Detection circuit and its applicable detection method and uninterruptible power supply system

Abstract

The present invention discloses a detection circuit and its applicable detection method and uninterruptible power supply system. The detection circuit is electrically connected to a static switch, and the static switch includes a silicon-controlled rectifier. The detection circuit includes: a high-pass filter, electrically connected to a first end and a second end of the static switch, for filtering out low-frequency components of a terminal voltage between the first end and the second end when the static switch is turned on, so as to generate a first signal; a low-pass filter, electrically connected to the high-pass filter, for filtering out high-frequency components of the first signal, so as to generate a second signal; an absolute value circuit, electrically connected to the low-pass filter, for converting the second signal into an absolute value, so as to generate an absolute value signal; and a judgment unit, electrically connected to the absolute value circuit, for judging whether a short-circuit abnormality occurs in the static switch according to the absolute value signal, wherein when the absolute value signal does not have a pulse signal, the judgment unit judges that a short-circuit abnormality occurs in the static switch.

Description

Technical Field

[0001] The present disclosure relates to a detection circuit, and more particularly to a detection circuit of a static switch and an applicable detection method and an uninterruptible power supply system. Background Art

[0002] Silicon Controlled Rectifier (SCR) is a commonly used electronic component in current industrial electronics. For example, SCR can be used in an uninterruptible power supply system to form a static switch. The uninterruptible power supply system can control the static switch accordingly according to the status of the received power (mains power), so that the uninterruptible power supply system can switch between the online mode (On-line mode) and the energy-saving mode (Eco mode).

[0003] However, when the UPS is initially powered on or in normal operation, if a short-circuit fault occurs in the silicon-controlled rectifier that constitutes the static switch (e.g., short-circuit abnormal conduction), a very large short-circuit current will flow between the UPS, causing great harm to the UPS.

[0004] In order to detect whether a short circuit fault occurs in the silicon-controlled rectifier, a conventional uninterruptible power supply system must use a current sensor (CT). After the uninterruptible power supply system is switched to an online mode, the current sensor is used to detect the reverse current caused by the short circuit fault of the silicon-controlled rectifier, and then the controller determines whether a short circuit fault occurs in the silicon-controlled rectifier based on the detection result of the current sensor.

[0005] However, since the silicon-controlled rectifier may also have a short-circuit fault when the uninterruptible power supply system is running in the energy-saving mode, and the aforementioned current sensor can only detect the reverse current caused by the short-circuit fault of the silicon-controlled rectifier after the uninterruptible power supply system is switched to the online mode, the detection technology of the current sensor used in the traditional uninterruptible power supply system cannot immediately detect the short-circuit fault of the silicon-controlled rectifier. As a result, the traditional uninterruptible power supply system cannot determine in real time whether the silicon-controlled rectifier has a short-circuit fault and take corresponding protection measures, so that the traditional uninterruptible power supply system may still be damaged due to the short-circuit fault of the silicon-controlled rectifier.

[0006] In view of this, it is necessary to provide a detection circuit and an applicable detection method and an uninterruptible power supply system to solve the problems faced by the prior art. Summary of the invention

[0007] The purpose of the present disclosure is to provide a detection circuit and its applicable detection method and uninterruptible power supply system. The detection circuit detects whether the static switch is operating normally or has a short-circuit fault based on the existing characteristics of the silicon-controlled rectifier of the static switch when it is normally turned on or short-circuited, so as to judge in real time whether the static switch is operating normally or has a short-circuit fault based on the detection result of the detection circuit.

[0008] To achieve the aforementioned purpose, the present disclosure provides a detection circuit electrically connected to a static switch, the static switch including at least one silicon-controlled rectifier, the detection circuit including: a high-pass filter electrically connected to a first end and a second end of the static switch, for filtering out low-frequency components of a terminal voltage between the first end and the second end when the static switch is turned on, so as to generate a first signal; a low-pass filter electrically connected to the high-pass filter, for filtering out high-frequency components of the first signal, so as to generate a second signal; an absolute value circuit electrically connected to the low-pass filter, for converting the second signal into an absolute value, so as to generate an absolute value signal; and a judgment unit electrically connected to the absolute value circuit, for judging whether a short-circuit abnormality occurs in the static switch according to the absolute value signal, wherein when the absolute value signal does not have a pulse signal, the judgment unit judges that a short-circuit abnormality occurs in the static switch.

[0009] To achieve the aforementioned purpose, the present disclosure further provides a detection method applicable to a static switch, the static switch comprising at least one silicon-controlled rectifier, the detection method comprising: when the static switch is turned on and there is a terminal voltage between the first end and the second end of the static switch, filtering out the low-frequency component of the terminal voltage to generate a first signal; amplifying the first signal to generate a differential signal; filtering out the high-frequency component of the differential signal to generate a second signal; and converting the second signal into an absolute value to generate an absolute value signal; and determining whether the absolute value signal has a pulse signal, wherein when the absolute value signal does not have a pulse signal, the static switch is determined to have a short-circuit abnormality.

[0010] To achieve the aforementioned purpose, the present disclosure further provides an uninterruptible power supply system, comprising: an input end; an output end; an electric energy conversion circuit electrically connected between the input end and the output end; a first static switch, the first static switch being electrically connected in series between the electric energy conversion circuit and the output end; a second static switch, comprising at least one silicon-controlled rectifier, the second static switch being electrically connected between the input end and the output end, and being electrically connected in parallel with the series structure of the electric energy conversion circuit and the first static switch; and a detection circuit electrically connected to the second static switch, the detection circuit comprising: a high-pass filter electrically connected between the first end and the second end of the second static switch two terminals, used to filter out the low-frequency components of the terminal voltage between the first terminal and the second terminal to generate a first signal when the second static switch is turned on; a low-pass filter, electrically connected to the high-pass filter, used to filter out the high-frequency components of the first signal to generate a second signal; an absolute value circuit, electrically connected to the low-pass filter, used to convert the second signal into an absolute value to generate an absolute value signal; and a judgment unit, electrically connected to the absolute value circuit, used to judge whether a short-circuit abnormality occurs in the static switch based on the absolute value signal, wherein when the absolute value signal does not have a pulse signal, the judgment unit judges that a short-circuit abnormality occurs in the static switch. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 Schematic diagram of a circuit block of a detection circuit according to a first preferred embodiment of the present disclosure;

[0012] Figure 2 The voltage-current characteristic curve diagram of the silicon-controlled rectifier detected by the detection circuit;

[0013] Figure 3 for Figure 1 The signal timing diagram of the output of some main circuits of the detection circuit shown;

[0014] Figure 4 For application Figure 1 The detection method of the detection circuit shown;

[0015] Figure 5 is a circuit block diagram of a detection circuit of a second preferred embodiment of the present disclosure;

[0016] Figure 6 for Figure 5 The signal timing diagram of the output of some main circuits of the detection circuit shown;

[0017] Figure 7 For application Figure 5 The detection method of the detection circuit shown;

[0018] Figure 8 for Figure 5 The detailed circuit structure diagram of the detection circuit shown;

[0019] Fig. 9A circuit block diagram of an uninterruptible power supply system according to a preferred embodiment of the present invention.

[0020] Description of reference numerals:

[0021] 1, 4: Detection circuit

[0022] 2: Static switch

[0023] 10: High pass filter

[0024] 11: Amplifier circuit

[0025] 12: Low pass filter

[0026] 13: Absolute value circuit

[0027] 14: Judgment unit

[0028] 40: Pulse detection circuit

[0029] 41: Multi-resonance oscillation circuit

[0030] 3: Uninterruptible power supply system

[0031] 30: Input terminal

[0032] 31: Output

[0033] 32: First static switch

[0034] 33: Second static switch

[0035] 34: Power conversion circuit

[0036] 35: Microcontroller

[0037] Vak: terminal voltage

[0038] VB: Trigger voltage

[0039] Vf1: First signal

[0040] Vf2: differential signal

[0041] Vf3: Second signal

[0042] Va: absolute value signal

[0043] Vs: Pulse detection signal

[0044] Vj: judgment signal

[0045] C1~C4: first capacitor to fourth capacitor

[0046] R1~R18: The first resistor to the eighteenth resistor

[0047] U1~U3: First amplifier~third amplifier

[0048] Z1~Z2: First clamping diode~second clamping diode

[0049] D1~D3: The first diode~the second diode

[0050] Vcc: voltage source

[0051] 410: Oscillation Control Integrated Circuit

[0052] TRIG: trigger end

[0053] THR: Threshold end

[0054] DISC: discharge end

[0055] OUT: Output

[0056] S1~S6: Steps of the detection method

[0057] 340: Switch

[0058] 341: AC / DC Converter

[0059] 342: Charging unit

[0060] 343: Rechargeable battery

[0061] 344: DC / AC Converter DETAILED DESCRIPTION

[0062] Some typical embodiments that embody the features and advantages of the present disclosure will be described in detail in the following description. It should be understood that the present disclosure can have various changes in different implementations without departing from the scope of the present disclosure, and the descriptions and drawings therein are essentially used for illustrative purposes rather than for limiting the present disclosure.

[0063] See also Figure 1 , Figure 2 and Figure 3 ,in Figure 1 is a circuit block diagram of a detection circuit of a first preferred embodiment of the present disclosure, Figure 2 The voltage-current characteristic curve of the silicon-controlled rectifier of the static switch detected by the detection circuit is shown in FIG. Figure 3 for Figure 1The signal timing diagram output by some main circuits of the detection circuit shown. As shown in the figure, the detection circuit 1 of the present embodiment is electrically connected to the static switch 2, wherein the static switch 2 includes at least one silicon-controlled rectifier, and the detection circuit 1 is used to detect whether a short-circuit abnormality occurs in the static switch 2 (that is, the static switch 2 is normally turned on or abnormally turned on due to a short circuit), and output a detection signal that can be used to determine whether the static switch 2 is normally turned on or abnormally turned on due to a short circuit. The detection principle architecture of the detection circuit 1 disclosed in the present invention is based on the study of the difference between normal and abnormal silicon-controlled rectifiers. It can be observed that when a normal silicon-controlled rectifier is powered on and turned on, the terminal voltage Vak of the silicon-controlled rectifier will have obvious positive and negative edge transition characteristics, for example, Figure 2 When the terminal voltage Vak shown is greater than the trigger voltage VB, the abnormal silicon-controlled rectifier usually has a resistive characteristic when it is turned on, that is, the voltage-current relationship of the silicon-controlled rectifier with a short-circuit abnormality is linear, so the silicon-controlled rectifier with a short-circuit abnormality does not have the obvious positive and negative edge transition characteristics of the terminal voltage Vak of the normal silicon-controlled rectifier. Therefore, the detection circuit 1 disclosed in the present invention obtains the positive and negative edge transition characteristics of the terminal voltage Vak of the normal silicon-controlled rectifier and converts it into a detection signal with a pulse. In this way, when the silicon-controlled rectifier is normal, the detection signal output by the detection circuit 1 will have a pulse. On the contrary, when the silicon-controlled rectifier is short-circuited abnormally, the detection signal output by the detection circuit 1 does not have a pulse signal. Therefore, whether the static switch 2 with the silicon-controlled rectifier is normally turned on or abnormally turned on due to a short circuit can be judged based on whether the detection signal has a pulse signal.

[0064] like Figure 1As shown, the detection circuit 1 of this embodiment includes a high-pass filter 10, a low-pass filter 12, an absolute value circuit 13 and a judgment unit 14. The input end of the high-pass filter 10 is electrically connected to the first end and the second end of the static switch 2, so as to filter out the low-frequency component of the terminal voltage Vak between the first end and the second end of the static switch 2 when the static switch 2 is turned on, so as to generate a first signal Vf1. The input end of the low-pass filter 12 is electrically connected to the output end of the high-pass filter 10, so as to filter out the high-frequency component of the first signal Vf1, so as to generate a second signal Vf3, wherein when the static switch 2 is normally turned on, the positive and negative edge transition characteristics of the terminal voltage Vak of the static switch 2 will be reflected on the second signal Vf3, that is, there are pulses (including positive pulses and negative pulses) on the second signal Vf3. The input end of the absolute value circuit 13 is electrically connected to the output end of the low-pass filter 12, and is used to convert the second signal Vf3 into an absolute value to generate an absolute value signal Va, wherein when the static switch 2 is normally turned on, the absolute value signal Va will have a positive pulse signal, so the absolute value signal Va constitutes a detection signal for judging whether the static switch 2 is normally turned on or abnormally turned on due to a short circuit. The judgment unit 14 is electrically connected to the output end of the absolute value circuit 13, and the judgment unit 14 judges whether the static switch 2 is normally turned on or abnormally turned on due to a short circuit according to the absolute value signal Va, wherein when the absolute value signal Va does not have a pulse signal, the judgment unit 14 judges that the static switch 2 has a short circuit abnormality, and conversely, when the absolute value signal Va has a pulse signal, the judgment unit 14 judges that the static switch 2 is normally turned on. In some embodiments, the judgment unit 14 may be, for example but not limited to, a microcontroller (MCU).

[0065] In some embodiments, such as Figure 1 As shown, the detection circuit 1 may further include an amplifier circuit 11, the input end of the amplifier circuit 11 is electrically connected to the output end of the high-pass filter 10, and the output end of the amplifier circuit 11 is electrically connected to the input end of the low-pass filter 10. The amplifier circuit 11 is used to amplify the first signal Vf1 by a gain to generate a differential signal Vf2, and the low-pass filter 10 filters out the high-frequency components of the differential signal Vf2 to generate a second signal Vf3.

[0066] And as Figure 3 As shown, when the static switch 2 is normally turned on, there is a pulse signal on the second signal Vf3, so that the absolute value signal Va also has a positive pulse signal. On the contrary, when the static switch 2 is abnormally short-circuited, the second signal Vf3 does not have any pulse signal, so that the absolute value signal Va also does not have any pulse signal. Therefore, according to whether the absolute value signal Va has a pulse signal, it is possible to judge in real time whether the static switch 2 is normally turned on or abnormally turned on due to a short circuit, so that corresponding protection measures can be taken in real time when the static switch 2 is abnormally turned on due to a short circuit, thereby reducing the risk of circuit damage caused by the short circuit fault of the static switch 2.

[0067] See also Figure 4 , which is applicable to Figure 1 The detection method of the detection circuit shown in the figure. The detection method of this embodiment first performs step S1, that is, when the static switch 2 is turned on, the low-frequency component of the terminal voltage Vak between the first end and the second end of the static switch 2 is filtered out by the high-pass filter 10 to generate a first signal Vf1. Then, step S2 is performed, and the first signal Vf1 is amplified by the amplifier circuit 11 to generate a differential signal Vf2. Next, step S3 is performed, and the high-frequency component of the differential signal Vf2 is filtered out by the low-pass filter 12 to generate a second signal Vf3. Then, step S4 is performed, and the second signal Vf3 is converted to an absolute value by the absolute value circuit 13 to generate an absolute value signal Va. Finally, step S5 is performed, and the judgment unit 14 is used to judge whether the absolute value signal Va has a pulse signal, wherein when the absolute value signal Va does not have a pulse signal, the static switch 2 is judged to have a short circuit abnormality. In addition, in step S5, when the absolute value signal Va has a pulse signal, the static switch 2 is judged to be normally turned on.

[0068] In some embodiments, the cutoff frequency of the high-pass filter 10 may be but is not limited to 73.5 Hz, and the cutoff frequency of the low-pass filter 12 may be but is not limited to 2.4 kHz.

[0069] See also Figure 5 and Figure 6 ,in Figure 5 is a circuit block diagram of a detection circuit of a second preferred embodiment of the present disclosure, Figure 6 for Figure 5 The signal timing diagram of the output of the detection circuit shown in FIG. Figure 5As shown, the judgment unit 14 includes a pulse detection circuit 40 and a multi-resonance oscillation circuit 41. The input end of the pulse detection circuit 40 is electrically connected to the output end of the absolute value circuit 13, and is used to convert the absolute value signal Va output by the absolute value circuit 13 into a pulse detection signal Vs. When the static switch 2 is normally turned on, the pulse detection circuit 40 converts the absolute value signal Va output by the absolute value circuit 13 into a pulse detection signal Vs that is a square wave signal. On the contrary, when the static switch 2 is short-circuited abnormally, the pulse detection circuit 40 converts the absolute value signal Va output by the absolute value circuit 13 into a pulse detection signal Vs that is not a square wave signal. The multi-resonance oscillation circuit 41 is electrically connected to the pulse detection circuit 40, and is used to determine whether the pulse detection signal Vs is a square wave signal when receiving the pulse detection signal Vs from the pulse detection circuit 40. When the multi-resonance oscillation circuit 41 determines that the pulse detection signal Vs is not a square wave signal, the absolute value signal Va is determined to have no pulse signal, and when the multi-resonance oscillation circuit 41 determines that the pulse detection signal Vs is a square wave signal, the absolute value signal Va is determined to have a pulse signal. To further explain, the multi-resonance oscillation circuit 41 generates a corresponding determination signal Vj according to whether the pulse detection signal is received. When the multi-resonance oscillation circuit 41 determines that the pulse detection signal Vs is a square wave signal, the output is a determination signal Vj of a high voltage level. On the contrary, when the multi-resonance oscillation circuit 4 determines that the pulse detection signal Vs is not a square wave signal, the output is a determination signal Vj of a low voltage level. In this embodiment, the determination signal Vj constitutes the detection signal output by the detection circuit 4, which can be used to determine whether the static switch 2 is normally turned on or abnormally turned on due to a short circuit.

[0070] In some embodiments, when the multi-resonance oscillation circuit 41 determines that the pulse detection signal Vs is not a square wave signal for a predetermined time length (eg Figure 6 When the time length is 0.2s-0.24s as shown in the figure, the multi-resonance oscillation circuit 4 outputs a judgment signal Vj of a low voltage level.

[0071] See also Figure 7 , which is applicable to Figure 5 The detection method of the detection circuit shown in FIG. Some steps of the detection method of this embodiment are similar to Figure 4 The steps of the detection method shown in FIG. 1 are the same as those of the detection method shown in FIG. 1 , so the same symbols are used here to indicate the same steps and no further description is given. Figure 4The detection method shown in the embodiment further includes steps S50 and S51 in step S5, wherein after executing step S4, step S50 in step S5 is executed to convert the absolute value signal Va output by the absolute value circuit 13 into a pulse detection signal Vs through the pulse detection circuit 40. Next, step S51 is executed to determine whether the pulse detection signal Vs is a square wave signal to determine whether the absolute value signal Va has a pulse signal, wherein when the pulse detection signal Vs is not a square wave signal, the absolute value signal Va is determined not to have a pulse signal, and vice versa, when the pulse detection signal Vs is a square wave signal, the absolute value signal Va is determined to have a pulse signal.

[0072] The following will be Figure 8 The detailed structure of the detection circuit disclosed in the present invention is further described, wherein Figure 5 The circuit structures of the high-pass filter 10, the amplifier circuit 11, the low-pass filter 12 and the absolute value circuit 13 of the detection circuit 4 are respectively similar to those of Figure 1 The circuit structures of the high-pass filter 10, the amplifier circuit 11, the low-pass filter 12 and the absolute value circuit 13 of the detection circuit 1 are the same. Figure 8 To illustrate Figure 5 The detailed circuit structure of the detection circuit 4 is shown in FIG. Figure 1 The detailed circuit structure of the detection circuit 1 shown will be described.

[0073] See also Figure 8 , and cooperate with Figure 5 ,in Figure 8 for Figure 5 Detailed circuit structure diagram of the detection circuit shown. As shown in the figure, the high-pass filter 10 includes a first capacitor C1, a second capacitor C2, a first resistor R1 and a second resistor R2. The first end of the first capacitor C1 is electrically connected to the first end of the static switch 2. The first end of the second capacitor C2 is electrically connected to the second end of the static switch 2. The first end of the first resistor R1 is electrically connected to the second end of the first capacitor C1, and the second end of the first resistor R1 is grounded. The first end of the second resistor R2 is electrically connected to the second end of the second capacitor C2, and the second end of the second resistor R2 is grounded.

[0074] The amplifier circuit 11 includes a third resistor R3, a fourth resistor R4, a first clamping diode Z1, a second clamping diode Z2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8 and a first amplifier U1. The first end of the third resistor R3 is electrically connected to the first end of the first resistor R1 of the high-pass filter 10. The first end of the fourth resistor R4 is electrically connected to the first end of the second resistor R2 of the high-pass filter 10. The cathode end of the first clamping diode Z1 is electrically connected to the second end of the third resistor R3. The cathode end of the second clamping diode Z2 is electrically connected to the second end of the fourth resistor R4, and the anode end of the second clamping diode Z2 is electrically connected to the anode end of the first clamping diode Z1. The first end of the fifth resistor R5 is electrically connected to the cathode end of the first clamping diode Z1. The first end of the sixth resistor R6 is electrically connected to the cathode end of the second clamping diode Z2. The first end of the seventh resistor R7 is electrically connected to the second end of the fifth resistor R5, and the second end of the seventh resistor R7 is grounded. The first end of the eighth resistor R8 is electrically connected to the second end of the sixth resistor R6, and the second end of the eighth resistor R8 is grounded. The inverting end of the first amplifier U1 is electrically connected to the first end of the seventh resistor R7, and the non-inverting end of the first amplifier U1 is electrically connected to the first end of the eighth resistor R8.

[0075] The low pass filter 12 comprises a third capacitor C3 and a ninth resistor R9. The ninth resistor R9 is electrically connected between the inverting terminal and the output terminal of the first amplifier U1. The third capacitor C3 and the ninth resistor R9 are electrically connected in parallel.

[0076] The absolute value circuit 13 includes a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a thirteenth resistor R13, a second amplifier U2, a first diode D1 and a second diode D2. The first end of the tenth resistor R10 is electrically connected to the output end of the low-pass filter 12. The inverting end of the second amplifier U2 is electrically connected to the second end of the tenth resistor R10. The eleventh resistor R11 is electrically connected between the inverting end and the output end of the second amplifier U2. The first end of the twelfth resistor R12 is electrically connected to the non-inverting end of the second amplifier U2, and the second end of the twelfth resistor R12 is grounded. The anode end of the first diode D1 is electrically connected to the first end of the tenth resistor R10. The anode end of the second diode D2 is electrically connected to the non-inverting end of the second amplifier U2, and the cathode end of the second diode D2 is electrically connected to the cathode end of the first diode D1. The first end of the thirteenth resistor R13 is electrically connected to the cathode end of the second diode D2, and the second end of the thirteenth resistor R13 is grounded. In this embodiment, the tenth resistor R10, the eleventh resistor R11, the twelfth resistor R12 and the second amplifier U2 may constitute an inverting amplifier, and the first diode D1, the second diode D2 and the thirteenth resistor R13 may constitute a positive logic circuit.

[0077] The pulse detection circuit 40 includes a third amplifier U3, a fourteenth resistor R14, a fifteenth resistor R16, a sixteenth resistor R16, a seventeenth resistor R17 and a third diode D3. The inverting terminal of the third amplifier U3 is electrically connected to the output terminal of the absolute value circuit 13. The first end of the fourteenth resistor R14 is electrically connected to the voltage source Vcc, and the second end of the fourteenth resistor R14 is electrically connected to the non-inverting terminal of the third amplifier U3. The first end of the fifteenth resistor R15 is electrically connected to the non-inverting terminal of the third amplifier U3, and the second end of the fifteenth resistor R15 is grounded. The first end of the sixteenth resistor R16 is electrically connected to the non-inverting terminal of the third amplifier U3. The anode end of the third diode D3 is electrically connected to the second end of the sixteenth resistor R16, and the cathode end of the third diode D3 is electrically connected to the output terminal of the third amplifier U3. The first end of the seventeenth resistor R17 is electrically connected to the voltage source Vcc, and the second end of the seventeenth resistor R17 is electrically connected to the output terminal of the third amplifier U3. In this embodiment, the voltage source Vcc is divided into a reference voltage by the fourteenth resistor R14 and the fifteenth resistor R15. The third amplifier U3, the sixteenth resistor R16 and the third diode D3 constitute a hysteresis amplifier to perform hysteresis comparison and convert the absolute value signal Va output by the absolute value circuit 13 into a pulse detection signal Vs.

[0078] The multi-resonance oscillation circuit 41 includes an eighteenth resistor R18, a fourth capacitor C4 and an oscillation control integrated circuit 410. The first end of the eighteenth resistor R18 is electrically connected to the voltage source Vcc. The first end of the fourth capacitor C4 is electrically connected to the second end of the eighteenth resistor R18, and the second end of the fourth capacitor C4 is grounded. The oscillation control integrated circuit 410 may be, but is not limited to, a 555 timing integrated circuit (timer IC), the trigger end TRIG of the oscillation control integrated circuit 410 is electrically connected to the output end of the pulse detection circuit 40, the threshold end THR of the oscillation control integrated circuit 410 is electrically connected to the second end of the eighteenth resistor R18, the discharge end DISC of the oscillation control integrated circuit 410 is electrically connected to the second end of the eighteenth resistor R18, and the output end OUT of the oscillation control integrated circuit 410 can output a judgment signal Vj. In this embodiment, the eighteenth resistor R18 and the fourth capacitor C4 constitute the charge and discharge time. Therefore, when the trigger terminal TRIG of the oscillation control integrated circuit 410 is triggered, the logic of the judgment signal Vj outputted from the output terminal of the oscillation control integrated circuit 410 will be switched from a high voltage level to a low voltage level within a predetermined time.

[0079] However Figure 8 The detailed circuits of the high-pass filter 10, amplifier circuit 11, low-pass filter 12, absolute value circuit 13, pulse detection circuit 40 and multi-harmonic oscillation circuit 41 shown are only one implementation method, and different implementation methods may be used according to actual needs and cost considerations.

[0080] See also Fig. 9 , which is a circuit block diagram of the uninterruptible power supply system of the preferred embodiment of the present disclosure. The uninterruptible power supply system 3 of the present embodiment includes an input terminal 30, an output terminal 31, a first static switch 32, a second static switch 33, an electric energy conversion circuit 34, a microcontroller 35 and at least one detection circuit. The first static switch 32 and the second static switch 33 each include at least one silicon-controlled rectifier. Each detection circuit can be electrically connected to the first end and the second end of the first static switch 32 or to the first end and the second end of the second static switch 33, and the detection circuit can also be Figure 1 The detection circuit shown in 1 or Figure 5 The detection circuit 4 shown in Figure 8 UPS3 includes Figure 1 The detection circuit 1 shown in the figure is electrically connected to the second static switch 33 for example. The power conversion circuit 34 is electrically connected between the input terminal 30 and the output terminal 31. When the power conversion circuit 34 is running, the power conversion circuit 34 can convert the power received by the input terminal 30 and output it at the output terminal 31. The first static switch 32 is electrically connected in series between the power conversion circuit 34 and the output terminal 31. The second static switch 33 is electrically connected between the input terminal 30 and the output terminal 31, and is electrically connected in parallel with the series structure of the power conversion circuit 34 and the first static switch 32. The detection circuit 1 is electrically connected to the second static switch 33 to detect whether the second static switch 33 is normally turned on or short-circuited. The microcontroller 35 is used to control the operation of the uninterruptible power supply system 3.

[0081] In this embodiment, the UPS 3 can operate in an online mode, an energy-saving mode, or a backup mode. When the input terminal 30 of the UPS 3 receives power normally, the UPS 3 can operate in the energy-saving mode or the online mode. When the input terminal 30 of the UPS 3 operates in the energy-saving mode, the first static switch 32 is controlled to be turned off and the second static switch 33 is controlled to be turned on, and the power conversion circuit 34 does not operate, so the power of the output terminal 31 of the UPS 3 is provided by the input terminal 30 via the bypassed second static switch 33. When the UPS 3 operates in an online mode, the first static switch 32 is controlled to be turned on, the second static switch 33 is controlled to be turned off, and the power conversion circuit 34 operates, so the power of the output terminal 31 of the UPS 3 is provided by the power conversion circuit 34 converting the power of the input terminal 30 of the UPS 3. In addition, when the input terminal 30 of the UPS 3 receives power abnormally, the UPS 3 operates in the backup mode.

[0082] In some embodiments, the power conversion circuit 34 further includes a switch 340, an AC / DC converter 341, a charging unit 342, a rechargeable battery 343, and a DC / AC converter 344. The switch 340 is electrically connected between the input terminal 30 of the uninterruptible power supply system 3 and the AC / DC converter 341. The AC / DC converter 341 is electrically connected between the switch 340 and the DC / AC converter 342. The DC / AC converter 344 is electrically connected between the AC / DC converter 341 and the first static switch 32. The charging unit 342 is electrically connected between the AC / DC converter 341 and the rechargeable battery 343. When the uninterruptible power supply system 3 operates in the energy-saving mode or the online mode, the switch 340 is in the on state. When the uninterruptible power supply system 3 operates in the backup mode, the power at the output terminal 31 of the uninterruptible power supply system 3 is provided by converting the power of the rechargeable battery 343 by the power conversion circuit 34.

[0083] In summary, the present disclosure provides a detection circuit and a detection method applicable thereto and an uninterruptible power supply system. The detection circuit outputs a corresponding detection signal in real time based on the obvious positive and negative edge transition characteristics of the terminal voltage of the silicon-controlled rectifier of the static switch when it is normally turned on, so that the judgment unit of the detection circuit can judge in real time whether the static switch is operating normally or has a short-circuit fault according to the detection result of the detection circuit, and then take corresponding protection measures, thereby reducing the risk of circuit damage caused by static switch failure.

Claims

1. A detection circuit electrically connected to a static switch, the static switch comprising at least one silicon-controlled rectifier, characterized in that: The detection circuit includes: a high-pass filter electrically connected to a first terminal and a second terminal of the static switch, for filtering out a low-frequency component of a voltage between the first terminal and the second terminal when the static switch is turned on, so as to generate a first signal; a low-pass filter, electrically connected to the high-pass filter, for filtering out high-frequency components of the first signal to generate a second signal; an absolute value circuit, electrically connected to the low-pass filter, for converting the second signal into an absolute value to generate an absolute value signal; as well as a judgment unit, electrically connected to the absolute value circuit, for judging whether a short circuit abnormality occurs in the static switch according to the absolute value signal, wherein when the absolute value signal does not have a pulse signal, the judgment unit judges that a short circuit abnormality occurs in the static switch; The judging unit further comprises: a pulse detection circuit electrically connected to the absolute value circuit for converting the absolute value signal into a pulse detection signal; as well as A multi-resonance oscillation circuit is electrically connected to the pulse detection circuit, and is used to determine whether the pulse detection signal is a square wave signal when the pulse detection signal is received from the pulse detection circuit, wherein when the multi-resonance oscillation circuit determines that the pulse detection signal is not a square wave signal, the absolute value signal is determined to have no pulse signal.

2. The detection circuit according to claim 1, characterized in that: The cutoff frequency of this high pass filter is 73.5 Hz.

3. The detection circuit according to claim 1, characterized in that: The cut-off frequency of the low-pass filter is 2.4kHz.

4. The detection circuit according to claim 1, characterized in that: Also includes: An amplifier circuit is electrically connected between the high-pass filter and the low-pass filter, and is used to amplify the first signal by a gain to generate a differential signal, wherein the low-pass filter is used to filter out high-frequency components of the differential signal to generate the second signal.

5. The detection circuit according to claim 1, characterized in that: The high-pass filter contains: a first capacitor, a first end of the first capacitor being electrically connected to the first end of the static switch; a second capacitor, a first end of the second capacitor being electrically connected to the second end of the static switch; a first resistor, a first end of the first resistor being electrically connected to a second end of the first capacitor, and a second end of the first resistor being grounded; and A second resistor, a first end of the second resistor is electrically connected to a second end of the second capacitor, and a second end of the second resistor is grounded.

6. The detection circuit according to claim 4, characterized in that: The amplifier circuit includes: a third resistor, a first end of the third resistor being electrically connected to the high pass filter; a fourth resistor, a first end of which is electrically connected to the high-pass filter; a first clamping diode, a cathode terminal of the first clamping diode being electrically connected to a second terminal of the third resistor; a second clamping diode, wherein a cathode terminal of the second clamping diode is electrically connected to a second end of the fourth resistor, and an anode terminal of the second clamping diode is electrically connected to an anode terminal of the first clamping diode; a fifth resistor, a first end of the fifth resistor being electrically connected to the cathode end of the first clamping diode; a sixth resistor, a first end of the sixth resistor being electrically connected to the cathode end of the second clamping diode; a seventh resistor, a first end of the seventh resistor being electrically connected to a second end of the fifth resistor, and a second end of the seventh resistor being grounded; an eighth resistor, a first end of the eighth resistor being electrically connected to a second end of the sixth resistor, and a second end of the eighth resistor being grounded; and A first amplifier, an inverting terminal of the first amplifier is electrically connected to the first end of the seventh resistor, and a non-inverting terminal of the first amplifier is electrically connected to the first end of the eighth resistor.

7. The detection circuit according to claim 6, characterized in that: The low-pass filter contains: a ninth resistor electrically connected between the inverting terminal of the first amplifier and an output terminal of the first amplifier; and A third capacitor is electrically connected in parallel with the ninth resistor.

8. The detection circuit according to claim 1, characterized in that: The absolute value circuit includes: a tenth resistor, a first end of the tenth resistor being electrically connected to an output end of the low-pass filter; a second amplifier, an inverting terminal of the second amplifier being electrically connected to a second terminal of the tenth resistor; an eleventh resistor electrically connected between the inverting terminal of the second amplifier and an output terminal of the second amplifier; a twelfth resistor, a first end of the twelfth resistor being electrically connected to a non-inverting end of the second amplifier, and a second end of the twelfth resistor being grounded; a first diode, an anode terminal of the first diode being electrically connected to the first end of the tenth resistor; a second diode, an anode terminal of the second diode being electrically connected to the output terminal of the second amplifier, and a cathode terminal of the second diode being electrically connected to a cathode terminal of the first diode; and A thirteenth resistor, a first end of the thirteenth resistor is electrically connected to the cathode end of the second diode, and a second end of the thirteenth resistor is grounded.

9. The detection circuit according to claim 1, characterized in that: The pulse detection circuit comprises: a third amplifier, an inverting terminal of the third amplifier being electrically connected to an output terminal of the absolute value circuit; a fourteenth resistor, a first end of the fourteenth resistor being electrically connected to a voltage source, and a second end of the fourteenth resistor being electrically connected to a non-inverting end of the third amplifier; a fifteenth resistor, a first end of the fifteenth resistor being electrically connected to the non-inverting end of the third amplifier, and a second end of the fifteenth resistor being grounded; a sixteenth resistor, a first end of the sixteenth resistor being electrically connected to the non-inverting end of the third amplifier; a third diode, an anode terminal of the third diode being electrically connected to a second terminal of the sixteenth resistor, and a cathode terminal of the third diode being electrically connected to an output terminal of the third amplifier; as well as A seventeenth resistor, a first end of the seventeenth resistor is electrically connected to the voltage source, and a second end of the seventeenth resistor is electrically connected to the output end of the third amplifier.

10. The detection circuit according to claim 4, characterized in that: The multi-resonance oscillation circuit comprises: an eighteenth resistor, a first end of the eighteenth resistor being electrically connected to a voltage source; a fourth capacitor, a first end of the fourth capacitor being electrically connected to a second end of the eighteenth resistor, and a second end of the fourth capacitor being grounded; and An oscillation control integrated circuit, a trigger end of the oscillation control integrated circuit is electrically connected to an output end of the pulse detection circuit, a threshold end of the oscillation control integrated circuit is electrically connected to the second end of the eighteenth resistor, and a discharge end of the oscillation control integrated circuit is electrically connected to the second end of the eighteenth resistor.

11. A detection method using the detection circuit according to any one of claims 1 to 10, applicable to a static switch, the static switch comprising at least one silicon-controlled rectifier, characterized in that: The test method includes: (a) when the static switch is turned on and a terminal voltage exists between a first terminal and a second terminal of the static switch, filtering out a low-frequency component of the terminal voltage to generate a first signal; (b) amplifying the first signal by a gain to generate a differential signal; (c) filtering out high frequency components of the differential signal to generate a second signal; (d) converting the second signal into an absolute value to generate an absolute value signal; as well as (e) determining whether the absolute value signal has a pulse signal, wherein when the absolute value signal does not have a pulse signal, the static switch is determined to have a short circuit abnormality.

12. The detection method according to claim 11, characterized in that: In step (a), low-frequency components below 73.5 Hz are filtered out.

13. The detection method according to claim 11, characterized in that: In step (c), high frequency components above 2.4 kHz are filtered out.

14. The detection method according to claim 11, characterized in that: The step (e) comprises: (f) converting the absolute value signal into a pulse detection signal; and (g) determining whether the pulse detection signal is a square wave signal, wherein when the pulse detection signal is not a square wave signal, the absolute value signal is determined to have no pulse signal.

15. An uninterruptible power supply system, characterized in that: Include: an input terminal; an output terminal; an electric energy conversion circuit electrically connected between the input end and the output end; a first static switch, the first static switch being electrically connected in series between the power conversion circuit and the output end; a second static switch, comprising at least one silicon-controlled rectifier, the second static switch being electrically connected between the input end and the output end, and being electrically connected in parallel with the series structure of the power conversion circuit and the first static switch; and A detection circuit is electrically connected to a second static switch, and the detection circuit comprises: a high-pass filter electrically connected to a first terminal and a second terminal of the second static switch, for filtering out a low-frequency component of a voltage between the first terminal and the second terminal when the second static switch is turned on, so as to generate a first signal; a low-pass filter, electrically connected to the high-pass filter, for filtering out high-frequency components of the first signal to generate a second signal; an absolute value circuit, electrically connected to the low-pass filter, for converting the second signal into an absolute value to generate an absolute value signal; as well as a judgment unit, electrically connected to the absolute value circuit, for judging whether a short circuit abnormality occurs in the static switch according to the absolute value signal, wherein when the absolute value signal does not have a pulse signal, the judgment unit judges that a short circuit abnormality occurs in the static switch; The judging unit further comprises: a pulse detection circuit electrically connected to the absolute value circuit for converting the absolute value signal into a pulse detection signal; as well as A multi-resonance oscillation circuit is electrically connected to the pulse detection circuit, and is used to determine whether the pulse detection signal is a square wave signal when the pulse detection signal is received from the pulse detection circuit, wherein when the multi-resonance oscillation circuit determines that the pulse detection signal is not a square wave signal, the absolute value signal is determined to have no pulse signal.

16. The uninterruptible power supply system according to claim 15, characterized in that: The cut-off frequency of the high-pass filter is 73.5 Hz, and / or the cut-off frequency of the low-pass filter is 2.4 kHz.

17. The uninterruptible power supply system according to claim 15, characterized in that: Also includes: An amplifier circuit is electrically connected between the high-pass filter and the low-pass filter, and is used to amplify the first signal by a gain to generate a differential signal, wherein the low-pass filter is used to filter out high-frequency components of the differential signal to generate the second signal.

18. The uninterruptible power supply system according to claim 17, characterized in that: The amplifier circuit includes: a third resistor, a first end of the third resistor being electrically connected to the high pass filter; a fourth resistor, a first end of which is electrically connected to the high-pass filter; a first clamping diode, a cathode terminal of the first clamping diode being electrically connected to a second terminal of the third resistor; a second clamping diode, wherein a cathode terminal of the second clamping diode is electrically connected to a second end of the fourth resistor, and an anode terminal of the second clamping diode is electrically connected to an anode terminal of the first clamping diode; a fifth resistor, a first end of the fifth resistor being electrically connected to the cathode end of the first clamping diode; a sixth resistor, a first end of the sixth resistor being electrically connected to the cathode end of the second clamping diode; a seventh resistor, a first end of the seventh resistor being electrically connected to a second end of the fifth resistor, and a second end of the seventh resistor being grounded; an eighth resistor, a first end of the eighth resistor being electrically connected to a second end of the sixth resistor, and a second end of the eighth resistor being grounded; and A first amplifier, an inverting terminal of the first amplifier is electrically connected to the first end of the seventh resistor, and a non-inverting terminal of the first amplifier is electrically connected to the first end of the eighth resistor.

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