CN117895455A - Three-phase electrical equipment and protection method thereof - Google Patents
Three-phase electrical equipment and protection method thereof Download PDFInfo
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Abstract
The application discloses three-phase electrical equipment and a protection method thereof, which realize the fault connection protection of a three-phase alternating current power supply of the three-phase electrical equipment. The three-phase electrical equipment comprises a driving board and a main control board, wherein a high-voltage power supply of the driving board is a three-phase alternating current power supply, and the driving board is provided with a three-phase alternating current power supply detection circuit; the driving board is used for detecting whether the wiring of the three-phase alternating current power supply is correct or not through the three-phase alternating current power supply detection circuit, and feeding back a detection result to the main control board; the main control board is used for closing the main control loop switch when the wiring of the three-phase alternating current power supply is correct.
Description
The present application claims priority from the chinese patent office, application number 202211259304.0, entitled "a three-phase electrical apparatus and method of protecting same", filed on day 14, 10, 2022, the entire contents of which are incorporated herein by reference.
Technical Field
The invention relates to the technical field of power electronics, in particular to three-phase electrical equipment and a protection method thereof.
Background
The three-phase electric equipment uses a three-phase alternating current power supply as a high-voltage power supply, and accidents can be caused when the three-phase alternating current power supply is abnormal such as phase shortage or misconnection of a zero line, so that the three-phase alternating current power supply must be protected for some important three-phase electric equipment (such as a three-phase frequency converter).
Disclosure of Invention
In view of the above, the present invention provides a three-phase electrical apparatus and a protection method thereof, so as to implement fault connection protection for a three-phase ac power supply of the three-phase electrical apparatus.
The three-phase electrical equipment comprises a driving board and a main control board, wherein a high-voltage power supply of the driving board is a three-phase alternating current power supply, and the driving board is provided with a three-phase alternating current power supply detection circuit;
the three-phase alternating current power supply detection circuit is configured to be capable of detecting whether the three-phase alternating current power supply is correctly wired;
the driving board is configured to be capable of detecting whether the three-phase alternating current power supply is correctly wired through the three-phase alternating current power supply detection circuit and feeding back a detection result to the main control board;
the main control board is configured to control the switch in the main control loop to be closed when a detection result representing that the three-phase alternating current power supply is correctly connected is received.
In one embodiment, the three-phase electrical apparatus further comprises a fan board, and a high-voltage power supply of the fan board is a bus voltage of the driving board;
any two or three of the three circuit boards, namely the drive board, the main control board and the fan board, share the same switching power supply, and the switching power supply can provide low-voltage power for control devices on the corresponding circuit boards.
In one embodiment, the three-phase ac power detection circuit includes: the first operational amplifier IC1, the second operational amplifier IC2, the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R6, the resistor R7 and the control unit;
one end of the resistor R1, one end of the resistor R6 and one end of the resistor R7 are used for one-to-one electric connection with a three-phase line outgoing terminal of a three-phase alternating current power supply;
the other end of the resistor R1 is electrically connected with the inverting input end of the first operational amplifier IC1 and one end of the resistor R2; the other end of the resistor R2 is electrically connected with the output end of the first operational amplifier IC 1;
the other end of the resistor R6 is electrically connected with the non-inverting input end of the first operational amplifier IC1, one end of the resistor R4 and the non-inverting input end of the second operational amplifier IC 2;
the other end of the resistor R4 is connected with the power supply voltage;
the other end of the resistor R7 is electrically connected with the inverting input end of the second operational amplifier IC2 and one end of the resistor R3; the other end of the resistor R3 is electrically connected with the output end of the second operational amplifier IC 2;
the output end of the first operational amplifier IC1 and the output end of the second operational amplifier IC2 are electrically connected with the control unit, and the control unit can detect whether the wiring of the three-phase alternating current power supply is correct or not according to the output voltages of the first operational amplifier IC1 and the second operational amplifier IC 2.
In one embodiment, the resistor R1, the resistor R6 and the resistor R7 are all megaohm-level, and the rest of the resistors in the three-phase ac power supply detection circuit are all kiloohm-level.
In one embodiment, the three-phase ac power supply detection circuit further includes: a resistor R5;
the non-inverting input end of the first operational amplifier IC1 is electrically connected with one end of a resistor R5, and the other end of the resistor R5 is grounded.
In one embodiment, the resistances of the resistor R1, the resistor R6, and the resistor R7 are equal, the resistances of the resistor R4 and the resistor R5 are equal, the resistances of the resistor R2 and the resistor R3 are equal, and the resistance of the resistor R4 is 2 times the resistance of the resistor R2.
In one embodiment, the control unit can detect whether the three-phase ac power supply is wired correctly or not according to the output voltages of the first operational amplifier and the second operational amplifier, and includes:
the control unit can receive the output voltages of the first operational amplifier and the second operational amplifier, calculate the voltage effective values of the two line voltages according to the corresponding relation between the output voltages of the first operational amplifier and the second operational amplifier and the two line voltages of the three-phase alternating current power supply, and judge that the three-phase alternating current power supply has wiring faults when judging that the voltage effective values of the two line voltages are lower than the preset voltage value or the absolute value of the difference between the voltage effective values of the two line voltages is larger than the preset voltage difference value.
In one embodiment, the preset voltage value is 266V and the preset voltage difference is 80V.
In one embodiment, the three-phase ac power supply detection circuit includes a phase voltage sampling unit and a comparing unit, where the phase voltage sampling unit is capable of detecting a phase voltage of the three-phase ac power supply to obtain a phase voltage detection signal, and comparing the phase voltage detection signal with a preset phase voltage reference signal by the comparing unit, where when the phase voltage detection signal is within a range of the preset phase voltage reference signal, it indicates that the connection is correct, otherwise, it determines that the connection is incorrect.
The three-phase electric equipment comprises a driving board and a main control board, wherein a high-voltage power supply of the driving board is a three-phase alternating current power supply, and a three-phase alternating current power supply detection circuit is additionally arranged on the driving board;
the method comprises the following steps:
the driving board detects whether the wiring of the three-phase alternating current power supply is correct or not through the three-phase alternating current power supply detection circuit, and feeds back a detection result to the main control board;
and when the wiring of the three-phase alternating current power supply is correct, the master control board controls the switch of the master control loop to be closed.
In one embodiment, the three-phase ac power detection circuit includes: the first operational amplifier IC1, the second operational amplifier IC2, the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R6, the resistor R7 and the control unit;
one end of the resistor R1, one end of the resistor R6 and one end of the resistor R7 can be electrically connected with a three-phase line outgoing terminal of a three-phase alternating current power supply in one-to-one mode;
the other end of the resistor R1 is electrically connected with the inverting input end of the first operational amplifier IC1 and one end of the resistor R2; the other end of the resistor R2 is electrically connected with the output end of the first operational amplifier IC 1;
the other end of the resistor R6 is electrically connected with the non-inverting input end of the first operational amplifier IC1, one end of the resistor R4 and the non-inverting input end of the second operational amplifier IC 2;
the other end of the resistor R4 is connected with the power supply voltage;
the other end of the resistor R7 is electrically connected with the inverting input end of the second operational amplifier IC2 and one end of the resistor R3; the other end of the resistor R3 is electrically connected with the output end of the second operational amplifier IC 2;
the output end of the first operational amplifier IC1 and the output end of the second operational amplifier IC2 are electrically connected with the control unit;
correspondingly, the driving board detects whether the wiring of the three-phase alternating current power supply is correct or not through the three-phase alternating current power supply detection circuit, and the driving board comprises:
the control unit can receive the output voltages of the first operational amplifier and the second operational amplifier, and calculate the voltage effective values of the two line voltages according to the corresponding relation between the output voltages of the first operational amplifier and the second operational amplifier and the two line voltages of the three-phase alternating current power supply;
and the control unit judges that the three-phase alternating current power supply has wiring faults when judging that the voltage effective values of the two line voltages are lower than a preset voltage value or the absolute value of the difference between the voltage effective values of the two line voltages is larger than a preset voltage difference value.
According to the technical scheme, whether the three-phase alternating current power supply wiring of the three-phase electric equipment is correct or not is detected, and the master control board in the three-phase electric equipment only closes the master control loop switch when the three-phase alternating current power supply wiring is correct, so that the three-phase alternating current power supply misconnection protection function is realized.
Drawings
In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic diagram of a three-phase electrical apparatus according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a three-phase AC power supply detection circuit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a three-phase AC power detection circuit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a three-phase AC power detection circuit according to an embodiment of the present invention;
fig. 5 is a flowchart of a protection method for three-phase electrical equipment according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present invention 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 invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1, an embodiment of the present invention discloses a three-phase electrical apparatus, including: the high-voltage power supply of the driving plate is a three-phase alternating current power supply, and the driving plate is provided with a three-phase alternating current power supply detection circuit;
the three-phase alternating current power supply detection circuit is configured to be capable of detecting whether the three-phase alternating current power supply is correctly wired;
the driving board is configured to detect whether the wiring of the three-phase alternating current power supply is correct or not through the three-phase alternating current power supply detection circuit, and feed back a detection result to the main control board;
the main control board is configured to control the switch K1 of the main control loop to be closed when the three-phase alternating current power supply is correctly connected. Specifically, the main control board controls the switch in the main control loop to be closed after receiving a detection result representing that the three-phase alternating current power supply is correctly connected.
Specifically, the high-voltage power supply of the driving board in the three-phase electrical equipment (for example, a three-phase frequency converter) disclosed by the embodiment of the invention is a three-phase alternating current power supply, the high-voltage power supply of the main control board is a single-phase/three-phase alternating current power supply, the three-phase alternating current power supply detection circuit is additionally arranged on the driving board, three-phase line outgoing terminals of the three-phase alternating current power supply are represented by r, s and t, and N in fig. 1 represents a zero line. The three-phase electric equipment is powered on, the driving board can be powered on first, then MCU (Microcontroller Unit) of the main control board and the driving board start working, communication handshake is carried out between the main control board and the MCU, the driving board can feed back information about whether three-phase alternating current power supply wiring is correct to the main control board, the main control board closes a main control loop switch K1 (generally a relay) when the three-phase alternating current power supply wiring is correct, and then control of loads is met, and a three-phase alternating current power supply misconnection protection function is achieved.
The main control loop switch K1 is connected in parallel with a resistor connected in series to the high-voltage power supply line of the main control board (a capacitor is arranged on the high-voltage power supply line of the main control board, when the main control loop switch K1 is started, the resistor is turned on, the resistor charges the capacitor, and after the capacitor is fully charged, the short-circuit resistor of the main control loop switch K1 is turned on, so that the efficiency is improved). The main control board closes the main control loop switch K1 when the three-phase alternating current power supply is correctly wired, and the damage of capacitor overvoltage on the high-voltage power supply inlet caused by the fact that the main control board is connected with two live wires can be avoided.
In still another embodiment, referring to fig. 1, the three-phase electrical apparatus may further include a fan board, the high-voltage power supply of which is a bus voltage VDC of the driving board, and the main control board generates the bus voltage VDC to supply power to the fan when the three-phase ac power supply is correctly wired, so that damage of the fan board due to misconnection of the phase lines may be avoided.
Further, any two or three of the three circuit boards, namely the driving board, the main control board and the fan board, can share the same switching power supply (only three circuit boards share the same switching power supply as an example in fig. 1), so as to save cost and reduce power consumption; the switch power supply can be arranged on the driving board and used as a low-voltage power supply of the corresponding circuit board to provide low-voltage power supply for control devices (such as chips and the like) on the corresponding circuit board, and as shown in fig. 1, the switch power supply is used for leading out the voltage VDD1 and accessing the low-voltage power supply end of the main control board, and the switch power supply is used for leading out the voltage VDD2 and accessing the low-voltage power supply end of the fan board.
The drive board in any of the embodiments described above is, for example, but not limited to, a drive board of a three-phase passive PFC (Power Factor Correction ) topology. The three-phase ac power supply in any of the above embodiments may be a three-phase four-wire ac power supply, or may be a three-phase three-wire ac power supply, and is not limited thereto.
The three-phase ac power detection circuit may include an optocoupler zero-crossing detection circuit that detects whether there is a phase loss or a wiring error by detecting the zero-crossing point of the zero-line. The three-phase ac power detection circuit may further include a phase sequence detector with which whether or not there is a wiring error is detected. The three-phase alternating current calibration circuit can further comprise a phase voltage sampling unit and a comparison unit, wherein the phase voltage sampling unit detects the phase voltage of the three-phase alternating current to obtain a phase voltage detection signal, the comparison unit compares the phase voltage detection signal with a preset phase voltage reference signal, when the phase voltage detection signal is within the range of the preset phase voltage reference signal, the correct wiring is indicated, and otherwise, the wiring is judged to be wrong. In particular, the three-phase ac power detection circuit may also be implemented using circuitry as provided below. That is, in any of the embodiments disclosed above, the three-phase alternating current power supply detection circuit includes: a first operational amplifier IC1, a second operational amplifier IC2, seven resistors R1 to R7, and a control unit (the control unit is not shown in fig. 2);
one end of the resistor R1, one end of the resistor R6 and one end of the resistor R7 can be electrically connected with a three-phase line outgoing terminal of a three-phase alternating current power supply in one-to-one mode;
the other end of the resistor R1 is electrically connected with the inverting input end of the first operational amplifier IC1 and one end of the resistor R2; the other end of the resistor R2 is electrically connected with the output end of the first operational amplifier IC 1;
the other end of the resistor R6 is electrically connected with the non-inverting input end of the first operational amplifier IC1, one end of the resistor R4, one end of the resistor R5 and the non-inverting input end of the second operational amplifier IC 2;
the other end of the resistor R4 is connected with the power supply voltage VCC, and the other end of the resistor R5 is connected with the ground GND;
the other end of the resistor R7 is electrically connected with the inverting input end of the second operational amplifier IC2 and one end of the resistor R3; the other end of the resistor R3 is electrically connected with the output end of the second operational amplifier IC 2;
the output end of the first operational amplifier IC1 and the output end of the second operational amplifier IC2 are electrically connected with the control unit, and the control unit can detect whether the wiring of the three-phase alternating current power supply is correct or not according to the output voltages of the first operational amplifier IC1 and the second operational amplifier IC 2.
The operational amplifier (op amp for short) itself has a power supply terminal and a ground terminal, only the power supply terminal and the ground terminal of the first op amp IC1 are shown in fig. 2, and the power supply terminal and the ground terminal of the second op amp IC2 are not shown in fig. 2; the power supply terminal of the first operational amplifier IC1, the power supply terminal of the second operational amplifier IC2, and the other end of the resistor R4 may be connected to the same power supply voltage VCC, or may be connected to different power supply voltages, the former being only an example in fig. 2.
In fig. 2, only an R phase (for receiving R-phase voltage Vr) of the three-phase ac power supply is connected to one end of the resistor R1, an s phase (for receiving s-phase voltage Vs) of the three-phase ac power supply is connected to one end of the resistor R6, and a t phase (for receiving t-phase voltage Vt) of the three-phase ac power supply is connected to one end of the resistor R7. The principle of operation of the scheme shown in fig. 2 is as follows:
the output voltage (such as 380V) of the three-phase ac power supply is high, and the conventional means is to sample the three-phase ac power supply through a voltage transformer, but the cost of the voltage transformer is high. In this regard, the embodiment of the invention realizes sampling of the voltage of the three-phase alternating current power supply output line through the operational amplifier and the voltage dividing resistor, and utilizes the high input impedance characteristic of the operational amplifier and the externally added voltage dividing resistor with high resistance (the voltage dividing resistor is shown as a resistor R1, a resistor R6 and a resistor R7 in fig. 2, and the resistance is far greater than the resistors R2 to R5, for example, the resistors R1, R6 and R7 can be set to megaohm level, and the resistors R2 to R5 are kiloohm level), so that the voltage and the current of the input operational amplifier are suitable, the use of a voltage transformer is omitted, and the cost is low.
The inverted input voltage Vr ' of the first operational amplifier IC1 is related to the r-phase voltage Vr, the non-inverting input voltages Vs ' of the first operational amplifier IC1 and the second operational amplifier IC2 are both related to the s-phase voltage Vs, and the inverted input voltage Vt ' of the second operational amplifier IC2 is related to the t-phase voltage Vt, so that the output voltage Vout1 of the first operational amplifier IC1 is related to the s-phase voltage, r-phase voltage, i.e., the line voltage Vsr, and the output voltage Vout2 of the second operational amplifier IC2 is related to the s-phase voltage, t-phase voltage, i.e., the line voltage Vst. Then, by tracking, collecting, storing and analyzing the output voltages Vout1 and Vout2 of the two operational amplifiers, the detection of the line voltages Vsr and Vst can be realized, so as to determine whether the three-phase ac power supply has a wiring fault.
The detection of the line voltages Vsr and Vst is achieved by performing tracking acquisition, storage and analysis on the output voltages Vout1 and Vout2 of the two operational amplifiers, which includes:
the control unit receives the output voltages of the two operational amplifiers, and reversely pushes out the voltage effective values of the line voltages Vsr and Vst according to the corresponding relation between the output voltages Vout1 and Vout2 of the two operational amplifiers and the line voltages Vsr and Vst, so as to realize the detection of the voltage effective values of the line voltages Vsr and Vst. In order to ensure the detection accuracy, the output voltages of the two operational amplifiers obtained by sampling need to be amplified first.
The effective values of the line voltages Vsr and Vst under the normal condition, namely under the condition of correct wiring, are 380V, and the error range of-25% -20% (the national standard is that the error of +/-10% is considered, the error range is widened for avoiding false alarm or missing alarm in the embodiment of the invention), and the effective values of the line voltages Vsr and Vst under the normal condition are generally within the range of 285-456V;
when a certain phase is out of phase, the effective voltage value between the fault phase and the normal phase is 190V, and the error range of-25% -20% is considered, wherein the effective voltage value between the fault phase and the normal phase is generally within the range of 143V-228V, and the effective voltage value between the normal phase and the normal phase is generally within the range of 285V-456V; for example:
if the r-phase is open, the absolute value of the difference between the line voltage Vsr and the effective value of vst=190V-380 v=180v, the effective value of the line voltage vsr=190V, and the effective value of vst=380v;
if the S-phase is open, the line voltage Vsr effective value=190V, the line voltage Vst effective value=190V, and the absolute value of the difference between the line voltages Vsr and Vst effective value=190V-190 v=0v;
if the T-phase is open, the line voltage Vst effective value=190V, the line voltage Vsr effective value=380V, and the absolute value of the difference between the line voltages Vsr and Vst effective value=190V-380 v=180V;
when the zero line is wrongly connected, namely, the one-phase live wire is wrongly connected into the zero line, the effective voltage value between the fault phase and the normal phase is 380/1.414 theoretically, and the error range of-25% -20% is considered, the effective voltage value between the fault phase and the normal phase is generally in the range of 201V-322V, and the effective voltage value between the normal phase and the normal phase is in the range of 285V-456V;
the method for judging whether the three-phase alternating current power supply is correctly connected or not after the voltage effective values of the two line voltages are calculated by the control unit comprises the following steps: and when judging that the voltage effective values of the two line voltages are lower than a preset voltage value or the absolute value of the difference between the voltage effective values of the two line voltages is larger than a preset voltage difference value, judging that the three-phase alternating current power supply has wiring faults. The preset voltage value is set to 266V, for example, and the preset voltage difference value is set to 80V, for example.
The specific correspondence between the output voltages Vout1 and Vout2 of the two operational amplifiers and the line voltages Vsr and Vst is determined by the resistance values of the resistors. Considering that the output voltage Vout1 of the first operational amplifier IC1 and the line voltage Vsr tend to have a linear relationship, and that the output voltage Vout2 of the second operational amplifier IC2 and the line voltage Vst tend to have a linear relationship, it is more intuitive to reflect the magnitudes of the line voltages Vsr and Vst with the two operational amplifier output voltages Vout1 and Vout2, so the embodiment of the present invention recommends setting the resistance values of the respective resistors based on this, with the resistance values set as (symbols R1 to R7 are used to represent both the resistors and the resistance values of the resistors): r1=r6=r7, r4=r5, r2=r3, r4=2×r2, and the resistance values of the circuit shown in fig. 2 can be set as shown in fig. 3.
Fig. 3 is a diagram of vcc=3.3v as an example, and the linear relationship between the output voltage Vout1 and the line voltage Vsr is derived by performing circuit analysis on fig. 3, while the linear relationship between the output voltage Vout2 and the line voltage Vst is derived as follows:
the op-amp has "weak short" and "weak broken" characteristics when the op-amp is in deep negative feedback. The virtual short refers to the fact that the voltages of the non-inverting input end and the inverting input end of the operational amplifier are equal; the "virtual break" means that the input currents of the non-inverting input terminal and the inverting input terminal of the operational amplifier are both zero.
In fig. 3, the first op-amp IC1 and the second op-amp IC2 are both in deep negative feedback. The "virtual off" characteristic of the first op-amp IC1 is hereby:
the arrangement of equation set 1 can be:
from the "virtual short" characteristic of the first op-amp IC1, it is possible to:
vr '=vs' (formula 1) in combination with equation set 2 and formula 1, can be obtained:
since R1> > R2, R1> > R4, formula 2 can be simplified as:
from equation 3, the relationship between the output voltage Vout1 and the s-phase voltage Vs, r-phase voltage Vr can be obtained:
since r4=2r2, the relationship between the output voltage Vout1 and the line voltage Vsr can be obtained by equation 4:
similarly, the relationship between the output voltage Vout2 and the line voltage Vst can be obtained:
as can be seen from equations 5 to 6, the output voltage Vout1 and the line voltage Vsr tend to have a linear relationship, and the output voltage Vout2 and the line voltage Vst tend to have a linear relationship. The waveform of Vout1 is a sine wave, and the waveform of Vout1 can be used for representing the waveform after the Vsr is linearly reduced; the waveform of Vout2 is a sine wave, and the waveform of Vout2 can be used to characterize a linearly scaled Vst waveform.
The resistance values in fig. 3 may be set to, for example, r1=960 kΩ, r2=2Ω, r4=4kΩ, but are not limited thereto.
In addition, the resistor R5 in any of the three-phase ac power supply detection circuits disclosed above may be omitted, as shown in fig. 4, the circuit after omitting the resistor R5 still satisfies the requirement of sampling the line voltages Vsr and Vst output by the three-phase ac power supply through the op amp and the voltage dividing resistor, so that the function of the three-phase ac power supply detection circuit can be realized, and the working principle thereof is only described with reference to the foregoing embodiments and is not repeated herein.
In any of the three-phase ac power supply detection circuits disclosed above, any resistor may be an independent resistor device, or may be a series, parallel or a combination of series and parallel of a plurality of resistor devices, which is not limited.
Corresponding to the embodiment of the equipment, the embodiment of the invention also discloses a protection method of the three-phase electrical equipment, wherein the three-phase electrical equipment comprises a driving board and a main control board, a high-voltage power supply of the driving board is a three-phase alternating current power supply, and a three-phase alternating current power supply detection circuit is additionally arranged on the driving board;
as shown in fig. 5, the method includes:
step S01: the driving board detects whether the wiring of the three-phase alternating current power supply is correct or not through the three-phase alternating current power supply detection circuit, and feeds back a detection result to the main control board;
step S02: when the three-phase alternating current power supply is correctly connected, the main control board closes the main control loop switch.
In one embodiment, the three-phase ac power detection circuit includes: the first operational amplifier IC1, the second operational amplifier IC2, the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R6, the resistor R7 and the control unit;
one end of the resistor R1, one end of the resistor R6 and one end of the resistor R7 are used for one-to-one electric connection with a three-phase line outgoing terminal of a three-phase alternating current power supply;
the other end of the resistor R1 is electrically connected with the inverting input end of the first operational amplifier IC1 and one end of the resistor R2; the other end of the resistor R2 is electrically connected with the output end of the first operational amplifier IC 1;
the other end of the resistor R6 is electrically connected with the non-inverting input end of the first operational amplifier IC1, one end of the resistor R4 and the non-inverting input end of the second operational amplifier IC 2;
the other end of the resistor R4 is connected with the power supply voltage;
the other end of the resistor R7 is electrically connected with the inverting input end of the second operational amplifier IC2 and one end of the resistor R3; the other end of the resistor R3 is electrically connected with the output end of the second operational amplifier IC 2;
the output end of the first operational amplifier IC1 and the output end of the second operational amplifier IC2 are electrically connected with the control unit;
correspondingly, the driving board detects whether the wiring of the three-phase alternating current power supply is correct or not through the three-phase alternating current power supply detection circuit, and the driving board comprises:
the control unit can receive the output voltages of the first operational amplifier and the second operational amplifier, and calculate the voltage effective values of the two line voltages according to the corresponding relation between the output voltages of the first operational amplifier and the second operational amplifier and the two line voltages of the three-phase alternating current power supply;
and the control unit judges that the three-phase alternating current power supply has wiring faults when judging that the voltage effective values of the two line voltages are lower than a preset voltage value or the absolute value of the difference between the voltage effective values of the two line voltages is larger than a preset voltage difference value.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the method disclosed in the embodiment, since it corresponds to the device disclosed in the embodiment, the description is relatively simple, and the relevant points are referred to the circuit/device part description.
The terms first, second and the like in the description and in the claims and in the above-described figures, are used for distinguishing between similar different objects and not necessarily for describing a particular sequential or chronological order. Moreover, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising" does not exclude the presence of other like elements in a process, method, article, or apparatus that comprises an element.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the embodiments of the invention. Thus, the present embodiments are not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (11)
1. The three-phase electrical equipment is characterized by comprising a driving board and a main control board, wherein a high-voltage power supply of the driving board is a three-phase alternating current power supply, and the driving board is provided with a three-phase alternating current power supply detection circuit;
the three-phase alternating current power supply detection circuit is configured to be capable of detecting whether the three-phase alternating current power supply is correctly wired;
the driving board is configured to be capable of detecting whether the three-phase alternating current power supply is correctly wired through the three-phase alternating current power supply detection circuit and feeding back a detection result to the main control board;
the main control board is configured to control the switch in the main control loop to be closed when a detection result representing that the three-phase alternating current power supply is correctly connected is received.
2. The three-phase electrical device of claim 1, further comprising a fan plate, a high voltage power supply of the fan plate being a bus voltage of the drive plate;
any two or three of the three circuit boards, namely the drive board, the main control board and the fan board, share the same switching power supply, and the switching power supply can provide low-voltage power for control devices on the corresponding circuit boards.
3. The three-phase electrical device according to claim 1, wherein the three-phase alternating current power supply detection circuit includes: the first operational amplifier IC1, the second operational amplifier IC2, the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R6, the resistor R7 and the control unit;
one end of the resistor R1, one end of the resistor R6 and one end of the resistor R7 are used for one-to-one electric connection with a three-phase line outgoing terminal of a three-phase alternating current power supply;
the other end of the resistor R1 is electrically connected with the inverting input end of the first operational amplifier IC1 and one end of the resistor R2; the other end of the resistor R2 is electrically connected with the output end of the first operational amplifier IC 1;
the other end of the resistor R6 is electrically connected with the non-inverting input end of the first operational amplifier IC1, one end of the resistor R4 and the non-inverting input end of the second operational amplifier IC 2;
the other end of the resistor R4 is connected with the power supply voltage;
the other end of the resistor R7 is electrically connected with the inverting input end of the second operational amplifier IC2 and one end of the resistor R3; the other end of the resistor R3 is electrically connected with the output end of the second operational amplifier IC 2;
the output end of the first operational amplifier IC1 and the output end of the second operational amplifier IC2 are electrically connected with the control unit, and the control unit can detect whether the wiring of the three-phase alternating current power supply is correct or not according to the output voltages of the first operational amplifier IC1 and the second operational amplifier IC 2.
4. A three-phase electrical device according to claim 3, wherein the resistors R1, R6 and R7 are megaohm-level, and the remaining resistors in the three-phase ac power detection circuit are kiloohm-level.
5. A three-phase electrical device according to claim 3, wherein the three-phase ac power supply detection circuit further comprises: a resistor R5;
the non-inverting input end of the first operational amplifier IC1 is electrically connected with one end of a resistor R5, and the other end of the resistor R5 is grounded.
6. The three-phase electrical device according to claim 5, wherein the resistances of the resistor R1, the resistor R6, and the resistor R7 are equal, the resistances of the resistor R4 and the resistor R5 are equal, the resistances of the resistor R2 and the resistor R3 are equal, and the resistance of the resistor R4 is equal to 2 times the resistance of the resistor R2.
7. The three-phase electrical apparatus according to any one of claims 3 to 6, wherein the control unit capable of detecting whether or not three-phase ac power supply wiring is correct based on output voltages of the first and second operational amplifiers includes:
the control unit can receive the output voltages of the first operational amplifier and the second operational amplifier, calculate the voltage effective values of the two line voltages according to the corresponding relation between the output voltages of the first operational amplifier and the second operational amplifier and the two line voltages of the three-phase alternating current power supply, and judge that the three-phase alternating current power supply has wiring faults when judging that the voltage effective values of the two line voltages are lower than the preset voltage value or the absolute value of the difference between the voltage effective values of the two line voltages is larger than the preset voltage difference value.
8. The three-phase electrical device according to claim 7, wherein the preset voltage value is 266V and the preset voltage difference is 80V.
9. The three-phase electrical device according to claim 1 or 2, wherein the three-phase ac power supply detection circuit comprises a phase voltage sampling unit and a comparison unit, the phase voltage sampling unit is capable of detecting the phase voltage of the three-phase ac power supply to obtain a phase voltage detection signal, the comparison unit is used for comparing the phase voltage detection signal with a preset phase voltage reference signal, when the phase voltage detection signal is within the range of the preset phase voltage reference signal, the connection is correct, otherwise, the connection is judged to be incorrect.
10. The three-phase electric equipment protection method is characterized in that the three-phase electric equipment comprises a driving board and a main control board, a high-voltage power supply of the driving board is a three-phase alternating current power supply, and a three-phase alternating current power supply detection circuit is additionally arranged on the driving board;
the method comprises the following steps:
the driving board detects whether the wiring of the three-phase alternating current power supply is correct or not through the three-phase alternating current power supply detection circuit, and feeds back a detection result to the main control board;
and when the wiring of the three-phase alternating current power supply is correct, the master control board controls the switch of the master control loop to be closed.
11. The method of claim 10, wherein the three-phase ac power supply detection circuit comprises: the first operational amplifier IC1, the second operational amplifier IC2, the resistor R1, the resistor R2, the resistor R3, the resistor R4, the resistor R6, the resistor R7 and the control unit;
one end of the resistor R1, one end of the resistor R6 and one end of the resistor R7 can be electrically connected with a three-phase line outgoing terminal of a three-phase alternating current power supply in one-to-one mode;
the other end of the resistor R1 is electrically connected with the inverting input end of the first operational amplifier IC1 and one end of the resistor R2; the other end of the resistor R2 is electrically connected with the output end of the first operational amplifier IC 1;
the other end of the resistor R6 is electrically connected with the non-inverting input end of the first operational amplifier IC1, one end of the resistor R4 and the non-inverting input end of the second operational amplifier IC 2;
the other end of the resistor R4 is connected with the power supply voltage;
the other end of the resistor R7 is electrically connected with the inverting input end of the second operational amplifier IC2 and one end of the resistor R3; the other end of the resistor R3 is electrically connected with the output end of the second operational amplifier IC 2;
the output end of the first operational amplifier IC1 and the output end of the second operational amplifier IC2 are electrically connected with the control unit;
correspondingly, the driving board detects whether the wiring of the three-phase alternating current power supply is correct or not through the three-phase alternating current power supply detection circuit, and the driving board comprises:
the control unit can receive the output voltages of the first operational amplifier and the second operational amplifier, and calculate the voltage effective values of the two line voltages according to the corresponding relation between the output voltages of the first operational amplifier and the second operational amplifier and the two line voltages of the three-phase alternating current power supply;
and the control unit judges that the three-phase alternating current power supply has wiring faults when judging that the voltage effective values of the two line voltages are lower than a preset voltage value or the absolute value of the difference between the voltage effective values of the two line voltages is larger than a preset voltage difference value.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211259304 | 2022-10-14 | ||
| CN2022112593040 | 2022-10-14 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117895455A true CN117895455A (en) | 2024-04-16 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310143705.8A Pending CN117895455A (en) | 2022-10-14 | 2023-02-20 | Three-phase electrical equipment and protection method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117895455A (en) |
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2023
- 2023-02-20 CN CN202310143705.8A patent/CN117895455A/en active Pending
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