second current signal output from the first current sensor 10 and the second current sensor 11, respectively, so that the value of the power transmitted to the ceiling transport vehicle 120 becomes a target value.

[0033] 3, in the contactless power supply system 110, the control devices 13 of the contactless power supply devices 1A, 1B, 1C, and 1D are connected to each other so that they can communicate with each other. In this embodiment, the control devices 13 communicate with each other using, for example, a half-duplex communication method. Specifically, the control devices 13 communicate with each other using, for example, RS485 communication. The control devices 13 communicate synchronization signals and data.

[0034] In the contactless power supply system 110, the current phase of an AC current generated by one of the contactless power supply devices 1A, 1B, 1C, and 1D is synchronized with the current phase of an AC current generated by the other three of the contactless power supply devices 1A, 1B, 1C, and 1D. In the contactless power supply system 110, by synchronizing the current phases of the AC currents of the contactless power supply devices 1A, 1B, 1C, and 1D, cancellation of the AC currents in the contactless power supply devices 1A, 1B, 1C, and 1D is suppressed.

[0035] In the contactless power feeding system 110, the phases of AC currents in the contactless power feeding devices 1A, 1B, 1C, and 1D are synchronized based on a synchronization signal transmitted from one of the contactless power feeding devices 1A, 1B, 1C, and 1D to the other three contactless power feeding devices. In the contactless power feeding system 110, one of the contactless power feeding devices 1A, 1B, 1C, and 1D serves as a main contactless power feeding device, and the other three contactless power feeding devices serve as sub contactless power feeding devices, and a synchronization signal is transmitted from the main contactless power feeding device to the sub contactless power feeding device. Hereinafter, the main contactless power feeding device that transmits the synchronization signal will be referred to as a "main power feeding device (an example of a first power feeding device)," and the sub contactless power feeding device that receives the synchronization signal will be referred to as a "sub power feeding device (an example of a second power feeding device)."

[0036] As shown in FIG. 4, each of the control devices 13 of the contactless power supply devices 1A, 1B, 1C, and 1D has a first communication unit 20, a second communication unit 21, a control unit 22, a synchronization processing unit 23, a current control unit 24, and a timer counter 25.

[0037] The first communication unit 20 performs data communication with the control devices 13 of the other contactless power supply devices 1A, 1B, 1C, and 1D. The first communication unit 20 transmits and receives data. In this embodiment, the first communication unit 20 performs communication using a half-duplex communication method. The first communication unit 20 is configured to be switchable between a transmission mode and a reception mode.

[0038] The first communication unit 20 of the main power supply device waits in a receiving mode and switches to a transmitting mode at a predetermined timing to transmit inquiry data to the sub power supply device. When the first communication unit 20 receives response data transmitted from the sub power supply device in the receiving mode, it outputs the response data to the control unit 22.

[0039] The first communication unit 20 of the sub-power supply device waits in a receiving mode and switches to a transmitting mode when it receives inquiry data transmitted from the main power supply device. The first communication unit 20 creates response data in response to the received inquiry data and transmits it to the main power supply device. The response data may include data indicating the device status (whether power is being supplied, whether the power is on or off, etc.).

[0040] The second communication unit 21 communicates synchronization signals with the control devices 13 of the other contactless power supply devices 1A, 1B, 1C, and 1D. The second communication unit 21 transmits and receives synchronization signals. In this embodiment, the second communication unit 21 communicates using a half-duplex communication method (see FIG. 4). The second communication unit 21 is provided so as to be switchable between a transmission mode and a reception mode. The second communication unit 21 switches between the transmission mode and the reception mode by the control unit 22.

[0041] When the second communication unit 21 is the main power supply device, it enters a transmission mode for transmitting a synchronization signal and transmits the synchronization signal output from the current control unit 24 to the sub power supply device. The second communication unit 21 transmits a synchronization signal whose value changes between two values, Hi and Low, at regular intervals (for example, 100 μs).

[0042] If the second communication unit 21 is a sub-power supply device, it enters a reception mode for receiving a synchronization signal and receives the synchronization signal. The second communication unit 21 of the sub-power supply device receives the synchronization signal at intervals of, for example, 100 μs. The second communication unit 21 outputs the received synchronization signal to the synchronization processing unit 23.

[0043] The control unit 22 switches between the main power supply device and the sub power supply device. When switching to the main power supply device, the control unit 22 sets the second communication unit 21 to a transmission mode and disables synchronization processing in the synchronization processing unit 23. When switching to the sub power supply device, the control unit 22 sets the second communication unit 21 to a reception mode and enables synchronization processing in the synchronization processing unit 23.

[0044] The control unit 22 switches between the main power supply device and the sub power supply device based on the presence or absence of power supply and the numbers set for the contactless power supply devices 1A, 1B, 1C, and 1D. In this embodiment, for example, the numbers "1" are set for the contactless power supply device 1A, "2" for the contactless power supply device 1B, "3" for the contactless power supply device 1C, and "4" for the contactless power supply device 1D.

[0045] In the switching process in the control unit 22, priorities are set for the presence or absence of power supply and the numbers of the contactless power supply devices 1A, 1B, 1C, and 1D. In this embodiment, the presence or absence of power supply is set as the first priority, and the numbers of the contactless power supply devices 1A, 1B, 1C, and 1D are set as the second priority. In other words, the presence or absence of power supply has a higher priority than the numbers of the contactless power supply devices 1A, 1B, 1C, and 1D. The control unit 22 switches between main and sub based on the presence or absence of power supply in the contactless power supply devices 1A, 1B, 1C, and 1D and the numbers of the contactless power supply devices 1A, 1B, 1C, and 1D.

[0046] The control unit 22 switches between the main and sub power supply devices 1A, 1B, 1C, and 1D by polling the other devices. The control unit 22 acquires the status of the other devices by polling and switches between the main and sub power supply devices. Specifically, the control unit 22 switches between the main and sub power supply devices based on a polling record and a response record to the polling record. When switching from the main power supply device to the sub power supply device, the control unit 22 transmits a main request record to the other devices. When the control unit 22 receives a main acceptance record from the other devices, it switches to the sub power supply device. The control unit 22 of the other devices switches to the main power supply device in response to the transmission of the main acceptance record.

[0047] An example of switching between the main and sub modes in the control unit 22 will be described with reference to Fig. 5. As shown in Fig. 5, the control unit 22 switches the contactless power supply devices 1A, 1B, 1C, and 1D among four states: main power supply device (power supply), sub power supply device (power supply), main power supply device (standby), and sub power supply device (standby).

[0048] For example, when contactless power supply devices 1A and 1C are on standby (standby state where they are not supplying power) and contactless power supply devices 1B and 1D are supplying power, control unit 22 of each of contactless power supply devices 1A, 1B, 1C, and 1D switches so that contactless power supply device 1B becomes the main power supply device (power supply) and contactless power supply devices 1A, 1C, and 1D become sub-power supply devices (standby, power supply). For example, when contactless power supply device 1C is on standby and contactless power supply devices 1A, 1B, and 1D are supplying power, control unit 22 of each of contactless power supply devices 1A, 1B, 1C, and 1D switches so that contactless power supply device 1A becomes the main power supply device (power supply) and contactless power supply devices 1B, 1C, and 1D become sub-power supply devices (standby, power supply).

[0049] For example, in the relationship between contactless power supply device 1A and contactless power supply device 1B, when contactless power supply device 1A is on standby and contactless power supply device 1B is supplying power, control unit 22 of each device switches so that contactless power supply device 1A becomes the sub-power supply device (standby) and contactless power supply device 1B becomes the main power supply device (power supply). After that, when contactless power supply device 1B goes on standby, control unit 22 of each device switches so that contactless power supply device 1A becomes the main power supply device (standby) and contactless power supply device 1B becomes the sub-power supply device. After that, when contactless power supply device 1A goes on power supply and then contactless power supply device 1B goes on power supply, control unit 22 of each device switches so that contactless power supply device 1A becomes the main power supply device (power supply) and contactless power supply device 1B becomes the sub-power supply device (power supply).

[0050] For example, in the relationship between contactless power supply device 1A and contactless power supply device 1B, when contactless power supply device 1A is supplying power and contactless power supply device 1B is on standby, control unit 22 of each device switches so that contactless power supply device 1A becomes the main power supply device (power supply) and contactless power supply device 1B becomes the sub-power supply device (standby). After that, when contactless power supply device 1A goes on standby, control unit 22 of contactless power supply device 1A switches so that contactless power supply device 1A becomes the main power supply device (standby). After that, when contactless power supply device 1A goes on power supply after going on power supply, control unit 22 of each device switches so that contactless power supply device 1A becomes the main power supply device (power supply) and contactless power supply device 1B becomes the sub-power supply device (power supply).

[0051] For example, in the relationship between contactless power supply device 1A and contactless power supply device 1B, when contactless power supply device 1A is supplying power and contactless power supply device 1B is on standby, control unit 22 of each device switches so that contactless power supply device 1A becomes the main power supply device (power supply) and contactless power supply device 1B becomes the sub-power supply device (standby). After that, when contactless power supply device 1B is supplying power, control unit 22 of contactless power supply device 1B switches so that contactless power supply device 1B becomes the sub-power supply device (power supply). After that, when contactless power supply device 1A is on standby, control unit 22 of each device switches so that contactless power supply device 1A becomes the sub-power supply device (standby) and contactless power supply device 1B becomes the main power supply device (power supply). Thereafter, when the contactless power supply device 1A is in the process of supplying power, the control units 22 of the respective devices perform switching so that the contactless power supply device 1A becomes the main power supply device (power supply) and the contactless power supply device 1B becomes the sub-power supply device (power supply).

[0052] As shown in Fig. 3, the synchronization processor 23 synchronizes the carrier cycle of the sub power supply device based on a synchronization signal transmitted from the main power supply device. The synchronization processor 23 corrects the carrier cycle of the sub power supply device based on the count value of the timer counter 25 and the synchronization signal. The timer counter 25 counts at a constant (predetermined) carrier cycle. In this embodiment, the constant carrier cycle is 9 kHz. That is, the timer counter 25 sets the predetermined carrier cycle to 9 kHz. However, the predetermined cycle is not limited to 9 kHz and may be another frequency.

[0053] FIG. 6 is a diagram showing the carrier period and synchronization signal in the timer counter 25. As shown in FIG. 6, the carrier period is a sawtooth wave. The synchronization signal is a square wave. In this embodiment, the synchronization signal is a U-phase positive signal. The synchronization signal is Hi (an example of a first value) when the count value of the timer counter 25 is less than a threshold value, and is Low (an example of a second value) when the count value is equal to or greater than the threshold value. Hi and Lo are 1-bit information. As shown in FIG. 6, the timer counter 25 counts up in one period of the synchronization signal.

[0054] The synchronization processor 23 generates an interrupt process when the value of the synchronization signal transmitted from the main power supply device changes, and compares the count value of the timer counter 25 at that timing with a determination value. The synchronization processor 23 stores the determination value. The determination value is set arbitrarily by the user. The determination value is set based on the communication time required for communication between the main power supply device and the sub power supply device, the control delay time of the synchronization process in the sub power supply device, and a threshold value. The communication time may include the delay time. The determination value is initially set to the intermediate value (threshold value) of the carrier cycle. The user changes (corrects) the determination value from the initial value by performing a predetermined input (operation).

[0055] 7(a) and 7(b) are diagrams showing examples of the judgment value. Fig. 7(a) shows an example in which the judgment value is an initial value. Fig. 7(b) shows an example in which the judgment value is a correction value. In the example shown in Fig. 7(b), the judgment value is set to a value whose count value is higher than the initial value (the intermediate value of the carrier period).

[0056] The synchronization processing unit 23 generates an interrupt process when it receives the synchronization signal output from the second communication unit 21. Specifically, the synchronization processing unit 23 generates an interrupt process at the falling edge of the synchronization signal (falling from Hi to Low). The synchronization processing unit 23 compares the falling edge of the synchronization signal with the carrier period counter, and performs synchronization processing based on the comparison result.

[0057] If the comparison result shows that the counter value is equal to the judgment value (counter value = judgment value), the synchronization processing unit 23 does not change the carrier period. If the comparison result shows that the counter value is smaller than the judgment value (counter value < judgment value), the synchronization processing unit 23 shortens the carrier period by a predetermined amount compared to the predetermined period. The predetermined amount is, for example, 0.5 μs. If the comparison result shows that the counter value is greater than the judgment value (counter value > judgment value), the synchronization processing unit 23 lengthens the carrier period by a predetermined amount compared to the predetermined period. The predetermined amount is, for example, 0.5 μs. After changing the carrier period of the timer counter 25, if the comparison result shows that the counter value is equal to the judgment value (counter value = judgment value), the synchronization processing unit 23 returns the carrier period to the predetermined period. Note that in this embodiment, "equal" may mean not only equal but also values ​​including slight differences within a preset range.

[0058] For example, as shown by P1 in Fig. 8, when the counter value is smaller than the judgment value, the synchronization processing unit 23 shortens the carrier period by a predetermined amount. When the counter value is still smaller than the judgment value, as shown by P2 in Fig. 8, the synchronization processing unit 23 keeps the carrier period shorter by a predetermined amount. When the counter value becomes equal to the judgment value, as shown by P3 in Fig. 8, the synchronization processing unit 23 sets the carrier period to a predetermined period. In other words, when the counter value and the judgment value match as a result of changing the carrier period, the synchronization processing unit 23 returns the carrier period to the predetermined period.

[0059] Current control unit 24 controls the current in contactless power supply devices 1A, 1B, 1C, and 1D. Current control unit 24 generates an AC current based on the count value of timer counter 25. When current control unit 24 is the main power supply device, it transmits a synchronization signal to the sub power supply device via second communication unit 21. When current control unit 24 is the sub power supply device, it synchronizes timer counter 25 based on the synchronization signal output from synchronization processing unit 23, and generates an AC current based on the count value of timer counter 25.

[0060] As described above, in the contactless power supply system 110 according to this embodiment, the sub power supply device generates an interrupt process when the value of the rectangular wave output signal transmitted from the main power supply device changes, and compares the count value of the timer counter at that time with a determination value. If the comparison result indicates that the count value is smaller than the determination value, the sub power supply device shortens the carrier period of the timer counter 25 to be shorter than a predetermined period. If the comparison result indicates that the count value is greater than the determination value, the sub power supply device lengthens the carrier period of the timer counter 25 to be longer than the predetermined period. In this way, in the contactless power supply system 110, the information (data, signals) transmitted from the main power supply device to the sub power supply device is a rectangular wave. This reduces the time required for the main power supply device to generate synchronization-related information and the time required for the sub power supply device to receive information. Furthermore, in the contactless power supply system 110, the time required from when the timer counter 25 reaches a threshold value to when the interrupt process is generated can be shortened, thereby enabling synchronization between the main power supply device and the sub power supply device to be achieved in a short time (high speed). Therefore, in the contactless power supply system 110, it is possible to speed up the synchronous control among a plurality of power supply devices.

[0061] In the contactless power feeding system 110 according to this embodiment, the determination value is set based on the communication time required for communication between the main power feeding device and the sub power feeding device and a threshold value. In this configuration, the determination value is set taking into consideration delays that occur in communication between the main power feeding device and the sub power feeding device. Therefore, in the contactless power feeding system 110, the main power feeding device and the sub power feeding device can be appropriately synchronized.

[0062] In the contactless power supply system 110 according to this embodiment, each of the Hi and Low values ​​of the synchronization signal is 1-bit information. In this configuration, since a change in the value of the synchronization signal can be determined by 1 bit, interrupt processing can be generated at high speed.

[0063] In the contactless power supply system 110 according to this embodiment, the sub-power supply device may shorten the carrier period of the timer counter 25 by a predetermined amount when the comparison result shows that the count value is smaller than the determination value, or may lengthen the carrier period of the timer counter by a predetermined amount when the comparison result shows that the count value is larger than the determination value, and may return the period of the timer counter 25 to the predetermined period when the comparison result shows that the count value is equal to the determination value after changing the S carrier period of the timer counter 25. In this configuration, the change in the period of the timer counter 25 is limited to a predetermined amount, thereby suppressing large changes in the carrier period.

[0064] In the contactless power feeding system 110 according to this embodiment, the control unit 22 of the control device 13 switches between the main power feeding device and the sub power feeding device based on the presence or absence of power feeding and the numbers set for the contactless power feeding devices 1A, 1B, 1C, and 1D. In this configuration, switching between the main power feeding device and the sub power feeding device can be performed appropriately.

[0065] Although the embodiments of the present invention have been described above, the present invention is not necessarily limited to the above-described embodiments, and various modifications are possible without departing from the spirit of the present invention.

[0066] In the above embodiment, an example has been described in which the contactless power supply system 110 is applied to the transportation system 100. However, the contactless power supply system 110 may be applied to other systems.

[0067] In the above embodiment, the power supply system is described as a contactless power supply system 110 that supplies power contactlessly. However, the form of power supply in the power supply system is not limited to contactless.

[0068] In the above embodiment, the contactless power supply system 110 is described as including four contactless power supply devices 1A, 1B, 1C, and 1D. However, the contactless power supply system 110 may include at least two contactless power supply devices.

[0069] In the above embodiment, the synchronization processing unit 23 generates an interrupt process at a falling edge (a transition from high to low) of the synchronization signal. However, the synchronization processing unit 23 may generate an interrupt process at a rising edge (a transition from low to high) of the synchronization signal.

[0070] In the above embodiment, an example has been described in which the traveling vehicle is an overhead transport vehicle 120. However, the moving body is not limited to an overhead transport vehicle, and may be any traveling vehicle that travels on a track rail T. For example, the traveling vehicle may be a floor transport vehicle (floor traveling vehicle). When the traveling vehicle is a floor transport vehicle, the track rail is laid on the floor surface.

[0071] The technical subject matter of one aspect of the present invention can be described as follows. [1] A power supply system including a first power supply device that generates an AC current, and one or more second power supply devices that generate an AC current synchronized in phase with the AC current of the first power supply device, Each of the first power supply device and the second power supply device includes a timer counter that counts at a predetermined cycle, and generates the AC current based on a count value of the timer counter; the first power supply device transmits a rectangular wave to the second power supply device, the rectangular wave having a first value when the count value of the timer counter is less than a threshold value, and a second value when the count value is equal to or greater than the threshold value; The second power supply device is generating an interrupt process at a timing when the value of the rectangular wave transmitted from the first power supply device changes, and comparing the count value of the timer counter at the timing with a determination value; If the count value is smaller than the determination value as a result of the comparison, the cycle of the timer counter is made shorter than the predetermined cycle; When the comparison result indicates that the count value is greater than the determination value, the cycle of the timer counter is made longer than the predetermined cycle. [2] The power supply system according to [1], wherein the determination value is a value set based on a communication time required for communication between the first power supply device and the second power supply device and the threshold value. [3] The power supply system according to [1] or [2], wherein each of the first value and the second value is one-bit information. [4] The second power supply device is If the count value is smaller than the determination value as a result of the comparison, the cycle of the timer counter is made shorter by a predetermined amount than the predetermined cycle; If the count value is greater than the determination value as a result of the comparison, the period of the timer counter is made longer by a predetermined amount than the predetermined period; The power supply system according to any one of [1] to [3], wherein, after the period of the timer counter is changed, if the comparison result shows that the count value is equal to the judgment value, the period of the timer counter is returned to the predetermined period. [5] The power supply system according to any one of [1] to [4], wherein the first power supply device and the second power supply device each supply power in a contactless manner. [6] each of the first power supply device and the second power supply device is set by performing switching control in each of a plurality of power supply devices; A number is assigned to each of the plurality of power supply devices, The power feeding system according to any one of [1] to [5], wherein switching to the first power feeding device or the second power feeding device is performed based on the presence or absence of power feeding and the number. [Explanation of symbols]

[0072] 1A, 1B, 1C, 1D...contactless power supply devices (first power supply device, second power supply device), 25...timer counter, 110...contactless power supply system (power supply system).

Claims

1. A power supply system including a first power supply device that generates an AC current, and one or more second power supply devices that generate an AC current synchronized in phase with the AC current of the first power supply device, Each of the first power supply device and the second power supply device includes a timer counter that counts at a predetermined cycle, and generates the AC current based on a count value of the timer counter; the first power supply device transmits a rectangular wave to the second power supply device, the rectangular wave having a first value when the count value of the timer counter is less than a threshold value, and a second value when the count value is equal to or greater than the threshold value; The second power supply device is generating an interrupt process at a timing when the value of the rectangular wave transmitted from the first power supply device changes, and comparing the count value of the timer counter at the timing with a determination value; If the count value is smaller than the determination value as a result of the comparison, the cycle of the timer counter is made shorter than the predetermined cycle; When the comparison result indicates that the count value is greater than the determination value, the cycle of the timer counter is made longer than the predetermined cycle.

2. The power supply system according to claim 1 , wherein the determination value is a value set based on a communication time required for communication between the first power supply device and the second power supply device and the threshold value.

3. The power supply system according to claim 1 , wherein each of the first value and the second value is one bit of information.

4. The second power supply device is If the count value is smaller than the determination value as a result of the comparison, the cycle of the timer counter is made shorter by a predetermined amount than the predetermined cycle; If the count value is greater than the determination value as a result of the comparison, the period of the timer counter is made longer by a predetermined amount than the predetermined period; 3. The power supply system according to claim 1, wherein after the period of the timer counter is changed, if the comparison result indicates that the count value is equal to the determination value, the period of the timer counter is returned to the predetermined period.

5. The power supply system according to claim 1 , wherein each of the first power supply device and the second power supply device supplies power in a contactless manner.

6. each of the first power supply device and the second power supply device is set by performing switching control in each of a plurality of power supply devices; A number is assigned to each of the plurality of power supply devices, The power supply system according to claim 1 or 2, wherein switching to the first power supply device or the second power supply device is performed based on whether or not power is being supplied and the number.

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