CN117930069A - Three-phase alternating current power supply monitoring circuit and three-phase electrical equipment - Google Patents
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Abstract
The application discloses a three-phase alternating current power supply monitoring circuit and three-phase electrical equipment, which realize monitoring of output voltage information of a three-phase alternating current power supply. The monitoring 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 each of R1, R6 and R7 is 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 R1 is connected with the inverting input end of IC1 and one end of R2; the other end of R2 is connected with the output end of the IC 1; the other end of R6 is connected with the non-inverting input end of the IC1, one end of R4 and the non-inverting input end of the IC 2; the other end of R4 is connected with a power supply voltage; the other end of R7 is connected with the inverting input end of the IC2 and one end of R3; the other end of R3 is connected with the output end of the IC 2; the output terminals of IC1 and IC2 are electrically connected with the control unit.
Description
Technical Field
The invention relates to the technical field of power electronics, in particular to a three-phase alternating current power supply monitoring circuit and three-phase electrical equipment.
Background
When monitoring and managing output voltage information of a three-phase ac power supply of a three-phase electrical device (for example, a three-phase inverter) is required, it is necessary to add a three-phase ac power supply monitoring circuit. The three-phase alternating current power supply monitoring circuit is used for monitoring (including tracking acquisition, storage and analysis) the output voltage information of the three-phase alternating current power supply, so that a user can monitor and manage conveniently.
Disclosure of Invention
In view of the above, the present invention provides a three-phase ac power supply monitoring circuit and a three-phase electrical apparatus to monitor output voltage information of a three-phase ac power supply.
A three-phase ac power monitoring circuit comprising: 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 is used for monitoring the output voltage information of the three-phase alternating current power supply 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 monitoring circuit are all kiloohm-level.
In one embodiment, the three-phase ac power supply monitoring 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.
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 monitors output voltage information of the three-phase ac power supply according to the output voltages of the first operational amplifier and the second operational amplifier, and includes:
The control unit receives the output voltages of the first operational amplifier and the second operational amplifier, and calculates the voltage 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.
In one embodiment, the control unit is further configured to determine that a wiring fault exists in the three-phase ac power supply when it is determined that the voltage effective values of the two line voltages are both lower than a preset voltage value or an absolute value of a difference between the voltage effective values of the two line voltages is greater than a preset voltage difference value.
In one embodiment, the preset voltage value is 266V and the preset voltage difference is 80V.
A three-phase electrical apparatus incorporating any one of the three-phase ac power monitoring circuits disclosed above.
In one embodiment, 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 three-phase alternating-current power supply monitoring circuit is additionally arranged on the driving board;
The driving board is used for feeding back information of whether the wiring of the three-phase alternating current power supply is correct or not 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.
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 is used for providing low-voltage power supply for a control device on the circuit board.
According to the technical scheme, the sampling of the line voltages Vsr and Vst output by the three-phase alternating current power supply is realized through the operational amplifier and the voltage dividing resistors (the voltage dividing resistors are the resistor R1, the resistor R6 and the resistor R7), and the voltage and the current of the input operational amplifier are proper by utilizing the high input impedance characteristic of the operational amplifier and the voltage dividing resistor with the high resistance value added externally, so that the cost is low. The output voltage of the first operational amplifier IC1 is related to the line voltage Vsr, the output voltage of the second operational amplifier IC2 is related to the line voltage Vst, the line voltages Vsr and Vst can be monitored through tracking, collecting, storing and analyzing the output voltages of the two operational amplifiers, and the monitoring function of the three-phase alternating current power supply monitoring circuit 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 AC power supply monitoring circuit according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a three-phase AC power monitoring circuit according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a three-phase AC power monitoring circuit according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a three-phase electrical apparatus according to an embodiment of the present invention;
Fig. 5 is a schematic diagram of still another three-phase electrical apparatus 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 ac power supply monitoring circuit, including: 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. 1);
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, 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 is used for monitoring the output voltage information of the three-phase alternating current power supply according to the output voltages of the first operational amplifier IC1 and the second operational amplifier IC 2.
In the embodiment of the present invention, 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. 1, and the power supply terminal and the ground terminal of the second op amp IC2 are not shown in fig. 1; 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. 1.
The three-phase alternating current power supply in the embodiment of the invention can be a three-phase four-wire system alternating current power supply, can also be a three-phase three-wire system alternating current power supply, and is not limited. In fig. 1, only an R phase (for receiving R-phase voltage Vr) of the three-phase ac power supply is connected to one end of a resistor R1, an s phase (for receiving s-phase voltage Vs) of the three-phase ac power supply is connected to one end of a 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 a resistor R7. The working principle of the embodiment of the invention 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 like a resistor R1, a resistor R6 and a resistor R7 in fig. 1, 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 performing tracking, collecting, storing and analyzing on the output voltages Vout1 and Vout2 of the two operational amplifiers, the monitoring of the line voltages Vsr and Vst can be achieved, and the monitoring function of the three-phase ac power supply monitoring circuit (for example, three-phase ac power supply wiring fault monitoring and/or three-phase ac power supply output line voltage value monitoring) can be achieved.
The monitoring 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 according to the corresponding relation between the output voltages Vout1 and Vout2 of the two operational amplifiers and the line voltages Vsr and Vst, the voltage values of the line voltages Vsr and Vst are reversely pushed out, so that the monitoring of the voltage values of the line voltages Vsr and Vst is realized. In order to ensure the detection accuracy, the output voltages of the two operational amplifiers obtained by sampling need to be amplified first.
In addition, 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 report 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 control unit can also 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 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. 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. 1 can be set as shown in fig. 2.
Fig. 2 is taken as an example of vcc=3.3v, and the linear relationship between the output voltage Vout1 and the line voltage Vsr, and the linear relationship between the output voltage Vout2 and the line voltage Vst are derived by performing circuit analysis on fig. 2:
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. 2, 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' (1)
Combining equation set 2 and equation 1, one can obtain:
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. 2 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 embodiments disclosed above may be omitted, as shown in fig. 3, 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 monitoring circuit can be realized, and the working principle thereof will be described with reference to the foregoing embodiments and will not be repeated herein.
In any of the embodiments disclosed above, for any resistor, it may be an independent resistor device, or may be a series, parallel, or a combination of series and parallel of multiple resistor devices, which is not limited.
In addition, the embodiment of the invention also discloses three-phase electrical equipment, and the three-phase electrical equipment is additionally provided with any three-phase alternating current power supply monitoring circuit disclosed by the invention.
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, zero line misconnection and the like, so that a three-phase alternating current power supply monitoring circuit is required to be additionally arranged for some important three-phase electric equipment (such as a three-phase frequency converter). In one embodiment, as shown in fig. 4, the three-phase electrical apparatus includes a driving board and a main control board, the high-voltage power supply of the driving board is a three-phase ac power supply, the high-voltage power supply of the main control board is a single-phase/three-phase ac power supply, the three-phase ac power supply monitoring circuit is additionally mounted on the driving board, and N in fig. 4 represents a zero line. The three-phase electric equipment is powered on, the driving board can be powered on first, then the MCU (Microcontroller Unit, micro control unit) of the main control board and the driving board starts working, communication handshake between the main control board and the MCU is carried out simultaneously, the driving board can feed back information about whether the wiring of the three-phase alternating current power supply is correct to the main control board, the main control board closes a main control loop switch K1 (generally a relay) when the wiring of the three-phase alternating current power supply is correct, and then the load control is met and the error connection protection function of the three-phase alternating current power supply is realized.
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).
Still referring to fig. 4, the three-phase electrical apparatus generally further includes a fan board, the high-voltage power supply of which is a bus voltage VDC of the driving board, and the main control board closes the switch K1 when the three-phase ac power supply is correctly wired, so that the fan board is prevented from being connected to two live wires to cause overvoltage damage to the electrolytic capacitor.
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. 4), 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. 4, 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 driving board is, for example, but not limited to, a driving board of a three-phase passive PFC (Power Factor Correction ) topology.
In fig. 4, only the three-phase ac power source is taken as an example of the three-phase four-wire ac power source, and the three-phase three-wire ac power source can be replaced by the three-phase four-wire ac power source, for example, as shown in fig. 5, and the working principle after replacement is not repeated.
In this specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different manner from other embodiments, and identical and similar parts of each embodiment are referred to each other, so that no further description is required.
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 embodiments described above are merely illustrative, wherein the elements illustrated as separate elements may or may not be physically separate, and the elements shown as elements may or may not be physical elements, may be located in one place, or may be distributed over a plurality of network elements. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment. Those of ordinary skill in the art will understand and implement the present invention without undue burden.
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 (10)
1. A three-phase ac power supply monitoring circuit, comprising: 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 is used for monitoring the output voltage information of the three-phase alternating current power supply according to the output voltages of the first operational amplifier IC1 and the second operational amplifier IC 2.
2. The three-phase ac power supply monitoring circuit of claim 1, wherein the resistor R1, the resistor R6, and the resistor R7 are all megaohms, and the remaining resistors in the three-phase ac power supply monitoring circuit are all kiloohms.
3. The three-phase ac power monitoring circuit of claim 1, further comprising: 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.
4. A three-phase ac power supply monitoring circuit according to claim 3, 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 2 times the resistance of the resistor R2.
5. The three-phase ac power supply monitoring circuit according to any one of claims 1 to 4, wherein the control unit monitors output voltage information of the three-phase ac power supply according to output voltages of the first operational amplifier and the second operational amplifier, comprising:
The control unit receives the output voltages of the first operational amplifier and the second operational amplifier, and calculates the voltage 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.
6. The three-phase ac power supply monitoring circuit according to claim 5, wherein the control unit is further configured to determine that a wiring fault exists in the three-phase ac power supply when it is determined that the voltage effective values of the two line voltages are both lower than a preset voltage value or an absolute value of a difference between the voltage effective values of the two line voltages is greater than a preset voltage difference value.
7. The three-phase ac power supply monitoring circuit of claim 6, wherein the predetermined voltage value is 266V and the predetermined voltage difference is 80V.
8. A three-phase electrical apparatus to which a three-phase ac power supply monitoring circuit as claimed in any one of claims 1 to 7 is attached.
9. The three-phase electrical device according to claim 8, wherein the three-phase electrical device comprises a drive board and a main control board, a high-voltage power supply of the drive board is a three-phase alternating-current power supply, and the three-phase alternating-current power supply monitoring circuit is additionally arranged on the drive board;
The driving board is used for feeding back information of whether the wiring of the three-phase alternating current power supply is correct or not 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.
10. The three-phase electrical device of claim 9, 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 driving board, the main control board and the fan board, share the same switching power supply, and the switching power supply is used for providing low-voltage power supply for control devices on the corresponding circuit boards.
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| CN202211259737.6A CN117930069A (en) | 2022-10-14 | 2022-10-14 | Three-phase alternating current power supply monitoring circuit and three-phase electrical equipment |
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| CN202211259737.6A CN117930069A (en) | 2022-10-14 | 2022-10-14 | Three-phase alternating current power supply monitoring circuit and three-phase electrical equipment |
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