Switching method and switching device of dual-power switch based on switching-on withdrawing mechanism

Abstract

The invention provides a switching method and a switching device of a dual-power switch based on a closing withdrawing mechanism, the switching device comprises a main contact branch and a main silicon controlled rectifier branch, the main contact branch and the main silicon controlled rectifier branch are respectively provided with a main magnetic control switch and a silicon controlled rectifier QN1, and the main contact branch or the main silicon controlled rectifier branch is provided with a main current transformer CTN1; a main current transformer CTN1 and a standby current transformer CTN2 are arranged on the main current transformer CTN1, a standby contact branch circuit and a standby silicon controlled rectifier branch circuit are arranged on the main current transformer CTN1, a standby magnetic control switch and a silicon controlled rectifier QN2 are arranged on the standby contact branch circuit and the standby silicon controlled rectifier branch circuit, a standby current transformer CTN2 is arranged on the standby contact branch circuit or the standby silicon controlled rectifier branch circuit, and the main current transformer CTN1 and the standby current transformer CTN2 are both connected with a contact just-open detection circuit; the current detection device is mounted on the output sides of the main power switch circuit and the standby power switch circuit; according to the invention, the current transformer is matched with the contact just-open detection circuit to directly detect the line current, and whether the circuit is just open can be accurately judged.

Description

Technical Field

[0001] The present application relates to the field of switch technology, and in particular to a dual-power switch switching method and a switching device thereof based on a retractable closing mechanism. Background Art

[0002] A dual power switch is an electrical component that connects two circuits simultaneously and can switch between them. When one circuit fails, the dual power switch can switch to the other circuit to ensure that the load continues to work stably. Therefore, the dual power switch is an indispensable and important component in the power supply system.

[0003] At present, the low-voltage field mainly adopts two types of technical solutions: mechanical transfer switches (ATS) and static transfer switches (STS), but both have significant technical limitations; the response time of traditional ATS usually exceeds 100ms, which is difficult to meet the high stability requirements of power supply for highly sensitive loads such as data centers and medical equipment; STS uses power electronic devices to achieve contactless switching, but due to high manufacturing and maintenance costs and complex heat dissipation design, it is difficult to use it on a large scale in ordinary industrial and civilian scenarios.

[0004] The industry is currently attempting to increase switching speeds to 10-30ms by optimizing the mechanical structure of an ATS, but faces two core challenges. The first is that the arc still needs to wait at least 10ms for the contacts to extinguish naturally when they separate, directly restricting further compression of the switching speed. In the timing of dual-power switching, accurate judgment of the main contact state is a prerequisite for ensuring reliable switching execution. However, existing ATSs rely on mechanical auxiliary contacts to indirectly detect the main contact state, which makes it difficult for mechanical auxiliary contacts to provide synchronous feedback on the main contact state. Furthermore, under conditions such as long-term vibration and temperature fluctuations, mechanical transmission components are prone to deformation or displacement, resulting in inaccurate contact position feedback signals. Delayed feedback causes a lag in the backup power supply closing command, prolonging the switching time. If the feedback is advanced, the backup power supply closes prematurely, causing the main and backup power supplies to be temporarily connected in parallel, creating a short-circuit risk. Unreliable feedback of the main contact state not only restricts the optimization space for switching speed but also directly threatens system operation safety, becoming a key bottleneck in achieving millisecond-level fast switching.

[0005] In order to solve the above technical problems, the present invention intends to accurately determine the state of the main contacts through current detection, adopt the idea of ​​retractable closing, and use the pre-action backup switch to close during the closing trigger period to shorten the switching time; after searching, no relevant existing technology was found.

[0006] Therefore, it is necessary to provide a new technical solution to solve the above technical problems. Summary of the Invention

[0007] The present application provides a dual power switch switching method based on a retractable closing mechanism, comprising the following steps:

[0008] S1: Real-time detection of whether there is a problem with the primary side power supply. If so, enter S2; otherwise, end the switching of the switch circuit;

[0009] S2: The control device outputs the primary side magnetic control switch opening signal and triggers the primary side thyristor to turn on; the pulse width required to delay the opening of the primary side magnetic control switch is TB;

[0010] S3: Determine whether the main contact of the primary side magnetic control switch is open. If so, execute S4; otherwise, execute S3 in a loop.

[0011] S4: The control device turns off the trigger signal of the primary side thyristor;

[0012] S5: Delay TC, the control device outputs the closing signal of the magnetic control switch of the backup side power supply;

[0013] S6: Determine whether the main current of the primary power supply is zero. If so, execute S7; otherwise, jump to S10.

[0014] S7: Maintain the closing signal of the magnetic control switch of the backup power supply for the TD duration or TE duration;

[0015] S8: The closing signal of the magnetic control switch that turns off the backup power supply;

[0016] S9: End the switching of the power switch;

[0017] S10: Determine whether the window period for retracting the closing of the magnetic control switch of the backup power supply is about to end. If so, execute S11; otherwise, return to S6;

[0018] S11: Cancel the closing signal of the magnetic control switch of the backup power supply and return to S6.

[0019] As a preferred solution, when the primary side is the main power switch circuit, the backup side is the backup power switch circuit; when the primary side is the backup power switch circuit, the backup side is the main power switch circuit.

[0020] As a preferred solution, the problem of the main power supply in S1 includes the voltage drop amplitude and duration TA of the sudden drop in the primary side power supply voltage.

[0021] As a preferred solution, the TA is 1ms-2ms.

[0022] As a preferred solution, the TB is 0.6ms-1ms.

[0023] As a preferred solution, the TC is 4ms-5ms.

[0024] As a preferred solution, the TD is 10ms-15ms, and the TE is 25ms-35ms; S11 returns to S6, and then executes S6 time, maintaining the closing signal of the TE duration.

[0025] As a preferred solution, in S6, the current transformer and the contact just-open detection circuit on the primary side contact branch are used to determine whether the main current of the primary side power supply is zero, or the current transformer and the contact just-open detection circuit on the primary side thyristor branch are used to determine whether the main current of the primary side power supply is zero.

[0026] As a preferred solution, when the primary side is the main power switching circuit, the CTN1 on the main contact branch and the contact just-open detection circuit are used to determine whether the main current on the main power side is zero, or the CTN1 on the main thyristor branch and the contact just-open detection circuit are used to determine whether the main current on the main power side is zero; when the primary side is the backup power switching circuit, the CTN2 on the backup contact branch and the contact just-open detection circuit are used to determine whether the main current on the backup side power supply is zero, or the CTN2 on the backup thyristor branch and the contact just-open detection circuit are used to determine whether the main current on the backup side power supply is zero.

[0027] The present application also provides a dual power switch device based on a closing and retractable mechanism, comprising

[0028] A main power switch circuit, comprising a main contact branch and a main thyristor branch connected in parallel, wherein the main contact branch is provided with a main magnetically controlled switch, the main thyristor branch is provided with a thyristor QN1, and the main contact branch or the main thyristor branch is provided with a main current transformer CTN1, and the main current transformer CTN1 is connected to a contact opening detection circuit;

[0029] A backup power switch circuit, comprising a backup contact branch and a backup thyristor branch connected in parallel, wherein the backup contact branch is provided with a backup magnetic switch, the backup thyristor branch is provided with a thyristor QN2, and the backup contact branch or the backup thyristor branch is provided with a backup current transformer CTN2, wherein the backup current transformer CTN2 is connected to a contact opening detection circuit;

[0030] A current detection device is installed on the output side of the main power switch circuit and the backup power switch circuit.

[0031] As a preferred solution, the current detection device adopts an output-end current transformer.

[0032] As a preferred solution, the main power switch circuit adopts three main power switch circuits arranged in parallel, three main contact branches are provided with three linked main contacts QF1, and the three linked main contacts QF1 are arranged in the main magnetic control switch; three main thyristor branches are respectively provided with thyristors QN1, N = A, B, C; three main contact branches or three main thyristor branches are respectively provided with main current transformers CTN1, N = A, B, C.

[0033] As a preferred solution, the backup power switch circuit adopts three backup power switch circuits arranged in parallel, three backup contact branches are provided with three linked main contacts QF2, the three linked main contacts QF2 are arranged in the backup magnetic control switch, and three backup thyristor branches are respectively provided with thyristors QN2, N = A, B, C; three backup contact branches or three backup thyristor branches are respectively provided with backup current transformers CTN2, N = A, B, C.

[0034] As a preferred solution, the contact just-opening detection circuit includes a sampling resistor R1 connected to both ends of the thyristor CN1 or the thyristor CN2, the sampling resistor R1 is connected to the amplifier circuit, the amplifier circuit is connected to the low-pass filter circuit 1, the low-pass filter circuit 1 is connected to the window comparison circuit, and the window comparison circuit is connected to the low-pass filter circuit 2.

[0035] As a preferred solution, the amplification circuit includes a resistor R1, one end of the resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is respectively connected to one end of the resistor R3 and the inverting input end of the operational amplifier U1, the other end of the resistor R3 is connected to the output end of the operational amplifier U1, and the other end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1.

[0036] As a preferred solution, the low-pass filter circuit 1 includes a resistor R4, the output end of the operational amplifier U1 is connected to one end of the resistor R4, the other end of the resistor R4 is connected to the window comparator circuit, and a capacitor C1 is provided between the resistor R4 and the window comparator circuit, and one end of the capacitor C1 is grounded.

[0037] As a preferred solution, the window comparator circuit includes resistor R5, resistor R6, resistor R7, resistor R8, operational amplifier U2.1, and operational amplifier U2.2. One end of resistor R4 is respectively connected to the inverting input terminal of operational amplifier U2.1 and the non-inverting input terminal of operational amplifier U2.2. The non-inverting input terminal of operational amplifier U2.1 is connected to one end of resistor R7 through wire one, and the other end of resistor R7 is grounded; the inverting input terminal of operational amplifier U2.2 is connected to one end of resistor R5 through wire two, and the other end of resistor R5 is connected to the positive power supply. Resistor R6 is provided between wire one and wire two. The output terminal of operational amplifier U2.1 is connected to the anode of diode D1, the output terminal of operational amplifier U2.2 is connected to the anode of diode D2, and the cathode of diode D1 and the cathode of diode D2 are connected to low-pass filter circuit two.

[0038] As a preferred solution, the second low-pass filter circuit includes a resistor R8 connected to the cathode of the diode D1 and the cathode of the diode D2. The resistor R8 is connected to the output terminal OUT through a wire three. The wire three is connected to one end of the capacitor C2, and the other end of the capacitor C2 is grounded.

[0039] This application has the following advantages:

[0040] 1. The traditional serial sequence of "waiting for the arc to extinguish → issuing a closing command" is changed to a parallel sequence of "issuing the command in advance + a revocable window period", shortening the overall switching time;

[0041] 2. Through secondary safety verification within the revocable window period, the short circuit risk caused by the main contact adhesion or feedback inaccuracy of the primary side magnetic control switch is eliminated, thereby improving the safety of switching;

[0042] 3. In a dual power supply design without power electronics, the characteristic of the magnetic switch that the closing command can be withdrawn during the uncompleted closing pulse width period is utilized, and the triggering time and acceleration time during the closing process are used in parallel to reduce the total time of series switching without affecting the safety switching at all;

[0043] 4. Compared with the traditional method that relies on the physical separation of mechanical auxiliary contacts to judge whether the contact has just been opened, which has a large error, the hardware circuit directly detects the line current through the current transformer and the contact just-open detection circuit, which can accurately determine whether the contact has just been opened;

[0044] 5. The dual power switch device can realize both contact opening detection and current zero-crossing detection, without relying on algorithm judgment, with fast response and high reliability.

[0045] 6. Significant cost advantage. It does not require the high-cost power electronic devices and high energy consumption of STS. It achieves performance breakthroughs by optimizing the mechanical switch control logic and is suitable for large-scale industrial deployment. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 is a circuit diagram of the switching device of the present application;

[0047] Figure 2 It is the waveform diagram during the dual power closing process;

[0048] Figure 3 This is the circuit diagram of the contact just-open detection circuit;

[0049] Figure 4 This is a logic diagram of the switching method according to the first embodiment of the present application;

[0050] Figure 5 This is a schematic diagram of the switching process of the switching method of the present application;

[0051] Reference numerals:

[0052] 1. Main contact branch; 2. Main thyristor branch; 3. Spare contact branch; 4. Spare thyristor branch; 5. Wire 1; 6. Wire 2; 7. Wire 3. DETAILED DESCRIPTION

[0053] The following is combined with Figure 1 、 2 3. The specific embodiments of the present invention are described in detail. It should be noted that the specific embodiments described herein are only used to illustrate and explain the present invention and are not used to limit the present invention.

[0054] Example 1:

[0055] like Figure 4 As shown, this embodiment provides a dual power switch switching method based on a retractable closing mechanism, comprising the following steps:

[0056] This embodiment is described by taking the primary side as the main power switch circuit and the backup side as the backup power switch circuit as an example:

[0057] S1: Real-time detection of whether there is a problem with the main power supply. If so, enter S2; otherwise, terminate the switching of the switching circuit; the main power supply problem in S1 includes the voltage drop amplitude and duration TA of the main power supply voltage drop; the voltage drop amplitude and duration TA of the voltage drop are limited according to the specific usage scenario of the user. Under normal circumstances, the duration TA is 1-2ms. When the voltage drop amplitude is less than 85%-90% of the normal voltage, it is considered a drop fault. The technician can make corresponding settings according to the specific situation;

[0058] S2: The control device outputs the main magnetic control switch opening signal and triggers the thyristor QN1 to turn on; the pulse width time required to delay the main magnetic control switch opening is TB, and the TB is 0.6ms-1ms;

[0059] S3: Determine whether the main contact QF1 of the main magnetic control switch is open. If so, execute S4; otherwise, execute S3 in a loop.

[0060] S4: The control device turns off the trigger signal of the thyristor QN1;

[0061] S5: Delay TC, the control device outputs the closing signal of the standby magnetic switch of the standby power supply; TC is 4ms-5ms;

[0062] S6: Determine whether the main current on the main power supply side is zero. If so, execute S7, otherwise jump to S10; specifically: determine whether the main current on the main power supply side is zero through CTN1 on the main contact branch and the contact just-open detection circuit or determine whether the main current on the main power supply side is zero through CTN1 on the main thyristor branch and the contact just-open detection circuit; the specific principle of determining whether the main current on the main power supply side is zero through CTN1 on the main contact branch and the contact just-open detection circuit is as follows: when there is a problem on the main power supply side, the main magnetic control switch is opened, triggering the thyristor QA1, QB1, and QC1 to turn on. When the main contact QF1 of the main magnetic control switch is disconnected, an arc will be generated between the contacts and the resistance between the contacts will increase. The current will automatically commutate to the main thyristor branch 2 connected in parallel with it. The main current transformers CTA1, CTB1, and CTC1 induce an electromotive force, which is sampled through the sampling resistor R1. After the operational amplifier U1 amplifies the signal, it is low-pass filtered by R4 and C1 and output to the subsequent window comparator circuit. The window comparator circuit detects that the input signal is outside the upper and lower threshold windows and outputs a high level, indicating that the contacts are disconnected. At this time, the trigger signals of the thyristors QA1, QB1, and QC1 are turned off. Due to the existence of the thyristor maintenance circuit, the thyristors QA1, QB1, and QC1 continue to remain in the on state. When the current of the thyristors QA1, QB1, and QC1 passes through zero, the main current transformers CTA1, CTB1, and CTC1 no longer have an induced voltage, and the input signal of the window comparator enters the upper and lower threshold windows and outputs a low level, indicating that the main switch current is zero; the logic of judging whether the main current on the main power supply side is zero through CTN2 and the contact just-open detection circuit on the main thyristor branch is opposite to the above. It outputs a high level before the main contact QF1 of the main magnetic control switch is disconnected, and outputs a low level after the contact is disconnected.

[0063] S7: Maintain the closing signal of the standby magnetic control switch for the duration of TD or TE; the TD is 10-15ms, and the TE is 25ms-35ms; when S6 directly executes S7, the closing signal is maintained for the duration of TD; after S11 returns to S6 and then executes S7, the closing signal is maintained for the duration of TE;

[0064] S8: The closing signal of the standby magnetic switch that turns off the standby power supply;

[0065] S9: End the switching of the power switch and complete the overall switching;

[0066] S10: Determine whether the window period for retracting the closing of the standby magnetic switch of the standby power supply is about to end. If so, execute S11; otherwise, return to S6;

[0067] S11: Cancel the closing signal of the standby magnetic switch of the standby power supply and return to S6.

[0068] The above process can also be switched from the backup power supply to the main power supply. The switching logic is the same and will not be described in detail here.

[0069] After the coil of the magnetic control switch is energized, it begins to magnetize. The stage when the main contact has not yet physically moved is the retractable window period. Taking the primary side as the main power switch circuit and the backup side as the backup power switch circuit as an example, the retractable window period of the main contact QF2 closing is explained as follows: Figure 2 The waveforms shown are during the dual power closing process, where CH1 is the coil current of the standby magnetic switch, and CH2 is the closing signal of the main contact QF2 of the standby magnetic switch. Figure 2 It can be seen that the closing process is divided into four moments T0, T1, T2, and T3. From the time the closing command is issued at T0 to the time the main contact QF2 starts to move at T1, the coil of the standby magnetic control switch begins to magnetize after being energized. This stage is the window period during which the closing can be withdrawn, and the main contact QF2 has not yet undergone physical displacement. If it is detected that the main current has not returned to zero or other abnormal signals are detected, the closing signal can be immediately turned off, the magnetization process can be terminated, and the closing command can be completely revoked. The general window period during which the closing can be withdrawn is 5-6ms; from the time the main contact QF2 starts to move at T1 to the time the main contact QF2 is closed in place, the magnetic control mechanism completes magnetization, and the main contact QF2 begins to accelerate under the electromagnetic driving force to complete the closing of the main contact QF2; from the time the main contact QF2 is closed in place at T2 to the time the closing signal is turned off at T3, the closing signal output is maintained during this stage to maintain the stability of the closing.

[0070] This embodiment combines the attached Figure 5 The advantages of this application are specifically explained: the traditional method requires waiting for at least half a power frequency cycle, i.e. 10ms, after the main contacts are disconnected to ensure that the arc naturally crosses zero and extinguishes before triggering the backup power supply to close; according to the retractable closing characteristics of the magnetic control mechanism and the switching method of the present invention, Figure 5Analysis of the switching process: The main power supply first outputs a trip pulse width signal and waits for the main contact QF1 to open, earlier than the traditional 10ms waiting period. 4ms-5ms after the main contact QF1 opens, the backup side power supply's backup magnetic switch is issued a closing signal, enabling parallel switching of the main and backup power supplies and shortening the overall switching time. Before the end of the retractable closing window period of the backup power supply main contact QF2, the main current is detected to see if it has returned to zero. If the current is zero, the original normal closing signal is maintained to continue the switching. If the current has not returned to zero, it is determined whether the retractable closing window period of the backup side power supply's backup magnetic switch is about to end. If so, the closing signal of the backup side power supply's backup magnetic switch is canceled, terminating the closing process to avoid a short circuit between the two power supplies. Otherwise, it continues to determine whether the main current of the primary side power supply is zero. The above determination of whether the retractable closing window period of the backup side power supply's backup magnetic switch is about to end is specifically when the time from T1 is less than or equal to 0.3ms, indicating that the retractable closing window period of the backup side power supply's backup magnetic switch is about to end.

[0071] This embodiment is also applicable to dual power supplies designed with pulse width controlled permanent magnet switches, and is also suitable for medium voltage dual power supply switching. In addition, in power electronic composite topologies, the role of the thyristor can be expanded to not only serve as a switching component, but also as a monitoring component for the switch's disconnection state.

[0072] Example 2:

[0073] like Figure 1 This embodiment provides a dual power switch switching device based on a retractable closing mechanism, including:

[0074] The present application provides a dual power switch device, comprising:

[0075] A main power switch circuit, comprising a main contact branch 1 and a main thyristor branch 2 connected in parallel, wherein the main contact branch 1 is provided with a main magnetically controlled switch, which adopts a magnetically controlled switch in the prior art, such as an electromagnetic relay, a magnetic latching relay, etc., and the main thyristor branch 2 is provided with a thyristor QN1. The main contact branch 1 or the main thyristor branch 2 is provided with a main current transformer CTN1, and the current transformer CTN1 is connected to a contact just-break detection circuit; when the main current transformer CTN1 is installed on the main contact branch 1, it cooperates with the contact just-break detection circuit to measure the contact current of the main power switch circuit; when the main current transformer CTN1 is installed on the main thyristor branch 2, it cooperates with the contact just-break detection circuit to measure the thyristor current, both of which can achieve the purpose of circulating current detection;

[0076] In this embodiment, the main power switch circuit includes three branches arranged in parallel representing three-phase electricity, namely, three main contact branches 1 and main thyristor branches 2 arranged in parallel. Three linked main contacts QF1 are provided on the three main contact branches 1, and the three linked main contacts QF1 are arranged in the main magnetic control switch; the three main thyristor branches 2 are respectively provided with thyristors QN1, N=A, B, C, that is, the three main thyristor branches 2 are respectively provided with thyristors QA1, QB1, and QC1, and the three main contact branches 1 or the three main thyristor branches 2 are respectively provided with main current transformers CTN1, N=A, C, that is, the three main contact branches 1 or the three main thyristor branches 2 are respectively provided with CTA1, CTB1, and CTC1; CTA1, CTB1, and CTC1 are respectively connected to contact separation detection circuits.

[0077] A backup power switch circuit, comprising a backup contact branch 3 and a backup thyristor branch 4 arranged in parallel, wherein the backup contact branch 3 is provided with a backup magnetically controlled switch, and the backup thyristor branch 4 is provided with a thyristor QN2. A backup current transformer CTN2 is provided on the backup contact branch 3 or the backup thyristor branch 4, and the current transformer CTN1 is connected to a contact just-break detection circuit; when the backup current transformer CTN2 is installed on the backup contact branch 3, it cooperates with the current detection circuit to measure the contact current of the backup power switch circuit. When the backup current transformer CTN2 is installed on the backup thyristor branch 4, it cooperates with the contact just-break detection circuit to measure the thyristor current. Both can achieve the purpose of circulating current detection;

[0078] In this embodiment, the standby power switch circuit includes three branches arranged in parallel representing three-phase electricity, namely, three standby contact branches 3 and standby thyristor branches 4 arranged in parallel, three standby contact branches 3 are provided with three linked main contacts QF2, and the three linked main contacts QF2 are arranged in the standby magnetic control switch. The three standby thyristor branches 4 are respectively provided with thyristors QN2, N=A, B, C, that is, the three standby thyristor branches 4 are respectively provided with thyristors QA2, QB2, and QC2, and the three standby contact branches 3 or the three standby thyristor branches 4 are respectively provided with main current transformers CTN2, N=A, B, C, that is, the three standby contact branches 3 or the three standby thyristor branches 4 are respectively provided with CTA2, CTB2, and CTC2, and CTA1, CTB1, and CTC1 are respectively connected to contact separation detection circuits.

[0079] A current detection device is installed on the output side of the main power switch circuit and the backup power switch circuit; the current detection device uses an output current transformer. In this embodiment, the UA output side of the main power switch circuit and the backup power switch circuit is provided with an output current transformer CTA, the UB output side is provided with an output current transformer CTB, and the UC output side is provided with an output current transformer CTC. The output current transformer CTA, the output current transformer CTB, and the output current transformer CTC are used to measure the output current, that is, to measure the load current.

[0080] The working principle of this application is as follows: Taking the primary side as the main power switch circuit and the backup side as the backup power switch circuit as an example, the working principle is explained:

[0081] When a problem occurs in the main power switch circuit, the controller outputs the opening signal of the main magnetic control switch of the main power switch circuit and triggers the thyristors QA1, QB1, and QC1, delaying the pulse width time required for the main contact QF1 to open. The required pulse width time is generally 0.6-1ms. Wait for the main contact QF1 to open. After the main contact QF1 has just opened, the trigger signal of the thyristors QA1, QB1, and QC1 is turned off; after a delay of 4-5ms, the closing signal of the backup magnetic control switch of the backup power switch circuit is output to judge the main current of the main power switch circuit. Is it zero? If it is zero, keep the closing signal, usually for 10-15ms; if it is not zero, judge whether the closing retractable window period of the standby magnetic control switch of the standby side power supply is about to end. The criterion for judging whether it is about to end is to judge whether the time from the moment T1 is less than or equal to 0.3ms. If it is, it means it is about to end; if the closing retractable window period is about to end, cancel the closing signal of the standby magnetic control switch of the standby side power supply and terminate the closing to avoid short circuit and loop closing between the two power supplies; otherwise, continue to judge whether the main current of the original side power supply is zero.

[0082] Example 3:

[0083] This embodiment specifically describes the contact opening detection circuit:

[0084] The contact just-open detection circuit includes a sampling resistor R1 connected to both ends of the thyristor CN1 or the thyristor CN2, the sampling resistor R1 is connected to an amplifier circuit, the amplifier circuit is used to amplify the voltage across the sampling resistor R1, the amplifier circuit is connected to a low-pass filter circuit 1, the low-pass filter circuit 1 is used to filter out high-frequency interference; the low-pass filter circuit 1 is connected to a window comparison circuit, the window comparison circuit is used to compare the output signal of the previous amplifier circuit to detect zero and non-zero currents flowing through the current transformer; the window comparison circuit is connected to a low-pass filter circuit 2, the low-pass filter circuit 2 can achieve the purpose of lagging output to ensure that the measured current is zero.

[0085] like Figure 3 As shown, specifically: the amplifying circuit is composed of a resistor R2, a resistor R3, and an operational amplifier U1, one end of the resistor R1 is connected to one end of the resistor R2, the other end of the resistor R2 is respectively connected to one end of the resistor R3 and the inverting input end of the operational amplifier U1, the other end of the resistor R3 is connected to the output end of the operational amplifier U1, and the other end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1.

[0086] The low-pass filter circuit 1 is composed of a resistor R4 and a capacitor C1. The output end of the above-mentioned operational amplifier U1 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the window comparator circuit. A capacitor C1 is provided between the resistor R4 and the window comparator circuit, and one end of the capacitor C1 is grounded.

[0087] The resistors R5, R6, R7, R8, operational amplifier U2.1, and U2.2 form a window comparator circuit. Specifically, one end of the resistor R4 is connected to the inverting input of the operational amplifier U2.1 and the non-inverting input of the operational amplifier U2.2, respectively. The non-inverting input of the operational amplifier U2.1 is connected to one end of the resistor R7 via a wire 1 5, and the other end of the resistor R7 is grounded. The inverting input of the operational amplifier U2.2 is connected to one end of the resistor R5 via a wire 2 6, and the other end of the resistor R5 is connected to the positive power supply. A resistor R6 is provided between the wire 1 5 and the wire 2 6. The output of the operational amplifier U2.1 is connected to the anode of the diode D1, the output of the operational amplifier U2.2 is connected to the anode of the diode D2, and the cathodes of the diodes D1 and D2 are connected to the low-pass filter circuit 2.

[0088] The second low-pass filter circuit includes a resistor R8 connected to the cathode of the diode D1 and the cathode of the diode D2. The resistor R8 is connected to the output terminal OUT through a third wire 7. The third wire 7 is connected to one end of the capacitor C2. The other end of the capacitor C2 is grounded.

[0089] Taking the case where the main thyristor branch 2 is provided with a main current transformer CTN1 and the backup thyristor branch 4 is provided with a backup current transformer CTN2 as an example, the contact just-open detection circuit is described:

[0090] The thyristor and the magnetic control switch are operated in parallel. When a problem occurs on the main power supply side, the main magnetic control switch on the main power supply side is opened, triggering the thyristor QA1, QB1, and QC1 to turn on. When the main contact QF1 of the main magnetic control switch is disconnected, an arc will be generated between the contacts and the resistance between the contacts will increase. The current will automatically commutate to the main thyristor branch 2 connected in parallel with it. The main current transformers CTA1, CTB1, and CTC1 will induce an electromotive force, which will be sampled through the sampling resistor R1. After the signal is amplified by the operational amplifier U1, it will be low-pass filtered by R4 and C1 and output to the next stage. Window comparator circuit: When the window comparator detects that the input signal is outside the upper and lower threshold windows, it outputs a high level, indicating that the contacts are disconnected. At this time, the trigger signals of the thyristors QA1, QB1, and QC1 are turned off. Due to the existence of the thyristor holding circuit, the thyristors QA1, QB1, and QC1 continue to remain in the on state. When the current of the thyristors QA1, QB1, and QC1 passes through zero, the main current transformers CTA1, CTB1, and CTC1 no longer have an induced voltage, and the input signal of the window comparator enters the upper and lower threshold windows, and the output is a low level, indicating that the main switch current is zero.

[0091] In addition, if the main current transformers CTA1, CTB1, and CTC1 are installed in the main contact branch 1 and the spare contact branch 3, the detection logic is opposite to the above. When the main contact QF1 of the main magnetic control switch outputs a high level before disconnection and outputs a low level after the contact is disconnected, this solution determines the contact state through current detection, does not rely on mechanical contacts, has a fast response, and provides accurate and reliable judgment conditions for the switching timing.

[0092] In summary, due to the adoption of the above technical solution, this application has the following advantages:

[0093] 1. The traditional serial sequence of "waiting for the arc to extinguish → issuing a closing command" is changed to a parallel sequence of "issuing the command in advance + a revocable window period", shortening the overall switching time;

[0094] 2. Through secondary safety verification within the revocable window period, the short circuit risk caused by the main contact adhesion or feedback inaccuracy of the primary side magnetic control switch is eliminated, thereby improving the safety of switching;

[0095] 3. In a dual power supply design without power electronics, the characteristic of the magnetic switch that the closing command can be withdrawn during the uncompleted closing pulse width period is utilized, and the triggering time and acceleration time during the closing process are used in parallel to reduce the total time of series switching without affecting the safety switching at all;

[0096] 4. Compared with the traditional method that relies on the physical separation of mechanical auxiliary contacts to judge whether the contact has just been opened, which has a large error, the hardware circuit directly detects the line current through the current transformer and the contact just-open detection circuit, which can accurately determine whether the contact has just been opened;

[0097] 5. The dual power switch device can realize both contact opening detection and current zero-crossing detection, without relying on algorithm judgment, with fast response and high reliability.

[0098] 6. Significant cost advantage. It does not require the high-cost power electronic devices and high energy consumption of STS. It achieves performance breakthroughs by optimizing the mechanical switch control logic and is suitable for large-scale industrial deployment.

[0099] The devices, connection relationships, etc. not specifically described above belong to the prior art and will not be described in detail in the present invention.

[0100] The preferred embodiment of the present application is described in detail above in conjunction with the accompanying drawings. However, the present application is not limited to the specific details in the above-mentioned embodiments. Within the technical concept of the present application, various simple modifications can be made to the technical solution of the present application, and these simple modifications all fall within the scope of protection of the present application.

[0101] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner unless there is any contradiction. In order to avoid unnecessary repetition, the various possible combinations of this application will not be described separately.

[0102] In addition, the various implementation methods of the present application can be arbitrarily combined, as long as they do not violate the concept of the present application, and they should also be regarded as the contents disclosed in the present application.

Claims

1. A dual power switch switching method based on a retractable closing mechanism, characterized in that: The steps include: S1: The control device detects in real time whether there is a problem with the primary side power supply. If so, it enters S2; otherwise, the switching of the switch circuit is terminated. S2: The control device outputs the primary side magnetic control switch opening signal and triggers the primary side thyristor to turn on; the pulse width required to delay the opening of the primary side magnetic control switch is TB; S3: Determine whether the main contact of the primary side magnetic control switch is open. If so, execute S4; otherwise, execute S3 in a loop. S4: The control device turns off the trigger signal of the primary side thyristor; S5: Delay TC, the control device outputs the closing signal of the magnetic control switch of the backup side power supply; S6: Determine whether the main current of the primary power supply is zero. If so, execute S7; otherwise, jump to S10. S7: Maintain the closing signal of the magnetic control switch of the backup power supply for the TD duration or TE duration; S8: The closing signal of the magnetic control switch that turns off the backup power supply; S9: End the switching of the power switch; S10: Determine whether the window period for retracting the closing of the magnetic control switch of the backup power supply is about to end. If so, execute S11; otherwise, return to S6; S11: Cancel the closing signal of the magnetic control switch of the backup power supply and return to S6.

2. A dual power switch switching method based on a retractable closing mechanism according to claim 1, characterized in that: When the primary side is the main power switching circuit, the standby side is the standby power switching circuit; when the primary side is the standby power switching circuit, the standby side is the main power switching circuit.

3. A dual power switch switching method based on a retractable closing mechanism according to claim 1, characterized in that: The problems of the main power supply in S1 include the voltage drop amplitude and duration TA of the primary side power supply voltage sudden drop.

4. A dual power switch switching method based on a retractable closing mechanism according to claim 1, characterized in that: In S6, whether the main current of the primary side power supply is zero is determined by the current transformer and the contact just-open detection circuit on the primary side contact branch, or whether the main current of the primary side power supply is zero is determined by the current transformer and the contact just-open detection circuit on the primary side thyristor branch.

5. A dual power switch device based on a retractable closing mechanism, characterized in that: include: A main power switch circuit, comprising a main contact branch (1) and a main thyristor branch (2) arranged in parallel, wherein the main contact branch (1) is provided with a main magnetic control switch, the main thyristor branch (2) is provided with a thyristor QN1, the main contact branch (1) or the main thyristor branch (2) is provided with a main current transformer CTN1, and the main current transformer CTN1 is connected to a contact opening detection circuit; A backup power switch circuit, comprising a backup contact branch (3) and a backup thyristor branch (4) arranged in parallel, the backup contact branch (3) being provided with a backup magnetic switch, the backup thyristor branch (4) being provided with a thyristor QN2, the backup contact branch (3) or the backup thyristor branch (4) being provided with a backup current transformer CTN2, the backup current transformer CTN2 being connected to a contact opening detection circuit; A current detection device is installed on the output side of the main power switch circuit and the backup power switch circuit.

6. A dual power switch device based on a closing retractable mechanism according to claim 5, characterized in that: The contact just-open detection circuit includes a sampling resistor R1 connected to both ends of the thyristor CN1 or the thyristor CN2, the sampling resistor R1 is connected to the amplifier circuit, the amplifier circuit is connected to the low-pass filter circuit 1, the low-pass filter circuit 1 is connected to the window comparator circuit, and the window comparator circuit is connected to the low-pass filter circuit 2.

7. A dual power switch device based on a closing retractable mechanism according to claim 6, characterized in that: The amplifier circuit is composed of a resistor R2, a resistor R3, and an operational amplifier U1. One end of the resistor R1 is connected to one end of the resistor R2, and the other end of the resistor R2 is respectively connected to one end of the resistor R3 and the inverting input end of the operational amplifier U1. The other end of the resistor R3 is connected to the output end of the operational amplifier U1, and the other end of the resistor R1 is connected to the non-inverting input end of the operational amplifier U1.

8. A dual power switch device based on a closing retractable mechanism according to claim 7, characterized in that: The low-pass filter circuit 1 is composed of a resistor R4 and a capacitor C1. The output end of the operational amplifier U1 is connected to one end of the resistor R4, and the other end of the resistor R4 is connected to the window comparator circuit. A capacitor C1 is provided between the resistor R4 and the window comparator circuit, and one end of the capacitor C1 is grounded.

9. A dual power switch device based on a retractable closing mechanism according to claim 8, characterized in that: The window comparison circuit includes a resistor R5, a resistor R6, a resistor R7, a resistor R8, an operational amplifier U2.1, and an operational amplifier U2.

2. One end of the resistor R4 is connected to the inverting input end of the operational amplifier U2.1 and the non-inverting input end of the operational amplifier U2.2 respectively. The non-inverting input end of the operational amplifier U2.1 is connected to one end of the resistor R7 through a wire 1 (5), and the other end of the resistor R7 is grounded. The inverting input end of the operational amplifier U2.2 is connected to one end of the resistor R5 through a wire 2 (6), and the other end of the resistor R5 is connected to a positive power supply. A resistor R6 is provided between the wire 1 (5) and the wire 2 (6). The output end of the operational amplifier U2.1 is connected to the anode of the diode D1, the output end of the operational amplifier U2.2 is connected to the anode of the diode D2, and the cathode of the diode D1 and the cathode of the diode D2 are connected to the low-pass filter circuit 2.

10. The dual power switch device according to claim 9, characterized in that: The second low-pass filter circuit includes a resistor R8 connected to the cathode of the diode D1 and the cathode of the diode D2. The resistor R8 is connected to the output terminal OUT through a third wire (7). The third wire (7) is connected to one end of the capacitor C2, and the other end of the capacitor C2 is grounded.

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