CN216490273U - Double-frequency-converter parallel driving topological structure with redundancy function - Google Patents
Double-frequency-converter parallel driving topological structure with redundancy function Download PDFInfo
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- CN216490273U CN216490273U CN202121030899.3U CN202121030899U CN216490273U CN 216490273 U CN216490273 U CN 216490273U CN 202121030899 U CN202121030899 U CN 202121030899U CN 216490273 U CN216490273 U CN 216490273U
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Abstract
The utility model relates to a double-frequency converter parallel driving topological structure with a redundancy function, which comprises 2 frequency converters connected in parallel, an input incoming line switch, an output reactor and an output switch which are respectively and correspondingly arranged, and also comprises a plurality of motors, bypass switches and motor change-over switches which are correspondingly arranged, wherein 1 speed regulating motor in the plurality of motors is driven by the frequency converters to regulate the speed and operate, and the rest of the constant speed motors are directly driven by a power grid to operate after being soft started by the frequency converters. The 2 frequency converters can be operated in parallel or in a single machine, after the frequency converters are connected in parallel to drive all the constant-speed motors to be started, 1 frequency converter is used for driving the speed-regulating motor to operate, and the other 1 frequency converter is used as a standby machine.
Description
Technical Field
The utility model relates to a topological structure of a frequency converter, in particular to a double-frequency-converter parallel driving topological structure with a redundancy function, which is applied to the field of frequency conversion soft starting and frequency conversion speed regulation driving of a motor.
Background
In some large-scale continuous production processes, a working condition that a plurality of high-power motors are driven simultaneously is usually involved, for example, a PDH process (propane dehydrogenation to propylene) in the chemical industry needs a heat pump, a product gas compressor and the like to work simultaneously, the pumps and the compressors are driven by the motors, and the motor power is very high and is generally between 10MW and 50 MW. In order to improve the reliability of the system, a plurality of motors are generally sequentially and softly started by 1 high-power frequency converter and then directly driven by a power grid. However, after the motor is directly driven by the power grid, the motor starts to operate at a constant rotating speed, and the energy-saving effect of the motor achieved by speed regulation operation through driving of a frequency converter cannot be achieved, so that the problem of low system operation efficiency exists. Especially when a high-power load runs, the electric energy saved by using the frequency converter for driving and adjusting has a non-negligible influence on the running cost of an enterprise, and the problem of energy consumption is particularly obvious. If the frequency converter is directly adopted to drive the speed regulation to operate in the whole production process, the problems of large number of frequency converter components and low operation reliability exist, and once the whole production process is interrupted due to the fault of the frequency converter, the economic loss caused to enterprises is very large. Therefore, for the application occasions, how to realize the energy-saving effect of the speed-regulating operation of the motor and ensure the operation reliability of the whole system has important significance on the premise of not increasing the cost greatly.
Disclosure of Invention
The utility model aims to overcome the problems in the prior art and discloses a double-frequency-converter parallel driving topological structure with a redundancy function, which not only can realize the energy-saving effect of the speed-regulating operation of a motor, but also can ensure the operation reliability of a frequency-converting driving system in the whole large-scale continuous production process.
The utility model is realized in the following way: the utility model provides a two frequency converter parallel drive topological structure with redundancy function which characterized in that: the double-frequency-converter parallel driving topological structure comprises 2 first frequency converters VFD1# and second frequency converters VFD2# which are connected in parallel, wherein the input ends of the two frequency converters are correspondingly and respectively connected to a first section of bus through a first input incoming line switch KL1 and connected to a second section of bus through a second input incoming line switch KL2, the output ends of the two frequency converters are respectively and sequentially connected with one end of an output first reactor L1 and a first output switch KD1, one end of a second reactor L2 and one end of a second output switch KD2, the other end of the first output switch KD1 is connected with the other end of the second output switch KD2 in parallel, the double-frequency-converter parallel driving topological structure further comprises n constant speed motors MA and 1 speed regulating motor MB, n is an integer greater than or equal to 1, the constant speed motor MA is directly driven by a power grid to operate after being soft started by the frequency converters, the speed regulating motor MB is driven by the frequency converters to operate, the speed regulating motor is connected with the second section of bus, corresponding bypass switches are respectively arranged on connecting lines between each constant speed motor and the bus, each motor is also respectively connected to a line between two parallel ends of the first output switch KD1 and the second output switch KD2, and corresponding motor change-over switches are respectively arranged on the lines. In the n constant-speed motors MA, the power of at least 1 motor is larger than that of a single motor in 2 frequency converters, and the power of 1 speed-regulating motor MB is smaller than or equal to that of a single motor in 2 frequency converters. And 2 frequency converters, an input incoming line switch, an output switch, a bypass switch and a motor change-over switch are all three-phase, and the voltage grade is alternating current 220V-35 kV.
The other ends of the first incoming line switch KL1 and the second incoming line switch KL2 which are respectively connected with the two sections of buses can be connected in parallel, and then are correspondingly connected to the input ends of the two frequency converters through the third input incoming line switch KL3 and the fourth input incoming line switch KL4 which are connected in parallel, and when the bypass switch is applied to occasions with requirements on the starting sequence of the motor, a bypass switch can be additionally arranged on a connecting circuit between the speed regulating motor and the buses.
According to the field configuration, the 2 frequency converters and the motors can only use the same section of bus, and can also respectively adopt a plurality of sections of buses to supply power.
The utility model has the beneficial effects that: the utility model adopts 2 frequency converters with smaller power and a plurality of change-over switches to replace the topological structure design of 1 frequency converter with large power in the prior art, and the overall cost is not greatly increased compared with the prior art. When the power of the motor needing soft start is larger than that of a single frequency converter, the soft start is carried out by adopting a mode of parallel operation of 2 frequency converters, after the soft start is finished, the 2 frequency converters are controlled to be switched into a single operation mode through a change-over switch, aiming at a speed regulating motor with the power smaller than or equal to the power of the single frequency converter in the system, the speed regulating operation can be realized only by driving one frequency converter, the other frequency converter is used as a standby machine, when the frequency converter for driving the motor to carry out the speed regulating operation fails, the motor can be continuously driven by the frequency converter used as the standby machine to carry out the speed regulating operation, the unplanned halt of the system is avoided, the energy-saving effect of the speed regulating operation of the motor can be realized, and the reliability of the system is ensured.
Drawings
FIG. 1 is a schematic illustration of the structure of the present invention.
Fig. 2 is a block diagram schematically showing the structure of embodiment 1 of the present invention.
In the figure: 1. a first section of bus; 2. And a second section of bus.
Detailed Description
The utility model is further described with reference to the following figures and specific examples.
According to the attached drawing 1, the utility model relates to a dual-frequency converter parallel driving topological structure with a redundancy function, which comprises 2 first frequency converters VFD1# and second frequency converters VFD2# which are connected in parallel, wherein the input ends of the two frequency converters are correspondingly and respectively connected to a first section of bus 1 through a first input incoming line switch KL1 and connected to a second section of bus 2 through a second input incoming line switch KL2, the output ends of the two frequency converters are respectively and sequentially connected with one ends of a first output reactor L1 and a first output switch KD1, and one ends of a second reactor L2 and a second output switch KD2, and the other end of the first output switch KD1 is connected with the other end of the second output switch KD2 in parallel.
The double-frequency converter parallel driving topological structure also comprises n constant speed motors MA and 1 speed regulating motor MB, wherein n is an integer larger than or equal to 1, the constant-speed motor MA is driven by a frequency converter to be soft-started and then is controlled by a switch to be directly driven by a power grid to operate, the speed-regulating motor MB is driven by the frequency converter to regulate the speed to operate, wherein m motors in the n constant speed motors MA are connected with the first section of bus 1, n-m motors are connected with the second section of bus 2, m is an integer more than or equal to 0 and less than or equal to n, the speed regulating motor is connected with the second section of bus, corresponding bypass switches are respectively arranged on a connecting line between each constant speed motor and the bus, each motor is also respectively connected to a line between two parallel ends of the first output switch KD1 and the second output switch KD2, and corresponding motor change-over switches are respectively arranged on the circuits. The sequence of the n constant-speed motors MA is MA _1, … … MA _ m and … … MA _ n, the sequence of the correspondingly arranged bypass switches is KPA _1, … … KPA _ m and … … KPA _ n, and the sequence of the correspondingly arranged motor change-over switches is KMA _1, … … KMA _ m and … … KMA _ n. The speed regulating motor MB is correspondingly provided with a motor change-over switch KMB.
In the n constant-speed motors MA, the power of at least 1 motor is larger than that of a single motor in 2 frequency converters, and the power of 1 speed-regulating motor MB is smaller than or equal to that of a single motor in 2 frequency converters. The frequency converter, the input incoming line switch, the output switch, the bypass switch and the motor change-over switch are all three-phase, and the voltage grade is alternating current 220V-35 kV.
According to field configuration, the frequency converter and the motor can only use the same section of bus, and can also respectively supply power by adopting a plurality of sections of buses.
Where no requirement is placed on the motor start sequence, a typical control and operation method of the present invention is described as follows:
in the initial state, all switches are in the off state.
When the electric automobile speed control system works, the first input incoming line switch KL1 and the second input incoming line switch K2 are closed, 2 frequency converters (a first frequency converter VFD1# and a second frequency converter VFD2 #) are electrified to finish, then the first output switch KD1 and the second output switch KD2 are closed, the 2 frequency converters run in parallel, and each of the constant speed motors MA _ 1-MA _ n is started according to the instruction of a superior control system.
Taking starting the first constant speed motor MA _1 as an example, the first motor change-over switch KMA _1 is closed first, the frequency converter drives the first constant speed motor MA _1 to the power grid frequency, then the frequency converter adjusts the amplitude and the phase of the output voltage, so that the amplitude and the phase of the output voltage of the frequency converter are close to or consistent with those of the first section of bus power grid voltage, then the first bypass switch KPA _1 is closed, then the first motor change-over switch KMA _1 is opened, then the first constant speed motor MA _1 is directly driven by the power grid through the first section of bus, and the soft starting is completed.
When all the constant-speed motors are soft-started, the second output switch KD2 is opened, the motor change-over switch KMB is closed, 2 frequency converters are switched to a single-machine operation mode, the first frequency converter VFD1# drives the speed-regulating motor MB to operate according to the instruction of a superior control system, the second frequency converter VFD2# is in a hot standby state as a standby machine, when the first frequency converter VFD1# has a fault, the power electronic device driving pulse of the first frequency converter VFD1# is immediately blocked and the first output switch KD1 is opened, after the second frequency converter VFD2# detects that the first output switch KD1 is opened, the corresponding second output switch KD2 is immediately closed (or the superior control system sends out a closing instruction in advance, but the first output switch KD1 and the second output switch KD2 are ensured not to be closed at the same time), the second frequency converter VFD2# executes a rotation speed tracking restart function to detect the current rotation speed of the speed-regulating motor MB, and the speed regulating motor MB is driven to the set rotating speed, and is driven by the second frequency converter VFD2#, so that the interruption of the whole production process caused by the abnormal shutdown of the speed regulating motor MB can be effectively avoided. When the single machine operates, the output reactor can be bypassed by the switch, so that the electric energy loss can be reduced.
Meanwhile, a first input incoming line switch KL1 of the first frequency converter VFD1# can be disconnected, so that the fault frequency converter is offline, offline fault maintenance and recovery can be performed, and the repaired frequency converter is put into a standby state again.
Example 1:
according to fig. 2, in this embodiment, the other ends of the first incoming line switch KL1 and the second incoming line switch KL2, which are respectively connected to two segments of buses, are first connected in parallel, and then are correspondingly connected to the input ends of two frequency converters through the third incoming line switch KL3 and the fourth incoming line switch KL4, which are connected in parallel, respectively, that is, one ends of the third incoming line switch KL3 and the fourth incoming line switch KL4 are connected in parallel, and then are connected to the parallel connection end of the first incoming line switch KL1 and the second incoming line switch KL2, the other end of the third incoming line switch KL3 is connected to the first frequency converter VFD1#, the other end of the fourth incoming line switch KL4 is connected to the second frequency converter VFD2#, and meanwhile, a bypass switch KPB is further disposed on a connection line between the speed-regulating motor and the buses.
The present embodiment has two typical control and operation methods, which are respectively described as follows:
1. for applications where no motor start sequence is required:
in the initial state, all switches are in the off state.
When the electric automobile speed control system starts working, the first input incoming line switch KL1, the third input incoming line switch KL3 and the fourth input incoming line switch KL4 are firstly closed, 2 frequency converters (a first frequency converter VFD1# and a second frequency converter VFD2 #) are powered on and are all powered by a first section of bus, then the first output switch KD1 and the second output switch KD2 are closed, the 2 frequency converters run in parallel, and the constant speed motors MA _ 1-MA _ n are started firstly according to an instruction of a superior control system. Or the second input incoming line switch KL2, the third input incoming line switch KL3 and the fourth input incoming line switch KL4 can be closed at first, and 2 frequency converters are all powered by the second section of bus.
The subsequent control and working method is the same as that when the third input incoming line switch KL3 and the fourth input incoming line switch KL4 are not arranged. The bypass switch KPB can be in a normally closed state in the working condition.
2. For applications requiring a motor start sequence:
if the process requires that the speed regulating motor MB is operated firstly and then the constant speed motor MB can be started, the working mode is adopted. At this time, the speed regulation motor MB is driven by the frequency converter to execute the soft start function, the speed regulation motor MB is driven by the power grid after the soft start is completed, then the first frequency converter VFD1# and the second frequency converter VFD2# run in parallel, the command of the superior control system is executed to sequentially soft start each constant speed motor, after all the constant speed motors are soft started, the first frequency converter VFD1# and the second frequency converter VFD2# are switched to the single machine running mode, and the speed regulation motor MB is switched from the power grid drive to the frequency converter drive by utilizing the synchronous switching function of the frequency converters.
The specific operation mode is described as follows:
in the initial state, all switches are in the off state.
Because the speed regulation motor MB needs to run firstly, the speed regulation motor MB can be driven by a single machine of the first frequency converter VFD1# or the second frequency converter VFD2# to execute soft start, and can also be driven by the first frequency converter VFD1# and the second frequency converter VFD2# in parallel to execute soft start. The method is described by taking an example of performing soft start by driving a first frequency converter VFD1# single machine, when the work starts, firstly, a first input incoming line switch KL1 is closed, the first frequency converter VFD1# is electrified to be completed, then, a corresponding first output switch KD1 is closed, a first frequency converter VFD1# single machine operates, then, a motor change-over switch KMB is closed, the first frequency converter VFD1# drives a speed regulation motor MB to perform soft start, the first frequency converter VFD1# adjusts the amplitude and the phase of output voltage after the speed regulation motor MB is driven to the power grid frequency, so that the amplitude and the phase of the output voltage of the first frequency converter VFD1# are close to or consistent with those of the second section of bus power grid voltage, then, a bypass switch KPB is closed, then, the motor change-over switch KMB is opened, the speed regulation motor MB is directly driven by the power grid, and the soft start is completed.
After the soft start of the speed-regulating motor MB is finished, the first input incoming line switch KL1 and the second input incoming line switch KL2 are both closed, the first output switch KD1 and the first output switch KD2 are also closed, 2 frequency converters run in parallel, and the frequency converters start the constant-speed motors MA _ 1-MA _ n according to the instruction of a superior control system.
When all the constant-speed motors are soft-started, the second output switch KD2 is switched off, the motor change-over switch KMB is switched on, the frequency converter is switched to operate as a single machine, the first frequency converter VFD1# executes a synchronous switching function, and the speed-regulating motor MB is switched from being driven by a power grid to being driven by the frequency converter. The specific process is as follows: the first frequency converter VFD1# detects the voltage amplitude, the frequency and the phase of the second section of bus and outputs the same voltage, so that the output of the first frequency converter VFD1# is connected with the second section of bus in a grid-connected mode to operate, then the bypass switch KPB is disconnected, the speed regulating motor MB is switched from being driven by a power grid to being driven by the first frequency converter VFD1# and then normally operates in a speed regulating mode according to the instruction of a superior control system. At this time, the second inverter VFD2# is in a hot standby state, when the first inverter VFD1# fails, the power electronic device driving pulse of the first inverter VFD1# is immediately blocked and the first output switch KD1 is turned off, after the second inverter VFD2# detects that the first output switch KD1 is turned off, the corresponding second output switch KD2 is immediately turned on (or a superior control system sends out a close command in advance, but it is required to ensure that the first output switch KD1 and the second output switch KD2 are not turned on at the same time), the second inverter VFD2# performs a rotation speed tracking restart function, detects the current rotation speed of the speed regulation motor MB, and drives the speed regulation motor MB to a set rotation speed, and the speed regulation motor MB is driven by the second inverter VFD2#, so that the interruption of the whole production process caused by abnormal shutdown of the speed regulation motor MB can be effectively avoided.
Meanwhile, a first input incoming line switch KL1 of the first frequency converter VFD1# can be disconnected, so that the fault frequency converter is offline, offline fault overhauling and recovery can be performed, and the repaired frequency converter is put into a standby state again.
In the above two exemplary control methods, the main-standby operation relationship of the first frequency converter VFD1# and the second frequency converter VFD2# may be reversed.
The foregoing detailed description is only preferred embodiments of the present invention for the purpose of illustrating it in detail, and is not to be construed as limiting the present invention, and it will be apparent to those skilled in the art that various equivalent modifications, variations and substitutions can be made in the detailed description of the present invention, which are within the scope of the present invention. The scope of the utility model is defined by the description of the claims.
Claims (4)
1. The utility model provides a two frequency converter parallel drive topological structure with redundancy function which characterized in that: the double-frequency converter parallel driving topological structure comprises 2 first frequency converters VFD1# and a second frequency converter VFD2# which are connected in parallel, wherein the input ends of the two frequency converters are correspondingly and respectively connected to a first section of bus through a first input incoming line switch KL1 and connected to a second section of bus through a second input incoming line switch KL2, the output ends of the two frequency converters are respectively and sequentially connected with one end of an output first electric reactor L1 and a first output switch KD1, one end of a second electric reactor L2 and one end of a second output switch KD2, the other end of the first output switch KD1 is connected with the other end of the second output switch KD2 in parallel, the double-frequency converter parallel driving topological structure further comprises n constant speed motors MA and 1 speed regulating motor MB, wherein n is an integer larger than or equal to 1, the constant speed motor MA is directly driven by a power grid after being soft started by the frequency converters, the speed regulating motor MB is driven by the frequency converters to run, the speed regulating motor is connected with the second section of bus, corresponding bypass switches are respectively arranged on connecting lines between each constant speed motor and the bus, each motor is also respectively connected to a line between two parallel ends of the first output switch KD1 and the second output switch KD2, and corresponding motor change-over switches are respectively arranged on the connecting lines.
2. The dual-frequency converter parallel drive topology with the redundancy function according to claim 1, wherein: in the n constant-speed motors MA, the power of at least 1 motor is larger than that of a single motor in 2 frequency converters, and the power of 1 speed-regulating motor MB is smaller than or equal to that of a single motor in 2 frequency converters.
3. The dual-frequency converter parallel drive topology with the redundancy function according to claim 1, wherein: and 2 frequency converters, an input incoming line switch, an output switch, a bypass switch and a motor change-over switch are all three-phase, and the voltage grade is alternating current 220V-35 kV.
4. The dual-frequency converter parallel drive topology with the redundancy function according to claim 1, wherein: the other ends of the first input incoming line switch KL1 and the second input incoming line switch KL2, which are respectively connected with the two sections of buses, are firstly connected in parallel, and then are correspondingly connected to the input ends of the two frequency converters through a third input incoming line switch KL3 and a fourth input incoming line switch KL4 which are connected in parallel, and a bypass switch is arranged on a connecting line between the speed regulating motor and the buses.
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