CN117811398B

CN117811398B - Control method of high-frequency auxiliary converter

Info

Publication number: CN117811398B
Application number: CN202410211568.1A
Authority: CN
Inventors: 唐建明; 谭诗干; 黄旭辉; 钟康; 杨仁宝; 刘静
Original assignee: Shenzhen Tongye Technology Co ltd
Current assignee: Shenzhen Tongye Technology Co ltd
Priority date: 2024-02-27
Filing date: 2024-02-27
Publication date: 2024-05-17
Anticipated expiration: 2044-02-27
Also published as: CN117811398A

Abstract

The application relates to the technical field of electronic power, in particular to a control method of a high-frequency auxiliary current transformer, which comprises a control module and a plurality of parallel inversion modules, wherein each inversion module comprises a plurality of DCDC sub-modules and a DCAC sub-module; the input end of each DCDC sub-module is connected in parallel and is configured to be connected with the input voltage, and the output end of each DCAC sub-module is connected in parallel to output the target voltage; in the inversion module, the output end of each DCDC sub-module is connected in parallel to the input end of the corresponding DCAC sub-module; each DCDC sub-module at least comprises an input relay, and each DCAC sub-module at least comprises an output relay; the control module is respectively connected with each DCDC sub-module and each DCAC sub-module and is used for controlling input and output voltages. The high-frequency auxiliary converter can improve the parallel operation reliability, reduce the grounding failure risk, improve the maintenance efficiency and reduce the maintenance cost.

Description

Control method of high-frequency auxiliary converter

Technical Field

The application relates to the technical field of electronic power, in particular to a control method of a high-frequency auxiliary converter.

Background

The whole power module of the existing high-frequency auxiliary current transformer of the high-speed rail motor train unit and the urban rail is inconvenient to maintain and disassemble, consumes time and labor, and is high in maintenance cost, so that a novel high-frequency auxiliary current transformer is needed to improve maintenance efficiency and reduce maintenance cost.

Disclosure of Invention

In view of the above, the present application provides a control method of a high-frequency auxiliary converter.

The embodiment of the application provides a device which comprises a control module and a plurality of parallel inversion modules, wherein each inversion module comprises a plurality of DCDC sub-modules and a DCAC sub-module;

The input end of each DCDC sub-module is connected in parallel and is configured to be connected with an input voltage, and the output end of each DCAC sub-module is connected in parallel and is configured to be used as an alternating current output end; in the inversion module, the output end of each DCDC sub-module is connected in parallel to the input end of the corresponding DCAC sub-module;

Each DCDC sub-module at least comprises an input relay, and each DCAC sub-module at least comprises an output relay;

The control module is respectively connected with each DCDC sub-module and each DCAC sub-module and is used for carrying out parallel control on the corresponding connected DCDC sub-modules and the DCAC sub-modules through the input relay and/or the output relay so as to output target alternating voltage.

Further, the device also comprises a grounding detection device; the grounding detection device comprises three current limiting elements and a detection module; the first ends of the three current limiting elements are respectively and correspondingly connected with one phase of three-phase alternating current output ends of the high-frequency auxiliary converter, the second ends of the three current limiting elements are connected to the same node, the first end of the detection module is connected with the central point, and the second end of the detection module is grounded; the detection module is used for detecting electrical parameters between the node and the ground terminal so as to determine whether a ground fault and a fault type exist.

Another embodiment of the present application further provides a control method for a high-frequency auxiliary current transformer, where the control method is applicable to a high-frequency auxiliary current transformer provided in the first aspect of the present application; the method comprises the following steps:

controlling each DCDC sub-module and each DCAC sub-module to be integrated into a network;

And in the working process of the high-frequency auxiliary current transformer, acquiring the electrical parameter detected by the grounding detection device, and determining whether the high-frequency auxiliary current transformer has faults according to the electrical parameter.

Further, the electrical parameter includes an output voltage effective value of the high frequency auxiliary converter;

The determining whether the high-frequency auxiliary converter has a fault according to the electrical parameter comprises the following steps:

Determining whether the high-frequency auxiliary converter has single-phase grounding faults or not according to the relation between the output voltage effective value of the high-frequency auxiliary converter and a first voltage interval;

Determining whether the high-frequency auxiliary converter has an intermediate bus grounding fault according to the relation between the output voltage effective value of the high-frequency auxiliary converter and a second voltage interval;

and determining whether the high-frequency auxiliary converter has a series electric fault of an input voltage bus and an intermediate bus according to the magnitude relation between the effective value of the output voltage of the high-frequency auxiliary converter and the third voltage.

Further, the first voltage interval is (100 v,200 v); the second voltage interval is (200 v,520 v); the third voltage is in the range of (650 v,750 v).

Further, the electrical parameter further comprises a ground voltage; the method further comprises the steps of: and detecting the grounding voltage of each sub-module, if the grounding voltage is larger than a grounding voltage threshold value, determining a grounded sub-module in each DCDC sub-module and each DCAC sub-module, and switching off an input relay of the grounded sub-module.

Further, the controlling the DCDC sub-modules and the DCAC sub-modules to be incorporated into a network includes:

Sending a starting signal to each DCDC sub-module, and controlling the output voltage of each DCDC sub-module to gradually boost; in the boosting process, gradually adjusting the droop quantity of the corresponding output voltage according to the input power corresponding to each DCDC sub-module; until the output voltage of the DCDC sub-module is normal, the DCDC sub-module is integrated into a network;

And simultaneously, sending a starting command to the DCAC sub-modules, and detecting whether output voltage exists in each DCAC sub-module when the DCAC sub-modules perform inversion so as to determine whether the DCAC sub-modules serve as a host or a slave and are connected into a network to realize parallel operation current sharing control.

Further, the detecting whether the output voltage exists in each DCAC sub-module to determine whether the DCAC sub-module is used as a master or a slave to be connected to a network to realize parallel operation current sharing control includes:

If the output voltage is not detected after the output relay of the DCAC sub-module, delay is executed according to a preset delay strategy, and if the output voltage is not detected in the delay period, the input and output relay of the DCAC sub-module is controlled to be closed so that the DCAC sub-module becomes a host;

if the output voltage is detected after the output relay of the DCAC sub-module, controlling to execute phase locking so that the DCAC sub-module is set as a slave;

after confirming that the DCAC sub-module is successfully locked, controlling to close an input/output relay of the slave machine so as to enable the slave machine to be integrated into a network;

after the DCAC sub-modules are integrated into the network, corresponding amplitude and frequency are respectively adjusted according to the output active power and the output reactive power of each DCAC sub-module.

Further, the preset delay strategy includes:

Acquiring an ID value of the DCAC sub-module; the ID value is determined according to the sequence of inserting the DCAC sub-modules into the high-frequency auxiliary current transformer;

and setting delay time length for the corresponding DCAC sub-module according to the ID value and the set proportion.

Further, the confirming that the DCAC sub-module phase locking is successful includes:

if the slave detects that the phase difference between the three-phase output voltage and the parallel network voltage is smaller than the phase difference fixed value and the amplitude is similar, continuously detecting the phase and the amplitude in a preset time period;

If the phase and the amplitude do not exceed the offset range within the preset time period, the phase locking is confirmed to be successful.

The embodiment of the application has the following beneficial effects:

The embodiment of the application provides a high-frequency auxiliary converter, which is characterized in that each module independently works by modularization of the whole converter, when a certain module has a problem, the module can be cut off through an input relay and an output relay, other systems are not influenced, the disassembly is easy, the maintenance efficiency is improved, the maintenance cost is reduced, and the stability of the whole system is improved.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings that are required for the embodiments will be briefly described, it being understood that the following drawings only illustrate some embodiments of the present application and therefore should not be considered as limiting the scope of the present application. Like elements are numbered alike in the various figures.

Fig. 1 shows a first schematic structural diagram of a high frequency auxiliary current transformer according to some embodiments of the present application;

fig. 2 shows a second schematic structural diagram of a high frequency auxiliary current transformer according to some embodiments of the present application;

fig. 3 shows a third schematic structural diagram of a high frequency auxiliary current transformer according to some embodiments of the present application;

fig. 4 shows a fourth schematic structural diagram of a high frequency auxiliary current transformer according to some embodiments of the present application;

fig. 5 shows a schematic structural diagram of a DCDC sub-module in a high frequency auxiliary current transformer according to some embodiments of the present application;

fig. 6 is a schematic structural diagram of a DCAC sub-module in a high frequency auxiliary current transformer according to some embodiments of the present application;

fig. 7 is a schematic diagram showing a fifth configuration of a high-frequency auxiliary current transformer according to some embodiments of the present application;

Fig. 8 illustrates a schematic diagram of a DCDC sub-module parallel operation logic in a high frequency auxiliary current transformer according to some embodiments of the present application;

Fig. 9 shows a logic schematic diagram of a DCAC submodule current sharing algorithm in a high-frequency auxiliary current transformer according to some embodiments of the present application.

Description of main reference numerals:

100-an inversion module; a 110-DCDC sub-module; a 111-DCDC circuit; 112-DCDC input relay; 113-DCDC output relay; a 120-DCAC sub-module; a 121-DCAC circuit; 123-DCAC output relay; 124-a second voltage sensor; 125-a fourth voltage sensor; 126-a fifth voltage sensor; 127-a third voltage sensor; 200-a control module; 300-ground detection means; 410-a first output switch, 420-a second output switch; 430-a third output switch; 500-an external motor; 600-charger module.

Detailed Description

The following description of the embodiments of the present application will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present application, but not all embodiments.

The components of the embodiments of the present application generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the application, as presented in the figures, is not intended to limit the scope of the application, as claimed, but is merely representative of selected embodiments of the application. All other embodiments, which can be made by a person skilled in the art without making any inventive effort, are intended to be within the scope of the present application.

The terms "comprises," "comprising," "including," or any other variation thereof, are intended to cover a specific feature, number, step, operation, element, component, or combination of the foregoing, which may be used in various embodiments of the present application, and are not intended to first exclude the presence of or increase the likelihood of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing.

Furthermore, the terms "first," "second," "third," and the like are used merely to distinguish between descriptions and should not be construed as indicating or implying relative importance.

Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which various embodiments of the application belong. The terms (such as those defined in commonly used dictionaries) will be interpreted as having a meaning that is the same as the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein in connection with the various embodiments of the application.

Some embodiments of the present application are described in detail below with reference to the accompanying drawings. The embodiments described below and features of the embodiments may be combined with each other without conflict.

Conventionally, an auxiliary converter mounted on an existing rail transit vehicle such as a railway locomotive, a high-speed railway motor car, a subway vehicle and the like is one of the most critical power supply equipment of the vehicle, and is used for realizing power conversion from specific high-voltage direct current power supply of 1500V and the like to conventional voltage of three-phase alternating current 380VAC and the like and providing power supply for electromechanical equipment of the vehicle. The product technology is realized, the existing product is mostly realized by adopting the traditional technology and utilizing power elements such as high-capacity IGBT and the like, and an auxiliary converter generally comprises a set of power conversion module units.

The existing scheme and characteristics still have more defects, such as low parallel operation reliability, high ground failure risk, low maintenance efficiency, high maintenance cost and the like.

Accordingly, in order to solve the above-mentioned problems, the present application proposes a control method of a high-frequency auxiliary current transformer.

Fig. 1 is a schematic structural diagram of a high-frequency auxiliary current transformer according to an embodiment of the present application. The high-frequency auxiliary converter is used, for example, in a power supply device, which may be a motor or the like, without limitation.

In some embodiments, as shown in fig. 1, the high frequency auxiliary converter includes a control module 200 and a plurality of parallel inverter modules 100, each inverter module 100 including a plurality of DCDC sub-modules 110 and a DCAC sub-module 120. The input of each DCDC sub-module 110 is connected in parallel and configured to access an input voltage, and the output of each DCAC sub-module 120 is connected in parallel and configured as an ac output; in each inverter module 100, the output of each DCDC sub-module 110 is connected in parallel to the input of the corresponding DCAC sub-module 120. Each DCDC sub-module 110 includes at least one input relay (denoted by K in the figure) and each DCAC sub-module 120 includes at least one output relay (denoted by K in the figure). The control module 200 is connected to each DCDC sub-module 110 and each DCAC sub-module 120, and is configured to perform parallel control on the DCDC sub-module 110 and the DCAC sub-module 120 that are correspondingly connected through an input relay and the output relay, so as to output a target ac voltage.

Specifically, each DCDC sub-module 110 in each inverter module 100 aggregates the output voltages to be used as the input voltage of the DCAC sub-module 120, each DCAC sub-module 120 adjusts and outputs the input voltage, and each DCAC sub-module 120 aggregates the output voltages to be used as the target voltage to supply power to the connected external device (not shown in fig. 1). The input relay of each DCDC sub-module 110 controls the output of each DCDC sub-module voltage through an internal switch, and the output relay of each DCAC sub-module 120 controls the input of the DCAC sub-module voltage through an internal switch. The control module 200 is communicatively and electrically coupled to each DCDC sub-module 110 and each DCAC sub-module 120. The communication connection is used for acquiring the real-time information of each DCDC sub-module 110 and each DCAC sub-module 120, judging whether the sub-modules have faults or not according to the real-time information, and controlling the output relay and the input relay in each sub-module by the electric signals so as to enable each sub-module to be connected into the whole high-frequency auxiliary converter circuit or not. Wherein all DCDC sub-modules 110 and DCAC sub-modules 120 in each inverter module 100 correspond. For example, if one inverter module 100 includes three DCDC sub-modules 110 and one DCAC sub-module 120, the three DCDC sub-modules 110 respectively correspond to the DCAC sub-modules 120. The number of inverter modules 100 in the high-frequency auxiliary converter may be any one of 2 to 10, which is not limited herein. The number of DCDC sub-modules 110 in each inverter module 100 ranges from 2 to 5, which is not limited herein. The control module 200 is connected with other sub-modules through serial port/CAN communication to realize control of start-stop, isolation and the like of the sub-modules.

In some embodiments of the high-frequency auxiliary converter, as shown in fig. 2, a ground detection device 300 is further included, where the ground detection device 300 is connected to the output end of the DCAC sub-module 120, and is used for detecting whether the ground is connected to the ground.

Exemplarily, as shown in fig. 3 (3 sets of inverter modules 100 are taken as an example in fig. 3), the ground fault detection device 300 includes three current limiting elements (R1-R3 in the figure) and a detection module SVI; the first ends of the three current limiting elements are respectively and correspondingly connected with one power supply line of one phase in the three-phase alternating current output ends of the high-frequency auxiliary converter, the second ends of the current limiting elements are connected to the same central point, the first ends of the detection modules SVI are connected with the nodes, and the second ends of the detection modules SVI are grounded; the detection module SVI is configured to detect an electrical parameter between the node and the ground, so as to determine whether a ground fault and a fault type exist.

In the high frequency auxiliary converter of some embodiments, as shown in fig. 4, each DCDC sub-module 110 includes a DCDC input terminal J1 and a DCDC output terminal T1, and each DCAC sub-module 120 includes a DCAC input terminal J8, a fifth output terminal T5, a sixth output terminal T6, and a seventh output terminal T7. Each DCDC input J1 is connected in parallel and configured to input an external input voltage U1, for example, the external input voltage U1 is 1500V. The DCDC outputs T1 of all the DCDC sub-modules 110 in each inverter module 100 are connected in parallel to the eighth input J8 of the corresponding DCAC module. Each fifth output terminal T5 is connected in parallel to one end of the first output switch 410, each sixth output terminal T6 is connected in parallel to one end of the second output switch 420, each seventh output terminal T7 is connected in parallel to one end of the third output switch 430, and the other ends of the first output switch 410, the second output switch 420 and the third output switch 430 are respectively connected to three phase lines of the external motor 500. In addition to the connection of the external motor 500, other external loads may be connected here, without limitation.

Specifically, in each inverter module 100, the DCDC output terminal T1 outputs the regulated positive and negative voltages (for example, may be +650V and-650V), the voltages output by each DCDC sub-module 110 are aggregated to be input voltages of the corresponding DCAC sub-module 120, each DCAC sub-module 120 regulates the input voltages and outputs three-phase voltages to control the motor, the in-phase voltages output by each DCAC sub-module 120 are aggregated to be the phase voltages of the external motor 500 (for example, without setting, the fifth output terminal T5, the sixth output terminal T6 and the seventh output terminal T7 output U, V and W three-phase voltages, respectively, and then the U-phase voltages of the fifth output terminal T5 of each DCAC sub-module 120 are aggregated to be the U-phase voltages of the external motor 500). Wherein the first, second and third output switches 410, 420 and 430 control duty ratios of three-phase voltages of the external motor 500, respectively.

In the high frequency auxiliary converter of some embodiments, as shown in fig. 5, one input relay and one output relay are included in the DCDC sub-module 110. Specifically, each DCDC sub-module 110 further includes a DCDC circuit 111, a positive input terminal J11, a negative input terminal J12, and a DCDC output terminal T1; the DCDC input relay 112 and the DCDC output relay 113 in each DCDC sub-module 110 each include two control switches; the DCDC positive output terminal T11 and the DCDC negative output terminal T12 are connected to the positive and negative terminals of the corresponding DCAC sub-module 120, respectively. The DCDC circuit 111 includes a third input terminal J3, a fourth input terminal J4, a third output terminal T3, and a fourth output terminal T4; the third input end J3 is connected with a DCDC positive input end J11 through one control switch of the DCDC input relay 112, and the fourth input end J4 is connected with a DCDC negative input end J12 through the other control switch of the DCDC input relay 112; the third output terminal T3 is connected to the DCDC positive output terminal T11 through one control switch of the DCDC output relay 113, and the fourth output terminal T4 is connected to the DCDC negative output terminal T12 through the other control switch of the DCDC output relay 113.

In the high frequency auxiliary converter of some embodiments, as shown in fig. 6, each DCAC sub-module 120 further includes a DCAC circuit 121, a DCAC positive input terminal J81, a DCAC negative input terminal J82, a fifth output terminal T5, a sixth output terminal T6, and a seventh output terminal T7; the DCAC output relay 123 in each DCAC sub-module 120 includes three control switches. The DCAC circuit 121 includes a tenth input terminal J10, an eleventh input terminal J11, an eighth output terminal T8, a ninth output terminal T9, and a tenth output terminal T10; the tenth input end J10 is connected with a DCAC positive input end J81, and the eleventh input end J11 is connected with a DCAC negative input end J82; the eighth output terminal T8 is connected to the fifth output terminal T5 through a first control switch of the DCAC output relay 123, the ninth output terminal T9 is connected to the sixth output terminal T6 through a second control switch of the DCAC output relay 123, and the tenth output terminal T10 is connected to the seventh output terminal T7 through a third control switch of the DCAC output relay 123. The DCAC sub-module 120 further includes a second voltage sensor 124, a third voltage sensor 127, a fourth voltage sensor 125, and a fifth voltage sensor 126. The positive and negative poles of the second voltage sensor 124 are respectively and correspondingly connected to the positive input terminal J81 of DCAC and the negative input terminal J82 of DCAC, the positive and negative poles of the third voltage sensor 127 are respectively and correspondingly connected to the sixth output terminal T6 and the seventh output terminal T7, the positive and negative poles of the fourth voltage sensor 125 are respectively and correspondingly connected to the fifth output terminal T5 and the sixth output terminal T6, and the positive and negative poles of the fifth voltage sensor 126 are respectively and correspondingly connected to the fifth output terminal T5 and the seventh output terminal T7. Specifically, the third, fourth and fifth voltage sensors 127, 125 and 126 detect the three-phase voltages output from the DCAC sub-module 120, respectively.

In some embodiments, as shown in fig. 7, the high-frequency auxiliary converter further includes another separate DCDC sub-module 110 as a charger module 600, where the charger module 600 directly takes power from the whole machine input, and is not affected by other power modules, so that power supply control is better ensured. Alternatively, the stand-alone charger module 600 may reduce 1500V to 110V for external power. Of course, other different switching voltages are also possible, without limitation.

Preferably, in all the above-mentioned high-frequency auxiliary converters, the MOS transistors in the DCDC sub-module 110 and the DCAC sub-module 120 are silicon carbide MOS transistors.

Specifically, the auxiliary converters of the existing high-speed rail motor train unit and urban rail all adopt the traditional IGBT as a switch tube, and the defects of the traditional IGBT are mainly that: the switching frequency is low, the size of the magnetic component is large, and the whole power module is large in size and heavy in weight; high losses, resulting in low efficiency (less than 92% efficiency) of the overall product. Therefore, the silicon carbide MOS tube can work at the carrier frequency of up to 400kHz, so that the size and weight of magnetic components such as an isolation transformer are greatly reduced, and modularization and light weight are realized. Preferably, the diodes in the auxiliary converter are also silicon carbide diodes.

The application also provides a control method of the high-frequency auxiliary current transformer, which is applicable to the high-frequency auxiliary current transformer of the embodiment, and exemplarily comprises the following steps:

S10, acquiring the electrical parameters detected by the grounding detection device 300 in the working process of the high-frequency auxiliary current transformer, and determining whether the high-frequency auxiliary current transformer has faults according to the electrical parameters.

Because the high-frequency auxiliary converter adopts the design of a plurality of groups of DCAC non-common buses, when in grounding fault, a single group is convenient to cut off and continue to operate, and therefore, the electric parameters comprise grounding voltage, and the control method of the high-frequency auxiliary converter further comprises the following steps: and detecting the grounding voltage of each sub-module, if the grounding voltage is larger than the grounding voltage threshold value, indicating that a certain sub-module is grounded, determining a grounded sub-module in each DCDC sub-module 110 and DCAC sub-module 120, marking the grounded sub-module as a grounding module, and disconnecting an input relay of the grounding module.

Specifically, the ground fault detection device 300 is divided into two stages:

First, self-checking stage.

When the high-frequency auxiliary converter meets the starting condition and is started for the first time after power-on, self-checking is carried out on the inside of the high-frequency auxiliary converter, and the main process is to control each sub-module in the high-frequency auxiliary converter to start an inversion process, so that the AC output contactor is kept to be disconnected to detect the inside of the high-frequency auxiliary converter. When the grounding voltage detected by the grounding voltage sensor is larger than an alternating current effective value (for example, 50V), the grounding fault of the high-frequency auxiliary converter is reported, meanwhile, the grounding condition of each sub-module is confirmed, the grounding module is found, and the fault of the grounding module is reported.

Second, run phase. And when the detected grounding voltage is larger than a voltage effective value (for example, 100V), the self-checking stage logic judges that the module is grounded, determines the grounding module, disconnects the input and output of the grounding module, and enables the system to exit, and reports a grounding alarm to the vehicle, so that the system can continue to operate.

Specifically, if the ground detection device 300 detects that there is a ground, a ground signal is generated and transmitted to the control module 200. After receiving the grounding signal, the control module 200 sequentially and individually disconnects the input relay and the output relay of one of the DCDC sub-module 110 and the DCAC sub-module 120 until the grounded sub-module is found. For example, the high-frequency auxiliary converter has two inverter modules 100, each inverter module 100 includes 2 DCDC sub-modules 110 and 1 DCAC sub-module 120, which are respectively a first DCDC sub-module 110, a second DCDC sub-module 110, a third DCDC sub-module 110, a fourth DCDC sub-module 110, a first DCAC sub-module 120 and a second DCAC sub-module 120, if the first DCDC sub-module is found to be grounded, the input relay and the output relay of the first DCDC sub-module 110 are first opened, then the ground detection device 300 detects the ground, if the first DCDC sub-module is found to be still grounded, the input relay and the output relay of the first DCDC sub-module 110 are closed, and any one of the remaining sub-modules is continuously opened until the grounded sub-module is found.

Further, the electrical parameter includes an output voltage effective value of the high frequency auxiliary converter; the determining in step S10 whether the high-frequency auxiliary converter has a fault according to the electrical parameter includes:

S110, determining whether the high-frequency auxiliary converter has a single-phase grounding fault or not according to the relation between the effective value of the output voltage of the high-frequency auxiliary converter and a first voltage interval; wherein the first voltage interval is (100 v,200 v). That is, if the effective value of the output voltage of the high-frequency auxiliary converter is within the first voltage interval, it indicates that a single-phase ground fault exists.

S120, determining whether the high-frequency auxiliary converter has a 650V middle bus grounding fault according to the relation between the output voltage effective value of the high-frequency auxiliary converter and a second voltage interval; the second voltage interval is (200 v,520 v). That is, if the effective value of the output voltage of the high-frequency auxiliary converter is within the second voltage interval, it indicates that there is a 650V intermediate bus ground fault.

S130, determining whether the high-frequency auxiliary converter has a series electric fault of a 1500V input voltage bus and a 650V intermediate bus according to the magnitude relation between the effective value of the output voltage of the high-frequency auxiliary converter and the third voltage. The third voltage is in a range of 700V or more, preferably 700V. That is, if the effective value of the output voltage of the high-frequency auxiliary converter is greater than the third voltage, it indicates that there is a series fault between the 1500V bus and the middle 650V bus.

And S20, controlling each DCDC sub-module and each DCAC sub-module to be integrated into a network.

During parallel operation and current sharing control, the DCDC sub-module 110 and the DCAC sub-module 120 perform parallel operation according to a start signal.

S210, for the DCDC sub-modules 110, the control module 200 sends a start signal to each of the DCDC sub-modules 110, and controls the output voltage of each of the DCDC sub-modules 110 to gradually boost; in the boosting process, the droop quantity of the corresponding output voltage is adjusted step by step according to the corresponding input power of each DCDC sub-module 110; until the DCDC sub-module 110 output voltage is normal.

Specifically, since the DCDC sub-module 110 output is directly connected to the bus capacitor of the DCAC sub-module 120, after the DCDC sub-module 110 obtains the start signal, the two machines respectively perform the gradual boosting of the output. In the boosting process, the two machines respectively regulate the sagging amount of the output voltage step by step through respective input power, the sagging amount of the output voltage of the DCDC sub-module 110 with high power is higher, and when the boosting is finished, the DCDC sub-module 110 outputs normally and the two machines achieve the current equalizing effect. For example, as shown in fig. 8, the PID loop in the figure performs PI operation after the difference between the current output voltage and the target voltage calculated in the previous step to obtain the frequency required by LLC, where PI parameters can be approximately formulated according to the LLC frequency range and the output voltage range, and the PI parameters are obtained by open loop experiments, and the frequencies are 65Khz to 150Khz, so that the output voltage can be adjusted to the respective target points for the full range input, that is, 650V-800V output voltage, and then kp= (1000/65-1000/150)/(800-650) = 0.05812 (us/V), and Ki takes 1/10 of Kp to ensure that static errors are eliminated while excessive oscillations are avoided being introduced, and that a single deviation value can be eliminated within 10 times of adjustment.

S220, before the DCAC sub-modules 120 are connected in a grid, the control module 200 sends a starting command to the DCAC sub-modules 120, and when the DCAC sub-modules 120 perform inversion, whether output voltages exist at the rear ends of the output relays of the DCAC sub-modules 120 or not is continuously detected, so that the DCAC sub-modules 120 are determined to be a master or a slave and are connected into a network to realize parallel operation current sharing control. That is, it is determined whether to directly close the relay as the master or to set the slave to perform the phase locking operation before closing the relay.

In one embodiment, in step S220, whether the output voltage exists after detecting the output relay of each DCAC sub-module 120 to determine whether the DCAC sub-module 120 is a master or a slave to be connected to a network to implement parallel operation current sharing control includes:

s221, if the output voltage is not detected after the output relay of the DCAC sub-module 120, performing delay according to a preset delay policy, and if the output voltage is not detected during the delay, the control module 200 controls to close the input-output relay (DCAC input relay and DCAC output relay) of the DCAC sub-module 120 so that the DCAC sub-module 120 becomes a host.

Specifically, a circuit formed by all the connected modules is called a network, a sub-module connected to the whole circuit is called a sub-module network connection, when the high-frequency auxiliary converter starts to work or when a sub-module needs to be connected (network connection) in the working process, each DCAC sub-module 120 firstly detects whether other DCAC sub-modules 120 are contained in the network (whether the condition that whether other sub-modules are connected is that the existing output voltage is detected or not is judged), if not, network connection operation is performed (an input relay and an output relay are closed), and a host mark is added to the DCAC sub-modules 120 as a host. By the mode, any DCAC sub-module 120 can be used as a host, and the problem that the whole machine cannot be started when the host fails in a fixed host mode can be effectively avoided. The delay policy in this embodiment is to wait for an existing networking submodule but is not yet stable, and therefore may not be detected.

Further, the preset delay strategy includes:

Acquiring an ID value of the DCAC sub-module 120; the ID value is determined according to the order in which the DCAC sub-modules 120 are inserted into the high frequency auxiliary current transformer; and setting a delay time length for the corresponding DCAC sub-module 120 according to the ID value and the set proportion.

Specifically, the ID value is the sequence number of the DCAC sub-module 120 inserted into the whole machine, the ID value is fixed after the DCAC sub-module is inserted into the whole machine, and the larger the ID value is in the delay strategy of the present application, the longer the delay is. For example: the DCAC sub-module 120 with ID value 01 is delayed by 0.5s and the DCAC sub-module 120 with ID value 02 is delayed by 1s. The delay strategy can enable any DCAC sub-module 120 to become a host, and can effectively avoid the problem that the whole machine cannot be started when the host fails in a fixed host mode.

And S222, if the output voltage is detected after the output relay of the DCAC sub-module 120, controlling to execute phase locking so that the DCAC sub-module 120 is set as a slave. That is, when the DCAC sub-module 120 detects an output voltage, indicating that an existing host is incorporated into the network, phase locking is performed, and the frequency, phase, and amplitude of the self three-phase output gradually approach the three-phase voltage on the network.

Specifically, if the DCAC sub-module 120 detects that the DCAC sub-module 120 is incorporated into the network, the DCAC sub-module 120 transmits the detected signal to the control module 200, and the control module 200 controls the frequency, phase and amplitude of the three-phase voltage output by the DCAC sub-module 120 to be correspondingly adjusted to the frequency, phase and amplitude of the three-phase voltage on the network; if the frequency, phase and amplitude of the three-phase voltage output by the DCAC sub-module 120 do not exceed the offset threshold corresponding to the frequency, phase and amplitude of the three-phase voltage on the network after the preset time period (0.1-1 s), the input relay and the output relay of the DCAC sub-module 120 are controlled to be conducted, and a slave flag is added to the DCAC sub-module 120.

And S223, after the DCAC sub-module is confirmed to be successfully locked, controlling to close the input/output relay of the slave machine so as to enable the slave machine to be integrated into a network. Further, the confirming that the DCAC sub-module 120 is successfully phase-locked in step S223 includes:

If the slave detects that the phase difference between the three-phase output voltage and the voltage on the parallel network is smaller than the phase difference fixed value and the amplitude is similar, continuously detecting the phase and the amplitude in a preset time period; the preset time period may be 500ms; if the phase and the amplitude do not exceed the offset range within the preset time period, the phase locking is confirmed to be successful.

S224, after the network is integrated, the corresponding amplitude and frequency are respectively adjusted according to the output active power and the output reactive power of each DCAC sub-module 120 so as to realize the current sharing effect.

For example, as shown in fig. 9, a logic diagram of the current sharing algorithm of the DCAC sub-module 120 is shown.

The embodiment of the application provides a high-frequency auxiliary converter, which is characterized in that each module independently works by modularization of the whole converter, when a certain module has serious faults, the module can be independently cut off through an input relay and an output relay, other systems are not influenced, the disassembly is easy, the maintenance efficiency is improved, the maintenance cost is reduced, and meanwhile, the stability of the whole system is also improved.

Each DCDC sub-module 110 is connected with a single DCAC sub-module 120 after being connected in parallel in pairs, each DCAC sub-module 120 connected in parallel does not share a bus (does not share input), each DCAC sub-module 120 is powered on two corresponding DCDC sub-modules 110 connected in parallel to form a single inversion system, and a plurality of inversion systems are connected in parallel through inversion output to form a three-phase alternating current output system. When the output of the single inverter module 100 is abnormal due to faults or the load of each inverter system is uneven due to severe external load jumping, the non-common bus can effectively avoid the alternating current parallel operation circulation caused by the mutual charging of the inverter modules 100. In addition, each module can be connected in parallel in a wireless mode, so that on-site maintenance is facilitated, and capacity expansion and redundancy design of the system are facilitated.

When the power module has serious faults, such as ground faults, the structure can rapidly judge the faulty power module through the action of the relay and cut off the single-path inversion system, thereby avoiding the whole system breakdown caused by single-machine faults.

In short, the application adopts the design that the multiple groups of inverter modules 100 do not share a bus, which is beneficial to inhibiting the circulation of the alternating current parallel operation. In other words, the inverter modules 100 in the application achieve the purpose of not sharing the dc bus by independently separating each inverter module 100, thereby more effectively inhibiting the ac parallel operation circulation. The method is convenient for cutting off the circulation, inputting an independent bus, controlling the output voltage and the frequency phase based on the voltage of the bus, and realizing better parallel operation.

The application also provides a power supply device comprising the high-frequency auxiliary converter.

Specifically, the power supply device in the present embodiment includes a motor or the like, and is not limited here.

It will be appreciated that the power supply device of the present embodiment corresponds to the high-frequency auxiliary current transformer of the above embodiment, and that the options of the high-frequency auxiliary current transformer are also applicable to the present embodiment, and will not be repeated here.

In the several embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other manners. The apparatus embodiments described above are merely illustrative, for example, of the flow diagrams and block diagrams in the figures, which illustrate the architecture, functionality, and operation of possible implementations of apparatus, methods and computer program products according to various embodiments of the present application. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, in alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems which perform the specified functions or acts, or combinations of special purpose hardware and computer instructions.

In addition, functional modules or units in various embodiments of the application may be integrated together to form a single part, or the modules may exist alone, or two or more modules may be integrated to form a single part.

The functions, if implemented in the form of software functional modules and sold or used as a stand-alone product, may be stored in a computer-readable storage medium. Based on such understanding, the technical solution of the present application may be embodied essentially or in a part contributing to the prior art or in a part of the technical solution in the form of a software product stored in a storage medium, comprising several instructions for causing a computer device (which may be a smart phone, a personal computer, a server, a network device, etc.) to perform all or part of the steps of the method according to the embodiments of the present application. And the aforementioned storage medium includes: a usb disk, a removable hard disk, a Read-Only Memory (ROM), a random access Memory (RAM, random Access Memory), a magnetic disk, or an optical disk, or other various media capable of storing program codes.

The foregoing is merely illustrative of the present application, and the present application is not limited thereto, and any person skilled in the art will readily recognize that variations or substitutions are within the scope of the present application.

Claims

1. A control method of a high-frequency auxiliary current transformer, which is characterized in that the control method is suitable for the high-frequency auxiliary current transformer; the high-frequency auxiliary converter comprises a control module and a plurality of parallel inversion modules, wherein each inversion module comprises a plurality of DCDC sub-modules and a DCAC sub-module; the input end of each DCDC sub-module is connected in parallel and is configured to be connected with an input voltage, and the output end of each DCAC sub-module is connected in parallel and is configured to be used as an alternating current output end; in the inversion module, the output end of each DCDC sub-module is connected in parallel to the input end of the corresponding DCAC sub-module; each DCDC sub-module at least comprises an input relay, and each DCAC sub-module at least comprises an output relay; the control module is respectively connected with each DCDC sub-module and each DCAC sub-module and is used for carrying out parallel control on the corresponding connected DCDC sub-modules and the DCAC sub-modules through the input relay and/or the output relay so as to output target alternating voltage; the high-frequency auxiliary converter further comprises a grounding detection device; the grounding detection device comprises three current limiting elements and a detection module; the first ends of the three current limiting elements are respectively and correspondingly connected with one phase of three-phase alternating current output ends of the high-frequency auxiliary converter, and the second ends of the three current limiting elements are connected to the same node; the first end of the detection module is connected with the node, and the second end of the detection module is grounded;

the detection module is used for detecting electrical parameters between the node and the ground end so as to judge whether a ground fault and a fault type exist or not;

the control method comprises the following steps:

in the working process of the high-frequency auxiliary current transformer, acquiring an electrical parameter detected by the grounding detection device, and determining whether the high-frequency auxiliary current transformer has a fault according to the electrical parameter;

The electrical parameter comprises an output voltage effective value of the high-frequency auxiliary converter;

Determining whether the high-frequency auxiliary converter has single-phase grounding faults or not according to the relation between the output voltage effective value of the high-frequency auxiliary converter and a first voltage interval; determining whether the high-frequency auxiliary converter has an intermediate bus grounding fault according to the relation between the output voltage effective value of the high-frequency auxiliary converter and a second voltage interval; determining whether the high-frequency auxiliary converter has a series electric fault between an input voltage bus and an intermediate bus according to the magnitude relation between the effective value of the output voltage of the high-frequency auxiliary converter and the third voltage; wherein the first voltage interval is smaller than the second voltage interval; the third voltage is greater than a maximum value of the second voltage interval.

2. The control method of a high frequency auxiliary current transformer according to claim 1, wherein the first voltage interval is (100 v,200 v); the second voltage interval is (200 v,520 v); the range of the third voltage is 700V or more.

3. The control method of a high frequency auxiliary current transformer according to claim 1, wherein the electrical parameter further comprises a ground voltage;

The method further comprises the steps of: and detecting the grounding voltage of each sub-module, if the grounding voltage is larger than a grounding voltage threshold value, determining a grounded sub-module in each DCDC sub-module and each DCAC sub-module, and switching off an input relay of the grounded sub-module.

4. The method of controlling a high frequency auxiliary current transformer according to claim 1, wherein said controlling each of said DCDC sub-modules and each of said DCAC sub-modules to be incorporated into a network comprises:

5. The method of claim 4, wherein detecting whether the output voltage exists in each DCAC sub-module to determine whether the DCAC sub-module is used as a master or a slave to be integrated into a network to realize parallel operation current sharing control, comprises:

6. The method according to claim 5, wherein the preset delay strategy comprises:

7. The method of claim 5, wherein said confirming that the DCAC sub-module phase lock is successful comprises: