CN111224412B - Micro-rail traffic power supply system, balancing device and control method thereof - Google Patents
Micro-rail traffic power supply system, balancing device and control method thereof Download PDFInfo
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
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Abstract
Micro-rail traffic power supply system, balancing unit and control method thereof, the balancing unit includes: the phase changer comprises a phase changer, an inductance group, a capacitance group and a controller, wherein the first end of the phase changer is used for connecting each phase of a transformer, the second end of the phase changer is connected with the inductance group or the capacitance group, and the controller is respectively connected with the inductance group, the capacitance group and the phase changer; a phase changer for changing a phase to which the inductance group or the capacitance group is connected; and the controller is used for receiving the current signal of each phase of the transformer, controlling the inductance group or the capacitance group to change the inductance value or the capacitance value according to the current signal and controlling the phase converter to change the phase. This application need not to load commutation, also need not the distributing type installation, more need not equipment such as too much current transformer, phase changer, still can realize three-phase power supply balance under the condition that the load is small in quantity.
Description
Technical Field
The application relates to the technical field of rail transit, in particular to a micro-rail transit power supply system, a balancing device and a control method of the micro-rail transit power supply system.
Background
The micro-rail traffic system adopts upright posts and overhead rail beams, two-person suspended type trolley automatic driving and line automatic dispatching command, and is an intelligent traffic system from door to door. The micro-rail intelligent transportation system is a novel light, low-speed and medium-low traffic volume public transportation mode, is a necessary component of an integrated, multi-mode and three-dimensional public transportation system, is in staggered development with other public transportation modes such as conventional public transportation, rail transportation and the like, is complementary with other public transportation modes, and is beneficial to and perfecting other public transportation modes.
The trolley of the system is supplied with power by the sliding contact line and the storage battery in the track, the sliding contact line is not arranged in the turnout, the power is supplied by the battery when the turnout is crossed, the sliding contact line in the track adopts low-voltage single-phase power supply, and thus the three-phase imbalance of power supply of a power grid is easily caused. The existing low-voltage single-phase load balancing power supply scheme is not suitable for the micro-rail traffic system, and a new power supply scheme needs to be designed for the micro-rail traffic system.
Disclosure of Invention
The embodiment of the application provides a micro-rail traffic power supply system, a balancing device and a control method thereof, so as to solve the technical problems.
In a first aspect, an embodiment of the present application provides a balancing apparatus, including: the phase changer comprises a phase changer, an inductance group, a capacitance group and a controller, wherein the first end of the phase changer is used for connecting each phase of a transformer, the second end of the phase changer is connected with the inductance group or the capacitance group, and the controller is respectively connected with the inductance group, the capacitance group and the phase changer;
the phase converter is used for changing the phase connected with the inductance group or the capacitance group;
and the controller is used for receiving the current signal of each phase of the transformer, controlling the inductance group or the capacitance group to change the inductance value or the capacitance value according to the current signal and controlling the phase converter to change the phase.
In a second aspect, an embodiment of the present application provides a power supply system for micro rail transit, including: transformers, current transformers, and balancing devices as described above; each phase of the transformer is connected with the balancing device, one end of the current transformer is connected with one phase of the transformer, the other end of the current transformer is connected with the balancing device, and the current transformer is used for collecting current signals and transmitting the current signals to the balancing device; each phase of the transformer is used for being in contact line connection with a track beam of a different section.
In a third aspect, an embodiment of the present application provides a method for implementing balance control by using the above balancing apparatus, including the following steps:
receiving a current signal of each phase of the transformer;
and controlling the inductance group or the capacitance group to change the inductance value or the capacitance value according to the current signal, and controlling the phase converter to change the phase so as to compensate the current among the phases of the transformer.
The beneficial effects are as follows:
according to the micro-rail traffic power supply system, the balancing device and the control method thereof, the balancing device is used for achieving three-phase power supply balance of the micro-rail traffic system, phase change of a load is not needed, distributed installation is not needed, too many devices such as a current transformer and a phase changer are not needed, and three-phase power supply balance can still be achieved under the condition that the number of the loads is small.
Drawings
Specific embodiments of the present application will be described below with reference to the accompanying drawings, in which:
FIG. 1 is a first schematic view showing a balance device according to an embodiment of the present invention;
FIG. 2 is a schematic structural diagram II of a balancing device in the embodiment of the present application;
fig. 3 shows a schematic structural diagram of a phase converter in an embodiment of the present application;
fig. 4 shows a schematic structural diagram of a micro-rail traffic power supply system in an embodiment of the present application;
fig. 5 is a flow chart illustrating implementation of the balance control method in the embodiment of the present application.
Detailed Description
In order to make the technical solutions and advantages of the present application more apparent, the following further detailed description of the exemplary embodiments of the present application with reference to the accompanying drawings makes it clear that the described embodiments are only a part of the embodiments of the present application, and not an exhaustive list of all embodiments. And the embodiments and features of the embodiments in the present description may be combined with each other without conflict.
The inventor notices in the process of invention that:
patent document CN207234413U discloses a "self-balancing regulating device for electric energy distribution of single-phase loads in three-phase power supply", which measures and collects the total switch current and the branch currents of each load, calculates the unbalanced load condition through a balancing control module, and then adjusts the phase connected to each load by controlling the load phase-changers on each load, thereby realizing three-phase load balancing.
The above technology has the following disadvantages:
1) when three-phase load is unbalanced, the control module can control partial load phase change, the load phase change is frequent, and simultaneously, the sudden phase change is unfavorable to the load;
2) if a better load balancing effect is achieved, more loads are needed to uniformly distribute the three-phase loads, and the method is not suitable for the condition of small load quantity;
3) the current transformer and the load phase converter are installed in a distributed mode, so that the cost of transmission and control cables is increased;
4) each load needs a current transformer and a load phase converter, and the device needs a larger number of current transformers and load phase converters.
In view of the defects in the prior art, the embodiments of the present application provide a micro-rail traffic system, a power supply system thereof, a balancing device and a control method thereof, which are described below.
Example 1
Fig. 1 shows a schematic structural diagram of a balancing device in an embodiment of the present application, as shown in the drawing.
The embodiment of the application provides a balancing unit, includes: the phase changer comprises a phase changer, an inductance group, a capacitance group and a controller, wherein the first end of the phase changer is used for connecting each phase of a transformer, the second end of the phase changer is connected with the inductance group or the capacitance group, and the controller is respectively connected with the inductance group, the capacitance group and the phase changer;
the phase converter is used for changing the phase connected with the inductance group or the capacitance group;
and the controller is used for receiving the current signal of each phase of the transformer, controlling the inductance group or the capacitance group to change the inductance value or the capacitance value according to the current signal and controlling the phase converter to change the phase.
In specific implementation, the balancing device can be electrically connected with each phase of the transformer, and the current of each phase of the transformer can be collected.
The controller receives a current signal of the current transformer, controls the switch states of the contactors in the inductance group and the capacitance group and the state of the phase changer through the control line, controls the contactor switches of the inductance group or the capacitance group to change the inductance value or the capacitance value, and controls different states of the phase changer to change the phase connected with the inductance group or the capacitance group.
The balancing device provided by the embodiment of the application can control the inductance or capacitance of the inductance or capacitance group in the balancing device according to the current signal of each phase of the transformer, and control the phase commutation of the phase commutator, thereby compensating the load imbalance of each phase of the transformer. Because this application only needs to change inductance group capacitance bank's value and phase changer commutation can realize load balance, need not load commutation, can not produce adverse effect to the load. In addition, the balance device is used for realizing balance without load phase change, so that a better load balance effect can be still achieved even under the condition of little load. In addition, because the load does not need the commutation in this application, only need gather the load total current of every looks of transformer, required current transformer quantity is less, and does not need every load all to dispose a load phase changer, and the quantity of required phase changer is also less, very big reduction equipment cost, simultaneously, because current transformer and phase changer need not the distributed installation, very big saving the cost of transmission and control cable.
In implementation, the transformer is a three-phase transformer including an a phase, a b phase and a c phase, the first end of the phase converter includes three ports, and the three ports are respectively connected with the a phase, the b phase and the c phase; the controller receives current signals of a phase, b phase and c phase of the transformer respectively.
During specific implementation, the transformer can be a three-phase transformer, the balancing device is electrically connected with three phases of the transformer, and three-phase currents of the transformer are collected simultaneously.
In the implementation, the number of the phase changers is 4, the number of the inductance groups is 2, and the number of the capacitance groups is 2; wherein 2 commutators are connected with 2 inductance groups respectively, and 2 commutators are connected with 2 electric capacity groups respectively in addition.
During specific implementation, balancing unit can include 4 commutators, 2 inductance groups, 2 electric capacity groups and 1 controller, and wherein 2 commutators are connected with 2 inductance groups respectively, and 2 commutators are connected with 2 electric capacity groups respectively in addition, and 4 commutators are connected with the controller respectively and are controlled the commutation by the controller, and inductance group and electric capacity group all are connected with the controller and are controlled inductance value or capacitance value that changes by the controller.
Fig. 2 shows a schematic structural diagram ii of the balancing device in the embodiment of the present application, as shown in the drawing.
In the implementation, the inductor group is formed by connecting a plurality of inductor modules in parallel, wherein the inductor modules are formed by connecting an inductor and an electromagnetic contactor in series; the capacitor group is formed by connecting a plurality of capacitor modules in parallel, wherein the capacitor modules are formed by connecting capacitors and electromagnetic contactors in series; the controller controls the inductance group or the capacitance group to change the inductance value or the capacitance value by controlling the switch of the contactor of the inductance group or the capacitance group.
In specific implementation, the inductance values of the inductor modules may be the same or different, and the capacitance values of the capacitor modules may be the same or different. When the controller controls the inductance or capacitance group to change the inductance or capacitance, the inductance or capacitance can be changed by changing the number of the inductance or capacitance modules, or by changing the number of the inductance or capacitance group, or by combining the two methods.
The plurality of inductance modules can enable the current of the inductance group to change within a certain interval in the process from complete turn-off to complete turn-on, and similarly, the plurality of capacitance modules can enable the current of the capacitance group to change within a certain interval in the process from complete turn-off to complete turn-on.
In specific implementation, the number of the inductance modules may be 3, the inductance value of each inductance module may be 10mH, 20mH, 30mH, the number of the capacitance modules may be 6, and the capacitance value of each capacitance module may be 200uF, 250uF, 300uF, 400uF, 1000 uF.
Each phase converter may have 5 ports, of which 3 ports are connected to the three phases of the transformer and 2 ports are connected to the inductor bank or capacitor bank for changing the phase to which the inductor bank or capacitor bank is connected.
In implementation, the controller acquires the current signal of each phase of the transformer specifically by acquiring the current signal through a current transformer respectively connected to each phase of the transformer.
During specific implementation, the number of the current transformers can be 3, and each phase of the three-phase transformer can be provided with one current transformer for collecting current of each phase.
According to the embodiment of the application, balanced power supply of micro-rail traffic can be realized only by arranging one transformer, one balancing device and 3 current transformers in each area, and compared with the prior art, the number of devices and the cost are greatly reduced.
In implementation, the phase converter comprises A, B, C, D4 contacts, a first blade m for switching connection between two contacts AB, a second blade n for switching connection between two contacts CD, the contact a for connecting the phase a of the transformer, the contact B, C for connecting the phase b of the transformer, and the contact D for connecting the phase c of the transformer; the other end of the first blade m and the other end of the second blade n are connected with the inductance group, or the other end of the first blade m and the other end of the second blade n are connected with the capacitance group.
In specific implementation, the other end of the first blade m and the other end of the second blade n are connected to the inductor bank, which may be: the other end of the first blade m is connected with one end of the inductance group, and the other end of the second blade n is connected with the other end of the inductance group.
The other end of the first blade m and the other end of the second blade n are connected with the capacitor bank, and may be: the other end of the first blade m is connected with one end of the capacitor bank, and the other end of the second blade n is connected with the other end of the capacitor bank.
Fig. 3 shows a schematic structural diagram of a phase converter in an embodiment of the present application, and as shown in the figure, the phase converter may include 4 states:
m and n are respectively connected with a and b;
m and n are respectively connected with b and c;
③ m and n are respectively connected with c and a;
and m and n are suspended.
In the state I, an inductance group or a capacitance group is connected to the phases a and b of the transformer;
in the second state, the inductance group or the capacitance group is connected to the b phase and the c phase of the transformer;
in the state III, an inductance group or a capacitance group is connected to the phases c and a of the transformer;
in the state IV, the inductance group or the capacitance group is not connected with the transformer.
In an implementation, the controller may include:
the first calculation unit is used for calculating the current magnitude and the phase according to the current signal;
the second calculation unit is used for calculating current target values of capacitors or inductors which need to be compensated among phases according to the current magnitude and the phase;
the first control unit is used for controlling the current which can be provided by the inductance group and the capacitance group to be close to the current target value according to the current target value;
and the second control unit is used for controlling the state of the phase converter according to the current target value so as to enable the inductance group and the capacitance group to be correspondingly connected.
In specific implementation, the working principle of the balancing device provided by the embodiment of the application can be as follows:
the controller receives current signals collected by the mutual inductor, the current magnitude and the phase of each section of sliding contact line are obtained through calculation, a capacitance or inductance current target value needing compensation at each phase is obtained through calculation according to a balance control algorithm, the contactor switch is controlled to enable the current provided by the inductance group and the capacitance group to be close to the current target value, the phase changer state is controlled to enable the capacitance inductance group to be connected with the corresponding phase, and therefore three-phase current balance is achieved.
In an implementation, the second calculating unit is configured to calculate a current target value of a capacitance or an inductance that needs to be compensated for between phases by using the following formula:
ab phase to phase current target value to be compensated
Target current value needing compensation between bc phases
Target current value needing compensation between ca phases
Wherein the content of the first and second substances,
In specific implementation, the balance control algorithm in the embodiment of the present application may be as follows:
assuming that only the trolley power is used for the trolley on the sliding contact line of the I section of track beam, the current is I1The phase angle lags the a, b phase voltage
Then it can be calculated that, in order to balance the three-phase current and compensate the reactive current of the load, the capacitor is required to be connected between the phases a and b, and the current is
b. c is required for phase separationTo be connected to a capacitor and having a current of
c. a is connected to an inductor between phases and has a current of
The directions of the capacitor current and the inductor current are opposite, the capacitor current is recorded as a positive current, the inductor current is recorded as a negative current, and therefore, the compensation current required between the phases a and b is
b. c the required compensation current between phases is
c. a required compensation current between phases is
The trolley with I-section track beam sliding contact line has the current I1The phase angle lags the a, b phase voltage
The trolley with the sliding contact line of the II sections of track beams has the current I2The phase angle lags the b and c phase voltages
The trolley with the sliding contact line of the III sections of track beams has the current I3The phase angle lags the phase voltage of c and a
According to the superposition principle, the required compensation current between the phases a and b can be calculated to be
b. c the required compensation current between phases is
c. a required compensation current between phases is
When the required compensation current value is a positive value, the capacitor should be connected, and when the required compensation current value is a negative value, the inductor should be connected. According to the formulae (1) to (3), Iab、Ibc、IcaThere are at most 2 negative values, so at most 2 inductor banks are needed, and at most 3 positive values, so at most 3 capacitor banks are needed. Compensating for reactive current is not a primary purpose, so when Iab、Ibc、IcaWhen both are positive values, the actual compensation current I is controlled according to the balance principleRab、IRbc、IRcaWhen the three phases are balanced as shown in formulas (4) to (6), respectively, IRab、IRbc、IRcaAt least 1 of which is 0, so that a maximum of 2 capacitor banks are required in order to achieve three-phase balance.
IRab＝Iab-min(Iab,Ibc,Ica) (4)
IRbc＝Ibc-min(Iab,Ibc,Ica) (5)
IRca＝Ica-min(Iab,Ibc,Ica) (6)
In summary, the target value of the three-phase actual compensation current is:
and configuring the capacitance and inductance set according to the target value of the three-phase actual compensation current to achieve the compensation current target, so that the three-phase current balance can be realized.
In an implementation, the first control unit includes:
the first control subunit is used for determining the capacitance module to be input according to the current target value and the capacitance value of each capacitance module in the capacitance group when the current target value between two phases of the transformer is a positive value;
and the second control subunit is used for determining the inductance module to be input according to the current target value and the inductance value of each inductance module in the inductance group when the current target value between the two phases of the transformer is a negative value.
In specific implementation, assuming that a current target value between phases a and b of the transformer is a positive value, determining a capacitance module to be input according to the current target value and a capacitance value of each capacitance module in the capacitance group may be: assuming that the current values that can be compensated after the capacitances of the capacitor module p and the capacitor module q are switched on are added and then approach the current target value, the first control subunit of the controller can control the capacitor module p and the capacitor module q to be put into use;
similarly, assuming that the current target value between the phases b and c of the transformer is a negative value, determining the inductance module to be input according to the current target value and the inductance value of each inductance module in the inductance group may be: assuming that the sum of the current values that can be compensated after the inductances of the inductance module x, the inductance module y, and the inductance module z are turned on is close to the current target value, the second control subunit of the controller may control the inductance module x, the inductance module y, and the inductance module z to be put into use.
Example 2
The embodiment of the application provides a little rail traffic power supply system includes: transformers, current transformers, and balancing devices as described above; each phase of the transformer is connected with the balancing device, one end of the current transformer is connected with one phase of the transformer, the other end of the current transformer is connected with the balancing device, and the current transformer is used for collecting current signals and transmitting the current signals to the balancing device; each phase of the transformer is used for being in contact line connection with a track beam of a different section.
Fig. 4 shows a schematic structural diagram of a micro rail traffic power supply system in an embodiment of the present application, as shown in the figure, a phase a, a phase b, and a phase c of a three-phase transformer are respectively connected to different sections of track beam contact lines, and power is supplied to a load by using phase-to-phase voltages, and in addition, the phase a, the phase b, and the phase c of the three-phase transformer are also respectively connected to a current transformer 1 and a balancing device, the phase b of the three-phase transformer is respectively connected to a current transformer 2 and a balancing device, and the phase c of the three-phase transformer is respectively connected to a current transformer 3 and a balancing device. And the current transformer 1, the current transformer 2 and the current transformer 3 are all connected with the balancing device.
The micro-rail traffic power supply system provided by the embodiment of the application adopts the transformer interphase voltage for power supply, so that zero sequence unbalanced current is eliminated, and in addition, the balancing device is adopted to compensate the unbalanced current between each phase of the transformer so as to ensure the balance of each phase of the transformer, so that the required equipment is few, the cost is low, no influence is caused on the load, and the three-phase current of the transformer can be balanced when the load is very small.
In implementation, the micro-rail traffic power supply system provided in the embodiment of the present application may further include: and the track beam is connected with a power supply system of the micro-rail traffic system through a track beam contact line.
In specific implementation, the micro-rail traffic power supply system in the embodiment of the application can directly use the existing 380V power distribution system to supply power, and can also use a power supply system other than micro-rail traffic to supply power.
The micro-rail traffic power supply system provided by the embodiment of the application utilizes the interphase voltage to supply power, eliminates zero-sequence unbalanced current, utilizes the balancing device to compensate the interphase unbalanced current, and achieves the purpose of balancing each phase of current of the transformer.
Considering that the micro rail traffic power supply system is generally applied to a long distance, and the length of the rail beam of one micro rail traffic power supply system is approximately between 1 and several tens of kilometers, the embodiment of the present application can also be implemented in the following manner.
In implementation, the track beam is divided into N areas, each area is supplied with power by a transformer, the track beam in each area is divided into M sections, two sliding contact lines of each section of track beam are connected with two phases of the transformer, and the sliding contact lines of the track beam are used for connecting a load; and both N and M are positive integers.
The track beam can be divided into several areas, each area is supplied with power by a transformer, and in one area, the track beam is divided into several sections, each section is supplied with power by the interphase voltage of the transformer, so that zero sequence current is avoided.
In order to balance the power supply of the micro-rail traffic power supply system as much as possible, the embodiment of the present application may also be implemented in the following manner.
In practice, the track beam is evenly divided into M sections in each zone.
In the embodiment of the application, the track beam in each area can be uniformly divided into M sections, because the track beam line lengths are the same, the number of the trolleys borne by each section is relatively balanced, the difference is not too large, and the power supply balance of the micro-rail traffic power supply system can be further ensured by combining the compensation control of the balancing device.
In practice, M may be a multiple of 3.
During specific implementation, the track beam trolley line can be divided into 3 sections, 6 sections, 9 sections and the like in the embodiment of the application, and the application does not limit the specific number of the sections.
Example 3
Based on the same inventive concept, the embodiment of the present application further provides a method for controlling by using the balancing apparatus of embodiment 1, which is described below.
Fig. 5 is a schematic flow chart illustrating an implementation of a balance control method in an embodiment of the present application, and as shown in the figure, the embodiment of the present application provides a method for implementing balance control by using the balancing apparatus in embodiment 1, including the following steps:
and 502, controlling an inductance value or a capacitance value of an inductance group or a capacitance group according to the current signal, and controlling the phase converter to change the phase so as to compensate the current among the phases of the transformer.
According to the control method provided by the embodiment of the application, the inductance value or the capacitance value of the inductance group or the capacitance group in the balancing device can be controlled to change according to the current signal of each phase of the transformer, and the phase change of the phase changer is controlled, so that the load imbalance of each phase of the transformer is compensated. Because this application only needs to change inductance group capacitance bank's value and phase changer commutation can realize load balance, need not load commutation, can not produce adverse effect to the load. In addition, the balance device is used for realizing balance without load phase change, so that a better load balance effect can be still achieved even under the condition of little load. In addition, because the load does not need the commutation in this application, only need gather the load total current of every looks of transformer, required current transformer quantity is less, and does not need every load all to dispose a load phase changer, and the quantity of required phase changer is also less, very big reduction equipment cost, simultaneously, because current transformer and phase changer need not the distributed installation, very big saving the cost of transmission and control cable.
In an implementation, the controlling an inductance group or a capacitance group to change an inductance value or a capacitance value according to the current signal and controlling the phase converter to perform phase conversion to compensate the current between the phases of the transformer includes:
calculating the current magnitude and phase according to the current signal;
calculating a current target value of the capacitor or the inductor which needs to be compensated among phases according to the current magnitude and the phase;
and controlling the current which can be provided by the inductance group and the capacitance group to be close to the current target value according to the current target value, and controlling the state of the phase changer to enable the inductance group and the capacitance group to be connected with the corresponding phase.
In implementation, the target current value of the capacitor or inductor to be compensated is calculated according to the current magnitude and the phase, and is calculated according to the following formula:
ab phase to phase current target value to be compensated
Target current value needing compensation between bc phases
Target current value needing compensation between ca phases
Wherein the content of the first and second substances,
In an implementation, the controlling the current that can be provided by the inductance group and the capacitance group to be close to the current target value according to the current target value includes:
when the current target value between two phases of the transformer is a positive value, determining a capacitor module to be input according to the current target value and the capacitance value of each capacitor module in the capacitor bank;
and when the current target value between two phases of the transformer is a negative value, determining the inductance module required to be input according to the current target value and the inductance value of each inductance module in the inductance group.
Example 4
The application is further explained in connection with a 380V voltage three-phase powered micro-rail traffic system.
Taking a zone as an example, the zone accommodates 300 carts to run, assuming that each cart has a power of 2.5kw and a power factor of 0.9.
The inductor group and the capacitor group in the balancing device are configured as follows:
every group electric capacity disposes 5 electric capacity modules, and the capacitance value of 5 electric capacity modules is respectively: 251.4uF, 502.8uF, 1005.7uF, 2011.4uF and 4022.8uF, which can respectively provide 30A, 60A, 120A, 240A and 480A capacitance currents; each group of inductors is provided with 5 inductor modules, and the inductance values of the 5 inductor modules are respectively as follows: 40.3mH, 20.2mH, 10.1mH, 5.04mH and 2.52mH, respectively, and can provide 30A, 60A, 120A, 240A and 480A inductive currents, so that each group of capacitance and inductive current can realize the change between 30A and 930A with the step length of 30A.
Taking two large imbalance conditions that may occur as an example:
(1) 200 vehicles at the I section, 80 vehicles at the II section and 20 vehicles at the III section;
(2) 80 vehicles in the I section, 200 vehicles in the II section and 20 vehicles in the III section.
Calculating according to the working condition (1):
to obtain I1＝1461.9A，
I2＝584.8A，
I3＝146.2A，
The three-phase positive sequence current is 1266.3A, the negative sequence current is about 2003.9A, and the negative sequence unbalance degree is up to 158.2%.
According to the required compensating current between a and b phases
b. c required compensation current between phases
c. a required compensation current between phases
Calculated to obtain IRab＝409.5A、IRbc＝962.23A、IRca＝-392.1A。
Therefore, the controller of the balancing device can control ab to connect the capacitor group at intervals, input capacitors (420A, c, bc) to connect the capacitor group at intervals, input capacitors (930A, ca) to connect the inductor group at intervals, and input inductors (930A, c, 390A). The final three-phase positive sequence current is 1134.2A, the negative sequence current is reduced to 9.34A, the negative sequence unbalance is reduced to 0.82%, and the power factor is 1.
According to the working condition (2)
To obtain I1＝584.8A，
I2＝1461.9A，
I3＝146.2A，
The three-phase positive sequence current is 1266.3A, the negative sequence current is about 2015.8A, and the three-phase positive sequence current is negativeThe order imbalance is as high as 159.2%.
Calculated according to equations (1) to (3):
IRab＝-428.8A、IRbc＝865.3A、IRca＝519.5A。
therefore, the controller of the balancing device can control ab to connect the inductance group at intervals, put the inductances (420A), (bc) to connect the capacitance group at intervals, put the capacitances (1), (c), (870A), (ca) to connect the capacitance group at intervals, put the capacitances (iv) and (v), and put the inductance current (510A). The final three-phase positive sequence current is 1137.2A, the negative sequence current is about 28.2A, the negative sequence imbalance is 2.47%, and the power factor is 1.
It can be seen from this application embodiment that this application can effectively improve the unbalanced condition of little rail traffic power supply system, can compensate the idle current of dolly load simultaneously.
According to the embodiment of the application, by designing the micro-rail traffic power supply system, the balancing device and the control method thereof, under the condition of a small number of loads, three-phase power supply balance of the micro-rail traffic system is realized, and meanwhile, phase change of the loads, distributed installation and excessive current transformers are not needed.
The technical scheme provided by the embodiment of the application has the following advantages:
1) the micro-rail traffic power supply system utilizes the interphase voltage to supply power to eliminate zero-sequence unbalanced current, and can directly utilize the existing 380V power distribution system to supply power;
2) the load does not need to be phase-changed when the balancing device carries out balance control, and the load is not influenced;
3) the balance control effect is not influenced by the number of loads, and the three-phase current can be balanced when the loads are few;
4) the balancing device is installed in a centralized manner without excessive control cables;
5) only the total current of the load needs to be collected, and excessive current transformers are not needed.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.
While the preferred embodiments of the present application have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all alterations and modifications as fall within the scope of the application.
Claims (17)
1. A balancing device, comprising: the phase changer comprises a phase changer, an inductance group, a capacitance group and a controller, wherein the first end of the phase changer is used for connecting each phase of a transformer, the second end of the phase changer is connected with the inductance group or the capacitance group, and the controller is respectively connected with the inductance group, the capacitance group and the phase changer;
the phase converter is used for changing the phase connected with the inductance group or the capacitance group;
the controller is used for receiving a current signal of each phase of the transformer, controlling the inductance or capacitance of the inductance or capacitance group to change according to the current signal and controlling the phase of the phase changer to change the phase;
the phase converter comprises A, B, C, D4 contacts, a first blade m for switching connection between two contacts AB, a second blade n for switching connection between two contacts CD, the contact A is used for connecting the phase a of the transformer, the contact B, C is used for connecting the phase b of the transformer, and the contact D is used for connecting the phase c of the transformer; the other end of the first blade m and the other end of the second blade n are connected with the inductance group, or the other end of the first blade m and the other end of the second blade n are connected with the capacitance group.
2. The balancing apparatus of claim 1, wherein the transformer is a three-phase transformer including a-phase, b-phase, and c-phase, the first end of the phase converter includes three ports, the three ports respectively connecting the a-phase, b-phase, and c-phase; the controller receives current signals of a phase, b phase and c phase of the transformer respectively.
3. The balancing apparatus of claim 2, wherein there are 4 inverters, 2 inductor banks, and 2 capacitor banks; wherein 2 commutators are connected with 2 inductance groups respectively, and 2 commutators are connected with 2 electric capacity groups respectively in addition.
4. The balancing apparatus of claim 1, wherein the inductor group is formed by connecting a plurality of inductor modules in parallel, each inductor module being formed by connecting an inductor and an electromagnetic contactor in series; the capacitor group is formed by connecting a plurality of capacitor modules in parallel, wherein the capacitor modules are formed by connecting capacitors and electromagnetic contactors in series; the controller controls the inductance group or the capacitance group to change the inductance value or the capacitance value by controlling the switch of the contactor of the inductance group or the capacitance group.
5. A balancing device according to claim 1, wherein the controller is adapted to acquire the current signal for each phase of the transformer by means of a current transformer connected to each phase of the transformer.
6. The balancing apparatus of claim 1, wherein the controller comprises:
the first calculation unit is used for calculating the current magnitude and the phase according to the current signal;
the second calculation unit is used for calculating current target values of capacitors or inductors which need to be compensated among phases according to the current magnitude and the phase;
the first control unit is used for controlling the current which can be provided by the inductance group and the capacitance group to be close to the current target value according to the current target value;
and the second control unit is used for controlling the state of the phase converter according to the current target value so as to enable the inductance group and the capacitance group to be correspondingly connected.
7. The balancing apparatus according to claim 6, wherein the second calculating unit is configured to calculate the target current value of the capacitor or inductor to be compensated for between the phases by using the following formula:
ab phase to phase current target value to be compensated
Target current value needing compensation between bc phases
Target current value needing compensation between ca phases
Wherein the content of the first and second substances,
8. The balancing apparatus of claim 6, wherein the first control unit comprises:
the first control subunit is used for determining the capacitance module to be input according to the current target value and the capacitance value of each capacitance module in the capacitance group when the current target value between two phases of the transformer is a positive value;
and the second control subunit is used for determining the inductance module to be input according to the current target value and the inductance value of each inductance module in the inductance group when the current target value between the two phases of the transformer is a negative value.
9. A power supply system for micro-rail traffic, comprising: a transformer, a current transformer, and a balancing device according to any one of claims 1 to 8; each phase of the transformer is connected with the balancing device, one end of the current transformer is connected with one phase of the transformer, the other end of the current transformer is connected with the balancing device, and the current transformer is used for collecting current signals and transmitting the current signals to the balancing device; each phase of the transformer is used for being in contact line connection with a track beam of a different section.
10. The power supply system for micro-rail traffic according to claim 9, further comprising: and the track beam is connected with a power supply system of the micro-rail traffic system through a track beam contact line.
11. The power supply system for micro-rail traffic according to claim 10, wherein the track beam is divided into N sections, each section is supplied with power by a transformer, the track beam in each section is divided into M sections, two trolley lines of each section of track beam are connected with two phases of the transformer, and the track beam trolley lines are used for connecting loads; and both N and M are positive integers.
12. The power supply system for micro-rail transit of claim 11, wherein the rail beam is evenly divided into M sections in each zone.
13. The power supply system for micro-rail traffic according to claim 11, wherein M is a multiple of 3.
14. A method for implementing balance control using the balancing apparatus according to any one of claims 1 to 8, comprising the steps of:
receiving a current signal of each phase of the transformer;
and controlling the inductance group or the capacitance group to change the inductance value or the capacitance value according to the current signal, and controlling the phase converter to change the phase so as to compensate the current among the phases of the transformer.
15. The method of claim 14, wherein controlling the set of inductors or capacitors to change inductance or capacitance and controlling the phase inverters to commutate to compensate for the current between the phases of the transformer according to the current signal comprises:
calculating the current magnitude and phase according to the current signal;
calculating a current target value of the capacitor or the inductor which needs to be compensated among phases according to the current magnitude and the phase;
and controlling the current which can be provided by the inductance group and the capacitance group to be close to the current target value according to the current target value, and controlling the state of the phase changer to enable the inductance group and the capacitance group to be connected with the corresponding phase.
16. The method according to claim 15, wherein the current target value of the capacitance or inductance to be compensated for between the phases is calculated according to the current magnitude and phase, and is calculated according to the following formula:
ab phase to phase current target value to be compensated
Target current value needing compensation between bc phases
Target current value needing compensation between ca phases
Wherein the content of the first and second substances,
17. The method of claim 15, wherein controlling the current provided by the inductor bank and the capacitor bank to approach the current target value according to the current target value comprises:
when the current target value between two phases of the transformer is a positive value, determining a capacitor module to be input according to the current target value and the capacitance value of each capacitor module in the capacitor bank;
and when the current target value between two phases of the transformer is a negative value, determining the inductance module required to be input according to the current target value and the inductance value of each inductance module in the inductance group.
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| CN102223099B (en) * | 2011-06-15 | 2013-02-27 | 重庆大学 | Adaptive three-phase balanced control cascaded three-phase bridge converter |
| CN203387194U (en) * | 2013-06-06 | 2014-01-08 | 国家电网公司 | A three-phase load unbalance compensator |
| US9236743B2 (en) * | 2013-07-31 | 2016-01-12 | Shehab Ahmed | Apparatus and method for voltage and current balancing in generation of output power in power generation systems |
| CN204835544U (en) * | 2015-06-04 | 2015-12-02 | 刘友仁 | Low -voltage load is from balancing unit based on three select a load change over switch module |
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| CN205901318U (en) * | 2016-07-13 | 2017-01-18 | 深圳市泰昂能源科技股份有限公司 | A controlling means for unbalanced three phase and reactive compensation |
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| CN207190810U (en) * | 2017-08-07 | 2018-04-06 | 中建空列（北京）工程设计研究院有限公司 | Empty iron rail system with power reservoir capacity |
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| CN108152729A (en) * | 2018-01-12 | 2018-06-12 | 江苏南瑞泰事达电气有限公司 | A kind of detection device and method of three-phase current unbalance regulating device |
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