TWI718926B - Detection circuit, detection method and uninterruptible power system using the same - Google Patents

Abstract

A detection circuit is disclosed. The detection circuit is electrically connected to a static switch comprising a silicon-controlled rectifier. The detection circuit comprises a high pass filter, a low pass filter, an absolute value circuit and a judgement unit. The high pass filter is electrically connected between a first terminal and a second terminal of the static switch, and is used to filter out a low frequency component of a terminal voltage between the first terminal and the second terminal to generate a first signal when the static switch is turned on. The low pass filter is electrically connected to the high pass filter, and is used to filter out a high frequency component of the first signal to generate a second signal. The absolute value circuit is electrically connected to the low pass filter, and is used to convert the second signal to an absolute value to generate an absolute value signal. The judging unit is electrically connected to the absolute value circuit, and is used to judge whether an abnormal condition that is a short-circuited in the static switch is occurred according to the absolute value signal. When the absolute value signal does not have a pulse signal, the judgment unit judges that the abnormal condition that is the short-circuited is occurred in the static switch.

Description

Detection circuit and its applicable detection method and uninterruptible power system

This case is about a detection circuit, especially a static switch detection circuit and its applicable detection method and uninterruptible power system.

Silicon Controlled Rectifier (SCR) is a commonly used electronic component in industrial electronics. For example, a silicon controlled rectifier can be used in an uninterrupted power system to form a static switch, so that the uninterrupted power system can be based on the received electrical energy (Mains power) status and correspondingly control the static switch, so that the uninterruptible power system can be switched between the online mode (On-line mode) and the energy-saving mode (Eco mode).

However, when the uninterruptible power system is initially powered on or in normal operation, if the silicon controlled rectifier that constitutes the static switch has a short-circuit fault (such as abnormal short-circuit conduction), a very large short-circuit current will flow between the uninterruptible power systems. , Thus causing great harm to the uninterruptible power system.

In order to detect whether the silicon controlled rectifier has a short-circuit fault, the traditional uninterruptible power system must use a current sensor (CT) to detect the reaction caused by the short-circuit fault of the silicon controlled rectifier after the uninterruptible power system is converted to online mode. Sink current, so that the controller determines whether the silicon controlled rectifier has a short-circuit fault based on the detection result of the current sensor.

However, since the silicon controlled rectifier may also have a short-circuit fault when the uninterruptible power system is operating in the energy-saving mode, and the aforementioned current sensor can only detect the reaction caused by the short-circuit fault of the silicon controlled rectifier after the uninterruptible power system is switched to the online mode. Sink current, so the current sensor detection technology used in traditional uninterrupted power systems cannot detect the short-circuit fault of the silicon controlled rectifier immediately, which causes the traditional uninterrupted power system to be unable to instantly determine whether the silicon controlled rectifier has a short-circuit fault. Corresponding protective measures, so that the traditional uninterruptible power system may still be damaged due to the short-circuit fault of the silicon controlled rectifier.

In view of this, it is necessary to provide a detection circuit and its applicable detection method and uninterruptible power system to solve the problems faced by the conventional technology.

The purpose of this case is to provide a detection circuit and its applicable detection method and uninterruptible power system. The detection circuit detects whether the static switch is normal based on the existing characteristics of the static switch's silicon controlled rectifier when it is normally turned on or short-circuited abnormally. Operation or short-circuit failure, according to the detection result of the detection circuit to instantly determine whether the static switch is in normal operation or short-circuit abnormality.

To achieve the aforementioned purpose, this case provides a detection circuit which is electrically connected to a static switch. The static switch includes at least one silicon controlled rectifier. The detection circuit includes: a high-pass filter, which is electrically connected to the first end and the second end of the static switch, for the static switch. When the switch is turned on, the low-frequency component of the terminal voltage between the first terminal and the second terminal is filtered out to generate the first signal; the low-pass filter is electrically connected to the high-pass filter to filter out the high-frequency component of the first signal , To generate a second signal; an absolute value circuit, which is electrically connected to a low-pass filter, for absolute value of the second signal to generate an absolute value signal; and a judging unit, which is electrically connected to the absolute value circuit to be based on the absolute value signal To determine whether the static switch has a short-circuit abnormality, where the absolute value signal does not have a pulse signal, the judging unit determines that the static switch has a short-circuit abnormality.

In order to achieve the aforementioned purpose, this case provides another detection method suitable for static switches. The static switch includes at least one silicon controlled rectifier. The detection method includes: when the static switch is turned on, there is a terminal voltage between the first terminal and the second terminal of the static switch. At the time, filter out the low-frequency component of the terminal voltage to generate the first signal; amplify the gain of the first signal to generate the differential signal; filter out the high-frequency component of the differential signal to generate the second signal; and the second signal The absolute value is converted to generate an absolute value signal; it is judged whether the absolute value signal has a pulse signal. In the case that the absolute value signal does not have a pulse signal, the static switch is judged as a short circuit abnormality.

In order to achieve the foregoing purpose, this case provides an uninterruptible power system, including: an input terminal; an output terminal; an electric energy conversion circuit electrically connected between the input terminal and the output terminal; a first static switch electrically connected in series to the electric energy conversion Between the circuit and the output terminal; the second static switch includes at least one silicon controlled rectifier, the second static switch is electrically connected between the input terminal and the output terminal, and is 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 to the first end and the second end of the second second static switch, for filtering out the first end when the second static switch is turned on The low-frequency component of the terminal voltage between the terminal and the second terminal is used to generate the first signal; the low-pass filter is electrically connected to the high-pass filter to filter out the high-frequency component of the first signal to generate the second signal; The value circuit is electrically connected to the low-pass filter for absolute value of the second signal to generate an absolute value signal; and the judging unit is electrically connected to the absolute value circuit for judging whether the static switch is short-circuited according to the absolute value signal Abnormal, where in the case that the absolute value signal does not have a pulse signal, the judging unit judges that the static switch has a short-circuit abnormality.

Some typical embodiments embodying the features and advantages of this case will be described in detail in the following description. It should be understood that this case can have various changes in different aspects, all of which do not depart from the scope of this case, and the descriptions and drawings therein are essentially for illustrative purposes, rather than limiting the case.

Please refer to Figure 1, Figure 2, and Figure 3. Figure 1 is the circuit block diagram of the detection circuit of the first preferred embodiment of the present invention, and Figure 2 is the silicon controlled rectifier of the static switch detected by the detection circuit. Voltage-current characteristic curve diagram. Figure 3 is a timing diagram of the signal output by part of the main circuit of the detection circuit shown in Figure 1. As shown in the figure, the detection circuit 1 of this 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 the static switch 2 has a short circuit abnormality (that is, the static switch 2 is Normal conduction or short-circuit abnormal conduction), and output a detection signal for judging that the static switch 2 is normally conduction or short-circuit abnormal conduction. The detection principle of the detection circuit 1 in this case is based on the study of the difference between normal and abnormal silicon controlled rectifiers. It can be observed that when the normal silicon controlled rectifier is energized and turned on, the terminal voltage Vak of the silicon controlled rectifier will be obvious. Positive and negative edge transition characteristics, for example, when the terminal voltage Vak shown in Figure 2 is greater than the trigger voltage VB, but abnormal silicon controlled rectifiers usually have resistive characteristics when they are turned on, that is, the voltage-current of the short-circuit abnormal silicon controlled rectifier The relationship is linear, so the short-circuit abnormal silicon controlled rectifier does not have obvious positive and negative edge transition characteristics like the normal silicon controlled rectifier terminal voltage Vak. Therefore, the detection circuit 1 in this case captures the normal silicon controlled rectifier terminal The transition characteristics of the positive and negative edges of the voltage Vak are converted into a pulsed detection signal. In this way, when the silicon controlled rectifier is normal, the detection signal output by the detection circuit 1 will have pulses. On the contrary, the silicon controlled rectifier will be a short circuit. When abnormal, the detection signal output by the detection circuit 1 does not have a pulse signal, so it can be judged whether the static switch 2 with the silicon controlled rectifier is normally turned on or short-circuited abnormally based on whether the detection signal has a pulse signal.

As shown in FIG. 1, 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 terminal of the high-pass filter 10 is electrically connected to the first terminal and the second terminal of the static switch 2 for filtering out the terminal voltage Vak between the first terminal and the second terminal of the static switch 2 when the static switch 2 is turned on The low-frequency component of the signal to generate the first signal Vf1. The input terminal of the low-pass filter 12 is electrically connected to the output terminal of the high-pass filter 10 to filter the high-frequency components of the first signal Vf1 to generate the second signal Vf3. When the static switch 2 is normally turned on, the static switch 2 The positive and negative edge transition characteristics of the terminal voltage Vak 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 terminal of the absolute value circuit 13 is electrically connected to the output terminal of the low-pass filter 12 for absolute value of the second signal Vf3 to generate the absolute value signal Va. When the static switch 2 is normally turned on, the absolute value signal Va will be There is a positive pulse signal, so the absolute value signal Va constitutes a detection signal used to determine whether the static switch 2 is normally turned on or short-circuit abnormally turned on. The judging unit 14 is electrically connected to the output terminal of the absolute value circuit 13, and the judging unit 14 judges that the static switch 2 is normally turned on or short-circuited abnormally based on the absolute value signal Va. In the case that the absolute value signal Va does not have a pulse signal, it is judged The unit 14 determines that the static switch 2 has a short-circuit abnormality. On the contrary, when the absolute value signal Va has a pulse signal, the determination unit 14 determines that the static switch 2 is normally turned on. In some embodiments, the judging unit 14 may be, for example, but not limited to, a microcontroller (MCU) or the like.

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

As shown in Figure 3, 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, Then the second signal Vf3 does not have any pulse signal, so that the absolute value signal Va does not have any pulse signal. Therefore, according to whether the absolute value signal Va has a pulse signal, it can be immediately determined that the static switch 2 is normally turned on or short-circuited abnormally. When the static switch 2 is short-circuited and abnormally turned on, the corresponding protective measures can be taken immediately, thereby reducing the risk of circuit damage caused by the short-circuit fault of the static switch 2.

Please refer to Figure 4, which is a detection method suitable for the detection circuit shown in Figure 1. The detection method of this embodiment first executes step S1, that is, when the static switch 2 is turned on, the low-frequency component of the terminal voltage Vak between the first terminal and the second terminal of the static switch 2 is filtered by the high-pass filter 10 to generate The first signal Vf1. Then, step S2 is executed to amplify the first signal Vf1 by a gain by the amplifying circuit 11 to generate a differential signal Vf2. Then, step S3 is executed to filter the high-frequency components of the differential signal Vf2 by the low-pass filter 12 to generate the second signal Vf3. Then, in step S4, the absolute value circuit 13 generates the absolute value of the second signal Vf3 to generate the absolute value signal Va. Finally, step S5 is executed, and the judging unit 14 is used to judge whether the absolute value signal Va has a pulse signal. In the case that the absolute value signal Va does not have a pulse signal, the static switch 2 is judged as 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.

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

Please refer to Figures 5 and 6, where Figure 5 is a circuit block diagram of the detection circuit of the second preferred embodiment of the present case, and Figure 6 is the signal output by part of the main circuit of the detection circuit shown in Figure 5 Timing diagram. In some embodiments, as shown in FIG. 5, the judgment unit 14 includes a pulse detection circuit 40 and a multi-resonance oscillation circuit 41. The input terminal of the pulse detection circuit 40 is electrically connected to the output terminal of the absolute value circuit 13 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 the pulse detection signal Vs as a square wave signal. On the contrary, when the static switch 2 has a short-circuit abnormality, the pulse detection circuit 40 sets the absolute value The pulse detection signal Vs converted into the absolute value signal Va output by the circuit 13 is not a square wave signal. The multi-resonance oscillation circuit 41 is electrically connected to the pulse detection circuit 40 for determining whether the pulse detection signal Vs is a square wave signal when the pulse detection signal Vs is received from the pulse detection circuit 40. The multi-resonance oscillation circuit 41. When it is judged that the pulse detection signal Vs is not a square wave signal, the absolute value signal Va is judged to have no pulse signal. When the multi-resonance oscillation circuit 41 judges that the pulse detection signal Vs is a square wave signal, the absolute value signal Va is judged to have a pulse. To further illustrate, the multi-resonant oscillation circuit 41 generates a corresponding determination signal Vj based on 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 high The voltage level judgment signal Vj, on the contrary, when the multi-resonant oscillation circuit 4 judges that the pulse detection signal Vs is not a square wave signal, it outputs a low voltage level judgment signal Vj. In this embodiment, the detection circuit 4 is formed by the judgment signal Vj to output a detection signal that can be used to judge whether the static switch 2 is normally turned on or short-circuit abnormally turned on.

In some embodiments, when the multi-resonance oscillating circuit 41 determines that the pulse detection signal Vs is not a square wave signal for a predetermined time length (for example, the time length of 0.2s-0.24s as shown in Fig. 6), it is multi-resonant The output of the oscillating circuit 4 is a low-voltage level judgment signal Vj.

Please refer to Figure 7, which is a detection method suitable for the detection circuit shown in Figure 5. Some steps of the detection method of this embodiment are similar to the steps of the detection method shown in FIG. 4, and therefore, only the same symbols are used here to indicate the same steps and will not be repeated. Compared with the detection method shown in Figure 4, the step S5 of the detection method of this embodiment further includes steps S50 and S51. After step S4 is executed, step S50 in step S5 is executed, and the pulse detection is used to detect The circuit 40 converts the absolute value signal Va output by the absolute value circuit 13 into a pulse detection signal Vs. Then, 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 judged not to have Pulse signal, on the contrary, when the pulse detection signal Vs is a square wave signal, the absolute value signal Va is judged to have a pulse signal.

The detailed structure of the detection circuit in this case will be further explained in Fig. 8. The circuit structures of the high-pass filter 10, the amplifying circuit 11, the low-pass filter 12 and the absolute value circuit 13 of the detection circuit 4 shown in Fig. 5 are respectively The circuit structure of the high-pass filter 10, amplifier circuit 11, low-pass filter 12, and absolute value circuit 13 of the detection circuit 1 shown in Fig. 1 is the same, so Fig. 8 is used to describe the detection circuit shown in Fig. 5 4, the detailed circuit structure of the detection circuit 1 shown in FIG. 1 will not be described.

Please refer to Fig. 8 in conjunction with Fig. 5. Fig. 8 is a detailed circuit structure diagram of the detection circuit shown in Fig. 5. 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 terminal of the first capacitor C1 is electrically connected to the first terminal of the static switch 2. The first terminal of the second capacitor C2 is electrically connected to the second terminal 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.

The amplifier circuit 11 includes a third resistor R3, a fourth resistor R4, a first clamp diode Z1, a second clamp diode Z2, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, and an eighth resistor. R8 and the 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 clamp diode Z1 is electrically connected to the second end of the third resistor R3. The cathode end of the second clamp diode Z2 is electrically connected to the second end of the fourth resistor R4, and the anode end of the second clamp diode Z2 is electrically connected to the anode end of the first clamp diode Z1. The first end of the fifth resistor R5 is electrically connected to the cathode end of the first clamp diode Z1. The first end of the sixth resistor R6 is electrically connected to the cathode end of the second clamp 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.

The low-pass filter 12 includes 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 is electrically connected in parallel with the ninth resistor R9.

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 terminal and the output terminal 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 terminal of the first diode D1 is electrically connected to the first terminal 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 can constitute an inverting amplifier, and the first diode D1, the second diode D2, and the tenth The three resistors R13 constitute a positive logic circuit.

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 end of the third amplifier U3. The first end of the fifteenth resistor R15 is electrically connected to the non-inverting end of the third amplifier U3, and the second end of the fifteenth resistor R15 is grounded. The first terminal 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 end 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 end 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.

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 can be, but is not limited to, a 555 timer IC. The trigger terminal TRIG of the oscillation control integrated circuit 410 is electrically connected to the output terminal of the pulse detection circuit 40, and the oscillation control integrated circuit 410 is The threshold terminal THR is electrically connected to the second terminal of the eighteenth resistor R18, the discharge terminal DISC of the oscillation control integrated circuit 410 is electrically connected to the second terminal of the eighteenth resistor R18, and the output terminal OUT of the oscillation control integrated circuit 410 The judgment signal Vj can be output. In this embodiment, the eighteenth resistor R18 and the fourth capacitor C4 constitute the charging and discharging time. Therefore, when the trigger terminal TRIG of the oscillation control integrated circuit 410 is triggered, the oscillation control integrated circuit 410 outputs the output within a predetermined period of time. The logic of the judgment signal Vj output by the terminal will be changed from a high voltage level to a low voltage level.

However, the detailed circuits of the high-pass filter 10, the amplifying circuit 11, the low-pass filter 12, the absolute value circuit 13, the pulse detection circuit 40, and the multi-resonance circuit 41 shown in Fig. 8 are only one implementation mode. It can vary depending on actual needs and cost considerations.

Please refer to Figure 9, which is a circuit block diagram of the uninterruptible power system of the preferred embodiment of the present invention. The uninterruptible power system 3 of this embodiment includes an input terminal 30, an output terminal 31, a first static switch 32, and a second The static switch 33, the power conversion circuit 34, the 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 terminal and the second terminal of the first static switch 32 or to the first terminal and the second terminal of the second static switch 33, and the detection circuit can be as shown in Figure 1. The detection circuit 1 or the detection circuit 4 shown in Fig. 5, and Fig. 8 illustrates that the uninterruptible power system 3 includes the detection circuit 1 shown in Fig. 1, and the detection circuit 1 is electrically connected to the second static switch 33. . 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 operating, 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 electric energy conversion circuit 34 and the first static switch 32. The detection circuit 1 is electrically connected to the second static switch 33 for detecting and judging whether the second static switch 33 is normally turned on or short-circuited abnormally. The microcontroller 35 is used to control the operation of the uninterruptible power system 3.

In this embodiment, the uninterruptible power system 3 can operate in an online mode, an energy-saving mode, or a backup mode. When the input terminal 30 of the uninterruptible power system 3 receives power normally, the uninterruptible power system 3 can operate in an energy-saving mode Or in online mode, where when the input terminal 30 of the uninterruptible power system 3 is operating in the energy-saving mode, the first static switch 32 is controlled to be off and the second static switch 33 is controlled to be on, and the power conversion circuit 34 does not operate Therefore, the electric energy of the output terminal 31 of the uninterruptible power system 3 is provided by the input terminal 30 via the second static switch 33 bypassed. When the uninterruptible power system 3 is operating in the online mode, the first static switch 32 is controlled to be on, the second static switch 33 is controlled to be off, and the power conversion circuit 34 operates, so the output terminal 31 of the uninterruptible power system 3 The electric energy is provided by the electric energy conversion circuit 34 to convert the electric energy of the input terminal 30 of the uninterruptible power system 3. In addition, when the input terminal 30 of the uninterruptible power system 3 receives abnormal power, the uninterrupted power system 3 operates in a backup mode.

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 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 system 3 is operating in the energy-saving mode or the online mode, the switch 340 is turned on. When the uninterrupted power system 3 is operating in the backup mode, the power of the output terminal 31 of the uninterrupted power system 3 is converted by the power conversion circuit 34 to convert the power of the rechargeable battery 343 to provide it.

In summary, this case provides a detection circuit and its applicable detection method and uninterruptible power system. The detection circuit will have obvious positive and negative edge transition characteristics based on the terminal voltage of the static switch silicon controlled rectifier when it is normally turned on. , To output the corresponding detection signal in real time, so that the judgment unit of the detection circuit can judge whether the static switch is normal operation or short-circuit fault according to the detection result of the detection circuit, and then take corresponding protective measures, thereby reducing the failure caused by the static switch The resulting risk of circuit damage.

1, 4: Detection circuit 2: Static switch 10: High pass filter 11: Amplifying circuit 12: Low-pass filter 13: Absolute value circuit 14: Judgment unit 40: Pulse detection circuit 41: Multi-resonance oscillation circuit 3: Uninterruptible power system 30: Input 31: output 32: The first static switch 33: The second static switch 34: Electric energy conversion circuit 35: Microcontroller Vak: terminal voltage VB: trigger voltage Vf1: The first signal Vf2: Differential signal Vf3: second signal Va: Absolute value signal Vs: Pulse detection signal Vj: Judgment signal C1~C4: The first capacitor ~ the fourth capacitor R1~R18: the first resistor to the eighteenth resistor U1~U3: The first amplifier ~ the third amplifier Z1~Z2: The first clamp diode ~ the second clamp diode D1~D3: The first diode ~ the second diode Vcc: voltage source 410: Oscillation Control Integrated Circuit TRIG: trigger terminal THR: Threshold DISC: discharge terminal OUT: output terminal S1~S6: Steps of the detection method 340: switch 341: AC/DC converter 342: Charging Unit 343: Rechargeable battery 344: DC/AC converter

Figure 1 is a circuit block diagram of the detection circuit of the first preferred embodiment of the present invention; Figure 2 is the voltage-current characteristic curve of the silicon controlled rectifier detected by the detection circuit; Figure 3 is a timing diagram of signals output by part of the main circuits of the detection circuit shown in Figure 1; Figure 4 is a detection method suitable for the detection circuit shown in Figure 1; Fig. 5 is a circuit block diagram of the detection circuit of the second preferred embodiment of the present invention; Figure 6 is a timing diagram of signals output by part of the main circuits of the detection circuit shown in Figure 5; Figure 7 is a detection method suitable for the detection circuit shown in Figure 5; Figure 8 is a detailed circuit structure diagram of the detection circuit shown in Figure 5; Figure 9 is a circuit block diagram of the uninterruptible power system of the preferred embodiment of the present invention.

1: Detection circuit

2: Static switch

10: High pass filter

11: Amplifying circuit

12: Low-pass filter

13: Absolute value circuit

14: Judgment unit

Vak: terminal voltage

Vf1: The first signal

Vf2: Differential signal

Vf3: second signal

Va: Absolute value signal

Claims (20)

A detection circuit is electrically connected to a static switch. The static switch includes at least one 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 When the static switch is turned on, it filters out the low-frequency component of the voltage at one end between the first terminal and the second terminal to generate a first signal; a low-pass filter is electrically connected to the high-pass filter to filter out the The high-frequency component of the first signal to generate a second signal; an absolute value circuit electrically connected to the low-pass filter for absolute value of the second signal to generate an absolute value signal; and a judgment unit , The absolute value circuit is electrically connected to determine whether the static switch has a short-circuit abnormality based on the absolute value signal. In the case that the absolute value signal does not have a pulse signal, the judging unit determines that the static switch has a short-circuit abnormality. The detection circuit according to claim 1, wherein the cut-off frequency of the high-pass filter is 73.5 Hz. The detection circuit according to claim 1, wherein the cut-off frequency of the low-pass filter is 2.4 kHz. The detection circuit according to claim 1, further comprising: an amplifying circuit electrically connected between the high-pass filter and the low-pass filter for amplifying the first signal by a gain to generate a differential signal, The low-pass filter is used to filter high frequency components of the differential signal to generate the second signal. The detection circuit according to claim 1, wherein the judging unit further includes: A pulse detection circuit electrically connected to the absolute value circuit for converting the absolute value signal into a pulse detection signal; and a multi-resonance oscillation circuit electrically connected to the pulse detection circuit for judging the pulse detection signal Whether it is a square wave signal, wherein when the multi-resonance oscillation circuit determines that the pulse detection signal is not a square wave signal, the absolute value signal is judged to have no pulse signal. The detection circuit according to claim 1, wherein the high-pass filter comprises: a first capacitor, a first terminal of the first capacitor is electrically connected to the first terminal of the static switch; a second capacitor, the first terminal A first end of the two capacitors is electrically connected to the second end of the static switch; a first resistor, a first end of the first resistor is electrically connected to a second end of the first capacitor, the first resistor A second end is 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. The detection circuit according to claim 4, wherein the amplifying circuit includes: a third resistor, a first end of the third resistor is electrically connected to the high-pass filter; a fourth resistor, a first end of the fourth resistor One end is electrically connected to the high-pass filter; a first clamping diode, a cathode end of the first clamping diode is electrically connected to the second end of the third resistor; a second clamping diode A pole body, a cathode end of the second clamp diode is electrically connected to the second end of the fourth resistor, an anode end of the second clamp diode and an anode end of the first clamp diode are electrically connected An extreme electrical connection; a fifth resistor, a first end of the fifth resistor is electrically connected to the cathode end of the first clamping diode; A sixth resistor, a first end of the sixth resistor is electrically connected to the cathode end of the second clamp diode; a seventh resistor, a first end of the seventh resistor and the fifth resistor A second end is electrically connected, the second end of the seventh resistor is grounded; an eighth resistor, a first end of the eighth resistor is electrically connected to a second end of the sixth resistor, and the eighth resistor The second end is grounded; and a first amplifier, an inverting end of the first amplifier is electrically connected to the first end of the seventh resistor, and a non-inverting end of the first amplifier is connected to the eighth resistor The first end is electrically connected. The detection circuit according to claim 7, wherein the low-pass filter comprises: a ninth resistor electrically connected between the inverting terminal of the first amplifier and an output terminal of the first amplifier; and a first Three capacitors are electrically connected in parallel with the ninth resistor. The detection circuit according to claim 1, wherein the absolute value circuit includes: a tenth resistor, a first end of the tenth resistor is electrically connected to an output end of the low-pass filter; a second amplifier, the first end An inverting terminal of the two amplifiers is electrically connected to a second terminal of the tenth resistor; an eleventh resistor is 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 is electrically connected to a non-inverting end of the second amplifier, a second end of the twelfth resistor is grounded; a first diode, the An anode end of the first diode is electrically connected to the first end of the tenth resistor; a second diode, an anode end of the second diode is electrically connected to the output end of the second amplifier, the A cathode end of the second diode is electrically connected to a cathode end 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. The detection circuit according to claim 5, wherein the pulse detection circuit comprises: a third amplifier, an inverting terminal of the third amplifier is electrically connected to an output terminal of the absolute value circuit; a fourteenth resistor, A first end of the fourteenth resistor is electrically connected to a voltage source, a second end of the fourteenth resistor is electrically connected to a non-inverting end of the third amplifier; a fifteenth resistor, the tenth A first end of one of the five resistors is electrically connected to the non-inverting end of the third amplifier, a second end of one of the fifteenth resistors is grounded; a sixteenth resistor, one of the first ends of the sixteenth resistor is electrically connected At the non-inverting end of the third amplifier; a third diode, an anode end of the third diode is electrically connected to a second end of the sixteenth resistor, and a cathode of the third diode The terminal is electrically connected to an output terminal of the third amplifier; and 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 terminal of the third amplifier. The detection circuit according to claim 5, wherein the multi-resonance oscillation circuit comprises: an eighteenth resistor, one of the first ends of the eighteenth resistor is electrically connected to a voltage source; a fourth capacitor, the fourth capacitor A first terminal is electrically connected to a second terminal of the eighteenth resistor, and a second terminal of the fourth capacitor is grounded; and an oscillation control integrated circuit, a trigger terminal of the oscillation control integrated circuit and the An output terminal of the pulse detection circuit is electrically connected, a threshold terminal of the oscillation control integrated circuit is electrically connected to the second terminal of the eighteenth resistor, and a discharge terminal of the oscillation control integrated circuit is electrically connected to the tenth The second end of the eight resistors is electrically connected. A detection method is suitable for a static switch, the static switch includes at least one silicon controlled rectifier, the detection method includes: (a) when the static switch is turned on and there is between a first end and a second end of the static switch When a terminal voltage is applied, filter out the low frequency component of the terminal voltage to generate a first signal; (b) amplify the first signal by a gain to generate a differential signal; (c) filter out the high of the differential signal Frequency components to generate a second signal; (d) absolute value of the second signal to generate an absolute value signal; and (e) determine whether the absolute value signal has a pulse signal, where the absolute value signal If there is no pulse signal, the static switch is judged to have a short-circuit abnormality. The detection method according to claim 12, wherein in step (a), low frequency components below 73.5 Hz are filtered out. The detection method according to claim 12, wherein in step (a), high frequency components above 2.4 kHz are filtered out. The detection method according to claim 12, wherein 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 judged to have no pulse signal. An uninterruptible power system includes: an input terminal; an output terminal; an electric energy conversion circuit electrically connected between the input terminal and the output terminal; A first static switch electrically connected in series between the power conversion circuit and the output terminal; a second static switch including at least one silicon controlled rectifier, the second static switch electrically connected to the input terminal and the output terminal Between the output terminals and 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 a second static switch. The detection circuit includes: a high-pass filter electrically connected to the A first terminal and a second terminal of the second static switch are used to filter out the low-frequency component of the voltage at one end between the first terminal and the second terminal when the second static switch is turned on to generate a first A signal; a low-pass filter electrically connected to the high-pass filter 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 with To absolute value the second signal to generate an absolute value signal; and a judging unit, electrically connected to the absolute value circuit, for judging whether the static switch has a short-circuit abnormality according to the absolute value signal, wherein In the case that the absolute value signal does not have a pulse signal, the judging unit judges that the static switch has a short-circuit abnormality. The uninterruptible power system according to claim 16, wherein 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. The uninterruptible power system according to claim 16, further comprising: an amplifying circuit electrically connected between the high-pass filter and the low-pass filter for amplifying the first signal by a gain to generate a differential Signal, wherein the low-pass filter is used to filter high frequency components of the differential signal to generate the second signal. The uninterruptible power system according to claim 16, further comprising: a pulse detection circuit electrically connected to the absolute value circuit for converting the absolute value signal into a pulse detection signal; and a multi-resonant oscillation circuit, electric The pulse detection circuit is connected to determine whether the pulse detection signal is a square wave signal. When the multi-resonance oscillation circuit determines that the pulse detection signal is not a square wave signal, the absolute value signal is judged to have no pulse signal . The uninterruptible power system according to claim 18, wherein the amplifying circuit includes: a third resistor, a first end of the third resistor is electrically connected to the high-pass filter; a fourth resistor, the fourth resistor A first end is electrically connected to the high-pass filter; a first clamp diode, a cathode end of the first clamp diode is electrically connected to the second end of the third resistor; a second clamp Bit diode, a cathode end of the second clamp diode is electrically connected to the second end of the fourth resistor, and an anode end of the second clamp diode is electrically connected to the first clamp diode An anode terminal is electrically connected; a fifth resistor, a first end of the fifth resistor is electrically connected to the cathode terminal of the first clamp diode; a sixth resistor, a first end of the sixth resistor Is electrically connected to the cathode end of the second clamp diode; a seventh resistor, a first end of the seventh resistor is electrically connected to a second end of the fifth resistor, and the first end of the seventh resistor Two ends are grounded; an eighth resistor, a first end of the eighth resistor is electrically connected to a second end of the sixth resistor, and the second end of the eighth resistor is grounded; and A first amplifier, an inverting end of the first amplifier is electrically connected to the first end of the seventh resistor, and a non-inverting end of the first amplifier is electrically connected to the first end of the eighth resistor.

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