Power supply system and voltage detection method

Abstract

A power supply system comprises a voltage conversion circuit and at least one voltage detector. The voltage conversion circuit is used for converting AC voltage into DC voltage. The voltage detector comprises a voltage division circuit, a phase voltage detection circuit and a line voltage detection circuit. The voltage division circuit is coupled to the voltage conversion circuit to receive the AC voltage. The voltage division circuit comprises a plurality of impedance elements and a plurality of voltage division nodes so as to output a plurality of divided voltages. The phase voltage detection circuit is coupled to one of the voltage division nodes of the voltage division circuit so as to generate a phase voltage detection signal according to one of the divided voltages. The line voltage detection circuit is coupled to a part of the voltage division nodes of the voltage division circuit so as to generate a line voltage detection signal according to a part of the divided voltages. The invention also relates to a voltage detection method.

Description

Technical Field

[0001] The present disclosure relates to a power supply system, and in particular to a power supply system and a voltage detection method. Background Art

[0002] With the rapid development of economy and industry, the importance of power system is increasing day by day. Generally speaking, most industrial equipment is driven by direct current. Therefore, there needs to be a conversion device between the power distribution system and the equipment to convert the alternating current provided by the power grid into direct current. The stability of power during transmission and conversion is one of the important performance indicators of the power system. Summary of the invention

[0003] The present disclosure relates to a power supply system, comprising a voltage conversion circuit and at least one voltage detector. The voltage conversion circuit is used to convert an AC voltage into a DC voltage. The voltage detector comprises a voltage divider circuit, a phase voltage detection circuit and a line voltage detection circuit. The voltage divider circuit is coupled to the voltage conversion circuit to receive an AC voltage. The voltage divider circuit comprises a plurality of impedance elements and a plurality of voltage divider nodes to output a plurality of voltage divider voltages. The phase voltage detection circuit is coupled to one of the voltage divider nodes of the voltage divider circuit to generate a phase voltage detection signal according to one of the voltage divider voltages. The line voltage detection circuit is coupled to a portion of the voltage divider nodes of the voltage divider circuit to generate a line voltage detection signal according to a portion of the voltage divider voltages.

[0004] The present disclosure also relates to a voltage detection method, comprising: coupling a first voltage detector to a plurality of first detection nodes of a medium voltage system cabinet, and coupling a second voltage detector to a plurality of second detection nodes of the medium voltage system cabinet, wherein the first detection nodes are coupled between a plurality of phase voltage input nodes and a plurality of first circuit elements, and the second detection nodes are coupled between the first circuit elements and a plurality of second circuit elements; obtaining a plurality of first phase voltage detection signals of the first detection nodes through the first voltage detector, and obtaining a plurality of second phase voltage detection signals of the second detection nodes through the second voltage detector; determining whether the first phase voltage detection signals and the second phase voltage detection signals are normal through a controller; and generating an abnormal signal when the first phase voltage detection signals are normal but one of the second phase voltage detection signals is abnormal.

[0005] Accordingly, by providing the divided voltage to the phase voltage detection circuit and the line voltage detection circuit with the same voltage divider circuit, the structure of the voltage detector can be simplified. In addition, by respectively obtaining the phase voltage detection signals of different detection nodes, the circuit elements that have abnormalities in the medium voltage system cabinet can be quickly and accurately identified. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Figure 1Schematic diagram of a power supply system according to some embodiments of the present disclosure.

[0007] Figure 2 Schematic diagram of a voltage detector and a controller according to some embodiments of the present disclosure.

[0008] Figure 3 FIG. 4 is a flow chart of a voltage detection method according to some embodiments of the present disclosure.

[0009] Figure 4A The waveform diagram is a phase voltage detected by a power supply system according to some embodiments of the present disclosure.

[0010] Figure 4B The waveform diagram is a phase voltage detected by a power supply system according to some embodiments of the present disclosure.

[0011] Figure 5 is a schematic diagram of a voltage detector according to some embodiments of the present disclosure.

[0012] Figures 6A to 6C is a schematic diagram of a voltage detector according to some embodiments of the present disclosure.

[0013] Figure 7 FIG. 4 is a flow chart of a voltage detection method according to some embodiments of the present disclosure.

[0014] Description of reference numerals:

[0015] 100: Power supply system

[0016] 110: Voltage conversion circuit

[0017] 111: Power control circuit

[0018] 120: Voltage detector

[0019] 120A: First voltage detector

[0020] 120B: Second voltage detector

[0021] 120C: Third voltage detector

[0022] 121: Voltage divider circuit

[0023] 122: Detection circuit

[0024] 123: Buffer circuit

[0025] 130: Controller

[0026] 131: Sampling circuit

[0027] 132: Processing circuit

[0028] 200: Voltage detector

[0029] 210: Voltage divider circuit

[0030] 220: Phase voltage detection circuit

[0031] 220A-220C: Phase voltage detection circuit

[0032] 221: Amplifier circuit

[0033] 230: Line voltage detection circuit

[0034] 230A-230C: Line voltage detection circuit

[0035] 231: Amplifier circuit

[0036] Er1: Protection element

[0037] Es1: Protection element

[0038] Et1: Protection element

[0039] Er2: Power switching element

[0040] Es2: Power switching element

[0041] Et2: Power switching element

[0042] R1-R6: Impedance elements

[0043] Na-Nc: Detection Node

[0044] Nr1: The first detection node

[0045] Ns1: The first detection node

[0046] Nt1: The first detection node

[0047] Nr2: Second detection node

[0048] Ns2: Second detection node

[0049] Nt2: Second detection node

[0050] Nr3: The third detection node

[0051] Ns3: The third detection node

[0052] Nt3: The third detection node

[0053] Na1-Na2: voltage divider node

[0054] Nb1-Nb2: voltage dividing node

[0055] Nc1-Nc2: voltage dividing node

[0056] Nx: floating node

[0057] Vr: AC voltage

[0058] Vs: AC voltage

[0059] Vt: AC voltage

[0060] Vpm: DC voltage

[0061] Va: normal voltage

[0062] Vb: Abnormal voltage

[0063] F1: During the test

[0064] F2: During the test

[0065] Vr1: First phase voltage detection signal

[0066] Vs1: First phase voltage detection signal

[0067] Vt1: First phase voltage detection signal

[0068] Vr2: Second phase voltage detection signal

[0069] Vs2: Second phase voltage detection signal

[0070] Vt2: Second phase voltage detection signal

[0071] Vr3: The third phase voltage detection signal

[0072] Vs3: The third phase voltage detection signal

[0073] Vt3: The third phase voltage detection signal

[0074] S301-S309: Steps

[0075] S701-S707: Steps DETAILED DESCRIPTION

[0076] The following will disclose multiple embodiments of the present invention with the accompanying drawings. For the purpose of clear description, many practical details will be described together in the following description. However, it should be understood that these practical details should not be used to limit the present invention. That is, in some embodiments of the present invention, these practical details are not necessary. In addition, in order to simplify the drawings, some conventional structures and elements will be shown in the drawings in a simple schematic manner.

[0077] In this document, when an element is referred to as "connected" or "coupled", it may refer to "electrically connected" or "electrically coupled". "Connected" or "coupled" may also be used to indicate that two or more elements cooperate or interact with each other. In addition, although the terms "first", "second", etc. are used in this document to describe different elements, the terms are only used to distinguish between elements or operations described by the same technical terms. Unless the context clearly indicates otherwise, the terms do not specifically refer to or imply an order or sequence, nor are they used to limit the present invention.

[0078] Figure 1 The figure shows a schematic diagram of a power supply system 100 according to some embodiments of the present disclosure. In one embodiment, the power supply system 100 can be applied as a medium voltage system cabinet (such as a solid-state transformer, a medium voltage substation or a medium voltage inverter) to convert the AC voltage provided by the power grid into a DC voltage Vpm. Among them, "medium voltage" refers to a voltage used for transmission / conversion of kilovolts (Kv), for example: 10 kV to 35 kV, but the present disclosure is not limited to this.

[0079] The power supply system 100 (medium voltage system cabinet) includes a voltage conversion circuit 110, one or more voltage detectors 120A-120C and a controller 130. The voltage conversion circuit 110 is used to receive multiple AC voltages through multiple phase voltage input nodes. In one embodiment, the voltage conversion circuit 110 is used to receive a three-phase voltage of 10 kV to 35 kV, that is, Figure 1 The labeled AC voltage Vr / Vs / Vt. The number of voltage detectors can be adjusted arbitrarily according to the detection requirements (eg, the number of nodes that need to be detected in the power supply system 100).

[0080] like Figure 1 As shown, the voltage conversion circuit 110 includes a plurality of circuit elements with different functions and a power control circuit 111, and the power control circuit 111 is coupled to the circuit elements and the controller 130. In one embodiment, the circuit elements can be divided into a first circuit element (such as: protection elements Er1, Es1, Et1) and a second circuit element (such as: power switch elements Er2, Es2, Et2), and are used to form a plurality of conversion sub-circuits. For example: the first conversion sub-circuit includes a protection element Er1 and a power switch element Er2, which are used to receive the AC voltage of the R phase; the second conversion sub-circuit includes a protection element Es1 and a power switch element Es2, which are used to receive the AC voltage of the S phase; the third conversion sub-circuit includes a protection element Et1 and a power switch element Et2, which are used to receive the AC voltage of the T phase. The phases of the AC voltages of the R phase, the S phase, and the T phase differ from each other by 120 degrees.

[0081] The first circuit element, namely the protection element Er1 / Es1 / Et1, is used to disconnect the power control circuit 111 from the AC voltage Vr / Vs / Vt when an overcurrent (such as an inrush current) occurs in the conversion sub-circuit. In other words, when the current flowing through the protection element Er1 / Es1 / Et1 exceeds the set threshold, the corresponding protection element will automatically shut down (that is, shut down according to its element characteristics to form an open circuit). The protection element Er1 / Es1 / Et1 can be implemented by a fuse or an overcurrent protection element; the second circuit element, namely the power switch element Er2, Es2, Et2, is used to be selectively turned on or off to control the input of the AC voltage Vr / Vs / Vt. For example, when the AC voltage Vr of the R phase is too large, the power switch element Er2 will be controlled by the controller 130 to shut down to prevent the excessive voltage from damaging the power supply system 100 (medium voltage system cabinet). The power switch elements Er2, Es2, and Et2 can be implemented by a relay or a contactor.

[0082] For the convenience of subsequent description, the “node between the phase voltage input node and the first circuit element (such as: protection element Er1 / Es1 / Et1)” is referred to as the first detection node Nr1 / Ns1 / Nt1; the “node between the first circuit element (such as: protection element Er1 / Es1 / Et1) and the second circuit element (such as: power switching element Er2 / Es2 / Et2)” is referred to as the second detection node Nr2 / Ns2 / Nt2; and the “node between the second circuit element (such as: power switching element Er2 / Es2 / Et2) and the power control circuit 111” is referred to as the third detection node Nr3 / Ns3 / Nt3.

[0083] The voltage detectors 120A-120C are respectively connected to the first detection node Nr1 / Ns1 / Nt1, the second detection node Nr2 / Ns2 / Nt2 and the third detection node Nr3 / Ns3 / Nt3 to detect the phase voltage and the line voltage. The line voltage (Line to Line Voltage, Line Voltage) refers to the voltage between phase voltages of different phases, also known as the phase-to-phase voltage.

[0084] The controller 130 is coupled to the voltage detectors 120A-120C to receive the phase voltage and line voltage detected by the voltage detectors 120A-120C and determine whether the internal circuit elements are abnormal according to the detected phase voltage. The controller 130 can also transmit the detected line voltage to the power control circuit 111 to perform phase lock control (e.g., generate a clock signal for controlling each circuit element in the power supply system 100) or adjust the power factor (e.g., adjust the switching frequency of each circuit element in the power supply system 100).

[0085] Figure 2 FIG. 1 is a schematic diagram of a voltage detector 120 and a controller 130 . Figure 2 The voltage detector 120 shown in FIG. 1 may be applied to Figure 1 Any one of the voltage detectors 120A-120C in the embodiment. The voltage detector 120 includes a voltage divider circuit 121 and a detection circuit 122. The voltage divider circuit 121 is coupled to the detection node to receive the AC voltage and generate a divided voltage with a lower voltage value according to the AC voltage. The detection circuit 122 is coupled to the voltage divider circuit 121 to generate a phase voltage detection signal and a line voltage detection signal according to the divided voltage.

[0086] In some embodiments, a buffer circuit 123 may be provided between the voltage divider circuit 121 and the detection circuit 122. The buffer circuit 123 is used to provide decoupling from adjacent circuits when there is local damage in the detection circuit 122, so that the damaged circuit will not affect or destroy the working behavior of other voltage divider circuits 121 or detection circuits 122. The detailed circuit will be described in subsequent paragraphs and drawings.

[0087] In one embodiment, the voltage detector 120 integrates the phase voltage detection circuit and the line voltage detection circuit into the same device to simplify the circuit structure and improve the circuit cost and volume. The detailed circuit will be described in the subsequent paragraphs and drawings.

[0088] The controller 130 includes a sampling circuit 131 and a processing circuit 132. The sampling circuit 131 is coupled to the detection circuit 122 to receive the phase voltage detection signal and the line voltage detection signal, and convert the signal from an analog format to a digital format. The processing circuit 132 is coupled to the sampling circuit 131 to analyze the phase voltage detection signal and the line voltage detection signal. The processing circuit 132 is used to determine whether the voltage detector 120 and the voltage of the detection node are abnormal according to the phase voltage detection signal and the line voltage detection signal, and further control the operation of the conversion subcircuit and the power control circuit 111. Specifically, the processing circuit 132 compares multiple phase voltage detection signals (or multiple line voltage detection signals) to determine whether there is an abnormality in the multiple phase voltage detection signals.

[0089] Figure 3 It is a flow chart of a voltage detection method according to some embodiments of the present disclosure. In this embodiment, the power supply system 100 (medium voltage system cabinet) detects the voltage conversion circuit 110 through steps S301 to S309.

[0090] In step S301, when the power supply system 100 receives the AC voltage Vr / Vs / Vt through the phase voltage input nodes, the power supply system 100 will also obtain auxiliary power from the auxiliary power supply to drive the controller 130 and the voltage detectors 120A-120C. In one embodiment, the power supply system 100 receives the AC voltage Vr / Vs / Vt through the power grid, and the auxiliary power supply is a power supply device different from the power grid, such as provided by an energy storage device, an uninterruptible power supply or other low-voltage AC mains.

[0091] In step S302, the first voltage detector 120A obtains a plurality of first phase voltage detection signals corresponding to the first detection nodes Nr1 / Ns1 / Nt1. In some embodiments, since the first detection nodes Nr1 / Ns1 / Nt1 are detected at this time, the controller 130 may first turn off the power switch elements Er2 / Es2 / Et2.

[0092] In step S303, the controller 130 determines whether all the first phase voltage detection signals are normal. If so, step S304 is executed. If any of the first phase voltage detection signals is abnormal (e.g., exceeds the expected voltage range), step S309 is executed. For example, the controller 130 compares the first phase voltage detection signals. If the difference between the three first phase voltage detection signals exceeds the preset range (e.g., the voltages are 10kV, 10kV, 0kV, and the difference is 10kV), it means that there is an abnormality between the first phase voltage detection signals.

[0093] If any of the first phase voltage detection signals is abnormal, the controller 130 will generate an abnormal signal corresponding to the abnormal first detection node. For example, if the first phase voltage detection signal corresponding to the first detection node Nr1 / Ns1 is normal, but the first phase voltage detection signal corresponding to the first detection node Nt1 is abnormal, it means that the circuit element adjacent to the first detection node Nt1 may be abnormal (for example, the phase voltage input node receiving the R-phase AC voltage may be damaged).

[0094] In step S304, when the controller 130 receives the first phase voltage detection signal, or when the controller 130 determines that the first phase voltage detection signals are all normal, the controller 130 obtains multiple second phase voltage detection signals corresponding to the second detection nodes Nr2 / Ns2 / Nt2 through the second voltage detector 120B.

[0095] In step S305, the controller 130 determines whether the second phase voltage detection signals are all normal. For example, the controller 130 compares the second phase voltage detection signals. If the difference between the three second phase voltage detection signals exceeds a preset range (e.g., the voltages are 10 kV, 10 kV, and 0 kV, respectively, and the difference is 10 kV), there is an abnormality between these second phase voltage detection signals.

[0096] If the second phase voltage detection signals are all normal, step S306 is executed, and the controller 130 also turns on the power switch elements Er2 / Es2 / Et2. If any of the second phase voltage detection signals is abnormal (eg, exceeds the expected voltage range), step S309 is executed.

[0097] In step S309, if any of the second phase voltage detection signals is abnormal, the controller 130 will generate an abnormal signal corresponding to the abnormal second detection node (or corresponding to the first circuit element). For example, if the second phase voltage detection signal corresponding to the second detection node Nr2 / Ns2 is normal, but the second phase voltage detection signal corresponding to the second detection node Nt2 is abnormal, it means that the first circuit element adjacent to the second detection node Nt2 (i.e., the protection element Et1) may be abnormal. Therefore, the controller 130 will generate an abnormal signal corresponding to the detection node and / or the circuit element.

[0098] In step S306 , if all second phase voltage detection signals are normal, the controller 130 turns on the power switch elements Er2 / Es2 / Et2 , and obtains a plurality of third phase voltage detection signals corresponding to the third detection nodes Nr3 / Ns3 / Nt3 through the third voltage detector 120C.

[0099] In step S307, the controller 130 determines whether the third phase voltage detection signals are all normal. If so, step S308 is executed. At this time, since the voltages of all detection nodes meet the set thresholds, it means that the voltage conversion circuit 110 components in the power supply system 100 (medium voltage system cabinet) are all operating normally, and the detection process can be terminated.

[0100] If any of the third phase voltage detection signals is abnormal (e.g., exceeds the expected voltage range), step S309 is executed. At this time, the controller 130 will generate an abnormal signal corresponding to the abnormal third detection node (or corresponding to the second circuit element). For example, if the third phase voltage detection signal corresponding to the third detection node Nr3 / Ns3 is normal, but the third phase voltage detection signal corresponding to the third detection node Nt3 is abnormal, it means that the second circuit element adjacent to the third detection node Nt3 (i.e., the power switch element Et2) may be abnormal. Therefore, the controller 130 will generate an abnormal signal corresponding to the detection node and / or circuit element.

[0101] In the above-mentioned embodiment, although "obtaining corresponding phase voltage detection signals through different voltage detectors 120A-120C" is described as different steps, in some embodiments, the controller 130 can obtain multiple phase voltage detection signals through the voltage detectors 120A-120C at the same time, rather than obtaining the phase voltage detection signals in sequence. For ease of understanding, Figures 4A and 4B are used as examples for explanation.

[0102] Figure 4A The figure shows an embodiment of detecting phase voltage of the power supply system 100 (medium voltage system cabinet). The controller 130 and the voltage detectors 120A-120C are driven by receiving power provided by the auxiliary power supply during the detection period F1. Figure 4A In the figure, the top waveform represents the voltages of the three first detection nodes Nr1 / Ns1 / Nt1 detected by the first voltage detector 120A; the middle waveform represents the voltages of the three second detection nodes Nr2 / Ns2 / Nt2 detected by the second voltage detector 120B; and the bottom waveform represents the voltages of the three third detection nodes Nr3 / Ns3 / Nt3 detected by the third voltage detector 120C.

[0103] like Figure 4A As shown, during the time period t0-t1, the controller 130 obtains the voltage of each first detection node Nr1 / Ns1 / Nt1 through the first voltage detector 120A. In this embodiment, the voltage of each first detection node Nr1 / Ns1 / Nt1 is a normal voltage Va.

[0104] At the same time, at time points t0-t1, the controller 130 also detects the voltage of each second detection node Nr2 / Ns2 / Nt2 through the second voltage detector 120B. In this embodiment, the voltage of each second detection node Nr2 / Ns2 / Nt2 is a normal voltage Va, indicating that the voltages at both ends of the protection element Er1 / Es1 / Et1 are normal, and therefore the protection element Er1 / Es1 / Et1 is not abnormal.

[0105] In addition, during the time point t0-t1, since the controller 130 is determining whether the protection element Er1 / Es1 / Et1 is abnormal, it is not necessary to determine the voltage of the third detection node Nr3 / Ns3 / Nt3 during this time point. Therefore, during the time point t0-t1, the power switch element Er2 / Es2 / Et2 is turned off, and the voltage of the third detection node Nr3 / Ns3 / Nt3 is zero. In other words, the third voltage detector 120C does not need to detect the voltage of each third detection node Nr3 / Ns3 / Nt3. In addition, it should be specifically mentioned here that the controller 130 can obtain and determine the voltage of each detection node through the voltage detectors 120A-120C at the same time, and can also obtain and determine the voltage of each detection node through the voltage detectors 120A-120C in sequence, and the present disclosure is not limited to this.

[0106] After time point t1, the controller 130 turns on the power switch element Er2 / Es2 / Et2, and detects the voltage of each third detection node Nr3 / Ns3 / Nt3 through the third voltage detector 120C. In this embodiment, the voltage of the third detection node Nr3 / Ns3 is normal, but the third detection node Nt3 is too low and abnormal, indicating that the voltage across the power switch element Et2 is abnormal, so the controller 130 can determine / confirm that the power switch element Et2 is abnormal. It should be noted that although Figure 4A In the embodiment, the normal voltage is marked as Va and the abnormal voltage is marked as Vb, but in other embodiments, the normal voltages of different detection nodes may have errors, but are roughly the same. For example, the error between multiple phase voltages detected by the same voltage detector is 10%, and the error between multiple phase voltages detected by different voltage detectors on the same conversion subcircuit is 1%.

[0107] Figure 4B Another embodiment of detecting phase voltage of the power supply system 100 (medium voltage system cabinet) is shown. The controller 130 receives power provided by the auxiliary power supply during the detection period F2 to be driven. During the time point t0-t1, the controller 130 detects the voltage of each first detection node Nr1 / Ns1 / Nt1 through the first voltage detector 120A. In this embodiment, the voltage of each first detection node Nr1 / Ns1 / Nt1 is a normal voltage Va.

[0108] At the same time, at time points t0 to t1, the controller 130 also detects the voltages of the second detection nodes Nr2 / Ns2 / Nt2 through the second voltage detector 120B. In this embodiment, the voltages of the second detection nodes Nr2 / Ns2 are all normal voltages Va, but the second detection node Nt2 is an abnormal voltage Vb, indicating that the voltages across the protection element Et1 are abnormal, so the controller 130 will generate an abnormal signal corresponding to the second detection node Nt2 and / or the protection element Et1.

[0109] As mentioned above, since the controller 130 has determined that the voltage across the protection element Et1 is abnormal, the voltage of the third detection node Nt3 must be abnormal due to the abnormality of the protection element Et1. In some embodiments, the controller 130 does not need to turn on the power switch element Er2 / Es2 / Et2, but directly generates an abnormal signal to allow the management personnel to perform maintenance inspections.

[0110] Through the aforementioned voltage detection method, the controller 130 can detect the voltages of different detection nodes through the voltage detectors 120A~120B respectively, and accordingly, the location where the abnormality may occur in the power supply system 100 (medium voltage system cabinet) can be accurately and efficiently determined for the management personnel to perform maintenance in real time.

[0111] The aforementioned steps S301 to S309 are used to detect the phase voltage to determine whether the circuit elements in the power supply system 100 (medium voltage system cabinet) are abnormal. In other embodiments, when the controller 130 detects the phase voltages of different detection nodes respectively, the line voltages of different detection nodes can be detected by the voltage detectors 120A to 120C at the same time. The voltage detectors 120A to 120C can generate a plurality of first line voltage detection signals, a plurality of second line voltage detection signals, and a plurality of third line voltage detection signals corresponding to the first detection node Nr1 / Ns1 / Nt1, the second detection node Nr2 / Ns2 / Nt2, and the third detection node Nr3 / Ns3 / Nt3. The controller 130 transmits the line voltage detection signals to the power control circuit 111, so that the power control circuit 111 generates a phase-locked control signal according to the line voltage detection signals, or is used to adjust the power factor, wherein the phase-locked control signal is used to generate a clock signal applied to the power supply system 100.

[0112] Figure 5 FIG. 2 is a schematic diagram of a voltage detector 200 according to some embodiments of the present disclosure. The voltage detector 200 may be applied to Figure 1 Each voltage detector 120A to 120C, or applied to Figure 2 A voltage detector 120 is shown. Figure 1 The controller 130 is shown coupled to the voltage detectors 120A- 120C to receive phase voltage detection signals or line voltage detection signals from the voltage detectors 120A- 120C.

[0113] The voltage detector 200 has a plurality of detection nodes Na / Nb / Nc, and the detection nodes Na / Nb / Nc are used to couple to different detection nodes in the voltage conversion circuit 110. For example, if the voltage detector 200 is used as Figure 1In the first voltage detector 120A shown, the detection nodes Na / Nb / Nc are respectively coupled to the first detection nodes Nr1 / Ns1 / Nt1, and coupled to the protection elements Er1 / Es1 / Et1 through the first detection nodes Nr1 / Ns1 / Nt1 to detect the first phase voltage detection signal.

[0114] Similarly, if the voltage detector 200 is used as Figure 1 The second voltage detector 120B shown in the figure, the detection nodes Na / Nb / Nc will be coupled to the second detection nodes Nr2 / Ns2 / Nt2 respectively, and coupled to the protection element Er1 / Es1 / Et1 and the power switch element Er2 / Es2 / Et2 through the second detection nodes Nr2 / Ns2 / Nt2 to detect the second phase voltage detection signal.

[0115] Similarly, if the voltage detector 200 is used as Figure 1 The third voltage detector 120C shown, the detection nodes Na / Nb / Nc will be coupled to the third detection node Nr3 / Ns3 / Nt3 respectively, and coupled to the power switch element Er2 / Es2 / Et2 and the power control circuit 111 through the third detection node Nr3 / Ns3 / Nt3 to detect the third phase voltage detection signal.

[0116] Please refer to FIGS. 1 and 5 , the voltage detector 200 includes a voltage divider circuit 210, a phase voltage detection circuit 220, and a line voltage detection circuit 230. The voltage divider circuit 210 is coupled to the voltage conversion circuit 110, and includes a plurality of impedance elements R1-R6 and a plurality of voltage division nodes Na1 / Na2 / Nb1 / Nb2 / Nc1 / Nc2. The voltage divider circuit 210 is used to divide the AC voltage of the voltage conversion circuit 110 through the impedance elements R1-R6 to generate respective divided voltages on the voltage division nodes Na1 / Na2, Nb1 / Nb2, and Nc1 / Nc2. For example, the divided voltage of the voltage division node Na1 / Na2 corresponds to the R phase, the divided voltage of the voltage division node Nb1 / Nb2 corresponds to the S phase, and the divided voltage of the voltage division node Nc1 / Nc2 corresponds to the T phase.

[0117] In one embodiment, the voltage divider circuit 210 includes a plurality of voltage divider sub-circuits to respectively receive AC voltages of different phases and generate a plurality of voltage divider voltages of corresponding phases. For example, the impedance elements R1 / R2 are used to form a first voltage divider sub-circuit to receive the AC voltage of the R phase; the impedance elements R3 / R4 are used to form a second voltage divider sub-circuit to receive the AC voltage of the S phase; and the impedance elements R5 / R6 are used to form a third voltage divider sub-circuit to receive the AC voltage of the T phase.

[0118] In one embodiment, one end of each of the voltage divider sub-circuits is a detection node Na / Nb / Nc, and the other end of each of the voltage divider sub-circuits is connected (eg, in a Y-shaped connection) to the same floating node Nx (ie, a voltage neutral point).

[0119] In one embodiment, the voltage divider circuit 210 is used to reduce the voltages of a plurality of AC voltages into divided voltages to meet the operating voltages of the phase voltage detection circuit 220 and the line voltage detection circuit 230 .

[0120] The phase voltage detection circuit 220 is coupled to the voltage divider circuit 210 to generate phase voltage detection signals according to the voltage divider voltages on each voltage divider node. In one embodiment, the phase voltage detection circuit 220 includes one or more amplifier circuits 221, and the amplifier circuit 221 may include an operational amplifier, an input resistor, and a negative feedback circuit. Each amplifier circuit 221 is coupled to a different voltage divider node and corresponds to a different phase (for example, coupled to the voltage divider nodes Na1 / Nc1 / Nb2, respectively) to obtain phase voltage detection signals of different phases. The number of amplifier circuits 221 can be adjusted arbitrarily according to the detection requirements.

[0121] In one embodiment, the phase voltage detection circuit 220 generates a phase voltage detection signal of a corresponding phase according to one of the reference voltage and the voltage division voltage of the floating node Nx. Specifically, one input terminal (e.g., negative terminal) of the amplifier circuit 221 is coupled to the floating node Nx, and the other input terminal (e.g., positive terminal) of the amplifier circuit 221 is coupled to a voltage division node and / or the floating node Nx. Since those skilled in the art can understand the operating principle of generating the phase voltage by the amplifier circuit, it will not be described in detail here.

[0122] The line voltage detection circuit 230 is coupled to the voltage divider circuit 210 and is coupled to each detection node through the voltage divider circuit 210. The line voltage detection circuit 230 is used to generate a line voltage detection signal according to the divided voltage of a portion of the divided voltage nodes (corresponding to two nodes with different phases, such as the divided voltage nodes Nb1 and Na2). Figure 5 As shown, the line voltage detection circuit 230 includes one or more amplifier circuits 231, and the amplifier circuit 231 may include an operational amplifier, an input resistor, and a negative feedback circuit. Each amplifier circuit 231 is coupled to two of the voltage divider sub-circuits to obtain divided voltages corresponding to different phases and generate a line voltage detection signal. The number of amplifier circuits 231 can be adjusted arbitrarily according to the detection requirements.

[0123] For example, one input terminal (e.g., negative terminal) of the amplifier circuit 231 is coupled to the voltage-dividing node Nb1 to obtain the voltage-dividing voltage corresponding to the S phase. Another input terminal (e.g., positive terminal) of the amplifier circuit 231 is coupled to the voltage-dividing node Na2 to obtain the voltage-dividing voltage corresponding to the R phase. The amplifier circuit 231 generates a line voltage detection signal between the R phase and the S phase according to the voltage-dividing node Nb1 and the voltage-dividing node Na2. Similarly, other amplifier circuits 231 can obtain line voltage detection signals between other phases. Since those skilled in the art can understand the operating principle of generating line voltage by an amplifier circuit, it will not be repeated here.

[0124] The voltage detector 200 of the present disclosure is applied to a medium voltage system cabinet. To convert the kilovolt AC voltage Vr / Vs / Vt into an operating voltage (e.g., 3.3 volts) that meets the requirements of the controller 130, the voltage divider circuit 210 usually needs to use a large number of resistors with a relatively high withstand voltage. Figure 5 As shown, in this embodiment, the voltage detector 200 provides the divided voltage to the phase voltage detection circuit 220 and the line voltage detection circuit 230 through the same voltage divider circuit. In other words, the voltage detector 200 can use the same resistor plate to connect the phase voltage detection circuit 220 and the line voltage detection circuit 230 (that is, the phase voltage detection circuit 220 and the line voltage detection circuit 230 share the same divided voltage), forming a simplified voltage detection structure. Accordingly, it will be able to effectively save circuit elements and improve device costs.

[0125] In some embodiments, the voltage detector 200 may further include one or more buffer circuits. The buffer circuit may be a signal follower coupled between the voltage divider circuit 210 and the phase voltage detection circuit 220 and / or coupled between the voltage divider circuit 210 and the line voltage detection circuit 230 .

[0126] Figures 6A to 6C FIG. 2 is a schematic diagram of a voltage detector 200 according to various embodiments of the present disclosure. Fig. 6A As shown, the buffer circuit 240 is coupled between part of the detection nodes of the voltage divider circuit 210 and the phase voltage detection circuit 220. Specifically, the buffer circuit 240 is coupled to the amplifier circuit 221 (such as Figure 5 The buffer circuit 250 is coupled between the positive terminal of the voltage divider circuit 210 and the voltage divider circuit 230 to prevent the operation of other amplifier circuits 221 from being affected when a part of the amplifier circuit 221 is damaged. The buffer circuit 250 is coupled between part of the detection nodes of the voltage divider circuit 210 and the line voltage detection circuit 230. Specifically, the buffer circuit 250 is coupled to the amplifier circuit 231 (as shown in FIG. Figure 5 between the positive terminal of the resistor (as shown) and the voltage divider circuit.

[0127] Figure 6B FIG. 2 is a schematic diagram showing that the voltage detector 200 only has a buffer circuit 240. Figure 6C The schematic diagram shown is a voltage detector 200 having only a buffer circuit 250. In other words, the location and quantity of the buffer circuit 250 can be adjusted arbitrarily according to circuit requirements.

[0128] Figure 7 FIG. 1 is a flow chart of a voltage detection method according to another embodiment of the present disclosure. In this embodiment, the power supply system 100 (medium voltage system cabinet) detects the voltage conversion circuit 110 through steps S701 to S707.

[0129] In step S701, the power supply system 100 obtains auxiliary power from the auxiliary power supply to drive the controller 130 and the voltage detectors 120A to 120C. In step S702, the first voltage detector 120A obtains a plurality of first phase voltage detection signals corresponding to the first detection node Nr1 / Ns1 / Nt1. The second voltage detector 120B obtains a plurality of second phase voltage detection signals corresponding to the second detection node Nr2 / Ns2 / Nt2. The third voltage detector 120C obtains a plurality of third phase voltage detection signals corresponding to the third detection node Nr3 / Ns3 / Nt3. In one embodiment, at this time, the controller 130 controls the power switch element Er2 / Es2 / Et2 to be in the off state, so the third phase voltage detection signal must be zero.

[0130] In step S703, the controller 130 determines whether the first phase voltage detection signal and the second phase voltage detection signal are both normal. If the first phase voltage detection signal and the second phase voltage detection signal are both normal, step S704 is executed. If any one of the first phase voltage detection signal and the second phase voltage detection signal is abnormal (e.g., exceeds the expected voltage range), step S706 is executed to generate an abnormal signal.

[0131] For example, if the first phase voltage detection signal corresponding to the first detection node Nr1 is abnormal (eg, exceeds an expected range), the controller 130 will generate an abnormal signal corresponding to the first detection node Nr1.

[0132] If the first phase voltage detection signals are all normal, but the second phase voltage detection signal is abnormal, the controller 130 will generate an abnormal signal corresponding to the “abnormal second phase voltage detection signal” or “abnormal circuit element”. For example, if the first detection node Nr1 is normal, but the second phase voltage detection signal of the second detection node Nr2 is abnormal, the controller 130 will generate an abnormal signal corresponding to the second detection node Nr2 (or the protection element Er1).

[0133] In step S704, the controller 130 turns on the power switch element Er2 / Es2 / Et2. At the same time, the controller 130 obtains a plurality of second phase voltage detection signals corresponding to the second detection node Nr2 / Ns2 / Nt2 through the second voltage detector 120B, and obtains a plurality of third phase voltage detection signals corresponding to the third detection node Nr3 / Ns3 / Nt3 through the third voltage detector 120C. Since it has been confirmed in step S703 that the first detection node Nr1 / Ns1 / Nt1 has no abnormality, it is not necessary to obtain a plurality of first phase voltage detection signals corresponding to the first detection node Nr1 / Ns1 / Nt1 at this time. However, in other embodiments, the controller 130 can still continue to obtain a plurality of first phase voltage detection signals corresponding to the first detection node Nr1 / Ns1 / Nt1 through the first voltage detector 120A.

[0134] In step S705, the controller 130 determines whether the second phase voltage detection signal and the third phase voltage detection signal are both normal. If the second phase voltage detection signal and the third phase voltage detection signal are both normal, step S707 is executed. At this time, the voltages of all detection nodes meet the set thresholds, indicating that the voltage conversion circuit 110 components in the power supply system 100 (medium voltage system cabinet) are all operating normally, so the detection process can end.

[0135] If any of the second phase voltage detection signals and the third phase voltage detection signals is abnormal (e.g., exceeds the expected voltage range), step S706 is executed to generate an abnormal signal. Specifically, if the second phase voltage detection signals are all normal, but the third phase voltage detection signal is abnormal, the controller 130 will generate an abnormal signal corresponding to "abnormal third phase voltage detection signal" or "abnormal circuit element". For example, if the second detection node Nr2 is normal, but the third phase voltage detection signal of the third detection node Nr3 is abnormal, the controller 130 will generate an abnormal signal corresponding to the third detection node Nr3 (or the power switch element Er2).

[0136] In some embodiments, when the above Figure 3 or Figure 7 After confirming that the voltages of each detection node are normal, the controller 130 can continue to or periodically receive the first / second / third phase voltage detection signal and repeat the above-mentioned Figure 3 or Figure 7 A voltage detection method is provided to monitor the voltage status of the power supply system 100.

[0137] The various elements, method steps or technical features in the aforementioned embodiments may be combined with each other and are not limited to the order of textual description or the order of presentation of the drawings in the present disclosure.

[0138] Although the present disclosure has been disclosed in the above-mentioned embodiments, it is not intended to limit the present disclosure. Any person skilled in the art may make various changes and modifications without departing from the concept and scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be determined by the claims.

Claims

1. A power supply system, comprising: a voltage conversion circuit for converting an AC voltage into a DC voltage; and At least one voltage detector, comprising: a voltage divider circuit coupled to the voltage conversion circuit to receive the AC voltage, wherein the voltage divider circuit comprises a plurality of impedance elements and a plurality of voltage division nodes to output a plurality of divided voltages; a phase voltage detection circuit coupled to one of the voltage division nodes of the voltage division circuit to generate a phase voltage detection signal according to one of the voltage division voltages; and The line voltage detection circuit is coupled to a part of the voltage division nodes of the voltage division circuit to generate a line voltage detection signal according to a part of the voltage division voltages.

2. The power supply system as claimed in claim 1, wherein the voltage conversion circuit comprises a plurality of conversion sub-circuits, the conversion sub-circuits are used to receive a plurality of alternating voltages of different phases, and the voltage divider circuit further comprises: A plurality of voltage-dividing subcircuits are coupled to the conversion subcircuits and a floating node to generate the divided voltages according to the AC voltages, wherein the phase voltage detection circuit generates the phase voltage detection signal according to a reference voltage of the floating node and one of the divided voltages.

3. The power supply system as claimed in claim 2, wherein the phase voltage detection circuit comprises a plurality of amplifier circuits, an input terminal of each of the amplifier circuits is coupled to the floating node, and another input terminal of each of the amplifier circuits is coupled to the floating node and one of the voltage divider sub-circuits.

4. The power supply system as claimed in claim 3, wherein the phase voltage detection circuit further comprises: A plurality of buffer circuits are coupled between the amplifying circuits and the voltage dividing sub-circuits.

5. The power supply system as claimed in claim 2, wherein the line voltage detection circuit comprises a plurality of amplifier circuits, each of the amplifier circuits is coupled to two of the voltage divider sub-circuits to generate the line voltage detection signal according to two of the divided voltages.

6. The power supply system as claimed in claim 5, wherein the line voltage detection circuit further comprises: A buffer circuit is coupled between the amplifying circuits and the voltage dividing sub-circuits.

7. The power supply system as claimed in claim 1, wherein the voltage conversion circuit comprises a plurality of protection elements and a plurality of power switch elements, and the at least one voltage detector comprises: a first voltage detector, coupled to the protection elements, for detecting a plurality of first phase voltage detection signals; and a second voltage detector coupled to a plurality of detection nodes between the protection elements and the power switch elements, for detecting a plurality of second phase voltage detection signals; The power supply system further includes a controller, which is coupled to the at least one voltage detector to receive the first phase voltage detection signals and the second phase voltage detection signals. 8 . The power supply system as claimed in claim 7 , wherein the controller is used to compare the second phase voltage detection signals to determine whether the second phase voltage detection signals are abnormal. 9 . The power supply system as claimed in claim 8 , wherein when the controller determines that one of the second phase voltage detection signals is abnormal, the controller generates an abnormal signal according to one of the protection elements corresponding to the one of the second phase voltage detection signals. 10 . The power supply system as claimed in claim 7 , wherein the voltage conversion circuit further comprises a power control circuit, the power control circuit is coupled to the controller to generate a phase lock control signal according to the line voltage detection signal.

11. A voltage detection method, comprising: A first voltage detector is coupled to a plurality of first detection nodes of a medium voltage system cabinet, and a second voltage detector is coupled to a plurality of second detection nodes of the medium voltage system cabinet, wherein the first detection nodes are coupled between a plurality of phase voltage input nodes and a plurality of first circuit elements, and the second detection nodes are coupled between the first circuit elements and a plurality of second circuit elements; Obtaining a plurality of first phase voltage detection signals of the first detection nodes through the first voltage detector, and obtaining a plurality of second phase voltage detection signals of the second detection nodes through the second voltage detector; Determining, by a controller, whether the first phase voltage detection signals and the second phase voltage detection signals are normal; and When the first phase voltage detection signals are normal but one of the second phase voltage detection signals is abnormal, an abnormal signal is generated.

12. The voltage detection method according to claim 11, further comprising: When determining whether the first phase voltage detection signals and the second phase voltage detection signals are normal, the second circuit elements are turned off. 13 . The voltage detection method as claimed in claim 12 , wherein the first circuit elements include a plurality of protection elements, and when a current flowing through one of the protection elements exceeds a set threshold, the one of the protection elements will be automatically disconnected.

14. The voltage detection method according to claim 11, further comprising: When the controller determines that one of the second phase voltage detection signals is abnormal, an abnormal signal corresponding to a corresponding one of the first circuit elements is generated.

15. The voltage detection method according to claim 11, further comprising: A plurality of third phase voltage detection signals of a plurality of third detection nodes of the medium voltage system cabinet are obtained through a third voltage detector, wherein the third voltage detector is coupled to the third detection nodes, and the third detection nodes are coupled between the second circuit elements and a power control circuit.

16. The voltage detection method according to claim 15, further comprising: When the controller determines that one of the third phase voltage detection signals is abnormal, another abnormal signal corresponding to a corresponding one of the second circuit elements is generated. 17 . The voltage detection method as claimed in claim 16 , wherein the second circuit elements comprise a plurality of power switch elements.

18. The voltage detection method according to claim 11, further comprising: coupling a plurality of line voltage detection circuits to the first detection nodes, the second detection nodes and a plurality of third detection nodes of the medium voltage system cabinet; and The line voltage detection circuits are used to detect a plurality of first line voltage detection signals, a plurality of second line voltage detection signals and a plurality of third line voltage detection signals corresponding to the first detection nodes, the second detection nodes and the third detection nodes.

19. The voltage detection method according to claim 18, further comprising: A phase-locked control signal is generated according to the first line voltage detection signals, the second line voltage detection signals and the third line voltage detection signals.

20. The voltage detection method as claimed in claim 11, wherein the medium voltage system cabinet is used to receive a plurality of AC voltages through the phase voltage input nodes, and the voltage detection method further comprises: The controller is driven by an auxiliary power supply.

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