Switching control system

Abstract

A switching control system includes: a plurality of switching units configured to respectively receive one of a plurality of alternating currents and to be coupled to a load; a detection unit configured to detect each of the alternating currents; and a control unit configured to, after receiving the switching signal, in response to detecting that the power supply alternating current and the standby alternating current in the alternating current are both in a polarity half cycle and the voltage difference between the power supply alternating current and the standby alternating current is less than a preset voltage, execute the following steps: closing a first conduction direction of the power supply switch unit; starting a second conduction direction of the standby switch unit; closing the second conduction direction of the power supply switch unit; the first conduction direction of the standby switch unit is started; wherein the first conduction direction is opposite to the direction of the polarity half cycle, and the second conduction direction is the same as the direction of the polarity half cycle.

Description

Technical Field

[0001] The present disclosure relates to a switching control system, and in particular to a switching control system using a bidirectional switch. Background Art

[0002] In order to ensure the stability of power supply of electronic equipment and minimize the power supply cost, it is usually necessary to manage the power supply, and automatic switching is one of the core of power management. However, automatic switching switches traditionally use relays as their switches. Due to the mechanical structure characteristics of relays, they are prone to problems such as long switching time and inability to withstand large transient currents. In addition, according to the inventor's knowledge, some automatic switching switch structures are composed of relays, silicon controlled rectifiers (SCRs), and diodes. This structure uses SCRs to withstand transient currents and adds diodes to the conduction path. The forward bias and internal resistance of the diodes suppress transient currents. This structure increases the number of components. Some automatic switching switch structures are composed of relays, SCRs, transistor switches, and diodes. The transistor switches have the ability to cut off when large currents flow and a shorter switching time. The diodes are used to prevent reverse currents. This structure requires additional diodes to prevent reverse currents from flowing through the transistor switches, thereby increasing the number of components. Some automatic switching switch structures are composed of a rectifier circuit and two sets of transistor switches connected in parallel with diodes. The AC power supply is rectified into a DC power with a lower voltage by the rectifier circuit. This allows the circuit components to withstand a lower voltage, but this structure needs to consider the rectifier circuit components. Summary of the invention

[0003] In view of this, some embodiments of the present invention provide a switching control system, which enables the circuit to maintain normal operation during the switching process through its architecture and control circuit, thereby achieving uninterrupted power supply, thereby improving the problems of the prior art.

[0004] Some embodiments of the present invention provide a switching control system, comprising: a plurality of switch units, configured to respectively receive one of a plurality of alternating currents and a coupled load; a detection unit, configured to detect each of the alternating currents; and a control unit, configured to, after receiving a switching signal, in response to detecting that the power supply alternating current and the backup alternating current in the alternating currents are both within a polarity half-cycle and the voltage difference between the two is less than a preset voltage, execute: turning off the first conduction direction of the power supply switch unit of the power supply alternating current; turning on the second conduction direction of the backup switch unit of the backup alternating current; turning off the second conduction direction of the power supply switch unit; and turning on the first conduction direction of the backup switch unit; wherein the first conduction direction of the power supply switch unit and the backup switch unit is opposite to the direction of the polarity half-cycle, the second conduction direction of the power supply switch unit and the backup switch unit is the same as the direction of the polarity half-cycle, and the power supply switch unit and the backup switch unit are included in the switch units.

[0005] In some embodiments of the present invention, a pair of transistor switches are connected in reverse series to form a bidirectional switch unit, replacing traditional relays and SCRs.

[0006] Based on the above, some embodiments of the present invention provide a switching control system, which can prevent the AC power supply from short-circuiting and maintain normal operation during the switching process by first shutting down the first conduction direction of the power switch unit of the power supply AC and simultaneously maintaining the second conduction direction of the backup switch unit of the backup AC power open before the second conduction direction of the backup switch unit is opened, thereby achieving the effect of uninterrupted power supply. In addition, since the switching control system uses a bidirectional switch to replace the traditional relay (relay) and silicon controlled rectifier (silicon controlled rectifier, SCR), its architecture is simple, so the power supply AC and the backup AC can be quickly switched through the aforementioned switching control system to achieve a backup function. Some embodiments of the present invention are composed of a pair of transistor switches connected in reverse series to form a bidirectional switch unit, which replaces the traditional relay and SCR, and does not require an additional diode to prevent reverse current. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a block diagram of a switching control system according to an embodiment of the present invention;

[0008] Figure 2 is a circuit block diagram of a switching control system according to some embodiments of the present invention;

[0009] Figure 3 is a schematic diagram of switch unit control according to some embodiments of the present invention;

[0010] Figure 4 is a schematic diagram of voltage and current switching according to some embodiments of the present invention;

[0011] Figure 5 is a schematic diagram of switch unit control according to some embodiments of the present invention;

[0012] Figure 6 is a schematic diagram of voltage and current switching according to some embodiments of the present invention;

[0013] Figure 7 is a circuit block diagram of a power switch unit according to some embodiments of the present invention;

[0014] Figure 8 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention;

[0015] Fig. 9 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention;

[0016] Fig.10 is a block diagram of a standby switch unit circuit according to some embodiments of the present invention;

[0017] Fig.11 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention;

[0018] Fig.12 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention;

[0019] Fig.13 is a circuit block diagram of a power switch unit and a standby switch unit according to some embodiments of the present invention;

[0020] Fig.14 is a schematic diagram of switch unit control according to some embodiments of the present invention;

[0021] Fig.15 is a circuit block diagram of a switching control system according to some embodiments of the present invention;

[0022] Fig.16 is a schematic diagram of switch unit control according to some embodiments of the present invention;

[0023] Fig.17 is a schematic diagram of switch unit control according to some embodiments of the present invention;

[0024] Fig.18 is a circuit block diagram of a power switch unit according to some embodiments of the present invention;

[0025] Fig.19 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention;

[0026] Fig. 20 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention;

[0027] Fig.21 is a circuit block diagram of a power switch unit according to some embodiments of the present invention;

[0028] Fig. 22 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention;

[0029] Fig.23 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention;

[0030] Fig.24 is a circuit block diagram of a power switch unit according to some embodiments of the present invention;

[0031] Fig.25 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention;

[0032] Fig.26 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention;

[0033] Fig. 27 is a block diagram of a standby switch unit circuit according to some embodiments of the present invention;

[0034] Fig.28 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention;

[0035] Fig.29 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention;

[0036] Fig.30 is a block diagram of a standby switch unit circuit according to some embodiments of the present invention;

[0037] Fig.31 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention;

[0038] Fig.32 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention;

[0039] Fig.33 is a block diagram of a standby switch unit circuit according to some embodiments of the present invention;

[0040] Fig.34 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention;

[0041] Fig.35 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention;

[0042] Fig.36 is a circuit diagram of a voltage detection circuit according to some embodiments of the present invention;

[0043] Fig.37 is a flow chart of a switching control method according to an embodiment of the present invention;

[0044] Fig.38A as well as Fig.38B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention;

[0045] Fig.39A as well as Fig.39B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention;

[0046] Fig.40A as well as Fig.40B is a schematic diagram of a control method of a standby switch unit according to some embodiments of the present invention;

[0047] Fig.41A as well as Fig.41B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention;

[0048] Fig.42A as well as Fig.42B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention;

[0049] Fig.43A as well as Fig.43B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention;

[0050] Fig.44A as well as Fig.44B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention;

[0051] Fig.45A as well as Fig.45B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention;

[0052] Fig.46A as well as Fig.46B is a schematic diagram of a control method of a standby switch unit according to some embodiments of the present invention;

[0053] Fig.47A as well as Fig.47Bis a schematic diagram of a control method of a standby switch unit according to some embodiments of the present invention;

[0054] Fig.48A as well as Fig.48B is a schematic diagram of a control method of a standby switch unit according to some embodiments of the present invention;

[0055] Fig.49A as well as Fig.49B is a schematic diagram of a backup switch unit control method according to some embodiments of the present invention.

[0056]

Explanation of symbols

[0057] 100: Switch control system

[0058] 101-1~101-N: Switching unit

[0059] N: positive integer

[0060] 102: Detection Unit

[0061] 103: Control unit

[0062] 104: Load

[0063] 105-1~105-N: alternating current

[0064] 102-1,102-2: Voltage detection module

[0065] 10111,10112,10121,10122,701,702,1001,1002,1301,1302,1303,1304,1501,1502,1503,1504,1505,1506,1507,1508,1801,1802,1803,1804,2101,2102,2103,2104,2401,2402,2403,2404,2701,2702,2703,2704,3001,3002,3003,3004,3301,3302,3303,3304: transistor

[0066] 201,1509:First phase line

[0067] 202,1511: Second phase line

[0068] 203: Neutral line

[0069] Vin: Voltage

[0070] Iin: current

[0071] t: time

[0072] t1,t2,t3,t4,tw,ts: time points

[0073] 1510: First neutral line

[0074] 1512: Second neutral line

[0075] 3600: Voltage detection circuit

[0076] 3601,3602:Amplifier

[0077] 3603,3604,3605,3606,R1,R2: resistor

[0078] Vcc: supply voltage

[0079] Vref: reference voltage

[0080] S3701~S3706: Steps DETAILED DESCRIPTION

[0081] The aforementioned and other technical contents, features and effects of the present invention will be clearly presented in the following detailed description of the embodiments with reference to the accompanying drawings. The thickness or size of each element in the accompanying drawings is expressed in an exaggerated, omitted or schematic manner for the understanding and reading of people familiar with this technology, and the size of each element is not completely its actual size, and is not used to limit the limiting conditions for the implementation of the present invention, so it has no technical substantive significance. Any structural modification, change in proportional relationship or adjustment of size, without affecting the effects and purposes that can be achieved by the present invention, should still fall within the scope of the technical content disclosed by the present invention. The same reference numerals will be used to represent the same or similar elements in all drawings.

[0082] Figure 1 is a block diagram of a switching control system according to an embodiment of the present invention. Figure 1 The switching control system 100 includes a plurality of switch units 101-1 to 101-N, a detection unit 102 and a control unit 103, wherein N is a positive integer. The plurality of switch units 101-1 to 101-N are configured to receive one of a plurality of alternating currents 105-1 to 105-N, respectively, for example, the switch unit 101-1 is coupled to the alternating current 105-1, and the switch unit 101-2 is coupled to the alternating current 105-2. The switch units 101-1 to 101-N are configured to couple to the load 104. The control unit 103 may be implemented by a digital microcontroller or an analog controller, which is not limited by the present invention. The detection unit 102 is configured to detect the voltage and current of each of the alternating currents 105-1 to 105-N.

[0083] Each of the multiple switch units 101-1 to 101-N has two conduction directions. For example, the two conduction directions of the switch unit 101-1 are: the direction from the AC power 105-1 to the load 104 and the direction from the load 104 to the AC power 105-1. The two conduction directions of the other switch units 101-1 to 101-N are similar. The control unit 103 can turn on and off the two conduction directions of each of the multiple switch units 101-1 to 101-N by issuing a control signal. For example, the control unit 103 can simultaneously turn on the direction from the AC power 105-1 to the load 104 and the direction from the load 104 to the AC power 105-1 of the switch unit 101-1 by issuing a control signal; the control unit 103 can also turn on the direction from the AC power 105-1 to the load 104 of the switch unit 101-1 but turn off the direction from the load 104 to the AC power 105-1 by issuing a control signal.

[0084] Each of the AC currents 105-1 to 105-N is an AC current of the same frequency and amplitude, but the phases of the AC currents 105-1 to 105-N may be different. In some embodiments of the present invention, N=2 and the phase difference between the AC current 105-1 and the AC current 105-2 is 120 ° .

[0085] The following will describe in detail the switching control methods of some embodiments of the present invention and how the various modules of the switching control system 100 work in coordination with the accompanying drawings.

[0086] Fig.37 is a flow chart of a switching control method according to some embodiments of the present invention. Figure 1 and Fig.37 In this embodiment, the control unit 103 is configured to execute after receiving a switching signal. Fig.37Steps S3701 to S3706 are shown. In step S3701, the control unit 103 detects the power supply AC power and the backup AC power in the AC power 105-1 to 105-N through the detection unit 102. Among them, the power supply AC power is the power supply that is currently supplying power to the load 104, and the backup AC power is the power supply that will replace the power supply AC power to supply power to the load 104. In the following description, AC power 105-1 will be used as the power supply AC power and AC power 105-2 will be used as the backup AC power. In step S3702, the control unit 103 determines whether the power supply AC power and the backup AC power are both detected to be in a polarity half cycle and the voltage difference between the two is less than a preset voltage (that is, the similar point of the two voltages is detected). If yes, the control unit 103 executes step S3703 in response to detecting that both the power supply AC power and the backup AC power are in a polarity half cycle and the voltage difference between the two is less than a preset voltage, wherein the aforementioned polarity half cycle is selected from one of the group consisting of a positive half cycle and a negative half cycle, that is, the polarity half cycle is the positive half cycle of the AC power or the negative half cycle of the AC power. In some embodiments of the present invention, the control unit 103 selects (or is set by an external signal) one of the positive half cycle or the negative half cycle as the aforementioned polarity half cycle before executing step S3701, so as to determine in step S3702 that both the power supply AC power and the backup AC power are in a polarity half cycle.

[0087] If the control unit 103 does not detect that the power supply AC power and the backup AC power are both in the same polarity half cycle (for example, both are in the positive half cycle or both are in the negative half cycle) and the voltage difference between the two is less than a preset voltage (that is, the power supply AC power and the backup AC power are not in the same polarity half cycle or the voltage difference between the two is not less than the aforementioned preset voltage), the control unit 103 continues to detect the power supply AC power and the backup AC power. In this embodiment, the control unit 103 obtains the voltage of the power supply AC power and the voltage of the backup AC power through the detection unit 102, and the control unit 103 then calculates the voltage difference between the voltage of the power supply AC power and the voltage of the backup AC power, and the control unit 103 then determines whether the aforementioned voltage difference is less than the aforementioned preset voltage. The control unit 103 obtains the current of the power supply AC power and the current direction of the backup AC power through the detection unit 102 to determine whether the power supply AC power and the backup AC power are both in a polarity half cycle.

[0088] In some embodiments of the present invention, after receiving the aforementioned switching signal, the control unit 103 selects one of the AC power supplies 105 - 1 to 105 -N as a backup AC power supply.

[0089] In step S3703, the control unit 103 turns off the first conduction direction of the power switch unit of the AC power supply (AC 105-1), wherein the power switch unit of the AC power supply is a switch unit coupled to the AC power supply, in this example, the switch unit 101-1. The first conduction direction of the power switch unit of the AC power supply is opposite to the direction of the polarity half cycle. The aforementioned first conduction direction is opposite to the direction of the polarity half cycle, which means that the first conduction direction of the power switch unit is opposite to the current flow direction of the polarity half cycle. Please refer to Figure 1 For example, if the polarity half cycle is a positive half cycle, the first conduction direction of the power switch unit is from the load 104 to the AC power 105-1; if the polarity half cycle is a negative half cycle, the first conduction direction of the power switch unit is from the AC power 105-1 to the load 104.

[0090] In step S3704, the control unit 103 turns on the second conduction direction of the backup switch unit of the backup AC power (AC power 105-2), wherein the backup switch unit of the backup AC power is a switch unit coupled to the backup AC power, in this example, the switch unit 101-2. The second conduction direction of the backup switch unit of the backup AC power is the same as the direction of the polarity half cycle. The second conduction direction of the backup switch unit of the backup AC power is the same as the direction of the polarity half cycle, which means that the second conduction direction of the backup switch unit is the same as the current flow direction of the polarity half cycle. Please refer to Figure 1 For example, if the polarity half cycle is a positive half cycle, the second conduction direction of the standby switch unit is from the AC power 105-1 to the load 104; if the polarity half cycle is a negative half cycle, the second conduction direction of the standby switch unit is from the load 104 to the AC power 105-1.

[0091] In step S3705, the control unit 103 turns off the second conduction direction of the power switch unit, wherein the second conduction direction of the power switch unit supplying AC power is the same as the direction of the polarity half cycle. In step S3706, the control unit 103 turns on the first conduction direction of the standby switch unit, wherein the first conduction direction of the standby switch unit is opposite to the direction of the polarity half cycle.

[0092] In the above-mentioned embodiment, the first conduction direction of the power supply switch unit of the power supply AC is first turned off and the second conduction direction of the backup switch unit of the backup AC (AC 105-2) is kept open before the second conduction direction of the backup switch unit is turned on, which can prevent the AC power supply from short-circuiting and maintain normal operation during the switching process, thereby achieving the effect of uninterrupted power supply. In addition, since the switching control system 100 uses a bidirectional switch to replace the traditional relay and silicon controlled rectifier, its structure is simple, so through the switching control system 100 and Fig.37The switching control method described can quickly switch between the power supply AC power and the backup AC power to achieve a backup function.

[0093] Figure 2 is a circuit block diagram of a switching control system according to some embodiments of the present invention. Figure 1 as well as Figure 2 ,exist Figure 2 In the illustrated embodiment, the switching control system 100 receives AC power 105-1 from the outside as the power supply AC power, and receives AC power 105-2 from the outside as the backup AC power. The switching control system 100 includes a first phase line 201, a second phase line 202, and a neutral line 203. The first phase line 201 and the neutral line 203 are configured to receive the power supply AC power (AC power 105-1), and the second phase line 202 and the neutral line 203 are configured to receive the backup AC power (AC power 105-2). In this embodiment, the power supply switch unit of the power supply AC power is the switch unit 101-1, and the backup switch unit of the backup AC power is the switch unit 101-2. The voltage across the load 104 is Vin, and the current flowing through the load 104 is Iin.

[0094] In this embodiment, the detection unit 102 includes a voltage detection module 102-1 and a voltage detection module 102-2. The voltage detection module 102-1 is configured to detect the voltage of the AC power 105-1, and the voltage detection module 102-2 is configured to detect the voltage of the AC power 105-2.

[0095] The power supply switch unit (switch unit 101-1) includes a transistor 10111 (for the convenience of explanation, also referred to as the first transistor of the power supply switch unit hereinafter) and a transistor 10112 (for the convenience of explanation, also referred to as the second transistor of the power supply switch unit hereinafter); the standby switch unit includes a transistor 10121 (for the convenience of explanation, also referred to as the first transistor of the standby switch unit hereinafter) and a transistor 10122 (for the convenience of explanation, also referred to as the second transistor of the standby switch unit hereinafter), wherein the first transistor and the second transistor of the power supply switch unit are located on the first phase line 201 and are connected in reverse series, and the first transistor and the second transistor of the standby switch unit are located on the second phase line 202 and are connected in reverse series.

[0096] Figure 3 is a schematic diagram of switch unit control according to some embodiments of the present invention. Figure 4 is a schematic diagram of voltage and current switching according to some embodiments of the present invention. Fig.38A as well as Fig.38B It is a schematic diagram of a power switch unit control method according to some embodiments of the present invention. Fig.40A as well as Fig.40Bis a schematic diagram of a method for controlling a standby switch unit according to some embodiments of the present invention. Figure 2 , Figure 3 , Figure 4 , Fig.38A as well as Fig.40A In some embodiments of the present invention, the aforementioned polarity half cycle is a positive half cycle. The first transistor (transistor 10111) and the second transistor (transistor 10112) of the power switch unit are both NMOS, and the drain of the first transistor of the power switch unit receives the power supply AC, the source of the first transistor of the power switch unit is connected to the source of the second transistor of the power switch unit, and the drain of the second transistor of the power switch unit is connected to the load (the connection method of the first transistor (transistor 10111) and the second transistor (transistor 10112) of the power switch unit is called a common source connection). The first transistor (transistor 10121) and the second transistor (transistor 10122) of the standby switch unit are both NMOS, the drain of the first transistor of the standby switch unit receives the standby AC, the source of the first transistor of the standby switch unit is connected to the source of the second transistor of the standby switch unit, and the drain of the second transistor of the standby switch unit is connected to the load (that is, the first transistor (transistor 10121) and the second transistor (transistor 10122) of the standby switch unit also adopt a common source connection).

[0097] In this embodiment, the aforementioned step S3703 includes a first step, the aforementioned step S3705 includes a second step; the aforementioned step S3704 includes a third step, and the aforementioned step S3706 includes a fourth step (the aforementioned first step, second step, third step, and fourth step are only used to distinguish the steps and have no order significance). In the first step, the control unit 103 sends a cutoff signal (such as Fig.38A The “╳” shown in the figure is used to turn off the gate of the first control transistor in the power switch unit to turn off the first control transistor in the power switch unit. Since the polarity half cycle is a positive half cycle, the first control transistor of the power switch unit is the second transistor in the power switch unit. In this embodiment, the aforementioned cut-off signal is a low voltage signal. Figure 3 As shown, t represents time. At time point t1, the voltage received by the gate of the second transistor (transistor 10112) in the power switch unit is a low voltage, and the second transistor (transistor 10112) in the power switch unit is cut off from time point t1. At this time, since the second transistor (transistor 10112) in the power switch unit is in the cut-off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the positive half-cycle) is turned off. It is worth noting that at this time, since the first transistor in the power switch unit is still turned on (such as Fig.38ATherefore, the second conducting direction of the power switch unit is still turned on.

[0098] In the second step, the control unit 103 sends a cut-off signal (eg Fig.38A The “╳” shown in the figure is used to turn off the gate of the second control transistor in the power switch unit to turn off the second control transistor in the power switch unit. Since the polarity half cycle is a positive half cycle, the second control transistor in the power switch unit is the first transistor in the power switch unit. Figure 3 As shown, at time point t3, the voltage received by the gate of the first transistor (transistor 10111) in the power switch unit is a low voltage, and the first transistor (transistor 10111) in the power switch unit is cut off after time point t3. At this time, since the first transistor (transistor 10111) and the second transistor (transistor 10112) in the power switch unit are both in the cut-off state, the first conduction direction and the second conduction direction of the power switch unit are both closed.

[0099] In the third step, the control unit 103 sends a conduction signal (such as Fig.40A The illustrated "○" is given to the gate of the first control transistor in the standby switch unit to turn on the first control transistor in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistor of the standby switch unit is the first transistor (transistor 10121) of the standby switch unit. In this embodiment, the aforementioned turn-on signal is a high voltage signal. Figure 3 As shown, at time point t2, the voltage received by the gate of the first transistor (transistor 10121) of the standby switch unit is a high voltage, and the first transistor (transistor 10121) of the standby switch unit starts to conduct after time point t2. At this time, since the first transistor (transistor 10121) of the standby switch unit is in the on state, the second conduction direction of the standby switch unit (i.e., the direction of the positive half cycle) is turned on. It is worth noting that at this time, since the second transistor (transistor 10112) in the standby switch unit is still off (as shown in FIG. 1 ), the second conduction direction of the standby switch unit (i.e., the direction of the positive half cycle) is turned on. Fig.40A Therefore, the first conducting direction of the standby switch unit is still closed.

[0100] In the fourth step, the control unit 103 sends a conduction signal (such as Fig.40A The illustrated "○" is given to the gate of the second control transistor in the standby switch unit to turn on the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the second control transistor of the standby switch unit is the second transistor (transistor 10122) of the standby switch unit. Figure 3As shown, at time point t4, the voltage received by the gate of the second transistor (transistor 10122) of the standby switch unit is a high voltage, and the second transistor (transistor 10122) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 10121) and the second transistor (transistor 10122) in the standby switch unit are both in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0101] See also Figure 4 Since the control unit 103 receives the switching signal before the time point tw, and detects at the time point tw that the power supply AC power and the standby AC power are both in the positive half cycle and the voltage difference between the two is less than a preset voltage, the switching control method S3703 to S3706 is executed. It can be seen from the switching waveforms of the voltage Vin and the current Iin that the power supply is not interrupted during the switching period.

[0102] Figure 5 is a schematic diagram of switch unit control according to some embodiments of the present invention. Figure 6 is a schematic diagram of voltage and current switching according to some embodiments of the present invention. Figure 2 , Figure 5 , Figure 6 , Fig.38B as well as Fig.40B In some embodiments of the present invention, the aforementioned polarity half cycle is a negative half cycle, the aforementioned step S3703 includes a first step, the aforementioned step S3705 includes a second step; the aforementioned step S3704 includes a third step, and the aforementioned step S3706 includes a fourth step. In the first step, the control unit 103 sends a cutoff signal (such as Fig.38B The “╳” shown in the figure is used to turn off the gate of the first control transistor in the power switch unit to turn off the first control transistor in the power switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistor of the power switch unit is the first transistor in the power switch unit. In this embodiment, the aforementioned cut-off signal is a low voltage signal. Figure 5 As shown, at time point t1, the voltage received by the gate of the first transistor (transistor 10111) in the power switch unit is a low voltage, and the first transistor (transistor 10111) in the power switch unit is cut off from time point t1. At this time, since the first transistor (transistor 10111) in the power switch unit is in the cut-off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the negative half-cycle) is turned off. It is worth noting that at this time, since the second transistor in the power switch unit is still turned on (such as Fig.38B Therefore, the second conduction direction (ie, the direction that is the same as the negative half-cycle) of the power switch unit is still turned on.

[0103] In the second step, the control unit 103 sends a cut-off signal (eg Fig.38B The “╳” shown in the figure is used to turn off the gate of the second control transistor in the power switch unit to turn off the second control transistor in the power switch unit. Since the polarity half cycle is a negative half cycle, the second control transistor of the power switch unit is the second transistor in the power switch unit. Figure 5 As shown, at time point t3, the voltage received by the gate of the second transistor (transistor 10112) in the power switch unit is a low voltage, and the second transistor (transistor 10112) in the power switch unit is cut off after time point t3. At this time, since the first transistor (transistor 10111) and the second transistor (transistor 10112) in the power switch unit are both in the cut-off state, the first conduction direction and the second conduction direction of the power switch unit are both turned off.

[0104] In the third step, the control unit 103 sends a conduction signal (such as Fig.40B The illustrated "○") is given to the gate of the first control transistor in the standby switch unit to turn on the first control transistor in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistor of the standby switch unit is the second transistor (transistor 10122) of the standby switch unit. In this embodiment, the aforementioned turn-on signal is a high voltage signal. Figure 5 As shown, at time point t2, the voltage received by the gate of the second transistor (transistor 10122) of the standby switch unit is a high voltage, and the second transistor (transistor 10122) of the standby switch unit starts to conduct after time point t2. At this time, since the second transistor (transistor 10122) of the standby switch unit is in the on state, the second conduction direction of the standby switch unit (i.e., the direction of the negative half cycle) is turned on. It is worth noting that at this time, since the first transistor (transistor 10121) in the standby switch unit is still off (as shown in FIG. 1 ), the gate of the second transistor (transistor 10122) of the standby switch unit is turned on. Fig.40B Therefore, the first conducting direction of the standby switch unit is still closed.

[0105] In the fourth step, the control unit 103 sends a conduction signal (such as Fig.40B The illustrated "○" is given to the gate of the second control transistor in the standby switch unit to turn on the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the second control transistor of the standby switch unit is the first transistor (transistor 10121) of the standby switch unit. Figure 5As shown, at time point t4, the voltage received by the gate of the first transistor (transistor 10121) of the standby switch unit is a high voltage, so the first transistor (transistor 10121) of the standby switch unit starts to conduct after time point t4. At this time, since both the first transistor (transistor 10121) and the second transistor (transistor 10122) in the standby switch unit are in the conducting state, both the first conduction direction and the second conduction direction of the standby switch unit are turned on.

[0106] Please refer to Figure 6 , because the control unit 103 receives a switching signal before time point ts and detects that both the supply alternating current and the standby alternating current are in the negative half cycle and the voltage difference between them is less than a preset voltage at time point ts, the foregoing switching control method S3703 - S3706 is executed. It can be seen from the switching waveforms of the voltage Vin and the current Iin that the power supply is not interrupted during the switching.

[0107] In the foregoing embodiment, both the power supply switch unit and the standby switch unit adopt a common-source connection. However, the power supply switch unit and the standby switch unit can also adopt a common-drain connection or a common-source connection respectively, but the cutoff sequence of the first transistor and the second transistor of the power supply switch unit and the conduction sequence of the first transistor and the second transistor of the standby switch unit need to be adjusted correspondingly. The specific implementation manner will be described in the following embodiments.

[0108] Figure 7 is a circuit block diagram of a power supply switch unit illustrated according to some embodiments of the present invention. Figure 8 is a schematic diagram of positive half-cycle switch unit control illustrated according to some embodiments of the present invention. Fig. 9 is a schematic diagram of negative half-cycle switch unit control illustrated according to some embodiments of the present invention. Fig.39A and Fig.39B is a schematic diagram of a power supply switch unit control method illustrated according to some embodiments of the present invention. Please refer to Figure 7 , Figure 8 , Fig. 9 , Fig.39A and Fig.39BIn some embodiments of the present invention, the power switch unit (switch unit 101-1) includes a transistor 701 (hereinafter also referred to as the first transistor of the power switch unit) and a transistor 702 (hereinafter also referred to as the second transistor of the power switch unit). The first transistor (transistor 701) and the second transistor (transistor 702) of the power switch unit are both NMOS, and the source of the first transistor of the power switch unit receives the power supply AC, the drain of the first transistor of the power switch unit is connected to the drain of the second transistor of the power switch unit, and the source of the second transistor of the power switch unit is connected to the load (the connection method of the first transistor (transistor 701) and the second transistor (transistor 702) of the power switch unit is called a common drain connection).

[0109] If the power switch unit adopts a common drain connection, the aforementioned step S3703 includes a first step, and the aforementioned step S3705 includes a second step (the aforementioned first step and second step are only used to distinguish the steps and have no sequential significance).

[0110] When the polarity half cycle is a positive half cycle, in the first step, the control unit 103 sends a cutoff signal (such as Fig.39A The “╳” shown in the figure is used to turn off the gate of the first control transistor in the power switch unit to turn off the first control transistor in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistor of the power switch unit is the first transistor in the power switch unit. In this embodiment, the aforementioned turn-off signal is a low voltage signal. Figure 8 As shown, at time point t1, the voltage received by the gate of the first transistor (transistor 701) in the power switch unit is a low voltage, and the first transistor (transistor 701) in the power switch unit is cut off from time point t1. At this time, since the first transistor (transistor 701) in the power switch unit is in the cut-off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the positive half-cycle) is turned off. It is worth noting that at this time, since the second transistor in the power switch unit is still turned on (such as Fig.39A In the second step, the control unit 103 sends a cut-off signal to the gate of the second control transistor in the power switch unit to cut off the second control transistor in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the second control transistor of the power switch unit is the second transistor in the power switch unit. Figure 8As shown, at time point t3, the voltage received by the gate of the second transistor (transistor 702) in the power switch unit is a low voltage, and the second transistor (transistor 702) in the power switch unit is cut off from time point t3. At this time, since the first transistor (transistor 701) and the second transistor (transistor 702) in the power switch unit are both in the cut-off state, the first conduction direction and the second conduction direction of the power switch unit are both turned off.

[0111] When the polarity half cycle is a negative half cycle, in the first step, the control unit 103 sends a cutoff signal (such as Fig.39B The “╳” shown in the figure is used to turn off the gate of the first control transistor in the power switch unit to turn off the first control transistor in the power switch unit. Since the polarity half cycle is a negative half cycle, the first control transistor of the power switch unit is the second transistor in the power switch unit. Fig. 9 As shown, at time point t1, the voltage received by the gate of the second transistor (transistor 702) in the power switch unit is a low voltage, and the second transistor (transistor 702) in the power switch unit is cut off from time point t1. At this time, since the second transistor (transistor 702) in the power switch unit is in the cut-off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the negative half-cycle) is turned off. It is worth noting that at this time, since the first transistor in the power switch unit is still turned on (such as Fig.39B The second conducting direction of the power switch unit is still turned on. In the second step, the control unit 103 sends a cut-off signal (such as Fig.39B The “╳” shown in the figure is used to turn off the gate of the second control transistor in the power switch unit to turn off the second control transistor in the power switch unit. Since the polarity half cycle is a negative half cycle, the second control transistor in the power switch unit is the first transistor in the power switch unit. Fig. 9 As shown, at time point t3, the voltage received by the gate of the first transistor (transistor 701) in the power switch unit is a low voltage, and the first transistor (transistor 701) in the power switch unit is cut off after time point t3. At this time, since the first transistor (transistor 701) and the second transistor (transistor 702) in the power switch unit are both in the cut-off state, the first conduction direction and the second conduction direction of the power switch unit are both closed.

[0112] Fig.10 is a block diagram of a backup switch unit circuit according to some embodiments of the present invention. Fig.11 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention. Fig.12FIG. 4 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention. Fig.41A as well as Fig.41B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention. Fig.10 , Fig.11 , Fig.12 , Fig.41A as well as Fig.41B In some embodiments of the present invention, the standby switch unit (switch unit 101-2) includes a transistor 1001 (hereinafter also referred to as the first transistor of the standby switch unit) and a transistor 1002 (hereinafter also referred to as the second transistor of the standby switch unit). The first transistor (transistor 1001) and the second transistor (transistor 1002) of the standby switch unit are both NMOS, and the source of the first transistor of the standby switch unit receives the power supply AC, the drain of the first transistor of the standby switch unit is connected to the drain of the second transistor of the standby switch unit, and the source of the second transistor of the standby switch unit is connected to the load (that is, in this embodiment, the standby switch unit adopts a common drain connection).

[0113] If the backup switch unit adopts a common drain connection, the aforementioned step S3704 includes a first step, and the aforementioned step S3706 includes a second step (the aforementioned first step and second step are only used to distinguish the steps and have no sequential significance).

[0114] When the polarity half cycle is a positive half cycle, in the first step, the control unit 103 sends a conduction signal (such as Fig.41A The illustrated "○") is given to the gate of the first control transistor in the standby switch unit to turn on the first control transistor in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistor of the standby switch unit is the second transistor in the standby switch unit. In this embodiment, the aforementioned turn-on signal is a high voltage signal. Fig.11 As shown, at time point t2, the voltage received by the gate of the second transistor (transistor 1002) of the standby switch unit is a high voltage, and the second transistor (transistor 1002) of the standby switch unit starts to conduct after time point t2. At this time, since the second transistor (transistor 1002) of the standby switch unit is in the on state, the second conduction direction of the standby switch unit (i.e., the direction that is the same as the positive half-cycle) is turned on. It is worth noting that at this time, since the first transistor (transistor 1001) in the standby switch unit is still off (as shown in FIG. 1 ), the second conduction direction of the standby switch unit (i.e., the direction that is the same as the positive half-cycle) is turned on. Fig.41AIn the second step, the control unit 103 sends a conduction signal to the gate of the second control transistor in the standby switch unit to turn on the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the second control transistor of the standby switch unit is the first transistor (transistor 1001) of the standby switch unit. Fig.11 As shown, at time point t4, the voltage received by the gate of the first transistor (transistor 1001) of the standby switch unit is a high voltage, and the first transistor (transistor 1001) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 1001) and the second transistor (transistor 1002) in the standby switch unit are both in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0115] When the polarity half cycle is a negative half cycle, in the first step, the control unit 103 sends a conduction signal (such as Fig.41B The illustrated "○" is provided to the gate of the first control transistor in the standby switch unit to turn on the first control transistor in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistor of the standby switch unit is the first transistor (transistor 1001) of the standby switch unit. Fig.12 As shown, at time point t2, the voltage received by the gate of the first transistor (transistor 1001) of the standby switch unit is a high voltage, and the first transistor (transistor 1001) of the standby switch unit starts to conduct after time point t2. At this time, since the first transistor (transistor 1001) of the standby switch unit is in the on state, the second conduction direction of the standby switch unit (i.e., the direction of the negative half cycle) is turned on. It is worth noting that at this time, since the second transistor (transistor 1002) in the standby switch unit is still off (as shown in FIG. 1 ), the gate of the first transistor (transistor 1001) of the standby switch unit starts to conduct after time point t2. Fig.41B In the second step, the control unit 103 sends a conduction signal to the gate of the second control transistor in the standby switch unit to turn on the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the second control transistor of the standby switch unit is the second transistor (transistor 1002) of the standby switch unit. Fig.12As shown, at time point t4, the voltage received by the gate of the second transistor (transistor 1002) of the standby switch unit is a high voltage, and the second transistor (transistor 1002) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 1001) and the second transistor (transistor 1002) in the standby switch unit are both in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0116] When implementing the power switch unit and the backup switch unit, they can be connected by a common source or a common drain, respectively, as long as the turn-off sequence of the first transistor and the second transistor of the power switch unit and the turn-on sequence of the first transistor and the second transistor of the backup switch unit described in the above embodiment are used accordingly. The following is an embodiment to illustrate the operation process of the switching control system 100 when the power switch unit adopts a common drain connection, the backup switch unit adopts a common source connection, and the polarity half cycle is a positive half cycle.

[0117] Fig.13 It is a circuit block diagram of a power switch unit and a standby switch unit according to some embodiments of the present invention. Fig.14 is a schematic diagram of switch unit control according to some embodiments of the present invention. Fig.13 as well as Fig.14 In some embodiments of the present invention, the aforementioned polarity half cycle is a positive half cycle. The first transistor (transistor 1301) and the second transistor (transistor 1302) of the power switch unit are both NMOS, and adopt a common drain connection mode; the first transistor (transistor 1303) and the second transistor (transistor 1304) of the standby switch unit are both NMOS, and adopt a common source connection mode.

[0118] like Fig.14 As shown, since the polarity half cycle is a positive half cycle, the power switch unit adopts a common drain connection, and the standby switch unit adopts a common source connection, so the control signals of the first transistor (transistor 1301) and the second transistor (transistor 1302) of the power switch unit are the same as Figure 8 The control signals shown are the same as those of the first transistor (transistor 1303) and the second transistor (transistor 1304) of the standby switch unit. Figure 3 The control signal of transistor 10121 and transistor 10122.

[0119] Fig.15 is a circuit block diagram of a switching control system according to some embodiments of the present invention. Figure 1 as well as Fig.15 ,exist Fig.15 In the illustrated embodiment, compared to Figure 2 , the switching control system 100 receives AC power 105-1 from the outside as the power supply AC power, and receives AC power 105-2 from the outside as the backup AC power; the switching control system 100 includes a first phase line 1509, a first neutral line 1510, a second phase line 1511, and a second neutral line 1512. The first phase line 1509 and the first neutral line 1510 are configured to receive the power supply AC power, and the second phase line 1511 and the second neutral line 1512 are configured to receive the backup AC power.

[0120] In this embodiment, the detection unit 102 includes a voltage detection module 102-1 and a voltage detection module 102-2. The voltage detection module 102-1 is configured to detect the voltage of the AC power 105-1, and the voltage detection module 102-2 is configured to detect the voltage of the AC power 105-2.

[0121] The power supply switch unit (switch unit 101-1) includes a transistor 1501 (hereinafter also referred to as the first transistor of the power supply switch unit), a transistor 1502 (hereinafter also referred to as the second transistor of the power supply switch unit), a transistor 1503 (hereinafter also referred to as the third transistor of the power supply switch unit) and a transistor 1504 (hereinafter also referred to as the fourth transistor of the power supply switch unit). The first transistor and the second transistor of the power supply switch unit are located on the first phase line 1509 and are connected in reverse series, and the third transistor and the fourth transistor of the power supply switch unit are located on the first neutral line 1510 and are connected in reverse series. The standby switch unit (switch unit 101-2) includes a transistor 1505 (hereinafter also referred to as the first transistor of the standby switch unit), a transistor 1506 (hereinafter also referred to as the second transistor of the standby switch unit), a transistor 1507 (hereinafter also referred to as the third transistor of the standby switch unit) and a transistor 1508 (hereinafter also referred to as the fourth transistor of the standby switch unit). The first transistor and the second transistor of the standby switch unit are located on the second phase line 1511 and are connected in reverse series, and the third transistor and the fourth transistor of the standby switch unit are located on the second neutral line 1512 and are connected in reverse series.

[0122] Fig.16 is a schematic diagram of switch unit control according to some embodiments of the present invention. Fig.42A as well as Fig.42B It is a schematic diagram of a power switch unit control method according to some embodiments of the present invention.

[0123] Fig.46A as well as Fig.46B is a schematic diagram of a method for controlling a standby switch unit according to some embodiments of the present invention. Figure 2 , Fig.16 , Fig.42A as well as Fig.46A, in some embodiments of the present invention, the aforementioned polarity half cycle is a positive half cycle. The first transistor (transistor 1501), the second transistor (transistor 1502), the third transistor (transistor 1503) and the fourth transistor (transistor 1504) of the power supply switch unit are all NMOS, and the first transistor (transistor 1501) and the second transistor (transistor 1502) of the power supply switch unit are connected in a common source manner; the third transistor (transistor 1503) and the fourth transistor (transistor 1504) of the power supply switch unit are connected in a common source manner. The first transistor (transistor 1505), the second transistor (transistor 1506), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) of the standby switch unit are all NMOS, and the first transistor (transistor 1505) and the second transistor (transistor 1506) of the standby switch unit are connected in a common source manner; the third transistor (transistor 1507) and the fourth transistor (transistor 1508) of the standby switch unit are connected in a common source manner.

[0124] In this embodiment, the aforementioned step S3703 includes a first step, the aforementioned step S3705 includes a second step; the aforementioned step S3704 includes a third step, and the aforementioned step S3706 includes a fourth step (the aforementioned first step, second step, third step, and fourth step are only used to distinguish the steps and have no order significance). In the first step, the control unit 103 sends a cutoff signal (such as Fig.42A The “╳” shown in the figure is given to the gate of the first control transistor in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistor in the power switch unit is the second transistor in the power switch unit. In this embodiment, the aforementioned cut-off signal is a low voltage signal. Fig.16 As shown, at time point t1, the voltage received by the gate of the second transistor (transistor 1502) in the power switch unit is a low voltage, and the second transistor (transistor 1502) in the power switch unit is cut off from time point t1. At this time, since the second transistor (transistor 1502) in the power switch unit is in the cut-off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the positive half-cycle) is turned off. It is worth noting that at this time, since the first transistor, the third transistor, and the fourth transistor in the power switch unit are still turned on (such as Fig.42A Therefore, the second conducting direction of the power switch unit is still turned on.

[0125] In the second step, the control unit 103 sends a cut-off signal (eg Fig.42AThe “╳” shown in the figure is given to the gates of the plurality of second control transistors in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the plurality of second control transistors of the power switch unit are the first transistor (transistor 1501), the third transistor (transistor 1503) and the fourth transistor (transistor 1504) in the power switch unit, as shown in FIG. Fig.16 As shown, at time point t3, the voltage received by the gates of the first transistor (transistor 1501), the third transistor (transistor 1503) and the fourth transistor (transistor 1504) in the power switch unit is a low voltage, and the first transistor (transistor 1501), the second transistor (transistor 1502), the third transistor (transistor 1503) and the fourth transistor (transistor 1504) in the power switch unit are cut off from time point t3. At this time, since the first transistor (transistor 1501), the second transistor (transistor 1502), the third transistor (transistor 1503) and the fourth transistor (transistor 1504) in the power switch unit are all in the cut-off state, the first conduction direction and the second conduction direction of the power switch unit are both closed.

[0126] In the third step, the control unit 103 sends a conduction signal (such as Fig.46A The illustrated "○" is given to the gates of the plurality of first control transistors in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistors in the standby switch unit are the first transistor (transistor 1505), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) in the standby switch unit. In this embodiment, the aforementioned conduction signal is a high voltage signal. Fig.16 As shown, at time point t2, the voltage received by the first transistor (transistor 1505), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) in the standby switch unit is a high voltage, and the first transistor (transistor 1505), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) of the standby switch unit start to be turned on after time point t2. At this time, since the first transistor (transistor 1505), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) of the standby switch unit are in the on state, the second conduction direction of the standby switch unit (i.e., the same direction as the positive half-cycle) is turned on. It is worth noting that at this time, since the second transistor (transistor 1506) in the standby switch unit is still turned off (as shown in FIG. 1 ), the voltage received by the first transistor (transistor 1505), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) of the standby switch unit are turned on. Fig.46A Therefore, the first conducting direction of the standby switch unit is still closed.

[0127] In the fourth step, the control unit 103 sends a conduction signal (such as Fig.46AThe illustrated "○" is given to the gate of the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the second control transistor in the standby switch unit is the second transistor (transistor 1506) in the standby switch unit. Fig.16 As shown, at time point t4, the voltage received by the gate of the second transistor (transistor 1506) of the standby switch unit is a high voltage, and the second transistor (transistor 1506) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 1505), the second transistor (transistor 1506), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) in the standby switch unit are all in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0128] Fig.17 is a schematic diagram of switch unit control according to some embodiments of the present invention. Figure 2 , Fig.17 , Fig.42B as well as Fig.46B In some embodiments of the present invention, the aforementioned polarity half cycle is a negative half cycle. In this embodiment, the aforementioned step S3703 includes the first step, the aforementioned step S3705 includes the second step (the aforementioned first step, second step, third step and fourth step are only used to distinguish the steps and have no order significance); the aforementioned step S3704 includes the third step, and the aforementioned step S3706 includes the fourth step. In the first step, the control unit 103 sends a cutoff signal (such as Fig.42B The “╳” shown in the figure is given to the gate of the first control transistor in the power switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistor in the power switch unit is the first transistor in the power switch unit. In this embodiment, the aforementioned cut-off signal is a low voltage signal. Fig.17 As shown, at time point t1, the voltage received by the gate of the first transistor (transistor 1501) in the power switch unit is a low voltage, and the first transistor (transistor 1501) in the power switch unit is cut off from time point t1. At this time, since the first transistor (transistor 1501) in the power switch unit is in the cut-off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the negative half-cycle) is turned off. It is worth noting that at this time, since the second transistor, the third transistor, and the fourth transistor in the power switch unit are still turned on (such as Fig.42B Therefore, the second conduction direction (ie, the direction that is the same as the negative half-cycle) of the power switch unit is still turned on.

[0129] In the second step, the control unit 103 sends a cut-off signal (eg Fig.42BThe “╳” is shown as a gate of each of the plurality of second control transistors in the power switch unit, wherein, since the polarity half cycle is a negative half cycle, the plurality of second control transistors of the power switch unit are the second transistor, the third transistor and the fourth transistor in the power switch unit. In this embodiment, the aforementioned cut-off signal is a low voltage signal. Fig.17 As shown, at time point t3, the voltage received by the gates of the second transistor (transistor 1502), the third transistor (transistor 1503) and the fourth transistor (transistor 1504) in the power switch unit is a low voltage, and the second transistor (transistor 1502), the third transistor (transistor 1503) and the fourth transistor (transistor 1504) in the power switch unit are cut off from time point t3. At this time, since the first transistor (transistor 1501), the second transistor (transistor 1502), the third transistor (transistor 1503) and the fourth transistor (transistor 1504) in the power switch unit are all in the cut-off state, the first conduction direction and the second conduction direction of the power switch unit are both closed.

[0130] In the third step, the control unit 103 sends a conduction signal (such as Fig.46B The illustrated "○" is given to the gates of the plurality of first control transistors in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistor in the standby switch unit is the second transistor (transistor 1506), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) in the standby switch unit. In this embodiment, the aforementioned conduction signal is a high voltage signal. Fig.17 As shown, at time point t2, the voltage received by the gates of the second transistor (transistor 1506), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) of the standby switch unit is a high voltage, and the second transistor (transistor 1506), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) of the standby switch unit start to conduct after time point t2. At this time, since the second transistor (transistor 1506), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) of the standby switch unit are in the on state, the second conduction direction of the standby switch unit (i.e., the same direction as the negative half-cycle) is turned on. It is worth noting that at this time, since the first transistor (transistor 1505) in the standby switch unit is still cut off (as shown in FIG. 1 ), the gates of the second transistor (transistor 1506), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) of the standby switch unit are in the on state. Fig.46B Therefore, the first conducting direction of the standby switch unit is still closed.

[0131] In the fourth step, the control unit 103 sends a conduction signal (such as Fig.46BThe illustrated "○" is given to the gate of the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the second control transistor in the standby switch unit is the first transistor (transistor 1505) in the standby switch unit. Fig.17 As shown, at time point t4, the voltage received by the gate of the first transistor (transistor 1505) of the standby switch unit is a high voltage, and the first transistor (transistor 1505) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 1505), the second transistor (transistor 1506), the third transistor (transistor 1507) and the fourth transistor (transistor 1508) in the standby switch unit are all in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0132] In the aforementioned embodiment, the power switch unit and the first transistor and the second transistor and the third transistor and the fourth transistor of the power switch unit are all connected with a common source. However, the first transistor and the second transistor and the third transistor and the fourth transistor of the power switch unit and the standby switch unit may also be connected with a common drain or a common source, respectively, but the cut-off sequence of the first transistor, the second transistor, the third transistor and the fourth transistor of the power switch unit and the turn-on sequence of the first transistor, the second transistor, the third transistor and the fourth transistor of the standby switch unit need to be adjusted accordingly. The specific implementation will be described in the following embodiments.

[0133] Fig.18 is a circuit block diagram of a power switch unit according to some embodiments of the present invention. Fig.19 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention. Fig. 20 FIG. 4 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention. Fig.43A as well as Fig.43B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention. Fig.18 , Fig.19 , Fig. 20 , Fig.43A as well as Fig.43BIn some embodiments of the present invention, the power switch unit (switch unit 101-1) includes a transistor 1801 (hereinafter also referred to as the first transistor of the power switch unit), a transistor 1802 (hereinafter also referred to as the second transistor of the power switch unit), a transistor 1803 (hereinafter also referred to as the third transistor of the power switch unit) and a transistor 1804 (hereinafter also referred to as the fourth transistor of the power switch unit), and the aforementioned transistors are all NMOS. The first transistor and the second transistor of the power switch unit are connected in a common source connection method; the third transistor and the fourth transistor of the power switch unit are connected in a common drain connection method.

[0134] If the power switch unit is connected using the aforementioned connection method, the aforementioned step S3703 includes a first step, and the aforementioned step S3705 includes a second step (the aforementioned first step and second step are only used to distinguish the steps and have no sequential significance).

[0135] When the polarity half cycle is a positive half cycle, in the first step, the control unit 103 sends a cutoff signal (such as Fig.43A The “╳” shown in the figure is a gate of the first control transistor in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistor in the power switch unit is the second transistor in the power switch unit. Fig.19 As shown, at time point t1, the voltage received by the gate of the second transistor (transistor 1802) in the power switch unit is a low voltage, and the second transistor (transistor 1802) in the power switch unit is cut off from time point t1. At this time, since the second transistor (transistor 1802) in the power switch unit is in the cut-off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the positive half cycle) is turned off. In the second step, the control unit 103 sends a cut-off signal (such as Fig.43A The “╳” shown in the figure is given to the gates of the plurality of second control transistors in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the second control transistors in the power switch unit are the first transistor (transistor 1801), the third transistor (transistor 1803) and the fourth transistor (transistor 1804) in the power switch unit. Fig.19As shown, at time point t3, the voltage received by the gates of the first transistor (transistor 1801), the third transistor (transistor 1803) and the fourth transistor (transistor 1804) in the power switch unit is a low voltage, and the first transistor (transistor 1801), the third transistor (transistor 1803) and the fourth transistor (transistor 1804) in the power switch unit are cut off from time point t3. At this time, since the first transistor (transistor 1801), the second transistor (transistor 1802), the third transistor (transistor 1803) and the fourth transistor (transistor 1804) in the power switch unit are all in the cut-off state, the first conduction direction and the second conduction direction of the power switch unit are both closed.

[0136] When the polarity half cycle is a negative half cycle, in the first step, the control unit 103 sends a cutoff signal (such as Fig.43B The “╳” shown in the figure is a gate of the first control transistor in the power switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistor in the power switch unit is the first transistor in the power switch unit. In this embodiment. Fig. 20 As shown, at time point t1, the voltage received by the gate of the first transistor (transistor 1801) in the power switch unit is a low voltage, and the first transistor (transistor 1801) in the power switch unit is cut off from time point t1. At this time, since the first transistor (transistor 1801) in the power switch unit is in the cut-off state, the first conduction direction (i.e., the direction opposite to the negative half-cycle) of the power switch unit is turned off. In the second step, a cut-off signal is sent to the gates of each of the multiple second control transistors in the power switch unit, wherein, since the polarity half-cycle is a negative half-cycle, the second control transistors in the power switch unit are the second transistor (transistor 1802), the third transistor (transistor 1803) and the fourth transistor (transistor 1804) in the power switch unit. As shown Fig. 20 As shown, at time point t3, the voltage received by the gates of the second transistor, the third transistor and the fourth transistor in the power supply switch unit is a low voltage, then the second transistor (transistor 1802), the third transistor (transistor 1803) and the fourth transistor (transistor 1804) in the power supply switch unit are cut off from time point t3.

[0137] Fig.21 is a circuit block diagram of a power switch unit according to some embodiments of the present invention. Fig. 22 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention. Fig.23 FIG. 4 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention. Fig.44A as well as Fig.44B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention. Fig.21 , Fig. 22 , Fig.23 , Fig.44A as well as Fig.44B In some embodiments of the present invention, the power switch unit (switch unit 101-1) includes a transistor 2101 (hereinafter also referred to as the first transistor of the power switch unit), a transistor 2102 (hereinafter also referred to as the second transistor of the power switch unit), a transistor 2103 (hereinafter also referred to as the third transistor of the power switch unit) and a transistor 2104 (hereinafter also referred to as the fourth transistor of the power switch unit), and the aforementioned transistors are all NMOS. The first transistor and the second transistor of the power switch unit are connected in a common drain connection method; the third transistor and the fourth transistor of the power switch unit are connected in a common source connection method.

[0138] If the power switch unit is connected using the aforementioned connection method, the aforementioned step S3703 includes a first step, and the aforementioned step S3705 includes a second step (the aforementioned first step and second step are only used to distinguish the steps and have no sequential significance).

[0139] When the polarity half cycle is a positive half cycle, in the first step, the control unit 103 sends a cutoff signal (such as Fig.44A The “╳” shown in the figure is a gate of the first control transistor in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistor in the power switch unit is the first transistor in the power switch unit. Fig. 22 As shown, at time point t1, the voltage received by the gate of the first transistor (transistor 2101) in the power switch unit is a low voltage, and the first transistor (transistor 2101) in the power switch unit is cut off from time point t1. At this time, since the first transistor (transistor 2101) in the power switch unit is in the cut-off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the positive half cycle) is turned off. In the second step, the control unit 103 sends a cut-off signal (such as Fig.44A The “╳” is shown as a gate of each of the plurality of second control transistors in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the second control transistors in the power switch unit are the second transistor (transistor 2102), the third transistor (transistor 2103) and the fourth transistor (transistor 2104) in the power switch unit. Fig. 22As shown, the second transistor (transistor 2102), the third transistor (transistor 2103) and the fourth transistor (transistor 2104) in the power switch unit are turned off after time point t3. At this time, since the first transistor (transistor 2101), the second transistor (transistor 2102), the third transistor (transistor 2103) and the fourth transistor (transistor 2104) in the power switch unit are all in the off state, the first conduction direction and the second conduction direction of the power switch unit are both turned off.

[0140] When the polarity half cycle is a negative half cycle, in the first step, the control unit 103 sends a cutoff signal (such as Fig.44B The “╳” shown in the figure is given to the gate of the first control transistor in the power switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistor in the power switch unit is the second transistor in the power switch unit. In this embodiment. Fig.23 As shown in FIG. 1 , the second transistor (transistor 2102) in the power switch unit is turned off after time point t1. At this time, since the second transistor (transistor 2102) in the power switch unit is in the off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the negative half cycle) is turned off. In the second step, a cutoff signal (such as Fig.44B The “╳” is shown as a gate of each of the plurality of second control transistors in the power switch unit, wherein, since the polarity half cycle is a negative half cycle, the second control transistors in the power switch unit are the first transistor (transistor 2101), the third transistor (transistor 2103) and the fourth transistor (transistor 2104) in the power switch unit. Fig.23 As shown, at time point t3, the first transistor (transistor 2101), the third transistor (transistor 2103) and the fourth transistor (transistor 2104) in the power switch unit are turned off starting from time point t3.

[0141] Fig.24 is a circuit block diagram of a power switch unit according to some embodiments of the present invention. Fig.25 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention. Fig.26 FIG. 4 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention. Fig.45A as well as Fig.45B is a schematic diagram of a power switch unit control method according to some embodiments of the present invention. Fig.24 , Fig.25 , Fig.26 , Fig.45A as well as Fig.45BIn some embodiments of the present invention, the power switch unit (switch unit 101-1) includes a transistor 2401 (hereinafter also referred to as the first transistor of the power switch unit), a transistor 2402 (hereinafter also referred to as the second transistor of the power switch unit), a transistor 2403 (hereinafter also referred to as the third transistor of the power switch unit) and a transistor 2404 (hereinafter also referred to as the fourth transistor of the power switch unit), and the aforementioned transistors are all NMOS. The first transistor and the second transistor of the power switch unit are connected in a common drain connection method; the third transistor and the fourth transistor of the power switch unit are also connected in a common drain connection method.

[0142] If the power switch unit is connected using the aforementioned connection method, the aforementioned step S3703 includes a first step, and the aforementioned step S3705 includes a second step (the aforementioned first step and second step are only used to distinguish the steps and have no sequential significance).

[0143] When the polarity half cycle is a positive half cycle, in the first step, the control unit 103 sends a cutoff signal (such as Fig.45A The “╳” shown in the figure is a gate of the first control transistor in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistor in the power switch unit is the first transistor in the power switch unit. Fig.25 As shown in FIG. 1 , the first transistor (transistor 2401) in the power switch unit is turned off after time point t1. At this time, since the first transistor (transistor 2401) in the power switch unit is in the off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the positive half cycle) is turned off. In the second step, the control unit 103 sends a cut-off signal (such as Fig.45A The “╳” is shown as a gate of each of the plurality of second control transistors in the power switch unit, wherein, since the polarity half cycle is a positive half cycle, the second control transistors in the power switch unit are the second transistor (transistor 2402), the third transistor (transistor 2403) and the fourth transistor (transistor 2404) in the power switch unit. Fig.25 As shown, at time point t3, the second transistor (transistor 2402), the third transistor (transistor 2403) and the fourth transistor (transistor 2404) in the power switch unit are turned off from time point t3. At this time, since the first transistor (transistor 2401), the second transistor (transistor 2402), the third transistor (transistor 2403) and the fourth transistor (transistor 2404) in the power switch unit are all in the off state, the first conduction direction and the second conduction direction of the power switch unit are both turned off.

[0144] When the polarity half cycle is a negative half cycle, in the first step, the control unit 103 sends a cutoff signal (such as Fig.45B The “╳” shown in the figure is given to the gate of the first control transistor in the power switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistor in the power switch unit is the second transistor in the power switch unit. In this embodiment. Fig.26 As shown in FIG. 1 , the second transistor (transistor 2402) in the power switch unit is turned off after time point t1. At this time, since the second transistor (transistor 2402) in the power switch unit is in the off state, the first conduction direction of the power switch unit (i.e., the direction opposite to the negative half cycle) is turned off. In the second step, a cutoff signal (such as Fig.45B The “╳” is shown as a gate of each of the plurality of second control transistors in the power switch unit, wherein, since the polarity half cycle is a negative half cycle, the second control transistors in the power switch unit are the first transistor (transistor 2401), the third transistor (transistor 2403) and the fourth transistor (transistor 2404) in the power switch unit. Fig.26 As shown, the first transistor (transistor 2401), the third transistor (transistor 2403) and the fourth transistor (transistor 2404) in the power supply switch unit are turned off after time point t3.

[0145] Fig. 27 is a block diagram of a backup switch unit circuit according to some embodiments of the present invention. Fig.28 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention. Fig.29 FIG. 4 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention. Fig.47A as well as Fig.47B is a schematic diagram of a method for controlling a standby switch unit according to some embodiments of the present invention. Fig. 27 , Fig.28 , Fig.29 , Fig.47A as well as Fig.47B In some embodiments of the present invention, the standby switch unit (switch unit 101-2) includes a transistor 2701 (hereinafter also referred to as the first transistor of the standby switch unit), a transistor 2702 (hereinafter also referred to as the second transistor of the standby switch unit), a transistor 2703 (hereinafter also referred to as the third transistor of the standby switch unit) and a transistor 2704 (hereinafter also referred to as the fourth transistor of the standby switch unit), and the aforementioned transistors are all NMOS. The first transistor and the second transistor of the standby switch unit are connected in a common source connection method; the third transistor and the fourth transistor of the standby switch unit are connected in a common drain connection method.

[0146] If the standby switch unit is connected using the aforementioned connection method, the aforementioned step S3704 includes a first step, and the aforementioned step S3706 includes a second step (the aforementioned first step and second step are only used to distinguish the steps and have no sequential significance).

[0147] When the polarity half cycle is a positive half cycle, in the first step, the control unit 103 sends a conduction signal (such as Fig.47A The illustrated "○" is given to the gates of the plurality of first control transistors in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistors in the standby switch unit are the first transistor (transistor 2701), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) in the standby switch unit. In this embodiment, the aforementioned conduction signal is a high voltage signal. Fig.28 As shown, at time point t2, the voltage received by the first transistor (transistor 2701), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) in the standby switch unit is a high voltage, and the first transistor (transistor 2701), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) of the standby switch unit start to be turned on after time point t2. At this time, since the first transistor (transistor 2701), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) of the standby switch unit are in the on state, the second conduction direction of the standby switch unit (i.e., the same direction as the positive half-cycle) is turned on. It is worth noting that at this time, since the second transistor (transistor 2702) in the standby switch unit is still turned off (as shown in FIG. 2 ), the voltage received by the first transistor (transistor 2701), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) of the standby switch unit are turned on. Fig.47A Therefore, the first conducting direction of the standby switch unit is still closed.

[0148] In the second step, the control unit 103 sends a conduction signal (such as Fig.47A The illustrated "○" is given to the gate of the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the second control transistor in the standby switch unit is the second transistor (transistor 2702) in the standby switch unit. Fig.28 As shown, at time point t4, the voltage received by the gate of the second transistor (transistor 2702) of the standby switch unit is a high voltage, and the second transistor (transistor 2702) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 2701), the second transistor (transistor 2702), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) in the standby switch unit are all in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0149] When the polarity half cycle is a negative half cycle, in the first step, the control unit 103 sends a conduction signal (such as Fig.47B The illustrated "○" is given to the gates of the plurality of first control transistors in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistor in the standby switch unit is the second transistor (transistor 2702), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) in the standby switch unit. Fig.29 As shown, at time point t2, the voltage received by the gate of the second transistor (transistor 2702), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) of the standby switch unit is a high voltage, and the second transistor (transistor 2702), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) of the standby switch unit start to be turned on after time point t2. At this time, since the second transistor (transistor 2702), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) of the standby switch unit are in the on state, the second conduction direction of the standby switch unit (i.e., the same direction as the negative half-cycle) is turned on. It is worth noting that at this time, since the first transistor (transistor 2701) in the standby switch unit is still cut off (as shown in FIG. 2 ), the gate of the second transistor (transistor 2702), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) of the standby switch unit are in the on state. Fig.47B Therefore, the first conducting direction of the standby switch unit is still closed.

[0150] In the second step, the control unit 103 sends a conduction signal (such as Fig.47B The illustrated "○" is given to the gate of the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the second control transistor in the standby switch unit is the first transistor (transistor 2701) in the standby switch unit. Fig.29 As shown, at time point t4, the voltage received by the gate of the first transistor (transistor 2701) of the standby switch unit is a high voltage, and the first transistor (transistor 2701) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 2701), the second transistor (transistor 2702), the third transistor (transistor 2703) and the fourth transistor (transistor 2704) in the standby switch unit are all in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0151] Fig.30 is a block diagram of a backup switch unit circuit according to some embodiments of the present invention. Fig.31 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention. Fig.32FIG. 4 is a schematic diagram of controlling a negative half-cycle switch unit according to some embodiments of the present invention. Fig.48A as well as Fig.48B is a schematic diagram of a method for controlling a standby switch unit according to some embodiments of the present invention. Fig.30 , Fig.31 , Fig.32 , Fig.48A as well as Fig.48B In some embodiments of the present invention, the standby switch unit (switch unit 101-2) includes a transistor 3001 (hereinafter also referred to as the first transistor of the standby switch unit), a transistor 3002 (hereinafter also referred to as the second transistor of the standby switch unit), a transistor 3003 (hereinafter also referred to as the third transistor of the standby switch unit) and a transistor 3004 (hereinafter also referred to as the fourth transistor of the standby switch unit), and the aforementioned transistors are all NMOS. The first transistor and the second transistor of the standby switch unit are connected in a common drain connection method; the third transistor and the fourth transistor of the standby switch unit are connected in a common source connection method.

[0152] If the standby switch unit is connected using the aforementioned connection method, the aforementioned step S3704 includes a first step, and the aforementioned step S3706 includes a second step (the aforementioned first step and second step are only used to distinguish the steps and have no sequential significance).

[0153] When the polarity half cycle is a positive half cycle, in the first step, the control unit 103 sends a conduction signal (such as Fig.48A The illustrated "○" is given to the gates of the plurality of first control transistors in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistors in the standby switch unit are the second transistor (transistor 3001), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) in the standby switch unit. In this embodiment, the aforementioned conduction signal is a high voltage signal. Fig.31 As shown, at time point t2, the voltage received by the second transistor (transistor 3002), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) in the standby switch unit is a high voltage, and the second transistor (transistor 3002), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) of the standby switch unit start to conduct after time point t2. At this time, since the second transistor (transistor 3002), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) of the standby switch unit are in the on state, the second conduction direction (i.e., the same direction as the positive half cycle) of the standby switch unit is turned on.

[0154] In the second step, the control unit 103 sends a conduction signal (such as Fig.48A The gate of the second control transistor in the standby switch unit is indicated by "○" as shown in the figure. Since the polarity half cycle is a positive half cycle, the second control transistor in the standby switch unit is the first transistor (transistor 3001) in the standby switch unit. In this embodiment, the aforementioned conduction signal is a high voltage signal. Fig.31 As shown, at time point t4, the voltage received by the gate of the first transistor (transistor 3001) of the standby switch unit is a high voltage, and the first transistor (transistor 3001) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 3001), the second transistor (transistor 3002), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) in the standby switch unit are all in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0155] When the polarity half cycle is a negative half cycle, in the first step, the control unit 103 sends a conduction signal (such as Fig.48B The illustrated "○" is given to the gates of the plurality of first control transistors in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistors in the standby switch unit are the first transistor (transistor 3001), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) in the standby switch unit. Fig.32 As shown, at time point t2, the voltage received by the gate of the first transistor (transistor 3001), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) of the standby switch unit is a high voltage, and the first transistor (transistor 3001), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) of the standby switch unit start to be turned on after time point t2. At this time, since the first transistor (transistor 3001), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) of the standby switch unit are in the on state, the second conduction direction (i.e., the same direction as the negative half cycle) of the standby switch unit is turned on.

[0156] In the second step, the control unit 103 sends a conduction signal (such as Fig.48B The illustrated "○" is given to the gate of the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the second control transistor in the standby switch unit is the second transistor (transistor 3002) in the standby switch unit. Fig.32As shown, at time point t4, the voltage received by the gate of the second transistor (transistor 3002) of the standby switch unit is a high voltage, and the second transistor (transistor 3002) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 3001), the second transistor (transistor 3002), the third transistor (transistor 3003) and the fourth transistor (transistor 3004) in the standby switch unit are all in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0157] Fig.33 is a block diagram of a backup switch unit circuit according to some embodiments of the present invention. Fig.34 is a schematic diagram of positive half-cycle switch unit control according to some embodiments of the present invention. Fig.35 FIG. 4 is a schematic diagram of negative half-cycle switch unit control according to some embodiments of the present invention. Fig.49A as well as Fig.49B is a schematic diagram of a method for controlling a standby switch unit according to some embodiments of the present invention. Fig.33 , Fig.34 , Fig.35 , Fig.49A as well as Fig.49B In some embodiments of the present invention, the standby switch unit (switch unit 101-2) includes a transistor 3301 (hereinafter also referred to as the first transistor of the standby switch unit), a transistor 3302 (hereinafter also referred to as the second transistor of the standby switch unit), a transistor 3303 (hereinafter also referred to as the third transistor of the standby switch unit) and a transistor 3304 (hereinafter also referred to as the fourth transistor of the standby switch unit), and the aforementioned transistors are all NMOS. The first transistor and the second transistor of the standby switch unit are connected in a common drain connection method; the third transistor and the fourth transistor of the standby switch unit are connected in a common drain connection method.

[0158] If the standby switch unit is connected using the aforementioned connection method, the aforementioned step S3704 includes a first step, and the aforementioned step S3706 includes a second step (the aforementioned first step and second step are only used to distinguish the steps and have no sequential significance).

[0159] When the polarity half cycle is a positive half cycle, in the first step, the control unit 103 sends a conduction signal (such as Fig.49AThe illustrated "○" is given to the gates of the plurality of first control transistors in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the first control transistors in the standby switch unit are the second transistor (transistor 3302), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) in the standby switch unit. In this embodiment, the aforementioned conduction signal is a high voltage signal. Fig.34 As shown, at time point t2, the voltage received by the second transistor (transistor 3301), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) in the standby switch unit is a high voltage, and the second transistor (transistor 3302), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) of the standby switch unit start to conduct after time point t2. At this time, since the second transistor (transistor 3302), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) of the standby switch unit are in the on state, the second conduction direction (i.e., the same direction as the positive half cycle) of the standby switch unit is turned on.

[0160] In the second step, the control unit 103 sends a conduction signal (such as Fig.49A The illustrated "○" is given to the gate of the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a positive half cycle, the second control transistor in the standby switch unit is the first transistor (transistor 3301) in the standby switch unit. Fig.34 As shown, at time point t4, the voltage received by the gate of the first transistor (transistor 3301) of the standby switch unit is a high voltage, and the first transistor (transistor 3301) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 3301), the second transistor (transistor 3302), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) in the standby switch unit are all in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0161] When the polarity half cycle is a negative half cycle, in the first step, the control unit 103 sends a conduction signal (such as Fig.49B The illustrated "○" is given to the gates of the plurality of first control transistors in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the first control transistors in the standby switch unit are the first transistor (transistor 3301), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) in the standby switch unit. Fig.35As shown, at time point t2, the voltage received by the gate of the first transistor (transistor 3301), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) of the standby switch unit is a high voltage, and the first transistor (transistor 3301), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) of the standby switch unit start to be turned on after time point t2. At this time, since the first transistor (transistor 3301), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) of the standby switch unit are in the on state, the second conduction direction (i.e., the same direction as the negative half cycle) of the standby switch unit is turned on.

[0162] In the second step, the control unit 103 sends a conduction signal (such as Fig.49B The illustrated "○" is given to the gate of the second control transistor in the standby switch unit, wherein, since the polarity half cycle is a negative half cycle, the second control transistor in the standby switch unit is the second transistor (transistor 3302) in the standby switch unit. Fig.35 As shown, at time point t4, the voltage received by the gate of the second transistor (transistor 3302) of the standby switch unit is a high voltage, and the second transistor (transistor 3302) of the standby switch unit starts to conduct after time point t4. At this time, since the first transistor (transistor 3301), the second transistor (transistor 3302), the third transistor (transistor 3303) and the fourth transistor (transistor 3304) in the standby switch unit are all in the on state, the first conduction direction and the second conduction direction of the standby switch unit are both turned on.

[0163] In the aforementioned embodiment, due to the use of semiconductor switches connected in reverse series, the signal can be turned on or off quickly, thereby achieving the effect of fast switching of power supply.

[0164] Fig.36 is a circuit diagram of a voltage detection circuit according to some embodiments of the present invention. Fig.36In some embodiments of the present invention, the voltage detection circuit 3600 may be included in the aforementioned voltage detection module 102-1 and the voltage detection module 102-2 to detect the voltage of the AC power 105-1 and the AC power 105-2. The voltage detection circuit 3600 includes an amplifier 3601, an amplifier 3602, and resistors 3603, 3604, 3605, and 3606. The resistance value of the resistors 3603 and 3604 is R1, and the resistance value of the resistors 3605 and 3606 is R2. The amplifiers 3601 and 3602 receive the power supply voltage Vcc of the voltage detection circuit 3600, and the voltage detection circuit 3600 is connected to the reference voltage Vref via the resistor 3605. The amplifiers 3601, the resistors 3603, 3604, 3605, and 3606 are connected via Fig.36 The connections shown form a differential amplifier that attenuates the detected voltage to a voltage range that can be processed by the microprocessor. Fig.36 The connection method shown forms a voltage follower and is used for impedance matching (high output impedance).

[0165] Please refer to Figure 1 In some embodiments of the present invention, the control unit 103 is configured to execute an emergency switching step in response to detecting that the voltage of the power supply AC power in the AC power 105-1 to 105-N is less than a threshold value so that the backup AC power in the AC power 105-1 to 105-N replaces the power supply AC power in the AC power 105-1 to 105-N to power the load 104.

[0166] In some embodiments of the present invention, the emergency switching step includes the aforementioned steps S3701 to S3706.

[0167] Based on the above, some embodiments of the present invention provide a switching control system, which can prevent the AC power supply from short-circuiting and maintain normal operation during the switching process by first shutting down the first conduction direction of the power supply switch unit of the power supply AC and maintaining the second conduction direction of the backup switch unit of the backup AC power open before the second conduction direction of the backup switch unit of the backup AC power is turned on, thereby achieving the effect of uninterrupted power supply. In addition, since the switching control system uses a bidirectional switch to replace the traditional relay and silicon controlled rectifier, its architecture is simple. Therefore, through the switching control system and the switching control method recorded in the aforementioned embodiments, the power supply AC and the backup AC can be quickly switched to achieve a backup function. Some embodiments of the present invention are composed of a bidirectional switch unit composed of a pair of transistor switches connected in reverse series to replace the traditional relay and SCR, without the need for an additional diode to prevent reverse current.

[0168] Although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Any person having ordinary knowledge in the technical field may make some changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the scope defined in the attached claims.

Claims

1. A switching control system, It is characterized in that Include: A plurality of switch units configured to respectively receive one of a plurality of alternating currents and couple a load; a detection unit configured to detect each of the alternating currents; as well as The control unit is configured to, after receiving the switching signal, execute the following in response to detecting that the power supply AC power and the standby AC power in the AC power are both in a polarity half cycle and the voltage difference between the power supply AC power and the standby AC power is less than a preset voltage: (a) turning off the first conduction direction of the power supply switch unit for supplying AC power; (b) turning on the second conduction direction of the backup switch unit of the backup AC power; (c) turning off the second conducting direction of the power switch unit; and (d) turning on the first conduction direction of the backup switch unit; wherein the first conduction direction of the power switch unit and the backup switch unit is opposite to the direction of the polarity half cycle, and the second conduction direction of the power switch unit and the backup switch unit is the same as the direction of the polarity half cycle, and the power switch unit and the backup switch unit are included in the switch units.

2. The switching control system according to claim 1, It is characterized in that The polarity half cycle is selected from one of a group consisting of a positive half cycle and a negative half cycle.

3. The switching control system according to claim 1, It is characterized in that The switching control system includes a first phase line, a second phase line and a neutral line, the first phase line and the neutral line are configured to receive the power supply AC power, the second phase line and the neutral line are configured to receive the backup AC power, the power supply switch unit and the backup switch unit both include a first transistor and a second transistor, the first transistor and the second transistor of the power supply switch unit are located on the first phase line and are connected in reverse series, and the first transistor and the second transistor of the backup switch unit are located on the second phase line and are connected in reverse series.

4. The switching control system according to claim 3, It is characterized in that The first transistor and the second transistor of the power switch unit are NMOS, the drain of the first transistor of the power switch unit receives the power supply AC, the source of the first transistor of the power switch unit is connected to the source of the second transistor of the power switch unit, and the drain of the second transistor of the power switch unit is connected to the load, the step (a) includes sending a cut-off signal to the gate of the first control transistor in the power switch unit, and the step (c) includes sending the cut-off signal to the gate of the second control transistor in the power switch unit; wherein, when the polarity half cycle is a positive half cycle, the first control transistor of the power switch unit is the second transistor in the power switch unit, and the second control transistor of the power switch unit is the first transistor in the power switch unit; and when the polarity half cycle is a negative half cycle, the first control transistor of the power switch unit is the first transistor in the power switch unit, and the second control transistor of the power switch unit is the second transistor in the power switch unit.

5. The switching control system according to claim 3, It is characterized in that The first transistor and the second transistor of the power switch unit are NMOS, a source of the first transistor of the power switch unit receives the power supply AC, a drain of the first transistor of the power switch unit is connected to the drain of the second transistor of the power switch unit, a source of the second transistor of the power switch unit is connected to the load, the step (a) includes sending a cut-off signal to the gate of the first control transistor in the power switch unit, and the step (c) includes sending the cut-off signal to the gate of the second control transistor in the power switch unit; wherein, when the polarity half cycle is a positive half cycle, the first control transistor of the power switch unit is the first transistor in the power switch unit, and the second control transistor of the power switch unit is the second transistor in the power switch unit; and when the polarity half cycle is a negative half cycle, the first control transistor of the power switch unit is the second transistor in the power switch unit, and the second control transistor of the power switch unit is the first transistor in the power switch unit.

6. A switching control system as claimed in any one of claim 4 or claim 5, It is characterized in that The first transistor and the second transistor of the backup switch unit are NMOS, the drain of the first transistor of the backup switch unit receives the backup alternating current, the source of the first transistor of the backup switch unit is connected to the source of the second transistor of the backup switch unit, and the drain of the second transistor of the backup switch unit is connected to the load, the step (b) includes sending a turn-on signal to the gate of the first control transistor in the backup switch unit, and the step (d) includes sending a turn-on signal to the gate of the second control transistor in the backup switch unit; wherein, when the polarity half cycle is the positive half cycle, the first control transistor of the backup switch unit is the first transistor of the backup switch unit, and the second control transistor of the backup switch unit is the second transistor of the backup switch unit; and when the polarity half cycle is the negative half cycle, the first control transistor of the backup switch unit is the second transistor in the backup switch unit, and the second control transistor of the backup switch unit is the first transistor in the backup switch unit.

7. A switching control system as claimed in any one of claim 4 or claim 5, It is characterized in that The first transistor and the second transistor of the backup switch unit are NMOS, the source of the first transistor of the backup switch unit receives the backup alternating current, the drain of the first transistor of the backup switch unit is connected to the drain of the second transistor of the backup switch unit, and the source of the second transistor of the backup switch unit is connected to the load, the step (b) includes sending a turn-on signal to the gate of the first control transistor in the backup switch unit, and the step (d) includes sending a turn-on signal to the gate of the second control transistor in the backup switch unit; wherein, when the polarity half cycle is the positive half cycle, the first control transistor of the backup switch unit is the second transistor of the backup switch unit, and the second control transistor of the backup switch unit is the first transistor of the backup switch unit; and when the polarity half cycle is the negative half cycle, the first control transistor of the backup switch unit is the first transistor in the backup switch unit, and the second control transistor of the backup switch unit is the second transistor in the backup switch unit.

8. The switching control system according to claim 1, It is characterized in that The switching control system includes a first phase line, a first neutral line, a second phase line and a second neutral line, the first phase line and the first neutral line are configured to receive the power supply AC power, the second phase line and the second neutral line are configured to receive the backup AC power, the power supply switch unit and the backup switch unit both include a first transistor, a second transistor, a third transistor and a fourth transistor, the first transistor and the second transistor of the power supply switch unit are located on the first phase line and are connected in reverse series, the third transistor and the fourth transistor of the power supply switch unit are located on the first neutral line and are connected in reverse series, the first transistor and the second transistor of the backup switch unit are located on the second phase line and are connected in reverse series, and the third transistor and the fourth transistor of the backup switch unit are located on the second neutral line and are connected in reverse series.

9. The switching control system according to claim 8, It is characterized in that The first transistor, the second transistor, the third transistor and the fourth transistor of the power switch unit are NMOS, the drain of the first transistor of the power switch unit and the drain of the third transistor of the power switch unit receive the power supply AC, the source of the first transistor of the power switch unit is connected to the source of the second transistor of the power switch unit, the source of the third transistor of the power switch unit is connected to the source of the fourth transistor of the power switch unit, the drain of the second transistor of the power switch unit and the drain of the fourth transistor of the power switch unit are connected to the load, and the step (a) includes sending a cut-off signal to the gate of the first control transistor in the power switch unit, so as to And the step (c) includes sending the cut-off signal to the gates of each of the multiple second control transistors in the power switch unit; wherein, when the polarity half-cycle is a positive half-cycle, the first control transistor in the power switch unit is the second transistor in the power switch unit, and the second control transistors in the power switch unit are the first transistor, the third transistor and the fourth transistor in the power switch unit; and when the polarity half-cycle is a negative half-cycle, the first control transistor in the power switch unit is the first transistor in the power switch unit, and the second control transistors in the power switch unit are the second transistor, the third transistor and the fourth transistor in the power switch unit.

10. The switching control system according to claim 8, It is characterized in that The first transistor, the second transistor, the third transistor and the fourth transistor of the power switch unit are NMOS, the drain of the first transistor of the power switch unit and the source of the third transistor of the power switch unit receive the power supply AC, the source of the first transistor of the power switch unit is connected to the source of the second transistor of the power switch unit, the drain of the third transistor of the power switch unit is connected to the drain of the fourth transistor of the power switch unit, the drain of the second transistor of the power switch unit and the source of the fourth transistor of the power switch unit are connected to the load, and the step (a) includes sending a cut-off signal to the gate of the first control transistor in the power switch unit, so as to And the step (c) includes sending the cut-off signal to the gates of each of the multiple second control transistors in the power switch unit; wherein, when the polarity half-cycle is a positive half-cycle, the first control transistor in the power switch unit is the second transistor in the power switch unit, and the second control transistors in the power switch unit are the first transistor, the third transistor and the fourth transistor in the power switch unit; and when the polarity half-cycle is a negative half-cycle, the first control transistor in the power switch unit is the first transistor in the power switch unit, and the second control transistors in the power switch unit are the second transistor, the third transistor and the fourth transistor in the power switch unit.

11. The switching control system according to claim 8, It is characterized in that The first transistor, the second transistor, the third transistor and the fourth transistor of the power switch unit are NMOS, the source of the first transistor of the power switch unit and the drain of the third transistor of the power switch unit receive the power supply AC, the drain of the first transistor of the power switch unit is connected to the drain of the second transistor of the power switch unit, the source of the third transistor of the power switch unit is connected to the source of the fourth transistor of the power switch unit, the source of the second transistor of the power switch unit and the drain of the fourth transistor of the power switch unit are connected to the load, and the step (a) includes sending a cut-off signal to the gate of the first control transistor in the power switch unit, so as to And the step (c) includes sending the cut-off signal to the gates of each of the multiple second control transistors in the power switch unit; wherein, when the polarity half-cycle is a positive half-cycle, the first control transistor in the power switch unit is the first transistor in the power switch unit, and the second control transistors in the power switch unit are the second transistor, the third transistor and the fourth transistor in the power switch unit; and when the polarity half-cycle is a negative half-cycle, the first control transistor in the power switch unit is the second transistor in the power switch unit, and the second control transistors in the power switch unit are the first transistor, the third transistor and the fourth transistor in the power switch unit.

12. The switching control system according to claim 8, It is characterized in that The first transistor, the second transistor, the third transistor and the fourth transistor of the power switch unit are NMOS, the source of the first transistor of the power switch unit and the source of the third transistor of the power switch unit receive the power supply AC, the drain of the first transistor of the power switch unit is connected to the drain of the second transistor of the power switch unit, the drain of the third transistor of the power switch unit is connected to the drain of the fourth transistor of the power switch unit, the source of the second transistor of the power switch unit and the source of the fourth transistor of the power switch unit are connected to the load, and the step (a) includes sending a cut-off signal to the gate of the first control transistor in the power switch unit, so as to And the step (c) includes sending the cut-off signal to the gates of each of the multiple second control transistors in the power switch unit; wherein, when the polarity half-cycle is a positive half-cycle, the first control transistor in the power switch unit is the first transistor in the power switch unit, and the second control transistors in the power switch unit are the second transistor, the third transistor and the fourth transistor in the power switch unit; and when the polarity half-cycle is a negative half-cycle, the first control transistor in the power switch unit is the second transistor in the power switch unit, and the second control transistors in the power switch unit are the first transistor, the third transistor and the fourth transistor in the power switch unit.

13. A switching control system as claimed in any one of claims 9, 10, 11 or 12, It is characterized in that The first transistor, the second transistor, the third transistor and the fourth transistor of the standby switch unit are NMOS, the drain of the first transistor of the standby switch unit and the drain of the third transistor of the standby switch unit receive the standby AC power, the source of the first transistor of the standby switch unit is connected to the source of the second transistor of the standby switch unit, the source of the third transistor of the standby switch unit is connected to the source of the fourth transistor of the standby switch unit, the drain of the second transistor of the standby switch unit and the drain of the fourth transistor of the standby switch unit are connected to the load, and the step (b) includes sending a turn-on signal to the gate electrodes of the plurality of first control transistors in the standby switch unit. The step (d) includes sending a turn-on signal to the gate of the second control transistor in the standby switch unit; wherein, when the polarity half-cycle is the positive half-cycle, the first control transistors in the standby switch unit are the first transistor, the third transistor and the fourth transistor in the standby switch unit, and the second control transistor in the standby switch unit is the second transistor in the standby switch unit; and when the polarity half-cycle is the negative half-cycle, the first control transistors in the standby switch unit are the second transistor, the third transistor and the fourth transistor in the standby switch unit, and the second control transistor in the standby switch unit is the first transistor in the standby switch unit.

14. A switching control system as claimed in any one of claims 9, 10, 11 or 12, It is characterized in that The first transistor, the second transistor, the third transistor and the fourth transistor of the standby switch unit are NMOS, the drain of the first transistor of the standby switch unit and the source of the third transistor of the standby switch unit receive the standby AC power, the source of the first transistor of the standby switch unit is connected to the source of the second transistor of the standby switch unit, the drain of the third transistor of the standby switch unit is connected to the drain of the fourth transistor of the standby switch unit, the drain of the second transistor of the standby switch unit and the source of the fourth transistor of the standby switch unit are connected to the load, and the step (b) includes sending a turn-on signal to the gate electrodes of the plurality of first control transistors in the standby switch unit. The step (d) includes sending a turn-on signal to the gate of the second control transistor in the standby switch unit; wherein, when the polarity half-cycle is the positive half-cycle, the first control transistors in the standby switch unit are the first transistor, the third transistor and the fourth transistor in the standby switch unit, and the second control transistor in the standby switch unit is the second transistor in the standby switch unit; and when the polarity half-cycle is the negative half-cycle, the first control transistors in the standby switch unit are the second transistor, the third transistor and the fourth transistor in the standby switch unit, and the second control transistor in the standby switch unit is the first transistor in the standby switch unit.

15. A switching control system as claimed in any one of claims 9, 10, 11 or 12, It is characterized in that The first transistor, the second transistor, the third transistor and the fourth transistor of the standby switch unit are NMOS, the source of the first transistor of the standby switch unit and the drain of the third transistor of the standby switch unit receive the standby AC power, the drain of the first transistor of the standby switch unit is connected to the drain of the second transistor of the standby switch unit, the source of the third transistor of the standby switch unit is connected to the source of the fourth transistor of the standby switch unit, the source of the second transistor of the standby switch unit and the drain of the fourth transistor of the standby switch unit are connected to the load, and the step (b) includes sending a turn-on signal to the gate electrodes of the plurality of first control transistors in the standby switch unit. The step (d) includes sending a turn-on signal to the gate of the second control transistor in the standby switch unit; wherein, when the polarity half-cycle is the positive half-cycle, the first control transistors in the standby switch unit are the second transistor, the third transistor and the fourth transistor in the standby switch unit, and the second control transistor in the standby switch unit is the first transistor in the standby switch unit; and when the polarity half-cycle is the negative half-cycle, the first control transistors in the standby switch unit are the first transistor, the third transistor and the fourth transistor in the standby switch unit, and the second control transistor in the standby switch unit is the second transistor in the standby switch unit.

16. A switching control system as claimed in any one of claims 9, 10, 11 or 12, It is characterized in that The first transistor, the second transistor, the third transistor and the fourth transistor of the standby switch unit are NMOS, the source of the first transistor of the standby switch unit and the source of the third transistor of the standby switch unit receive the standby AC power, the drain of the first transistor of the standby switch unit is connected to the drain of the second transistor of the standby switch unit, the drain of the third transistor of the standby switch unit is connected to the drain of the fourth transistor of the standby switch unit, the source of the second transistor of the standby switch unit and the source of the fourth transistor of the standby switch unit are connected to the load, and the step (b) includes sending a turn-on signal to the gate electrodes of each of the plurality of first control transistors in the standby switch unit. The step (d) includes sending a turn-on signal to the gate of the second control transistor in the standby switch unit; wherein, when the polarity half-cycle is the positive half-cycle, the first control transistors in the standby switch unit are the second transistor, the third transistor and the fourth transistor in the standby switch unit, and the second control transistor in the standby switch unit is the first transistor in the standby switch unit; and when the polarity half-cycle is the negative half-cycle, the first control transistors in the standby switch unit are the first transistor, the third transistor and the fourth transistor in the standby switch unit, and the second control transistor in the standby switch unit is the second transistor in the standby switch unit.

17. The switching control system according to claim 1, It is characterized in that The control unit is configured to execute an emergency switching step in response to detecting that the voltage of the power supply AC power is less than a threshold value, so that the backup AC power replaces the power supply AC power to supply power to the load.

18. The switching control system according to claim 17, It is characterized in that The emergency switching step includes: in response to detecting that the power supply AC power and the backup AC power in the AC power are both in the polarity half cycle and the voltage difference between the two is less than the preset voltage, executing the steps (a) to (d).

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