CN116581865B - Online undisturbed switching method and double-machine redundant high-voltage variable frequency system - Google Patents
Online undisturbed switching method and double-machine redundant high-voltage variable frequency system Download PDFInfo
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- CN116581865B CN116581865B CN202310858819.0A CN202310858819A CN116581865B CN 116581865 B CN116581865 B CN 116581865B CN 202310858819 A CN202310858819 A CN 202310858819A CN 116581865 B CN116581865 B CN 116581865B
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Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
- H02J9/062—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems for AC powered loads
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J9/00—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting
- H02J9/04—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source
- H02J9/06—Circuit arrangements for emergency or stand-by power supply, e.g. for emergency lighting in which the distribution system is disconnected from the normal source and connected to a standby source with automatic change-over, e.g. UPS systems
- H02J9/068—Electronic means for switching from one power supply to another power supply, e.g. to avoid parallel connection
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P27/00—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage
- H02P27/04—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage
- H02P27/06—Arrangements or methods for the control of AC motors characterised by the kind of supply voltage using variable-frequency supply voltage, e.g. inverter or converter supply voltage using dc to ac converters or inverters
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Business, Economics & Management (AREA)
- Emergency Management (AREA)
- Control Of Ac Motors In General (AREA)
Abstract
The invention discloses an online undisturbed switching method and a double-machine redundancy high-voltage variable frequency system, which belong to the field of power electronic control.
Description
Technical Field
The invention belongs to the field of power electronic control, and particularly relates to an online undisturbed switching method and a dual-machine redundancy high-voltage variable frequency system.
Background
Most of the existing high-voltage frequency converters adopt a topological structure with power units connected in series, the system is huge and complex, if the frequency converter fails in the operation process, the bypass function of the frequency converter does not work, the frequency converter can stop operation, and particularly in some important load occasions, the frequency converter fails to cause shutdown and production stopping of enterprises, so that huge economic loss can be brought to the enterprises. Based on the above, a redundant system is generally configured for the high-voltage frequency converter, and when one frequency converter fails, the high-voltage frequency converter can be switched to the other standby frequency converter, so that the normal production of enterprises is ensured. In the switching process of the high-voltage variable-frequency redundant system, the running state of the load motor cannot be detected in the action time of the contactor, and current impact can exist in direct switching.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides an online undisturbed switching method and a double-machine redundancy high-voltage variable frequency system, which are used for predicting and controlling the running state of a load motor in the action time of a contactor, reducing the current impact during switching and realizing the online undisturbed smooth switching of the high-voltage variable frequency system.
In order to achieve the above object, the present invention provides the following technical solutions:
an online undisturbed switching method, comprising the steps of:
s1, when a motor normally operates, data are continuously exchanged between a high-voltage frequency converter VFD1 and a high-voltage frequency converter VFD2 through CAN communication;
s2, when the switching condition is met, the contactor KM1 is disconnected and the contactor KM2 is closed, and the action time of the two contactors is respectively；
S3, predictingkBack electromotive force and residual magnetic current of the motor under alpha beta coordinate axis at +1 moment;
s4, iterating a predictive control algorithm until the action time of the contactor KM1 and the contactor KM2 is completed;
and S5, bringing the finally obtained back electromotive force and residual magnetic current into a control algorithm of the high-voltage frequency converter VFD2 to obtain an initial value of the output voltage of the high-voltage frequency converter VFD2, and smoothly controlling the switching of the high-voltage frequency conversion system after the output voltage of the high-voltage frequency converter VFD2 is linearly increased until the output voltage of the high-voltage frequency converter VFD2 is increased to a rated voltage value.
Further, in S3, a prediction equation of the back electromotive force under the αβ coordinate axis is:
，
，
wherein ,is thatk+Counter electromotive force component of motor under alpha coordinate axis at moment 1, < >>Is thatk+Counter electromotive force component of motor under beta coordinate axis at moment 1, < ->For the mutual inductance of the motor->Is thatkThe moment motor has a residual magnetic current component in the alpha coordinate axis,is thatkResidual magnetic current component of the motor under beta coordinate axis at moment, < >>For the program control period->Is thatkBack electromotive force component of the motor at moment alpha coordinate axis, < >>Is thatkCounter electromotive force component of the moment motor under beta coordinate axis, < + >>For the resistance of the rotor,Sfor slip, add>For the rotational speed->Is rotor leakage inductance.
Further, in the step S3, a prediction equation of the remanence current under the αβ coordinate axis is:
,
,
wherein ,is thatk+Residual magnetic current component of motor under alpha coordinate axis at moment 1, < >>Is thatk+Residual magnetic current component of motor under beta coordinate axis at moment 1, < >>Is thatkBack electromotive force component of the motor at moment alpha coordinate axis, < >>Is thatkCounter electromotive force component of the moment motor under beta coordinate axis, < + >>For the resistance of the rotor,Sfor slip, add>For the rotational speed->Is rotor leakage inductance.
Further, in S4, the number of control iterations isN，
,
wherein ,Nin order to control the number of iterations,for the contact actuation time, +.>Is a program control period.
Further, in the step S5, the calculation formula of the initial value of the output voltage of the high-voltage inverter VFD2 is as follows:
，
，
wherein ,、/>is the initial value of the output voltage of the high-voltage frequency converter VFD2 under the alpha beta coordinate axis, +.>、/>Iterating alpha beta coordinate axes for back electromotive forceNPost-secondary value,/, for>For stator resistance>、/>Iterating at alpha beta coordinate axis for remanence currentNPost-secondary value,/, for>The leakage inductance of the stator is d is a differential operator, and t is time.
The invention also provides a dual-redundancy high-voltage frequency conversion system for implementing the online undisturbed switching method, which comprises the following steps: the power grid Vin1, the power grid Vin2, the high-voltage frequency converter VFD1, the high-voltage frequency converter VFD2, the circuit breaker QF1, the circuit breaker QF2, the contactor KM1, the contactor KM2 and the load motor M.
The power grid Vin1 is connected with a breaker QF1 in series, the breaker QF1 is connected with a high-voltage frequency converter VFD1 in series, and the high-voltage frequency converter VFD1 is connected with a contactor KM1 in series; the power grid Vin2 is connected with a breaker QF2 in series, the breaker QF2 is connected with a high-voltage frequency converter VFD2 in series, and the high-voltage frequency converter VFD2 is connected with a contactor KM2 in series; the other ends of the contactor KM1 and the contactor KM2 are connected with each other and then connected to a load motor M; the high-voltage frequency converter VFD1 is connected with the high-voltage frequency converter VFD2 through CAN communication.
Further, an interlock is formed between the contactor KM1 and the contactor KM2.
Further, during normal operation of the contactor KM1 and the contactor KM2, the contactor KM1 is in a closed state, and the contactor KM2 is in an open state; the high-voltage frequency converter VFD1 breaks down, the double-machine redundant high-voltage frequency conversion system enters an automatic switching mode, the high-voltage frequency converter VFD1 enables automatic switching signals, and the contactor KM2 is closed while the contactor KM1 is disconnected; the high-voltage frequency converter VFD1 needs to be shut down for maintenance, and the double-machine redundant high-voltage frequency conversion system is used for manually switching off the contactor KM1 and simultaneously closing the contactor KM2 through a manual switching mode.
According to the technical scheme, the beneficial effects of the invention are as follows: the running state of the load motor in the action time of the contactor is predicted and controlled, so that the current impact during switching is reduced, and the online disturbance-free smooth switching of the high-voltage variable frequency system is realized; the two high-voltage frequency converters are standby, and are rapidly switched when in failure, so that the normal production of enterprises is ensured; the manual change-over switch is arranged, so that the timing maintenance requirement of the staff is met.
Drawings
FIG. 1 is a flow chart of an online undisturbed switching method according to the invention;
fig. 2 is a diagram of a dual-redundancy high-voltage variable frequency system provided by the invention.
Detailed Description
The following is only a preferred embodiment of the present invention. The present invention will be described in further detail with reference to the drawings and detailed description below to facilitate understanding of the present invention by those skilled in the art, and it should be noted that all the inventions which make use of the inventive concept are protected by the present invention insofar as the various changes are within the spirit and scope of the present invention as defined and defined by the appended claims without departing from the principle of the present invention.
Fig. 1 is a flowchart of an online undisturbed switching method according to the present invention. As shown in fig. 1, an online undisturbed switching method comprises the following steps:
s1, when a motor normally operates, data are continuously exchanged between a high-voltage frequency converter VFD1 and a high-voltage frequency converter VFD2 through CAN communication;
s2, when the switching condition is met, the contactor KM1 is disconnected and the contactor KM2 is closed, and the action time of the two contactors is respectively；
S3, predictingkBack electromotive force and residual magnetic current of the motor under alpha beta coordinate axis at +1 moment;
s4, iterating a predictive control algorithm until the action time of the contactor KM1 and the contactor KM2 is completed;
and S5, bringing the finally obtained back electromotive force and residual magnetic current into a control algorithm of the high-voltage frequency converter VFD2 to obtain an initial value of the output voltage of the high-voltage frequency converter VFD2, and smoothly controlling the switching of the high-voltage frequency conversion system after the output voltage of the high-voltage frequency converter VFD2 is linearly increased until the output voltage of the high-voltage frequency converter VFD2 is increased to a rated voltage value.
In the step S3, the prediction equation of the back electromotive force in the αβ coordinate axis is:
，
，
wherein ,is thatk+Counter electromotive force component of motor under alpha coordinate axis at moment 1, < >>Is thatk+Counter electromotive force component of motor under beta coordinate axis at moment 1, < ->For the mutual inductance of the motor->Is thatkThe moment motor has a residual magnetic current component in the alpha coordinate axis,is thatkResidual magnetic current component of the motor under beta coordinate axis at moment, < >>For the program control period->Is thatkBack electromotive force component of the motor at moment alpha coordinate axis, < >>Is thatkCounter electromotive force component of the moment motor under beta coordinate axis, < + >>For the resistance of the rotor,Sfor slip, add>For the rotational speed->Is rotor leakage inductance.
In the step S3, the prediction equation of the remanence current in the αβ coordinate axis is:
,
,
wherein ,is thatk+Residual magnetic current component of motor under alpha coordinate axis at moment 1, < >>Is thatk+The motor at time 1 is under the beta coordinate axisResidual magnetic current component, ">Is thatkBack electromotive force component of the motor at moment alpha coordinate axis, < >>Is thatkCounter electromotive force component of the moment motor under beta coordinate axis, < + >>For the resistance of the rotor,Sfor slip, add>For the rotational speed->Is rotor leakage inductance.
In the step S4, the control iteration number isN，
,
wherein ,Nin order to control the number of iterations,for the contact actuation time, +.>Is a program control period.
In the step S5, the initial value calculation formula of the output voltage of the high-voltage inverter VFD2 is:
，
，
wherein ,、/>is the initial value of the output voltage of the high-voltage frequency converter VFD2 under the alpha beta coordinate axis, +.>、/>Iterating alpha beta coordinate axes for back electromotive forceNPost-secondary value,/, for>For stator resistance>、/>Iterating at alpha beta coordinate axis for remanence currentNPost-secondary value,/, for>The leakage inductance of the stator is d is a differential operator, and t is time.
The invention also provides a double-machine redundant high-voltage frequency conversion system which is used for implementing the online undisturbed switching method. Fig. 2 is a diagram of a dual-redundancy high-voltage frequency conversion system according to the present invention, as shown in fig. 2, the dual-redundancy high-voltage frequency conversion system includes: the power grid Vin1, the power grid Vin2, the high-voltage frequency converter VFD1, the high-voltage frequency converter VFD2, the circuit breaker QF1, the circuit breaker QF2, the contactor KM1, the contactor KM2 and the load motor M.
Wherein, the power grid Vin1 is connected with a breaker QF1 in series, the breaker QF1 is connected with a high-voltage frequency converter VFD1 in series, and the high-voltage frequency converter VFD1 is connected with a contactor KM1 in series; the power grid Vin2 is connected with a breaker QF2 in series, the breaker QF2 is connected with a high-voltage frequency converter VFD2 in series, and the high-voltage frequency converter VFD2 is connected with a contactor KM2 in series; the other ends of the contactor KM1 and the contactor KM2 are connected with each other and then connected to a load motor M; the high-voltage frequency converter VFD1 is connected with the high-voltage frequency converter VFD2 through CAN communication.
Wherein an interlock is formed between the contact KM1 and the contact KM2. During normal operation of the contactor KM1 and the contactor KM2, the contactor KM1 is in a closed state, and the contactor KM2 is in an open state; when the high-voltage frequency converter VFD1 fails, the double-machine redundant high-voltage frequency conversion system enters an automatic switching mode, the high-voltage frequency converter VFD1 enables automatic switching signals, and the contactor KM2 is closed while the contactor KM1 is disconnected; when the high-voltage frequency converter VFD1 needs to be shut down for maintenance, the double-machine redundant high-voltage frequency conversion system manually cuts off the contactor KM1 and simultaneously closes the contactor KM2 through manual mode switching.
Although specific embodiments of the invention have been described in detail with reference to the accompanying drawings, it should not be construed as limiting the scope of protection of the invention. Various modifications and variations which may be made by those skilled in the art without the creative effort are within the scope of the patent claims.
Claims (5)
1. An online undisturbed switching method is characterized by comprising the following steps:
s1, when a motor normally operates, data are continuously exchanged between a high-voltage frequency converter VFD1 and a high-voltage frequency converter VFD2 through CAN communication;
s2, when the switching condition is met, the contactor KM1 is disconnected and the contactor KM2 is closed, and the action time of the two contactors is respectively；
S3, predictingkBack electromotive force and residual magnetic current of the motor under alpha beta coordinate axis at +1 moment; the prediction equation of the back electromotive force under the alpha beta coordinate axis is as follows:
，
，
wherein ,is thatk+Counter electromotive force component of motor under alpha coordinate axis at moment 1, < >>Is thatk+Counter electromotive force component of motor under beta coordinate axis at moment 1, < ->For the mutual inductance of the motor->Is thatkResidual magnetic current component of the motor under alpha coordinate axis at moment, < >>Is thatkResidual magnetic current component of the motor under beta coordinate axis at moment, < >>For the program control period->Is thatkBack electromotive force component of the motor at moment alpha coordinate axis, < >>Is thatkCounter electromotive force component of the moment motor under beta coordinate axis, < + >>For the resistance of the rotor,Sfor slip, add>For the rotational speed->Is rotor leakage inductance;
the prediction equation of the remanence current under the alpha beta coordinate axis is as follows:
,
,
wherein ,is thatk+Residual magnetic current component of motor under alpha coordinate axis at moment 1, < >>Is thatk+Residual magnetic current component of motor under beta coordinate axis at moment 1, < >>Is thatkBack electromotive force component of the motor at moment alpha coordinate axis, < >>Is thatkCounter electromotive force component of the moment motor under beta coordinate axis, < + >>For the resistance of the rotor,Sfor slip, add>For the rotational speed->Is rotor leakage inductance;
s4, iterating a predictive control algorithm until the action time of the contactor KM1 and the contactor KM2 is completed;
s5, bringing the finally obtained back electromotive force and residual magnetic current into a control algorithm of the high-voltage frequency converter VFD2 to obtain an initial value of the output voltage of the high-voltage frequency converter VFD2, and smoothly controlling the switching of a high-voltage frequency conversion system after the output voltage of the high-voltage frequency converter VFD2 is linearly increased until the output voltage of the high-voltage frequency converter VFD2 is increased to a rated voltage value; the initial value calculation formula of the output voltage of the high-voltage frequency converter VFD2 is as follows:
，
，
wherein ,、/>is the initial value of the output voltage of the high-voltage frequency converter VFD2 under the alpha beta coordinate axis, +.>、/>Iterating alpha beta coordinate axes for back electromotive forceNPost-secondary value,/, for>For stator resistance>、/>Iterating at alpha beta coordinate axis for remanence currentNPost-secondary value,/, for>The leakage inductance of the stator is d is a differential operator, and t is time.
2. The online bumpless switching method of claim 1, wherein in S4, the number of control iterations isN，
,
wherein ,Nin order to control the number of iterations,for the contact actuation time, +.>Is a program control period.
3. A dual-redundancy high-voltage variable frequency system, characterized by being used for implementing the online undisturbed switching method according to any one of claims 1 to 2; the dual-redundancy high-voltage frequency conversion system comprises: the power grid Vin1, the power grid Vin2, the high-voltage frequency converter VFD1, the high-voltage frequency converter VFD2, the circuit breaker QF1, the circuit breaker QF2, the contactor KM1, the contactor KM2 and the load motor M; the power grid Vin1 is connected with a breaker QF1 in series, the breaker QF1 is connected with a high-voltage frequency converter VFD1 in series, and the high-voltage frequency converter VFD1 is connected with a contactor KM1 in series; the power grid Vin2 is connected with a breaker QF2 in series, the breaker QF2 is connected with a high-voltage frequency converter VFD2 in series, and the high-voltage frequency converter VFD2 is connected with a contactor KM2 in series; the other ends of the contactor KM1 and the contactor KM2 are connected with each other and then connected to a load motor M; the high-voltage frequency converter VFD1 is connected with the high-voltage frequency converter VFD2 through CAN communication.
4. A dual redundant high voltage variable frequency system according to claim 3, wherein an interlock is formed between contactor KM1 and contactor KM2.
5. The dual redundant high voltage variable frequency system according to claim 4, wherein during normal operation of the contactor KM1 and the contactor KM2, the contactor KM1 is in a closed state, and the contactor KM2 is in an open state; the high-voltage frequency converter VFD1 breaks down, the double-machine redundant high-voltage frequency conversion system enters an automatic switching mode, the high-voltage frequency converter VFD1 enables automatic switching signals, and the contactor KM2 is closed while the contactor KM1 is disconnected; the high-voltage frequency converter VFD1 needs to be shut down for maintenance, and the double-machine redundant high-voltage frequency conversion system is used for manually switching off the contactor KM1 and simultaneously closing the contactor KM2 through a manual switching mode.
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| CN116915107B (en) * | 2023-09-11 | 2023-11-17 | 希望森兰科技股份有限公司 | Variable frequency soft start control method for vector start automatic VF switching control |
| CN117674395B (en) * | 2024-01-31 | 2024-04-16 | 湖南北顺源智能科技有限公司 | Multi-module serial high-voltage direct-current shore-based power redundancy switching method |
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