JP4579643B2 - Power supply system and power converter - Google Patents

Description

  The present invention relates to a power supply system and a power converter based on parallel operation of power converters, and relates to a parallel operation system of power converters that converts direct current into alternating current, and more particularly to an operation continuation system when the power converter is stopped.

  By operating in parallel a power converter that controls AC output (hereinafter referred to as “main machine”) and a power converter that controls output current (hereinafter referred to as “slave machine”), Benefits include improved power supply and improved power system reliability. In order to efficiently perform the parallel operation of the power converters, it is necessary to suppress the cross current flowing between the power converters.

In Patent Document 1, the AC current output from the main machine (AC power supply 1) for controlling the bus voltage is converted into an information form represented by a DC amount obtained by dividing the AC current into, for example, a phase, an amplitude, and an orthogonal component, This information is transmitted to the slave (AC power supply 2) that controls the output current using the communication means 20, and the slave 2 receives the AC output current information of the master 1 from the communication means 21 via the communication path 22. A method for controlling the AC output current based on the above is described (see FIGS. 6 and 7).
JP 2004-236394 A

  Patent Document 1 describes a state in which the power converter is started up and a state in which all the power converters are operating. However, the operation continuation method when the power converter stops during operation is considered. Absent. For this reason, for example, when the power converter that controls the bus voltage, that is, the main machine 1 is stopped, there is no power converter having a function of controlling the bus voltage, so the bus voltage becomes unstable and finally Becomes zero, the power supply to the load stops, the current command from the main unit becomes unstable, the output current of the slave unit 2 becomes larger than the actual load, boosts the bus voltage, and overloads the load. If applied, the load may be destroyed.

  The present invention solves the problems of the prior art, and even when the power converter that controls the bus voltage is stopped, the power supply system that stabilizes the bus voltage and does not stop the power supply to the load And it aims at providing a power converter.

  The present invention observes the bus voltage in the slave unit, and when the bus voltage is observed to be extremely high or low with respect to the command value of the bus voltage, or to the operating frequency of the bus voltage, the actual frequency When is extremely high or low, the function of the slave is switched to the master that controls the bus voltage. Means for switching the function of the slave unit may be provided based on the observation result or the observation result of the bus voltage.

  In addition, when the power converter that was operating as the main unit for controlling the bus voltage can be restarted, the power converter that is started by restarting the power converter as a slave unit and supplying power to the bus Since the number is the same as before the power converter is stopped, it is possible to prevent an increase in power borne by each power converter.

That is, this invention consists of the 1st power converter which controls the alternating voltage of a bus line, and the 2nd power converter which controls the alternating current supplied to a bus line, and supplies the alternating current which converted direct current to a bus line In the power supply system, each of the first and second power converters includes a conversion unit that converts the voltage on the bus side into a DC amount, an output voltage command that outputs the target voltage on the bus side in a DC amount, and power conversion Operation mode command generating means for receiving the state information of the vessel, determining the operation mode, and giving an operation command in the determined operation mode, and having a bus voltage control function and an output current control function, and voltage control The power supply system can operate in either the mode or the current control mode, and has a communication unit that transmits and receives information on an abnormal state in which each power converter is not stopped, deteriorated in function, or does not start.

  In addition, the present invention is a power supply system that operates in a voltage control mode when one of the second power converters receives information that the first power converter is in an abnormal state.

  The present invention further comprises bus state monitoring means for determining that the first power converter is in an abnormal state in which the first power converter is not stopped, deteriorated in function or rises due to a change in the bus voltage, and the bus state monitoring means is the first bus state monitoring means. When an abnormal state of the power converter is detected, one of the second power converters is a power supply system that operates in a voltage control mode.

  Furthermore, the present invention includes a communication discriminating unit that discriminates the operating state of the communication unit. When an abnormality is recognized in the communication unit by the communication discriminating unit, the detection result of the bus state monitoring unit is given priority. The power supply system operates in the determined operation mode of the power converter.

  In addition, the present invention is a power supply system in which the first power converter is restarted by operation in a current control mode when the first power converter does not stop, deteriorate in function, or does not start up.

  And this invention is a power supply system provided with the connection circuit interruption | blocking means which cut | disconnects these connections between the output terminal of a power converter, and a bus-line.

  Further, according to the present invention, the bus has a bus disconnection means that constitutes a power converter parallel connection group composed of one or more power converters at the time of disconnection, and the operation mode and operating status of each power converter, The power supply system includes an open / close command unit that gives an open / close command to the connection circuit cut-off unit or the busbar cut-off unit to be set to an open / close state determined according to an operating state of the communication unit.

In addition, the present invention is a power converter that has a bus voltage control function and an output current control function, and can operate in either a voltage control mode or a current control mode, and converts the voltage on the bus side into a DC amount. Operation mode command generating means for receiving an output voltage command for outputting a target voltage on the bus side in a DC amount and status information of the power converter, determining an operation mode, and giving an operation command in the determined operation mode And a power converter having communication means for transmitting / receiving abnormal state information indicating that the power converter has stopped or deteriorated in function to / from another power converter.

  According to the present invention, even if the first power converter that controls the bus voltage stops, the second power converter that controls the current immediately operates as the first power converter. The bus voltage can be stably maintained, and a highly reliable and high quality power supply system and power converter can be provided.

The best mode for carrying out the present invention will be described.
The present invention converts the alternating current output from the main machine into an information form represented by, for example, a DC amount obtained by dividing the alternating current into a phase, an amplitude, and a quadrature component. To transmit. The slave unit controls the AC output current based on the AC output current information of the main unit obtained from the communication means. In addition, each power converter has both the main and slave functions, and has a unique startup time.If the bus voltage does not rise after the startup time, If the bus voltage rises before the start-up time, it is operated as a slave. Hereinafter, the Example of the power supply system and power converter of this invention is described using FIGS.

  Example 1 will be described. As shown in FIG. 1, the power supply system of the present embodiment includes an AC power supply 1 and an AC power supply 2 connected to the bus 100, and one or more load devices (not shown) to which the AC power is supplied to the bus 100. Connected).

  The AC power source 1 includes a DC voltage source 11, a DC / AC converter 12 that uses the DC voltage source 11 as a power source and obtains an AC output, a filter circuit 13 that shapes an AC output output from the DC / AC converter 12, A transformer 14 connected between the bus 100 and the filter circuit 13 and absorbing the difference between these neutral point potentials, a conversion means 15 for converting the voltage on the bus side of the transformer 14 into a direct current, and a transformer The output voltage command (generator) 16 that outputs the target voltage on the bus side of 14 as a DC amount, and the AC output of the DC / AC converter 12 so that the output of the conversion means 15 and the output of the output voltage command 16 match. The output control means 17 to adjust, the conversion means 18 for converting the alternating current on the bus side of the transformer 14 into a direct current amount, and the output signal of the conversion means 18 are transmitted to and received from the AC power source 2 to be described later via the communication path 22. Communication means 21 and An output current control means 17a that adjusts an output signal of the means 18 using information of an AC output current of the AC power supply 2 that is an output of the communication means 21, and an output of the output voltage control means 17 or an output of the output current control means 17a Is a first power converter that operates in the voltage control mode and controls the AC voltage of the bus 100. The operation mode selection means 19 selects and outputs to the DC / AC converter 12.

  The AC power supply 2 is the same as the AC power supply 1, and includes a DC voltage source 11, a DC / AC converter 12, a filter circuit 13, a transformer 14, conversion means 15, and an output voltage command (generator) 16. The output control means 17, the conversion means 18, the communication means 21, the output current control means 17a, and the operation mode selection means 19, and operates in the current control mode and supplies the AC voltage supplied to the bus 100. It is the 2nd power converter to control.

  The power converter 1 serving as the main machine controls the bus voltage, converts the AC output current into a DC amount, and transmits information on the AC output current to the slave machine via the communication means. In addition, as a method of expressing the AC output current as a DC amount, there are a method of expressing with an amplitude and a phase, a method of decomposing into an orthogonal component, and expressing with an amplitude of a real axis component and an imaginary axis component. Further, the power converter 2 as the slave unit is configured so that the value obtained by converting the AC output current flowing into the bus into a DC amount matches the value of the DC amount of the AC output current of the main unit obtained through the communication means. Control AC output current.

  By transmitting AC output current information as a DC amount, there is no delay, and by using communication means, the effect of improving noise resistance can be obtained, and the AC output current of the slave unit can be safely and easily Therefore, parallel operation is realized in a state where no cross current occurs between the power converters.

  By the way, in the AC power supply system shown in FIG. 1, when the main machine stops for some reason, since the slave machine does not control the voltage of the bus 100, the bus voltage becomes unstable and eventually becomes zero. The power supply to the power supply stops or the current command from the main unit becomes indefinite, the output current of the slave unit becomes larger than the actual load, boosts the bus voltage, and overload is applied to the load, destroying the load Sometimes In order to prevent such a situation, in this embodiment, in the slave unit, information on the abnormal state such as abnormality of the bus voltage, for example, the frequency and the voltage extremely deviated from the fluctuation range at the time of steady operation. When the communication means receives via 22, the function of the slave device is switched to the control function of the voltage of the bus 100.

  When the slave control system has both a current control system and a voltage control system, normally only the current control system operates, and when the voltage and frequency of the bus voltage are out of the specified range. It can be easily realized by giving a dead band to the input of the control system of the voltage control system so that the tracking function of the voltage control system operates.

  As shown in FIG. 2, when the bus state monitoring means 40 is added to the slave unit 2 and an abnormality of the bus voltage is detected thereby, the function of the current control system is stopped and the function of the voltage control system is immediately activated. It may be operated.

  In addition to this, information necessary for starting voltage control from the main unit to the sub unit, for example, that the main unit has stopped or degraded, an instruction to start voltage control for the sub unit, and abnormal bus voltage Such information may be transmitted, and the slave device may start voltage control in response thereto.

  Note that a communication determination unit for determining the operating state of the communication unit 21 is provided, and when an abnormality is recognized in the communication unit 21 by the communication determination unit, the detection result of the bus state monitoring unit 40 is preferentially determined. It is also possible to operate in the operation mode.

  A second embodiment will be described. Another embodiment of the present invention is shown in FIG. FIG. 3 shows an embodiment in which a plurality of AC power supplies (power converters) 2 for supplying current to slave units, that is, buses, are connected. In FIG. 3, names 2-1, 2-2,. The AC power source (power converter) 1 of the main machine is configured to transmit AC output current information to the plurality of slave machines 2, and includes an operation mode command generation means 23. The AC power supplies 1 and 2 are the same as those in the first embodiment. The operation mode command generation means 23 receives the status information of each AC power supply from the communication means 1 of the AC power supplies 1 and 2, determines the operation mode of each AC power supply 1 and 2, and the operation determined for each AC power supply. Give the operation command in the mode. With this configuration, even when there are two or more slave devices, that is, when there are three or more power converters operating in parallel, parallel operation can be easily performed in a state where no cross current is generated.

  FIG. 4 shows a modification of the second embodiment. The AC power source (power converter) 1 and the AC power source (power converter) 2 have operation mode command generation means 23 inside. Similar effects can be achieved.

  The transmission information is the AC output current of the main unit 1 and the slave unit 2 controls the AC output current accordingly, so that even if the number of devices operating in parallel changes, The burden capacity is always uniform. Of course, even if there is a change in the number of operating units, only the burden on the main engine 1 does not increase, and the burden increases equally for all the power converters in operation. For this reason, it is not necessary to make the power capacity of the main unit 1 larger than that of the sub unit 2, and the power converter part can use common parts except for the configuration of the control part, ensuring high versatility. it can. According to this method, even when a converter that is operated in parallel is newly added and the number of operating units is increased while the devices are operating in parallel, the capacity of each device is uniform.

  A third embodiment will be described. As shown in FIG. 5, the power supply system of the present embodiment includes AC power supplies 1, 2-1, 2-2,..., 2-n and a bus 100 through a connection circuit interrupting means 31 including a disconnector. The bus 100 is connected and has a bus bar interrupting means 32 comprising a disconnector. AC power sources 1, 2-1, 2-2,..., 2-n are the same as the AC power sources 1 and 2 of the second embodiment. The connection power cutoff means 31 can disconnect the AC power sources 1, 2-1, 2-2,. In addition, the power line blocking means 32 can constitute a power converter parallel group composed of one or more AC power supplies when the bus line is blocked.

  And by providing an open / close command means for giving an open / close command to the connection circuit cut-off means or busbar cut-off means determined according to the operation mode and operating status of each power converter and the operating state of the communication means, It is possible to provide a power supply system including the appropriate number of first power converters and second power converters corresponding to the circuit state of the bus 100 and the circuit configuration thereof.

  As described in each of the above embodiments, the present invention is high by using the same device for both the main unit and the sub unit, and having each power converter have the functions of both the main unit and the sub unit, and switching appropriately. Versatility can be ensured.

1 is an explanatory diagram of a power supply system according to Embodiment 1. FIG. Explanatory drawing of the modification of the power converter in Example 1. FIG. Explanatory drawing of the connection form of the power supply system of Example 2. FIG. Explanatory drawing of the modification of the power supply system of Example 2. FIG. Explanatory drawing of the connection form of the power supply system of Example 3. FIG. Explanatory drawing of the power supply system of a prior art example. Explanatory drawing of the connection form of the power supply system of a prior art example.

Explanation of symbols

1, 2, 2-1, 2-2, 2-n ... power converter 11 ... DC voltage source, 12 ... DC / AC converter, 13 ... filter circuit, 14 ... transformer, 15, 18 ... conversion means, DESCRIPTION OF SYMBOLS 16 ... Output voltage command (generation means), 17 ... Output voltage control means, 17a ... AC output current control means, 19 ... Operation mode selection means 20, 21 ... Communication means, 22 ... Communication path, 23 ... Operation mode command generation means ,
31 ... Connection circuit blocking means, 32 ... Busbar blocking means 40 ... Busbar state monitoring means 100 ... Busbar

Claims (4)

A power supply system comprising a first power converter for controlling an alternating voltage of a bus and a second power converter for controlling an alternating current supplied to the bus, wherein the alternating current converted from direct current is supplied to the bus. The first and second power converters respectively receive conversion means for converting the voltage on the bus side into a direct current amount, an output voltage command for outputting the target voltage on the bus side in a direct current amount, and status information of the power converter. And an operation mode command generating means for determining an operation mode and giving an operation command in the determined operation mode, and having a bus voltage control function and an output current control function. both can operate either, have a communication means for transmitting and receiving stop, the information of the abnormal state is not reduced or rise function of each power converter,
A bus state monitoring means for determining that the first power converter is in an abnormal state in which the first power converter is not stopped, reduced in function or raised due to a change in the bus voltage, and the bus state monitoring means is in an abnormality of the first power converter; Upon detecting the condition, one of the second power converters operates in voltage control mode,
A communication discriminating unit for discriminating an operating state of the communication unit, and when an abnormality is recognized in the communication unit by the communication discriminating unit, the power converter determined by giving priority to the detection result of the bus state monitoring unit; A power supply system that operates in an operation mode . The power supply system according to claim 1, wherein
The first power converter is restarted by operation in a current control mode when the first power converter is not stopped, deteriorated in function or does not start up . The power supply system according to claim 1 or 2,
Power systems between the output terminal and the bus of the power converter, wherein Rukoto with a connection circuit breaking means for cutting these connections. The power supply system according to claim 3, wherein
The busbar has a busbar disconnecting means constituting a power converter parallel connection group consisting of one or more power converters at the time of disconnection, and the operation mode and operating status of each power converter and the operating status of the communication means. accordance with the switching command for opening and closing state of being determined, the connection circuit breaking means or power system characterized Rukoto comprises a switching command means for applying to said bus blocking means.

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