Dual power supply switching system and operating method therefor

Abstract

The present invention provides a dual power supply switching system and an operating method therefor. The dual power supply switching system selects a first power supply or a second power supply to supply power to a load coupled with an inductive device. The dual power supply switching system comprises a first thyristor, a second thyristor, a third thyristor, a fourth thyristor, and a controller, and the controller calculates a total magnetic flux on the basis of the current magnetic flux of the inductive device and a predicted magnetic flux of the second power supply. When the power supply source is switched from the first power supply to the second power supply, the controller separately controls the first thyristor and the second thyristor to be turned off, and determines, on the basis of electrical parameters of a first static transfer switch and a second static transfer switch, whether a commutation time is reached. When the commutation time is reached, on the basis that the total magnetic flux is less than a threshold, the controller correspondingly turns on at least one of the third thyristor and the fourth thyristor.

Description

Dual power switching system and operating method thereof Technical Field

[0001] The present disclosure relates to a switching system and an operating method thereof, and more particularly to a dual power switching system and an operating method thereof. Background Art

[0002] A static transfer switch (STS) is an essential component in data center power system configurations, providing uninterruptible power to critical equipment and other loads. It typically includes multiple silicon-controlled rectifiers (SiCs). STSs are typically powered by two or more independent power sources. If the primary power source falls outside of acceptable limits, they automatically switch from the primary source to the backup source, providing uninterruptible power to critical equipment and preventing power outages that could force downtime.

[0003] Typically, the output of a static transfer switch device is connected to critical equipment via a transformer. Because transformers are inductive devices, when the accumulated magnetic flux is too high, they can experience flux saturation. Therefore, if the primary power source exceeds an acceptable range and improper switching occurs between the two power sources, high inrush currents can be induced in the downstream transformer. When the inrush current is too high, it can overload upstream circuits or trip circuit breakers, leading to a power outage in the entire system. Therefore, the existing power switching method is to wait for the current flowing through the silicon-controlled rectifier of the main power source to drop to zero before turning on the silicon-controlled rectifier of the backup power source to avoid excessive inrush current. However, this switching method requires waiting for the current to drop to zero and an additional wait for the appropriate time to switch, resulting in an excessively long wait time and an excessively low output voltage, which still poses a risk of forced shutdown of critical equipment.

[0004] Therefore, how to design a dual power switching system and its operating method to avoid improper dual power switching has become a major research topic for the inventors of this case.

[0005] Summary of the Invention

[0006] In order to solve the above problems, the present disclosure provides a dual power switching system to overcome the problems of the prior art. Therefore, the dual power switching system disclosed in the present disclosure selects a first power supply or a second power supply to power a load coupled to an inductive device, and the dual power switching system includes a first static transfer switch, a second static transfer switch, and a controller. The first static transfer switch couples the first power supply and the inductive device, and includes a first thyristor and a second thyristor connected in reverse parallel. The second static transfer switch couples the second power supply and the inductive device, and includes a third thyristor and a fourth thyristor connected in reverse parallel, and the forward deflection direction of the first thyristor and the fourth thyristor is the same. The controller selectively controls the first thyristor, the second thyristor, the third thyristor, and the fourth thyristor according to whether the power supply source is the first power supply or the second power supply. When the power supply source is switched from the first power supply to the second power supply, the controller controls the first thyristor and the second thyristor to be turned off respectively, and determines whether the switching time has been reached based on the power parameters of the first static transfer switch and the second static transfer switch. The controller calculates the total magnetic flux according to the current magnetic flux of the inductive device and the expected magnetic flux of the second power supply, and when the switching time is reached, the controller switches on at least one of the third gate fluid and the fourth gate fluid according to the total magnetic flux being less than a threshold.

[0007] To address the aforementioned issues, the present disclosure provides an operating method for a dual power switching system to overcome the problems of the prior art. The dual power switching system of the present disclosure includes a first static transfer switch and a second static transfer switch coupled to an inductive device. The first static transfer switch includes a first thyristor and a second thyristor connected in anti-parallel, and the second static transfer switch includes a third thyristor and a fourth thyristor connected in anti-parallel. The operating method includes the following steps: (a) when the power source switches from the first power source to the second power source, controlling the first thyristor and the second thyristor to be turned off, respectively. (b) calculating the total magnetic flux based on the current magnetic flux of the inductive device and the expected magnetic flux of the second power source. (c) determining whether a switching time has been reached based on the power parameters of the first static transfer switch and the second static transfer switch. When the switching time has been reached, executing the following steps: (d1) determining whether the total magnetic flux is less than a threshold. (d2) when the total magnetic flux is less than the threshold, correspondingly turning on at least one of the third thyristor and the fourth thyristor.

[0008] The primary purpose and effectiveness of this disclosure is to provide a method for operating a dual-power switching system. This method utilizes four independent control signals to control the gate terminals, ensuring that the total magnetic flux does not exceed a threshold during a specific switching period. This ensures that the corresponding thyristors of the first and second static transfer switches are independently turned on, thereby shortening the power switching time and reducing inrush current.

[0009] To further understand the techniques, means, and effects employed by the present disclosure to achieve its intended objectives, please refer to the following detailed description and accompanying drawings of the present disclosure. It is believed that an in-depth and detailed understanding of the objectives, features, and characteristics of the present disclosure can be obtained from these drawings. However, the accompanying drawings are provided for reference and illustration purposes only and are not intended to limit the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG1 is a circuit block diagram of the dual power switching system disclosed herein;

[0011] FIG2 is a waveform diagram of the main power supply, backup power supply, and output power supply of the present disclosure;

[0012] FIG3 is a flow chart showing the determination of the switching time of the dual power switching system disclosed herein;

[0013] FIG4 is a switching timing flow chart of the dual power switching system disclosed herein;

[0014] FIG5A is a switching timing flow chart of the first embodiment of the dual power switching system disclosed herein;

[0015] FIG5B is a waveform diagram of the first embodiment of the dual power switching system disclosed herein;

[0016] FIG6A is a switching timing flow chart of the second embodiment of the dual power switching system disclosed herein; and

[0017] FIG. 6B is a waveform diagram of the second embodiment of the dual power switching system disclosed in the present invention.

[0018] DESCRIPTION OF REFERENCE NUMERALS 100: Dual power switching system 120: Inductive device 120A: First side winding 120B: Second side winding 121: Load 130: First static transfer switch 130a: First thyristor 130b: Second thyristor 131: Second static transfer switch 131a: Third thyristor 131b: Fourth thyristor 132, 133: Current sensor 134: Controller 110: First power source 111: Second power source V1, V2, Vo: Voltage signals I1, I2: Current signals Sc1-Sc4: Control signals f1, f2, fo: Magnetic flux Φ max :Upper limit magnetic flux-Φ max :Lower limit magnetic flux Φ thz :Threshold Φ LoadReal : Current magnetic flux fo, Φ future :Estimated magnetic flux Φ all :Total magnetic flux k flux : Polarity (S100) ~ (S360): Steps (A) ~ (C): Waveform t1 ~ t3: Time DETAILED DESCRIPTION

[0019] The technical content and detailed description of this disclosure are as follows with reference to the accompanying drawings:

[0020] Please refer to FIG1 for a circuit block diagram of the dual power switching system disclosed herein. The dual power switching system 100 primarily supplies power to a load 121 and includes a static transfer switch device, an inductive device 120, and a controller 134. The static transfer switch device includes a first static transfer switch 130 and a second static transfer switch 131. The load 121 may preferably be, but is not limited to, a critical load that requires uninterrupted and continuous operation, such as a server or a communication system. The first static transfer switch 130 is coupled to the first power source 110, and the second static transfer switch 131 is coupled to the second power source 111. The inductive device 120 includes a first side winding 120A and a second side winding 120B. The first side winding 120A is coupled to the first static transfer switch 130 and the second static transfer switch 131, and the second side winding 120B is coupled to the load 121. The controller 134 detects the power from the first power source 110 and the second power source 111, as well as the output power received by the inductive device 120, and accordingly regulates the first static transfer switch 130 and the second static transfer switch 131. The controller 134 primarily selects the first power source 110 or the second power source 111 to power the load 121 coupled to the inductive device 120. It is worth noting that, in one embodiment, the controller 134 may be a digital signal processor (DSP), but this is not a limitation. Any physical circuit capable of utilizing signals for circuit control, a control device containing built-in control software, and the like are encompassed within the scope of this embodiment.

[0021] Specifically, the dual power switching system 100 further includes a voltage sensor (not shown) and current sensors 132 and 133. The voltage sensor and current sensors 132 and 133 are coupled to the first power source 110 and the second power source 111, respectively, to detect voltage signals V1 and V2 and current signals I1 and I2 (i.e., power, but not limited to such) corresponding to the first power source 110 and the second power source 111. Furthermore, the voltage sensor is coupled to the first winding 120A or the second winding 120B of the inductive device 120 to detect a voltage signal Vo corresponding to the first winding 120A or the second winding 120B.

[0022] Referring to FIG2 , which shows the waveforms of the main power supply, backup power supply, and output power of the present disclosure, the voltage waveforms of the first power supply 110 and the second power supply 111 have a phase difference, but this is for illustrative purposes only and is not related to each other. In other words, the switching method of the present disclosure primarily controls magnetic flux, regardless of the magnitude of the phase difference. The controller 134 obtains the voltage signals V1, V2, and Vo and integrates them to obtain the magnetic fluxes f1 and f2 corresponding to the first power supply 110 and the second power supply 111, as well as the magnetic flux fo on the inductive device 120. The magnetic fluxes f1, f2, and fo are respectively the integrals of the voltage signal V1, and the magnetic flux f2 is the integral of the voltage signal V2. The magnetic flux fo is the integral of the voltage signal Vo, and the magnetic fluxes f1 and fo are consistent because the first static transfer switch 130 is turned on, connecting the first power supply 110 to the inductive device 120 and the first power supply 110. Since the integral of the voltage is the magnetic flux and the integral of the sine wave is still a sine wave, the magnetic fluxes f1, f2 and the expected magnetic flux fo are still sinusoidal waveforms.

[0023] Referring again to FIG. 2 , the first static transfer switch 130 and the second static transfer switch 131 each include multiple silicon-controlled rectifiers (SCRs). The first thyristor 130a and the second thyristor 130b of the first static transfer switch 130 are connected in anti-parallel, and the third thyristor 131a and the fourth thyristor 131b of the second static transfer switch 131 are also connected in anti-parallel. The thyristors 130a-131b are preferably silicon-controlled rectifiers, but are not limited thereto. Furthermore, the anodes and cathodes of the first thyristor 130a and the third thyristor 131a are arranged in the same direction, and the anodes and cathodes of the second thyristor 130b and the fourth thyristor 131b are arranged in the same direction. Therefore, the forward-biased direction of the first thyristor 130a and the fourth thyristor 131b is the same, and the forward-biased direction of the second thyristor 130b and the third thyristor 131a is the same.

[0024] Due to the characteristic of the thyristors 130a-131b, the controller 134 cannot shut off the thyristors 130a-131b via the gate terminals when current is flowing through them. Therefore, the thyristors 130a-131b are only shut off after the thyristors 130a-131b naturally continue to flow to zero or after forced commutation techniques are used to eliminate the anode current. Therefore, the primary purpose and effectiveness of the present disclosure is to provide an operating method for a dual-power switching system to operate dual-power switching. This operating method primarily utilizes four independent sets of control signals Sc1-Sc4 to control the gate terminals, ensuring that the total magnetic flux does not exceed a threshold during a specific commutation period. This ensures that the first static transfer switch 130 and the second static transfer switch 131 independently turn on the corresponding thyristors 130a-131b, thereby shortening the power switching transition time and reducing inrush current. After describing the structural features of the present disclosure, the operating method will be further described below and will not be elaborated upon here.

[0025] Specifically, the controller 134 of the present disclosure selectively controls the first thyristor 130a, the second thyristor 130b, the third thyristor 131a, and the fourth thyristor 131b, depending on whether the power source is the first power source 110 or the second power source 111. The controller 134 can be used to continuously and in real time calculate and capture the magnetic fluxes f1, f2, and fo in the first power source 110, the second power source 111, and the downstream inductive device 120 (such as, but not limited to, an inductive component such as a transformer). If a power failure event occurs (for example, but not limited to, an abnormality in the first power supply 110), the controller 134 provides control signals Sc1 and Sc2, respectively, to shut down the thyristors 130a and 130b in the working path of the first power supply 110. Then, based on the magnetic flux calculated from the currently detected voltage signals V1, V2, and Vo, and in accordance with the specific operating method of the disclosed design, the controller 134 provides control signals Sc3 and Sc4, respectively, to turn on the thyristors 131a and 131b in the backup path (i.e., the second power supply 111). This prevents improper switching between the two power supplies, which could cause a high inrush current in the downstream inductive device 120, and also prevents the output power from dropping too low to maintain stable operation of the load 121 due to waiting for the silicon-controlled rectifier to freewheel to zero. In accordance with the specific operating method of the disclosed design, the control signals Sc3 and Sc4 can be provided in stages to turn on the thyristors 131a and 131b, respectively (i.e., only one of the thyristors 131a and 131b is turned on during a specific switching period).

[0026] On the other hand, the controller 134 can detect the first current (i.e., current signal I1) flowing through the first static transfer switch 130 via the first current sensor 132 to determine whether the first static transfer switch 130 is on or off. In other words, the controller 134 can confirm whether the first static transfer switch 130 is correctly on / off via the first current (i.e., current signal I1), thereby confirming whether the entire dual power switching system 100 is operating normally. On the other hand, the controller 134 can simply determine whether the thyristors 130a and 130b are correctly on / off by detecting the voltage across the terminals of the thyristors 130a and 130b (via voltage signals V1 and Vo). Conversely, the controller 134 can confirm whether the second static transfer switch 131 is correctly on / off via the second current (i.e., current signal I2), thereby confirming whether the entire dual power switching system 100 is operating normally. Furthermore, it is also possible to simply determine whether the thyristors 130a and 130b are correctly turned on / off by detecting the voltage across the two ends of the thyristors 131a and 131b (via the voltage signals V2 and Vo).

[0027] In Figure 2, Φ max is the preset upper limit magnetic flux, and -Φ max The main feature of the present disclosure is that after the dual power supply is switched, the magnetic flux fo of the downstream inductive device 120 is always limited to the upper limit magnetic flux Φ max and the lower limit magnetic flux -Φ max To avoid the magnetic flux fo exceeding the range and causing the inductive device 120 to saturate and cause excessive surge current. max and the lower limit magnetic flux -Φ max All are based on the threshold Φ thz This disclosure takes the switching of the first power source 110 (i.e., as the main power source) to the second power source 111 (i.e., as the backup power source) as an example, and mainly obtains the current magnetic flux Φ of the inductive device 120 at the time of switching. LoadReal , and the expected magnetic flux Φ of the second power source 111 future The switching timing of the thyristors 131a and 131b is determined by calculating the two, wherein the magnetic flux Φ is expected to be future The calculation formula is: future =φ max -φ111……(Formula 1), or φ future =-φ max -φ111……(Formula 2).

[0028] By calculating the above formulas 1 and 2, we can obtain how much future magnetic flux will be added to the inductive device 120 after the first power source 110 switches to the second power source 111 (that is, the sum of the two can be the total magnetic flux Φ all ), which is calculated as: φ all =φ LoadReal +φ future ...(Formula 3).

[0029] Therefore, the total magnetic flux after switching Φ all Must be less than the threshold Φ thz To avoid improper switching between the two power sources and causing high inrush current in the downstream inductive device 120. Due to the off characteristics of the thyristors 130a-131b, in addition to considering the total magnetic flux Φ all Must be less than the threshold Φ thz In addition, it is also necessary to consider whether the second static transfer switch 131 can provide a reverse bias voltage to force the first static transfer switch 130 to be turned off when it is turned on, so as to achieve forced commutation and speed up the dual power switching speed.

[0030] Please refer to FIG3 for a flow chart of determining the switchable time of the dual power switching system disclosed herein, and refer to FIG1 and FIG2 in conjunction. The process in FIG3 is primarily for determining whether the switchable time has been reached, and is primarily based on the example of switching from the first power source 110 (i.e., serving as the main power source) to the second power source 111 (i.e., serving as the backup power source). When the switchable time has been reached, if the corresponding thyristors 131a-131b are turned on, a reverse bias can be provided to force the first static transfer switch 130 to shut down. Therefore, when the power source is to be switched from the first power source 110 to the second power source 111, the controller 134 provides control signals Sc1 and Sc2, respectively, to control the first thyristor 130a and the second thyristor 130b to shut down. At this point, it is possible that one of the two thyristors cannot be shut down successfully, or both of them cannot be shut down successfully. Therefore, the controller 134 can determine which of the first and second static transfer switches 130 and 131 is not switched off, or both are switched off, by detecting power parameters of the first and second static transfer switches 130 and 131. Furthermore, the controller 134 can determine whether the switching time of the remaining thyristors 130a and 130b has reached a switching time. The power parameters can be voltage signals V1, V2, and Vo, or current signals I1 and I2.

[0031] Taking Figure 3 as an example, after the controller 134 provides control signals Sc1 and Sc2 to control the first thyristor 130a and the second thyristor 130b to be turned off, the controller 134 then determines whether the voltage difference between the first voltage of the first power source 110 (corresponding to the voltage signal V1) and the load voltage of the inductive device 120 (corresponding to the voltage signal Vo) is greater than a voltage threshold (S100). If the controller 134 determines that the voltage difference is greater than the voltage threshold, it indicates that both thyristors 130a and 130b of the first static transfer switch 130 are turned off, resulting in a power difference between the first power source 110 and the inductive device 120. Therefore, the controller 134 determines that both the third thyristor 131a and the fourth thyristor 131b have reached their switching time (S120).

[0032] Conversely, if the result of step (S100) is negative, it indicates that one of the thyristors 130a and 130b of the first static transfer switch 130 has not yet been turned off. Therefore, the controller 134 determines whether the first current (corresponding to the current signal I1) is greater than zero (S140). If the first current (corresponding to the current signal I1) is greater than zero, it indicates that the first thyristor 130a has not yet been turned off. Therefore, the process proceeds to step (S160) to determine whether the second voltage (corresponding to the voltage signal V2) is greater than the load voltage (corresponding to the voltage signal Vo) of the inductive device 120. If the controller 134 determines that the second voltage (corresponding to the voltage signal V2) is greater than the load voltage (corresponding to the voltage signal Vo) of the inductive device 120, it indicates that turning on the third thyristor 131a for a specific period of time will provide a reverse bias to force the first thyristor 130a to turn off. Therefore, the controller 134 determines that the switching time of the third thyristor 131a has reached (S180). On the contrary, when the determination result of step (S160) is negative, the process returns to step (S100) to continue detection and determination.

[0033] If the determination result in step (S140) is negative, it indicates that the second thyristor 130b is not turned off. Therefore, the process proceeds to step (S200) to determine whether the second voltage (corresponding to the voltage signal V2) is less than the load voltage (corresponding to the voltage signal Vo) of the inductive device 120. If the controller 134 determines that the second voltage (corresponding to the voltage signal V2) is less than the load voltage (corresponding to the voltage signal Vo) of the inductive device 120, it indicates that turning on the fourth thyristor 131b during the specified period of time will provide a reverse bias to force the second thyristor 130b to turn off. Therefore, the controller 134 determines that the switching time of the fourth thyristor 131b has reached (S220). Conversely, if the determination result in step (S200) is negative, the process returns to step (S100) for continued testing and determination. It is worth noting that, in one embodiment, the process of FIG3 can be applied to the circuit architecture of FIG1, but is not limited thereto. Any multi-power switching system that can force commutation by supplying a reverse bias voltage should be included in the scope of this embodiment.

[0034] When the switching time is reached, the controller 134 can adjust the current magnetic flux Φ of the inductive device 120 according to the current magnetic flux Φ of the inductive device 120. LoadReal The expected magnetic flux Φ of the second power source 111 future Calculate the total magnetic flux Φ all When the switching time is reached, the controller 134 determines the total magnetic flux Φ all Is it less than the threshold Φ thz , according to the total magnetic flux Φ all Less than the threshold Φ thz Correspondingly, at least one of the third gate fluid 131a and the fourth gate fluid 131b is turned on. That is, the controller 134 can turn on only the third gate fluid 131a, only the fourth gate fluid 131b, or both the third gate fluid 131a and the fourth gate fluid 131b. The switching timing of each gate fluid will be further described below and will not be further elaborated here.

[0035] Please refer to FIG4 for a switching timing flow chart of the dual power switching system disclosed in this disclosure, and refer to FIG1 to FIG3 in conjunction. After the switching time is reached, the controller 134 needs to determine the switching timing of each thyristor to avoid the total magnetic flux Φ of the inductive device 120 being too large when the thyristor is switched. all Exceeding the threshold Φ thz Therefore, the controller 134 can generate a higher inrush current according to the current magnetic flux Φ LoadReal and the expected magnetic flux Φ future Calculate polarity k flux , and its calculation formula is: k flux =sgn(φ LoadReal ·φ future )……(Formula 4).

[0036] Where sgn is the sign function, which is used to determine the sign of a real number. Therefore, when the two are the same, the polarity is positive, otherwise it is negative. Since the flux calculation and switching operation of the dual power switching system are based on half a cycle, if the current flux Φ LoadReal is positive, and the future predicted magnetic flux Φ future When it is negative, the accumulated total magnetic flux Φ all must be less than the threshold Φ thz , (conversely, the current magnetic flux Φ LoadReal (This also applies when the voltage is negative). Therefore, during this period, reverse bias can be provided to forcibly turn off the thyristors that are not turned off, thereby achieving forced commutation. Therefore, in step (S300) of Figure 4, the first power supply 110 supplies power to the load 121, and the first thyristor 130a and the second thyristor 130b are conductive. Then, in step (S300), the controller 134 intends to switch the power source from the first power supply 110 to the second power supply 111, and therefore provides control signals Sc1 and Sc2 to respectively turn off the first thyristor 130a and the second thyristor 130b.

[0037] After this, the judgment result of one of the steps (S120), (S180) and (S220) in FIG3 can be obtained. Then, when the judgment result is step (S120) or (S180), the controller 134 can wait for the opportunity to enter step (S320) in FIG4. Therefore, the controller 134 can judge the polarity k according to the calculation result. flux Is it opposite, and is the second voltage (corresponding to the voltage signal V2) greater than zero? flux On the other hand, when the second voltage (corresponding to the voltage signal V2) is greater than zero, the controller 134 provides the control signal Sc3 to the third gate 131a to forcibly turn off the first gate 130a by turning on the third gate 131a. At this time, the controller 134 has not yet provided the control signal Sc4 to turn on the fourth gate 131b.

[0038] In step (S320), the first thyristor 130a is forced to turn off by the conduction of the third thyristor 131a, and the second thyristor 130b has been successfully turned off when the controller 134 provides the control signal Sc2. Therefore, the remaining fourth thyristor 131b has not yet turned on. However, if the fourth thyristor 131b is to be turned on, the total magnetic flux Φ after it is turned on must be considered. all Can it be less than the threshold Φ thz, in order to prevent the inductive device 120 from generating an excessive surge current. Therefore, in step (S320), it is still necessary to wait for the opportunity to conduct the fourth gate fluid 131b and enter the step (S340) of conducting the third gate fluid 131a and the fourth gate fluid 131b. That is, in step (S320), the controller 134 determines the total magnetic flux Φ all Is it less than the threshold Φ thz , and whether the second voltage (corresponding to the voltage signal V2) is less than zero. all Less than the threshold Φ thz , and the second voltage (corresponding to the voltage signal V2) is less than zero, it means that the fourth gate fluid 131b is turned on at this time to make the total magnetic flux Φ all Less than the threshold Φ thz Therefore, the controller 134 can independently conduct the third gate fluid 131a and the fourth gate fluid 131b, and after conducting the third gate fluid 131a, the controller 134 can further conduct the third gate fluid 131b according to the second voltage (corresponding to the voltage signal V2) being less than zero and the total magnetic flux Φ all Less than the threshold Φ thz The fourth thyristor 131 b is turned on to prevent the inductive device 120 from generating an excessive surge current.

[0039] On the other hand, the determination and operation mechanism of steps (S300) to (S360) is similar to that of steps (S300) to (S320), with the only difference being that the fourth gate fluid 131b is turned on first. The rest of the process is similar and will not be described in detail here. Similarly, the determination and operation mechanism of steps (S360) to (S340) is similar to that of steps (S320) to (S340), with the only difference being that the third gate fluid 131a is turned on last. The rest of the process is similar and will not be described in detail here.

[0040] On the other hand, if a specific condition is met in step (S300), the process can be switched directly to step (S340) to complete the dual power switching. Specifically, if the result of the judgment is step (S120), it means that after the controller 134 provides the control signals Sc1 and Sc2 to the first thyristor 130a and the second thyristor 130b, the first thyristor 130a and the second thyristor 130b have been successfully shut down. Under this condition, the controller 134 can determine the total magnetic flux Φ all Is it less than the threshold Φ thz , and polarity k flux When the controller 134 determines the total magnetic flux Φ all Less than the threshold Φ thz , and polarity k fluxAt the same time, the controller can simultaneously provide control signals Sc3 and Sc4 to the third thyristor 131a and the fourth thyristor 131b to achieve dual power switching without generating excessive inrush current in the inductive device 120. It is worth noting that, in one embodiment, the process of FIG4 can be applied to the circuit architecture of FIG1 , but this is not a limitation. Any multi-power switching system that can force commutation by providing a reverse bias voltage is also included in the scope of this embodiment.

[0041] Please refer to FIG5A for a switching timing flow chart of the first embodiment of the dual power switching system disclosed herein, and FIG5B for a waveform diagram of the first embodiment of the dual power switching system disclosed herein, and refer to FIG1 to FIG4 in conjunction. FIG5A shows the switching timing flow chart of step (S300) to step (S340) of FIG4, and FIG5B is a corresponding waveform diagram. In FIG5B, waveform (A) includes a first voltage of the first power supply 110 (corresponding to the voltage signal V1), a second voltage of the second power supply 111 (corresponding to the voltage signal V2), and a load voltage of the inductive device 120 (corresponding to the voltage signal Vo). Waveform (B) includes a first current of the first power supply 110 (corresponding to the current signal I1) and a second current of the second power supply 111 (corresponding to the current signal I2), and waveform (C) includes the total magnetic flux Φ of the inductive device 120. all .

[0042] At time t1, the controller 134 determines that both the third gate fluid 131a and the fourth gate fluid 131b have reached the switching time (step S120, FIG3). However, the controller 134 determines that if switching is performed at this time, the total magnetic flux Φ all Not less than the threshold Φ thz Therefore, the controller 134 waits without switching the third gate fluid 131a and the fourth gate fluid 131b. When the waiting time reaches time t2, the controller 134 determines the total magnetic flux Φ all Less than the threshold Φ thz Therefore, the controller 134 provides control signals Sc3 and Sc4 to conduct the third and fourth thyristors 131a and 131b, switching the input source from the first power source 110 to the second power source 111, completing the power switching operation (step S340, FIG. 4 ). Before time t2, the load 121 is powered by the first power source 110, so the voltage waveform Vo is identical to the voltage waveform V1. After time t2, the load 121 is powered by the second power source 111, so the voltage waveform Vo is identical to the voltage waveform V2.

[0043] Please refer to FIG6A for a switching timing flow chart of the second embodiment of the dual power switching system disclosed herein, and FIG6B for a waveform diagram of the second embodiment of the dual power switching system disclosed herein. Please refer to FIG1 to FIG5B in conjunction. In FIG6A, waveforms (A) to (C) are the same as those in FIG5A and will not be described again here. At time t1, the controller 134 determines the polarity k flux On the contrary, the third gate fluid 131a reaches the switching time (step S180, Figure 3). Therefore, the controller 134 first provides a control signal Sc3 to turn on the third gate fluid 131a, so as to force the first gate fluid 130a to be turned off by turning on the third gate fluid 131a (step S320, Figure 4). At this time, the voltage waveform Vo switches from the voltage waveform V1 to the voltage waveform V2. Then, when the time t2 is reached, the second voltage (corresponding to the voltage signal V2) is less than zero. Although the controller 134 can naturally switch on the fourth gate fluid 131b at this time, the controller 134 determines that if the fourth gate fluid 131b is turned on at this time, the total magnetic flux Φ all Greater than the threshold Φ thz Therefore, the controller 134 continues to wait and temporarily does not conduct the fourth gate fluid 131b. When the waiting time reaches t3, the controller 134 determines that after conducting the fourth gate fluid 131b at this time, the total magnetic flux Φ all Can be less than the threshold Φ thz Therefore, at time t3, the controller 134 turns on the fourth gate 131b to complete the power switching operation (step S340, FIG4 ).

[0044] However, the above description is only a detailed description and drawings of the preferred embodiments of the present disclosure. The features of the present disclosure are not limited thereto and are not intended to limit the present disclosure. The full scope of the present disclosure shall be based on the following claims. All embodiments that conform to the spirit of the claims of the present disclosure and similar variations thereof shall be included in the scope of the present disclosure. Any changes or modifications that can be easily conceived by any person skilled in the art within the scope of the present disclosure shall be covered by the following patent scope of this case.

Claims

1. A dual power switching system that selects a first power source or a second power source to power a load coupled to an inductive device, the dual power switching system comprising: A first static transfer switch, coupling the first power source and the inductive device, and comprising a first thyristor and a second thyristor connected in anti-parallel; a second static transfer switch coupled to the second power source and the inductive device, and comprising a third thyristor and a fourth thyristor connected in anti-parallel, wherein the first thyristor and the fourth thyristor have the same forward bias direction; and a controller, selectively controlling the first gate fluid, the second gate fluid, the third gate fluid, and the fourth gate fluid according to whether the power source is the first power source or the second power source; When the power source is switched from the first power source to the second power source, the controller controls the first thyristor and the second thyristor to be turned off respectively, and determines whether the switching time has arrived based on the power parameters of the first static transfer switch and the second static transfer switch; and The controller calculates a total magnetic flux based on a current magnetic flux of the inductive device and a predicted magnetic flux of the second power supply, and when the switching time is reached, the controller switches on at least one of the third gate fluid and the fourth gate fluid accordingly based on the total magnetic flux being less than a threshold.

2. The dual power switching system according to claim 1, wherein the power parameter includes a voltage difference, and when the voltage difference between the first voltage of the first power source and the load voltage of the inductive device is greater than a voltage threshold, the controller determines that the third gate fluid and the fourth gate fluid have reached the switching time.

3. The dual power switching system according to claim 1, wherein the power parameters include a first current of the first power supply and a second voltage of the second power supply, and when the controller determines that the first current is greater than zero and the second voltage is greater than the load voltage of the inductive device, the controller determines that the third thyristor has reached the switching time.

4. The dual power switching system according to claim 1, wherein the power parameters include a first current of the first power supply and a second voltage of the second power supply, and when the controller determines that the first current is less than zero and the second voltage is less than a load voltage of the inductive device, the controller determines that the fourth gate fluid has reached the switching time.

5. The dual power switching system according to claim 1, wherein the controller calculates the polarity based on the current magnetic flux and the expected magnetic flux, and when the switching time is reached, the controller turns on the third thyristor and forces the first thyristor to turn off based on the polarity being opposite and the second voltage of the second power supply being greater than zero.

6. The dual power switching system according to claim 5, wherein the controller independently turns on the third gate and the fourth gate, and after turning on the third gate, the controller turns on the fourth gate in response to the second voltage being less than zero and the total magnetic flux being less than the threshold.

7. The dual power switching system according to claim 1, wherein the controller calculates the polarity based on the current magnetic flux and the expected magnetic flux, and when the switching time is reached, the controller turns on the fourth gate fluid and forces the second gate fluid to turn off based on the polarity being opposite and the second voltage of the second power supply being less than zero.

8. The dual power switching system according to claim 7 , wherein the controller independently turns on the third gate and the fourth gate, and after turning on the fourth gate, the controller turns on the third gate in response to the second voltage being greater than zero and the total magnetic flux being less than the threshold.

9. The dual power switching system according to claim 1, wherein the controller calculates polarity based on the current magnetic flux and the expected magnetic flux, and when the switching time is reached, the controller turns on the third gate fluid and the fourth gate fluid based on the polarity being the same and the total magnetic flux being less than the threshold.

10. A method for operating a dual power switching system, the dual power switching system comprising a first static transfer switch and a second static transfer switch coupled to an inductive device, the first static transfer switch comprising a first thyristor and a second thyristor connected in anti-parallel, and the second static transfer switch comprising a third thyristor and a fourth thyristor connected in anti-parallel, the method comprising the following steps: When the power source is switched from the first power source to the second power source, the first thyristor and the second thyristor are respectively controlled to be turned off; calculating a total magnetic flux based on a current magnetic flux of the inductive device and an expected magnetic flux of the second power source; determining whether a switching time has been reached according to power parameters of the first static transfer switch and the second static transfer switch; When the switching time is reached, the following steps are performed: (d1) determining whether the total magnetic flux is less than a threshold value; and (d2) When the total magnetic flux is less than the threshold, at least one of the third gate fluid and the fourth gate fluid is turned on accordingly.

11. The operating method of the dual power switching system according to claim 10, wherein the power parameter comprises a voltage difference, and step (c) further comprises: (c11) determining whether the voltage difference between the first voltage of the first power source and the load voltage of the inductive device is greater than a voltage threshold; and (c12) determining that the third gate fluid and the fourth gate fluid have reached the switchable time based on the voltage difference being greater than the voltage threshold.

12. The operating method of the dual power switching system according to claim 10 , wherein the power parameter comprises a first current of the first power source and a second voltage of the second power source, and step (c) further comprises: (c21) determining whether the first current is greater than zero and whether the second voltage is greater than a load voltage of the inductive device; and (c22) Determining that the third thyristor reaches the switching time based on the first current being greater than zero and the second voltage being greater than the load voltage.

13. The operating method of the dual power switching system according to claim 10 , wherein the power parameter comprises a first current of the first power source and a second voltage of the second power source, and step (c) further comprises: (c31) determining whether the first current is less than zero and whether the second voltage is less than a load voltage of the inductive device; and (c32) Determining that the fourth gate fluid reaches the switching time based on the first current being less than zero and the second voltage being less than the load voltage.

14. The operating method of the dual power switching system according to claim 10, wherein step (b) further comprises: (b1) Calculating polarity based on the current magnetic flux and the expected magnetic flux.

15. The operating method of the dual power switching system according to claim 14, wherein when the switching time is reached, the following steps are further performed: (e1) determining whether the polarities are opposite and whether the second voltage of the second power supply is greater than zero; and (e2) When the polarities are opposite and the second voltage is greater than zero, the third thyristor is turned on and the first thyristor is forced to be turned off.

16. The method for operating a dual power switching system according to claim 15, wherein after step (e2), the method further comprises: (e3) executing step (d1) and determining whether the second voltage is less than zero; and (e4) When the answer to step (d2) is yes and the second voltage is less than zero, turning on the fourth gate fluid.

17. The operating method of the dual power switching system according to claim 14, wherein when the switching time is reached, the following steps are further performed: (f1) determining whether the polarities are opposite and whether the second voltage of the second power supply is less than zero; and (f2) When the polarity is opposite and the second voltage is less than zero, the fourth thyristor is turned on and the second thyristor is forced to be turned off.

18. The operating method of the dual power switching system according to claim 17, wherein after step (f2), the method further comprises: (f3) executing step (d1) and determining whether the second voltage is greater than zero; and (f4) When the answer to step (d2) is yes and the second voltage is greater than zero, turning on the third thyristor.

19. The operating method of the dual power switching system according to claim 14, wherein when the switching time is reached, the following steps are further performed: (g1) executing step (d1) and determining whether the polarities are the same; and (g2) When the answer to step (d2) is yes and the polarities are the same, conducting the third gate fluid and the fourth gate fluid.

Images