Magnetic latching indoor phase-change switch and phase-change method

Abstract

The application provides a household type commutation switch based on magnetic retention and a commutation method, wherein switch main contacts CD-A, CD-B and CD-C are connected with A phase, B phase and C phase of an incoming line, CD-A, CD-B and CD-C are connected with a common end, the common end is connected with a main contact CD-D and an SCR, CD-A, CD-B and CD-C are driven through a power relay combination operating coil and a power relay separation operating coil, the power relay combination operating coil is connected with a signal relay combination operating coil in parallel, the power relay separation operating coil is connected with a signal relay separation operating coil in parallel, and the combination operation instruction input ends of A phase, B phase and C phase are respectively connected with normally closed contacts in signal relay contacts of the remaining two phases in series. The application adopts a parallel and synchronous driving mode of the power relay coil and the signal relay coil to realize contact feedback and electrical interlocking, and eliminates the possibility of simultaneous closing of two or more contacts.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of power systems, in particular to a household-type commutation switch based on magnetic retention and a commutation method. BACKGROUND

[0002] In China, the low-voltage 400V distribution system in the transformer area, because most of the household appliances are single-phase loads, and the incoming line of the residential user is also mostly single-phase, the three-phase current imbalance is still a common problem; and the new energy vehicle charging pile in the transformer area is single-phase, which further aggravates the three-phase imbalance; due to the three-phase current imbalance, the zero line is overloaded and heated, causing energy consumption and also bringing the risk of line fire, so the three-phase imbalance has always been a problem to be solved in the low-voltage distribution system, and is also one of the mainstream directions of low-carbon energy saving of the power grid.

[0003] The industry has once promoted a transformer area type commutation switch, but it is designed for branch boxes, and is designed and installed outdoors, and the switching load current is above 100A, and the short-circuit current is more than 8kA, but due to the large size, high failure rate, outdoor design needs to be windproof, rainproof and dustproof, greatly increasing the design cost, and when installed, a large area of power supply needs to be stopped, and finally the promotion fails; for example, the low-voltage distribution network fast commutation method based on the magnetic latching relay with application number 201910213058.7, which combines the AC zero-crossing detection signal and the commutation switch state feedback signal and uses a timing logic control algorithm to complete the switching of the load phase sequence; the invention greatly shortens the power-off time in the commutation process, with a maximum power-off time of about 15ms, which does not affect the normal power consumption of household users, meets the AC zero-crossing switching principle, has a small error, does not produce an arc, and uses the commutation switch state feedback signal to set a suitable check time to judge and process whether the switching is successful, which can avoid phase-to-phase short circuit and ensure the normal operation of the low-voltage distribution network.

[0004] However, the above patent application uses voltage zero-crossing detection, and a three-phase PT is installed in the switch device, because of the setting of the three-phase PT, the size of the entire switch cannot be reduced, and it is not easy to be applied to the end of the transformer area distribution network, in addition, the patent application does not have any related technology of interlocking, and still cannot solve the problem of phase-to-phase short circuit, once the main circuit has two or more phase relays simultaneously closed, it will inevitably cause phase-to-phase short circuit and cause short-circuit tripping accident.

[0005] In summary, a new technical solution is needed to solve the above technical problems. SUMMARY

[0006] The application provides a magnetic holding type phase change switch for household, which comprises relays JDQa, JDQb and JDQc, one end of main contacts CD-A, CD-B and CD-C of the relays JDQa, JDQb and JDQc is connected with A phase, B phase and C phase of incoming lines respectively, the other end of the main contacts CD-A, CD-B and CD-C is connected with a common terminal, the common terminal is connected with a main contact CD-D of a relay JDQd, the CD-D is provided with a bidirectional thyristor SCR in parallel, a current measuring device is arranged on the common terminal of the CD-D and the SCR output terminal; the CD-A, CD-B and CD-C are driven through power relay combination operation coils and power relay separation operation coils, the power relay combination operation coils are arranged in parallel with signal relay combination operation coils, the power relay separation operation coils are arranged in parallel with signal relay separation operation coils, and the signal relay combination operation coils and the signal relay separation operation coils are used for driving double contacts of a signal relay; wherein a normally closed contact of the signal relay contacts of the B phase and the C phase is connected in series with the combination operation instruction input end of the A phase, a normally closed contact of the signal relay contacts of the A phase and the C phase is connected in series with the combination operation instruction input end of the B phase, and a normally closed contact of the signal relay contacts of the A phase and the B phase is connected in series with the combination operation instruction input end of the C phase.

[0007] As a preferred scheme, the current measuring device adopts a manganese copper sheet type resistance R.

[0008] As a preferred scheme, the resistance value of the manganese copper sheet type resistance is 100-500uΩ.

[0009] As a preferred scheme, the current measuring device adopts a current transformer CT, and the current transformer CT adopts a main current direct through type current transformer.

[0010] As a preferred scheme, the magnetic holding type phase change switch for household is installed at the end of a power distribution network of a power supply area.

[0011] As a preferred scheme, the phase change switch for household is installed at the end of the power distribution network of the power supply area through a card rail type installation mode.

[0012] As a preferred solution, the CD-A is driven by a power relay combination operation coil Coil-gl-a-h and a power relay separation operation coil Coil-gl-a-f, Coil-gl-a-h is connected in parallel with a signal relay combination operation coil Coil-xh-a-dz, Coil-gl-a-f is connected in parallel with a signal relay separation operation coil Coil-xh-a-fg, Coil-xh-a-dz and Coil-xh-a-fg are used to drive double contacts CD-a-nc1 and CD-a-nc2 of an A-phase signal relay; an A-phase combination operation instruction input terminal is connected in series with a normally closed contact CD-b-nc1 in signal relay contacts of a B-phase and a normally closed contact CD-c-nc1 in signal relay contacts of a C-phase.

[0013] The CD-B is driven by a power relay combination operation coil Coil-gl-b-h and a power relay separation operation coil Coil-gl-b-f, Coil-gl-b-h is connected in parallel with a signal relay combination operation coil Coil-xh-b-dz, Coil-gl-b-f is connected in parallel with a signal relay separation operation coil Coil-xh-b-fg, Coil-xh-b-dz and Coil-xh-b-fg are used to drive double contacts CD-b-nc1 and CD-b-nc2 of a B-phase signal relay; a B-phase combination operation instruction input terminal is connected in series with a normally closed contact CD-a-nc1 in signal relay contacts of an A-phase and a normally closed contact CD-c-nc2 in signal relay contacts of a C-phase.

[0014] The CD-C is driven by a power relay combination operation coil Coil-gl-c-h and a power relay separation operation coil Coil-gl-c-f, Coil-gl-c-h is connected in parallel with a signal relay combination operation coil Coil-xh-c-dz, Coil-gl-c-f is connected in parallel with a signal relay separation operation coil Coil-xh-c-fg, Coil-xh-c-dz and Coil-xh-c-fg are used to drive double contacts CD-c-nc1 and CD-c-nc2 of a C-phase signal relay; a C-phase combination operation instruction input terminal is connected in series with a normally closed contact CD-a-nc2 in signal relay contacts of an A-phase and a normally closed contact CD-c-nc2 in signal relay contacts of a B-phase.

[0015] A phase change method of a household type phase change switch based on magnetic retention, comprising the following steps:

[0016] S1: the MCU receives a phase change instruction;

[0017] S2: whether a first effective displacement of a zero-crossing signal IN0 is generated is monitored, if yes, jump to S3, otherwise continue to execute S2;

[0018] S3: issue JDQd sub-instruction to trigger SCR;

[0019] S4: enable timer interrupt, timer JSQ is cleared; at t0 moment, JDQd contact opens;

[0020] S5: determine whether the current value of timer JSQ is greater than or equal to t1, t1 is the time before the next current zero-crossing point t2, if yes, execute S6, otherwise continue to execute S5;

[0021] S6: issue original phase relay JDQX sub-instruction to stop triggering SCR; wherein, X = a, b, c;

[0022] S7: determine whether the current value of timer JSQ is greater than or equal to the time of the next current zero-crossing point t2, if yes, jump to S8, otherwise continue to execute S7;

[0023] S8: issue closing instruction of the relay JDQX of the phase to be switched at the current zero-crossing point t2;

[0024] S9: determine whether the current value of timer JSQ is greater than or equal to t3, t3 is the time after the next current zero-crossing point t2, if yes, jump to S10, otherwise continue to execute S9;

[0025] S10: original phase relay JDQX contact opens, determine whether the current of the contact and the current instantaneous value at the time are 0, if yes, jump to S11, otherwise jump to S12;

[0026] S11: determine whether the current value of timer JSQ is greater than or equal to t4, if yes, jump to S13, otherwise jump to S12;

[0027] S12: after 1ms delay, original phase relay JDQX contact opens, determine whether the current of the contact and the current instantaneous value at the time are 0, if yes, jump to S11, otherwise jump to S17;

[0028] S13: issue JDQd closing instruction;

[0029] S14: determine whether the current value of timer JSQ is greater than or equal to t5, if yes, jump to S15, otherwise continue to execute S14;

[0030] S15: determine whether the closing operation of the relay JDQX of the phase to be switched is executed, if yes, jump to S16, otherwise jump to S17;

[0031] S16: determine whether the current value of timer JSQ is greater than or equal to t6, if yes, re-trigger SCR, JDQd contact closes at t7 moment, and commutation is completed; otherwise, continue to execute S16;

[0032] S17: cancel the relay JDQX of the phase to be switched off combined command;

[0033] S18: timer JSQ is cleared, and the original phase relay JDQX and the relay JDQd combined command is issued;

[0034] S19: switching failure, alarm;

[0035] Wherein, the relay JDQX in the main circuit, X=a, b, c, JDQd, the operation time is T1, the whole process time is T2; , The error range between them is ±0.4ms; , , The error range between them is ±0.4ms.

[0036] As a preferred scheme, the .

[0037] As a preferred scheme, when the positive sequence switching, the overall switching time in each phase switching process is 6.67ms+ the phase difference between voltage and current, wherein, the phase difference between voltage and current is 0.1ms~0.7ms.

[0038] As a preferred scheme, the relay JDQX, X=a, b, c, JDQd adopts the power relay of magnetic retention.

[0039] The application has the following advantages:

[0040] 1, the application is designed in the last end of the distribution network in the district, such as household meter box to realize switching switch, realize small size, short installation time, small power range, not disturb the people;

[0041] 2, the application is designed in the last end of the distribution network in the district, without considering the rain and dustproof problem outdoors, reduce the cost of shell; similarly, due to the fault current in the last end is limited current, the application only needs to meet the UC2 level of short circuit current resistance, realize the compatibility of small size and resistance;

[0042] 3, the application adopts the double coil magnetic retention signal relay to realize the split and combined control of the main circuit, only needs driving power in the action moment, basically does not consume driving power after the action is completed, will not increase the electricity charge burden of the power grid and the user;

[0043] 4, the application adopts the parallel connection of power relay coil and signal relay coil, synchronous driving mode to realize contact feedback and electrical interlocking, and eliminate the possibility of two-phase or more contacts closed at the same time;

[0044] 5、The patent utilizes the commutation between thyristor and contact, the thyristor only participates in the moment, thus achieving the purpose of fast process control and no need of high power of the thyristor, and achieving the double effects of energy saving and speed;

[0045] 6、The application utilizes the characteristics of current zero point and natural zero of the thyristor current, realizes the non-arc opening and non-arc closing of all power contacts in the main circuit, and improves the electrical life of the contact to the mechanical life of 100,000 levels;

[0046] 7、The application does not adopt a voltage transformer, but separately draws the actuation time of the magnetic latching relay as the actuation time, and controls the closing time of the commutation operation in the commutation operation to be near the zero point of the phase voltage in the allowable time of the actuation time, and adds the rapidity of the relay itself, so that the closing has no impact and the volume is reduced and the cost is lowered.

[0047] 8、The relays of the application are all fast types, and can realize the non-power-off of all household appliances under the premise of non-arc and interlocking, i.e. non-inductive commutation. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 is the main circuit structure diagram of the commutation switch of the application;

[0049] Figure 2 is the main circuit structure diagram of another structure of the commutation switch of the application;

[0050] Figure 3 is the principle diagram of the main circuit single contact magnetic latching relay of the application;

[0051] Figure 4 is the fast type double-coil magnetic latching signal relay of the application;

[0052] Figure 5 is the three-phase magnetic latching power relay interlocking circuit of the application;

[0053] Figure 6 is the commutation timing diagram of the application;

[0054] Figure 7 is the logic block diagram of the A-phase commutation to B-phase of the application;

[0055] REFERENCE NUMERALS:

[0056] 1, power relay closing operation coil; 2, signal relay closing operation coil; 3, power relay opening operation coil; 4, signal relay opening operation coil. DETAILED DESCRIPTION

[0057] The following will be described in detail with reference to the accompanying drawings. Figure 1 to Figure 7The specific embodiments of the present application are described in detail. It should be noted that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0058] In the description of the present application, it should be noted that the terms "one end", "left side" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only used for the purpose of facilitating the description of the present application and simplifying the description, and do not indicate or imply that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "one", "two" are only for the purpose of description, and cannot be understood as indicating or implying relative importance. Embodiment one

[0059] The present application provides a magnetic household phase change switch, which is installed at the end of the distribution network in the transformer area, such as in the electric meter box before the electric meter; It is installed by card rail type or other quick installation method; It includes relays JDQa, JDQb and JDQc; As shown in Figure 1 , Figure 2 One end of the main contact CD-A, CD-B and CD-C of the relay JDQa, JDQb and JDQc is connected to the A phase, B phase and C phase of the incoming line, and the other end of the CD-A, CD-B and CD-C is connected to the common terminal, which is connected to the main contact CD-D of the relay JDQd, and the CD-D is provided with a bidirectional thyristor SCR in parallel, and the JDQa, JDQb, JDQc, JDQd and SCR are controlled by a single chip microcomputer (MCU); Due to the limitation of volume and the need to ensure the current carrying capacity and short circuit resistance, the relays JDQa, JDQb, JDQc and JDQd adopt magnetic latching relays, and the magnetic latching relays can only be selected as single main contact type, and the main contact has no auxiliary feedback contact. This patent selects the normally open single main contact type; The common terminal of the output end of the CD-D and the SCR is provided with a current measuring device, which is used for current measurement; The current measuring device adopts a resistor as shown in Figure 1 , Figure 2The current transformer CT is shown; when a resistor is used, preferably a manganese copper sheet type resistor with a resistance of 100uΩ-500uΩ, when a resistor is used, it can not only be used for current measurement, but also limit the short circuit current; the manganese copper sheet type resistor with a resistance of 100uΩ-500uΩ is used, and the current limiting is to limit the short circuit circuit after the short circuit occurs, because the system power voltage is certain, increasing the resistance in the loop can limit the short circuit current; the present application is used for the last end of the transformer distribution network, as is well known, the front end of the last end of the transformer distribution network has a meter front switch, the rear end has a meter rear switch and a micro breaker of the household, a total of 3 levels of current limiting circuit breakers, the short circuit current will be arc extinguished within half a cycle, which is consistent with the requirements of the related standard UC2 level detection, for the instantaneous huge energy, it will not affect the overall current of the family; when the current transformer CT is used, a main current direct through type current transformer is used.

[0060] Figure 3 The component principle diagram of the main loop single touch point magnetic latching relay in Figure 1 、 Figure 2 is shown, each single touch point magnetic latching relay is a double coil driving mode, wherein Vcc is the common end of the coil, connected to the positive end of the driving power supply, such as 5V, 12V, etc.; the left coil Coil-h is a combined operation driving coil, and the right coil Coil-f is a split operation driving coil; the lower CD is a normally open single touch point; when Coil-h pulse passes through, CD is closed, and after the pulse ends, the state of CD is maintained; when Coil-f pulse passes through, CD is opened, and after the pulse ends, the state of CD is maintained; as can be seen, the magnetic latching relay only needs driving power at the moment of action, and its state maintenance is the key to the low power consumption of the product; Figure 3 The CD in corresponds to the main touch point CD-A, CD-B, CD-C, CD-D of each relay in Figure 1 and Figure 2 .

[0061] The present application uses a fast type double coil magnetic latching signal relay to complete the electrical interlocking in Figure 1 and Figure 2 , the signal relay is small in size, small in power, fast in action speed, and the response time is ≤2ms; the component principle diagram is as shown in Figure 4 , 2 coils respectively represent relay action and reset, each having 2 pairs of normally open points and normally closed points, the present application selects to use the normally closed points for interlocking, represented by nc, and the normally open touch points are used for state detection, represented by no.

[0062] The CD-A, CD-B and CD-C are driven by the power relay combination operation coil 1 and the power relay separation operation coil 3, the power relay combination operation coil 1 is arranged in parallel with the signal relay combination operation coil 2, the power relay separation operation coil 3 is arranged in parallel with the signal relay separation operation coil 4, and the signal relay combination operation coil 2 and the signal relay separation operation coil 4 are used to drive the double contacts of the signal relay; wherein the A-phase combination operation instruction input end is connected in series with a normally closed contact in the signal relay contacts of the B-phase and the C-phase, the B-phase combination operation instruction input end is connected in series with a normally closed contact in the signal relay contacts of the A-phase and the C-phase, and the C-phase combination operation instruction input end is connected in series with a normally closed contact in the signal relay contacts of the A-phase and the B-phase; the signal relays of the A-phase, the B-phase and the C-phase are respectively configured with at least two normally closed contacts; the signal relay is an action state memory device, and the coil energization triggering condition is to perform combination operation on the corresponding phase relay, for example, when the JDQa performs combination operation, the corresponding A-phase signal relay coil is energized and acts, and remains in the action state until reset;

[0063] More specifically: the CD-A is driven by the power relay combination operation coil Coil-gl-a-h and the power relay separation operation coil Coil-gl-a-f, Coil-gl-a-h is connected in parallel with the signal relay combination operation coil Coil-xh-a-dz, Coil-gl-a-f is connected in parallel with the signal relay separation operation coil Coil-xh-a-fg, and Coil-xh-a-dz and Coil-xh-a-fg are used to drive the double contacts CD-a-nc1 and CD-a-nc2 of the A-phase signal relay; the A-phase combination operation instruction input end is connected in series with the normally closed contact CD-b-nc1 in the signal relay contacts of the B-phase and the normally closed contact CD-c-nc1 in the signal relay contacts of the C-phase;

[0064] The CD-B is driven by the power relay combination operation coil Coil-gl-b-h and the power relay separation operation coil Coil-gl-b-f, Coil-gl-b-h is connected in parallel with the signal relay combination operation coil Coil-xh-b-dz, Coil-gl-b-f is connected in parallel with the signal relay separation operation coil Coil-xh-b-fg, and Coil-xh-b-dz and Coil-xh-b-fg are used to drive the double contacts CD-b-nc1 and CD-b-nc2 of the B-phase signal relay; the B-phase combination operation instruction input end is connected in series with the normally closed contact CD-a-nc1 in the signal relay contacts of the A-phase and the normally closed contact CD-c-nc2 in the signal relay contacts of the C-phase;

[0065] The CD-C is driven by a power relay combined operation coil Coil-gl-c-h and a power relay separated operation coil Coil-gl-c-f, Coil-gl-c-h is connected in parallel with a signal relay combined operation coil Coil-xh-c-dz, Coil-gl-c-f is connected in parallel with a signal relay separated operation coil Coil-xh-c-fg, Coil-xh-c-dz and Coil-xh-c-fg are used to drive the double contacts CD-c-nc1 and CD-c-nc2 of the C-phase signal relay; the C-phase combined operation instruction input end is connected in series with the normally closed contact CD-a-nc2 in the signal relay contact of the A-phase and the normally closed contact CD-c-nc2 in the signal relay contact of the B-phase.

[0066] According to Figure 1 and Figure 2 , the three-phase incoming line has the possibility of simultaneous closing, and once the main circuit has two-phase or more relay main contacts simultaneously closed, it will inevitably cause inter-phase short circuit, resulting in short-circuit tripping accident; in order to avoid inter-phase short circuit, the above-mentioned electrical interlocking mechanism is designed, and the principle is: Figure 5 The circuit shown in the figure is Figure 1 and Figure 2 interlocking circuit designed for the power single-contact magnetic latching relay; wherein the large coils are the driving coils of the magnetic latching power relay, gl represents power, corresponding to the coil in Figure 3 , and its corresponding contact is also a power contact, that is, each CD signal in Figure 1 and Figure 2 ; the small coils are the driving coils of the magnetic latching signal relay, xh represents signal, corresponding to the coil in Figure 4 ; the coil of the power relay and the coil of the signal relay are directly connected in parallel and act synchronously; Coil-h and Coil-dz are connected in parallel, representing combined operation; Coil-f and Coil-fg are connected in parallel, representing separated operation; taking the A-phase as an example, only when the previous operation of the B-phase and the C-phase is not combined operation, can the two normally closed contacts of the A-phase combined operation instruction input end be in the closed state, and the A-phase can perform combined operation. If the previous operation of the B-phase is combined operation, the contacts CD-b-nc1 and CD-b-nc2 will be necessarily opened, and the A-phase and the C-phase combined operation instruction input end combined operation instruction input channel will be disconnected, thereby avoiding two-phase simultaneous closing and achieving the purpose of electrical interlocking.

[0067] Figure 6For the control principle of the commutation switch, taking switching from phase A to phase B as an example, the patent combines the current zero-crossing with the natural zero-crossing feature of the thyristor to ensure that no arc is generated when the main contact is opened; assuming that the magnetic holding power relay of the main circuit has a total operation time of T1, the power relay of the embodiment is generally measured to be about 2ms-4ms, of which the actuation time is ΔT1, and the measurement is 1.5ms-2ms, obviously T1 is greater than ΔT1; the total operation time of the closing operation is T2, the measurement of the embodiment is about 4.5ms-6ms, of which the actuation time is ΔT2, and the measurement is generally 3ms-4ms, obviously T2 is greater than ΔT2; the above T1, ΔT1, T2, ΔT2 corresponding to different types of power relays have different times.

[0068] When the MCU receives the instruction of switching from phase A to phase B, the JDQd sub-instruction and the SCR trigger instruction are issued at the first current zero-crossing after the current time, and the JDQd contact is opened at t0. Since the SCR is in parallel and in the on state, no arc is generated when the JDQd contact is opened, and the current is instantaneously commutated to the SCR thereafter.

[0069] At t1 before the next current zero-crossing t2, t1 is 8ms-9ms, the MCU issues the JDQa sub-instruction and stops triggering the SCR;

[0070] At the zero-crossing t2, t2 is 10ms, the JDQa is still in the actuation period, and the MCU issues the JDQb closing instruction at the same time;

[0071] At t3, t3 is about 11ms, the JDQa sub-operation is executed, and the contact is opened. At this time, since the SCR has been zero-crossed at the previous t2, the load current has naturally returned to zero, so the contact of the JDQa at t3 is also opened without arc, and the MCU can detect the current instantaneous value and the normally open contact of the A-phase relay at this time to ensure that the JDQa contact is indeed opened without arc and the synchronous contact is opened;

[0072] The subsequent t4 is the actuation time of the JDQb closing operation and the JDQd closing instruction. If the t3 detection is normal, the MCU output instruction at t4 does not need to be changed; if the t3 detection is not normal, such as detection of abnormal current or synchronous contact, the JDQb closing operation instruction pulse can be ended at t4;

[0073] Under the timing of normal execution of the instruction, the JDQb closing operation is executed at t5, and the contact is closed. Since the SCR is not triggered at this time, there is no current at this time;

[0074] At time t7, the JDQd operation is completed and its contacts close. At time t6, the SCR is retried by about 0.1ms, and the B-phase voltage is connected to the load, ensuring that there is no arc when the contacts close at time t7, and the commutation is completed.

[0075] In the main circuit described above, the total time for the power magnetic latching relays JDQX, X=a, b, c, and JDQd to operate separately is T1, and the total time for the operation to close is T2. , The error range is ±0.4ms; , , The error range is ±0.4ms. ; Figure 6 The specific values ​​corresponding to each time point t in the figure are for illustrative purposes only and should be based on actual measurements.

[0076] According to the timing sequence description, the load current returns to zero naturally at time t2 along with the SCR. At time t6, the SCR turns on and reconnects to the B-phase voltage. Subsequently, the B-phase relay contacts close at time t7. The entire current interruption time is [time missing]. That is, re-triggering SCR The time difference between the current at time t2 and the next current zero-crossing point t2 is measured to be 6ms-6.6ms in this embodiment. This interval will not cause power outages or shocks for any household appliances. At the same time, for the most common weakly inductive loads, the conduction at time t6 is just close to the zero-crossing point of the B-phase voltage, which basically achieves no impact at the moment of closing. Example 2

[0077] This embodiment provides a phase switching method for a magnetically latched in-home phase-change switch. Taking the switching from phase A to phase B as an example, the method includes the following steps:

[0078] S1: The MCU receives the commutation command to switch from phase A to phase B;

[0079] S2: Monitor whether the zero-crossing signal IN0 produces the first effective change, that is, monitor whether the first current zero-crossing point occurs from the current moment. If yes, jump to S3; otherwise, continue to execute S2. The core purpose of this step is to reduce switching losses and equipment impact.

[0080] S3: The MCU issues a JDQd instruction to trigger the SCR;

[0081] S4: Enable timer interrupt and clear timer JSQ; At time t0, the JDQd contact opens. Since there is an SCR in parallel and the SCR is in the ON state, no arc will be generated when the JDQd contact opens, and the current will be instantly switched to the SCR thereafter.

[0082] S5: judge whether the current value of the timer JSQ is greater than or equal to t1, t1 is the time before the next current zero point t2, if yes, execute S6, otherwise continue to execute S5;

[0083] S6: MCU sends the original phase relay JDQa split command to stop triggering the SCR;

[0084] S7: judge whether the current value of the timer JSQ is greater than or equal to the time of the next current zero point t2, if yes, jump to S8, otherwise continue to execute S7;

[0085] S8: send the relay JDQb closing command of the phase to be switched at the current zero point t2;

[0086] S9: judge whether the current value of the timer JSQ is greater than or equal to t3, t3 is the time after the next current zero point t2, if yes, jump to S10, otherwise continue to execute S9;

[0087] S10: the original phase relay JDQa contact opens, JDQa split operation is executed, its contact opens, at this time, since the SCR has been zero at the previous t2, the load current has naturally returned to zero, therefore, the contact of JDQa at t3 is also opened without arc, MCU judges whether the normally open contact no of the A-phase relay and the current instantaneous value at this time are 0, if yes, jump to S11, otherwise jump to S12;

[0088] S11: judge whether the current value of the timer JSQ is greater than or equal to t4, if yes, jump to S13, otherwise jump to S12;

[0089] S12: after delaying 1ms, the original phase relay JDQa contact opens, judge whether the current of the original A-phase relay normally open contact no and the current instantaneous value at this time are 0, if yes, jump to S11, otherwise jump to S17;

[0090] S13: send the JDQd closing command;

[0091] S14: judge whether the current value of the timer JSQ is greater than or equal to t5, if yes, jump to S15, otherwise continue to execute S14;

[0092] S15: judge whether the relay JDQb closing operation of the phase to be switched is executed, if yes, jump to S16, otherwise jump to S17;

[0093] S16: judge whether the current value of the timer JSQ is greater than or equal to t6, if yes, re-trigger the SCR, the commutation is completed, otherwise continue to execute S16;

[0094] S17: cancel the relay JDQb closing command of the phase to be switched;

[0095] S18: Timer JSQ is cleared, and commands to close the original phase relays JDQa and JDQd are issued; switch to the original phase to prevent power outages for users;

[0096] S19: Commutation failure, alarm issued.

[0097] In this embodiment, the total time for the opening operation of the power magnetic latching relay JDQX, X=a, b, c, JDQd in the main circuit is T1, and the total time for the closing operation is T2. , The error range is ±0.4ms; , , The error range is ±0.4ms; when switching phases in the positive sequence, the overall commutation time during the phase switching process is: 6.67ms + the phase difference between voltage and current, where the phase difference between voltage and current is 0.1ms~0.7ms, which is basically at the zero crossing point of the voltage to be commutated for a conventional weakly inductive load; better than the 15ms described in patent application number 201910213058.7.

[0098] That is, the voltage zero-crossing points of the three phases differ by 6.67ms. The voltage zero-crossing point of phase B lags behind the voltage zero-crossing point of phase A by 6.67ms. As for the weakly inductive load for household appliances, the current of phase A lags slightly behind the voltage of phase A by 0.1ms to 0.7ms. Therefore, the zero-crossing point of phase B voltage differs from the zero-crossing point of phase A current by about 6ms or slightly more. The purpose is to ensure that there is no impact on the time when the load is re-energized. This is also the reason why this application uses the current zero-crossing point instead of the voltage zero-crossing point.

[0099] The aforementioned 6.67ms is based on a mature principle in existing technology, as explained below: The cycle of a 50Hz AC current is 20ms, and the three phases differ by 120°, which is exactly 1 / 3 of 360°. Therefore, the zero-crossing interval is 1 / 3 of 20ms, approximately equal to 6.67ms.

[0100] Preferably, in this embodiment, the ideal state of the circuit design is that the relay is closed and the SCR is immediately turned on, and the two actions are closely linked to avoid the circuit from being empty or abnormal, but because the closing time of the relay is long, and the conduction of the SCR is real-time control, if the SCR is triggered after the relay is actually closed, t6 will lag behind t7, and cannot follow closely; therefore, t6 is triggered slightly in advance, and the real-time nature of the SCR is utilized, which can just link to t7 with delay, and it looks like t6 closely follows t7; specifically: t6 is the moment when the SCR is turned on instantly, relative to the relay, the SCR is real-time control, and the current path from the power supply to the load is formed at t6, thereby recharging the load, t7 closely follows t6, because the SCR itself is temporary and short, and the SCR cannot pass the load current for a long time, the closer t7 is to t6, the shorter the time the SCR alone bears the current, but because the relay will bounce when it is closed, the bounce time generally does not exceed 0.2 ms, and the actual measurement range is generally 0.05-0.2 ms, therefore, The relays JDQa, JDQb and JDQc are power relays with magnetic retention.

[0101] In summary, the present application has the following advantages:

[0102] 1. The present application realizes phase change switch in the household meter box, realizes small size, short installation time, small power outage range and no disturbance to the public; can be installed in the household meter box through card rail type installation and the like;

[0103] 2. The present application is designed at the end of the transformer area power distribution network, without considering the rain and dust prevention of outdoor, reducing the cost of the shell; similarly, because the fault current at the end is greatly limited, the present application only needs to meet the short-circuit current resistance of UC2 level, realizing the compatibility of small size and resistance;

[0104] 3. The present application uses a magnetic retention relay to realize the on-off control of the main circuit, only needs driving power at the moment of action, and basically does not consume driving power after the action is completed, which does not increase the electricity charge burden of the power grid and the user;

[0105] 4. The present application uses the parallel and synchronous driving mode of the power relay coil and the signal relay coil to realize contact feedback and electrical interlocking, and eliminates the possibility of simultaneous closing of two or more contacts;

[0106] 5. The present application uses the commutation between the SCR and the contact, and the SCR only participates momentarily, so as to achieve the purpose of process control and the SCR without high power, and achieve the dual effects of energy saving and speed;

[0107] 6. By using the current zero-crossing and the natural zero-crossing of the thyristor current, all power contacts of the main circuit are opened and closed without arc, and the electrical life of the contacts is improved to 100,000 times of the mechanical life;

[0108] 7. The application does not use a voltage transformer, but separately draws the action time of the magnetic latching relay as a trigger time, and the closing time of the phase change operation is controlled near the zero-crossing point of the phase voltage within the allowed time of the trigger time, and the relay itself is fast, and the closing time is realized without impact through timing control, and the volume is reduced and the cost is reduced.

[0109] 8. The relays of the application are fast, and can realize the uninterrupted power supply of all household appliances under the premise of arcless and interlocking, that is, inductive phase change.

[0110] In the specification provided by the application, a large number of specific details are described; however, it can be understood that the embodiments of the application can be practiced without these specific details, and in some examples, well-known methods, structures and techniques are not described in detail in order not to obscure the understanding of the specification.

[0111] Similarly, it should be understood that, in order to simplify the disclosure and help understand one or more of the various inventive aspects, in the above description of the exemplary embodiments of the application, various features of the application are sometimes grouped together in a single embodiment, figure, or description thereof; however, the method of the disclosure should not be interpreted as reflecting the intention that the claimed application requires more features than the features explicitly recorded in each claim. More precisely, as reflected in the following claims, the inventive aspects are in less than all the features of the previously disclosed single embodiment. Therefore, the claims following the specific embodiments are hereby expressly incorporated into the specific embodiments, wherein each claim itself is a separate embodiment of the application.

[0112] In addition, those skilled in the art can understand that although some embodiments described herein include certain features included in other embodiments rather than other features, the combination of features of different embodiments means within the scope of the application and forms different embodiments. For example, in the claims, any one of the claimed embodiments can be used in any combination.

[0113] It should be noted that the above-mentioned embodiments illustrate rather than limit the application, and that one skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word 'comprising' does not exclude the presence of elements or steps other than those listed in a claim. The word 'a' or 'an' preceding an element does not exclude the presence of a plurality of such elements. The application can be implemented by means of both hardware and software, and any combination thereof. In a unit claim, several devices can be listed with a comma. The use of the term 'about' along with a numerical value modifies that value, for example, 'about 5 minutes' means '5 minutes ± 0.5 minutes'. The word 'comprise', and variations such as 'comprising', 'comprises' and 'comprised of', when used in this document are used on the basis and understanding that they do not exclude the presence of other elements or additional steps.

[0114] To the extent various modifications and alterations of the application have been discussed herein, it will be appreciated that numerous variations on the described embodiments are possible. Accordingly, it is intended that all such alterations and modifications be considered as falling within the spirit and scope of the application.

[0115] The preferred embodiments of the application have been described above in detail with reference to the accompanying drawings, while the application is not limited to the above examples. Numerous modifications and alterations can be made to the application without departing from the spirit and scope of the application.

[0116] It should be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner, provided that there is no contradiction, and various possible combinations of the application will not be described again in order to avoid unnecessary repetition.

[0117] In addition, any combination of the various embodiments of the application can also be made, provided that it does not deviate from the idea of the application, and the application should also be considered as disclosed.

Claims

1. A magnetic latching phase-change switch for household, comprising relays JDQa, JDQb, JDQc, one end of main contacts CD-A, CD-B, CD-C of the relays JDQa, JDQb, JDQc is connected to A phase, B phase, C phase of incoming line respectively, the other end of the main contacts CD-A, CD-B, CD-C is connected to a common terminal, the common terminal is connected to main contact CD-D of relay JDQd, the main contact CD-D is provided with bidirectional thyristor SCR in parallel, a current measuring device is arranged on the common terminal of the output terminals of the main contact CD-D and the bidirectional thyristor SCR; characterized in that, The CD-A, CD-B and CD-C are driven by a power relay combination operation coil (1) and a power relay separation operation coil (3), the power relay combination operation coil (1) is arranged in parallel with a signal relay combination operation coil (2), the power relay separation operation coil (3) is arranged in parallel with a signal relay separation operation coil (4), the signal relay combination operation coil (2) and the signal relay separation operation coil (4) are used for driving double contacts of a signal relay; wherein a normally closed contact in the signal relay contacts of the B phase and the C phase is connected in series to the A phase combination operation instruction input end, a normally closed contact in the signal relay contacts of the A phase and the C phase is connected in series to the B phase combination operation instruction input end, and a normally closed contact in the signal relay contacts of the A phase and the B phase is connected in series to the C phase combination operation instruction input end; The CD-A is driven by a power relay combination operation coil Coil-gl-a-h and a power relay separation operation coil Coil-gl-a-f, Coil-gl-a-h is connected in parallel with a signal relay combination operation coil Coil-xh-a-dz, Coil-gl-a-f is connected in parallel with a signal relay separation operation coil Coil-xh-a-fg, Coil-xh-a-dz and Coil-xh-a-fg are used for driving double contacts CD-a-nc1 and CD-a-nc2 of an A phase signal relay; a normally closed contact CD-b-nc1 in the signal relay contacts of the B phase is connected in series to the A phase combination operation instruction input end, and a normally closed contact CD-c-nc1 in the signal relay contacts of the C phase is connected in series to the A phase combination operation instruction input end; The CD-B is driven by a power relay combination operation coil Coil-gl-b-h and a power relay separation operation coil Coil-gl-b-f, Coil-gl-b-h is connected in parallel with a signal relay combination operation coil Coil-xh-b-dz, Coil-gl-b-f is connected in parallel with a signal relay separation operation coil Coil-xh-b-fg, Coil-xh-b-dz and Coil-xh-b-fg are used for driving double contacts CD-b-nc1 and CD-b-nc2 of a B phase signal relay; a normally closed contact CD-a-nc1 in the signal relay contacts of the A phase is connected in series to the B phase combination operation instruction input end, and a normally closed contact CD-c-nc2 in the signal relay contacts of the C phase is connected in series to the B phase combination operation instruction input end; The CD-C is driven by the power relay combined operation coil Coil-gl-c-h and the power relay separated operation coil Coil-gl-c-f, Coil-gl-c-h is connected in parallel with the signal relay combined operation coil Coil-xh-c-dz, Coil-gl-c-f is connected in parallel with the signal relay separated operation coil Coil-xh-c-fg, Coil-xh-c-dz and Coil-xh-c-fg are used to drive the double contacts CD-c-nc1 and CD-c-nc2 of the C-phase signal relay; the C-phase combined operation instruction input end is connected in series with the normally closed contact CD-a-nc2 in the signal relay contact of the A-phase and the normally closed contact CD-c-nc2 in the signal relay contact of the B-phase.

2. A magnetic latching phase changing switch for use in a household appliance according to claim 1, characterized in that The current measuring device adopts a manganese copper sheet type resistor R.

3. A magnetic latching phase-changing switch for use in a household appliance according to claim 1, characterized in that, The current measuring device adopts a current transformer CT, and the current transformer CT adopts a main current direct through type current transformer.

4. A magnetic latching phase-changing switch for use in a household appliance according to claim 1, characterized in that, The magnetic holding indoor type commutator switch is installed at the end of the transformer area power distribution network.

5. A magnetic latching phase-changing switch for use in a household appliance according to claim 4, characterized in that The indoor type commutator switch is installed at the end of the transformer area power distribution network through a card rail type installation method.

6. A commutation method for a magnetic latching phase-change switch according to any one of claims 1 to 5, characterized in that, The method comprises the following steps: S1: receiving a commutation instruction; S2: monitoring whether the first effective displacement of the zero-crossing signal IN0 is generated, if yes, jumping to S3, otherwise, continuing to execute S2; S3: issuing a JDQd sub-instruction to trigger the SCR; S4: enabling the timer interrupt, and clearing the timer JSQ; at t0, the JDQd contact is opened; S5: judging whether the current value of the timer JSQ is greater than or equal to t1, t1 is the time before the next current zero-crossing point t2, if yes, executing S6, otherwise, continuing to execute S5; S6: issuing a JDQX sub-instruction of the original phase relay to stop triggering the SCR; wherein, X=a, b, c; S7: judging whether the current value of the timer JSQ is greater than or equal to the time of the next current zero-crossing point t2, if yes, jumping to S8, otherwise, continuing to execute S7; S8: issuing a JDQX closing instruction of the to-be-switched phase relay at the current zero-crossing point t2; S9: judging whether the current value of the timer JSQ is greater than or equal to t3, t3 is the time after the next current zero-crossing point t2, if yes, jumping to S10, otherwise, continuing to execute S9; S10: the JDQX contact of the original phase relay is opened, and judging whether the current of the normally open contact no of the original phase signal relay and the current instantaneous value at the time are 0, if yes, jumping to S11, otherwise, jumping to S12; S11: judging whether the current value of the timer JSQ is greater than or equal to t4, if yes, jumping to S13, otherwise, jumping to S12; S12: after delaying for 1 ms, the JDQX contact of the original phase relay is opened, and judging whether the current of the normally open contact no of the original phase signal relay and the current instantaneous value at the time are 0, if yes, jumping to S11, otherwise, jumping to S17; S13: issuing a JDQd closing instruction; S14: judging whether the current value of the timer JSQ is greater than or equal to t5, if yes, jumping to S15, otherwise, continuing to execute S14; S15: judge whether the relay JDQX of the phase to be switched is executed or not, if yes, jump to S16, if not, jump to S17; S16: judge whether the current value of the timer JSQ is greater than or equal to t6, if yes, re-trigger the SCR, the JDQd contact is closed at t7, and the phase switching is completed; otherwise, continue to execute S16; S17: cancel the relay JDQX of the phase to be switched; S18: clear the timer JSQ, and issue the JDQX and JDQd closing command of the original phase relay; S19: phase switching fails, and an alarm is given; In the main circuit, the power magnetic latching relay JDQX (X=a, b, c, JDQd) is divided into two operation processes with a time T1 and a combined operation process with a time T2. , .

7. A commutation method for a magnetic latching line switch according to claim 6, characterized in that The value range is .

8. A commutation method for a magnetic latching line switch according to claim 6, characterized in that, When the phase switching is in the positive sequence, the overall phase switching time in each phase switching process is 6.67 ms+the phase difference between the voltage and the current, wherein the phase difference between the voltage and the current ranges from 0.1 ms to 0.7 ms.

9. A commutation method for a magnetic latching line switch according to claim 6, characterized in that, The relays JDQX, X=a, b, c and JDQd are power relays with magnetic retention.

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