Direct-current self-starting circuit for voltage sag treatment device

Abstract

The utility model discloses a direct-current self-starting circuit for a voltage sag treatment device. The direct-current self-starting circuit comprises a thyristor bypass module, a monitoring module, a DVR module and a super capacitor, the thyristor bypass module comprises a thyristor device, a DSP master controller, a driving circuit, a bypass auxiliary power supply, an overcurrent protection circuit, a first relay, a bias holding circuit, a switch, a timing circuit, a first optocoupler and a second optocoupler; the monitoring module is connected with the bypass auxiliary power supply; the DVR module comprises a DC / DC power converter connected with the super capacitor and the monitoring module, an inverter bus connected with the DC / DC power converter, an inverter, an auxiliary power supply connected with the DC / DC power converter and the super capacitor, and a second relay; the second relay is connected with a second optocoupler and a bypass auxiliary power supply; the super capacitor is connected with the first relay.

Description

TECHNICAL FIELD

[0001] The utility model relates to power system technical field especially is related to a direct current self starting circuit for voltage sag management device. BACKGROUND

[0002] Voltage sag management device is used for when the grid voltage occurs short time drop, the quick compensation or isolation fault, the power electronic device or system of protection sensitive load is affected, it can detect voltage anomaly and take compensation measures in millisecond level time, ensure that load continues stable operation, can solve because short circuit fault, large motor starts, lightning etc. Cause voltage sag problem, prevent industrial production line downtime, data loss or equipment damage. Wherein, direct current self starting circuit is used for solving the emergency power supply of voltage sag management device and the initial charging problem of energy storage unit under the condition of voltage sag or interruption, specifically, direct current self starting circuit provides temporary power supply for the control chip, detection circuit of voltage sag management device through built-in energy storage element or energy collection module, to trigger main circuit start-up, in addition, direct current self starting circuit carries out pre-charging to energy storage unit when voltage sag management device powers on through low voltage direct current source or high resistance current limiting charging path, makes it reach the voltage threshold value of workable.

[0003] At present, the industry mainly includes three common direct current self-starting circuits, one of which is that the super capacitor is directly connected with the inverter bus through the direct current contactor, and the direct current self-starting switch drives the direct current relay driving circuit to attract the direct current relay. Since the voltage difference between the super capacitor voltage and the inverter module bus voltage is quite large, the inverter module bus is charged through the super capacitor, and a large impact current will be generated in the relay attracting moment, which is easy to cause damage to the inverter module bus capacitor. The second is that the super capacitor is connected in series with a current limiting resistor through the direct current contactor, and then directly connected to the inverter module bus, and the current limiting resistor is connected in parallel with the direct current contactor, and is provided with a differential pressure detection circuit, a relay driving circuit and a standby power supply. Although the current limiting resistor can avoid the impact current, since the short-circuit current limiting resistor contactor is connected in series in the main power circuit, the contactor is relatively large in size and high in price, and each direct current contactor needs to be provided with an independent driving circuit and a corresponding power supply circuit, so that the configuration is increased and the cost is increased; the super capacitor directly starts the inverter module direct current bus, which limits the upper limit value and the starting value of the super capacitor voltage or the inverter module direct current bus, and it is difficult to meet the demand of the high voltage direct current bus platform. The third is that the super capacitor is first connected through a specially designed DC / DC chopper circuit, and then the electric signal passing through the DC / DC chopper circuit is transmitted to the inverter module, so that the inverter module starts to work. The DC / DC chopper circuit usually includes 1-2 levels of direct current conversion circuit, power management circuit and voltage monitoring circuit. Although it avoids the limitation of the direct current bus, it needs to separately add 1-2 levels of direct current conversion circuit, and the power of the direct current conversion circuit is affected by the number of inverter modules configured by the system, which is easy to cause insufficient power or redundancy of the direct current conversion circuit; the centralized direct current conversion circuit will introduce a single point failure risk point for the whole machine system; after the whole machine system is started through the direct current self-starting circuit, the system recovers to normal power supply, and the direct current self-starting circuit cannot effectively self-turn off, which will cause unnecessary power loss and service life attenuation of the device. Practical new type content

[0004] Therefore, it is necessary to provide a direct current self-starting circuit for voltage sag treatment device with low failure rate, small bus voltage limitation, small size, low cost, avoiding power shortage or redundancy, small power loss and long service life.

[0005] A direct current self-starting circuit for voltage sag governance device, comprising a thyristor bypass module, a monitoring module, a DVR module and a super capacitor; the thyristor bypass module comprises a thyristor device for main power flow, a DSP master control connected with the thyristor device and used for detection and control, a driving circuit arranged between the thyristor device and the DSP master control and used for driving the thyristor device to act, a bypass auxiliary power supply used for powering the DSP master control and the driving circuit, an overcurrent protection circuit used for protecting the bypass auxiliary power supply, a starting unit used for starting the bypass auxiliary power supply, a first relay connected with the bypass auxiliary power supply, a bias maintenance circuit connected with the first relay and used for powering the first relay and connected with the super capacitor, a switch connected with the bias maintenance circuit to turn on and off the direct current self-starting circuit, a timing circuit connected with the bias maintenance circuit to cut off the bias maintenance circuit, a first optocoupler connected with the bypass auxiliary power supply and the bias maintenance circuit and used for disabling the direct current self-starting function in normal operation, and a second optocoupler connected with the bypass auxiliary power supply and the bias maintenance circuit and used for enabling the direct current self-starting signal; the monitoring module is connected with the bypass auxiliary power supply; the DVR module comprises a DC / DC power converter connected with the super capacitor and the monitoring module, an inverter bus connected with the DC / DC power converter, an inverter used for converting the voltage of the inverter bus into a rated alternating voltage, an auxiliary power supply connected with the DC / DC power converter and the super capacitor, and a second relay used for controlling the auxiliary power supply and the super capacitor to turn on and off and starting the inverter bus, wherein the second relay is connected with the second optocoupler and the bypass auxiliary power supply; and the super capacitor is connected with the first relay.

[0006] In one of the embodiments, the thyristor device is an SCR electronic bypass.

[0007] In one of the embodiments, an input end of the thyristor device is connected with a bypass alternating current input, and an output end of the thyristor device is connected with a bypass alternating current output; the starting unit comprises a first uncontrolled rectifier unit D1 connected with the bypass alternating current input and a second uncontrolled rectifier unit D2 connected with the bypass alternating current output; a negative pole of the first uncontrolled rectifier unit D1 is connected in parallel with a negative pole of the second uncontrolled rectifier unit D2, and connected with a positive pole of the bypass auxiliary power supply through a first line; and a positive pole of the first uncontrolled rectifier unit D1 is connected in parallel with a positive pole of the second uncontrolled rectifier unit D2, and connected with a negative pole of the bypass auxiliary power supply through a second line.

[0008] In one of the embodiments, the overcurrent protection circuit comprises a first resistor R1 connected in series with the first line, and a second resistor R2 connected in series with the second line; a positive pole of the super capacitor and the first resistor R1 are connected in series with the first relay, a negative pole of the super capacitor and the second resistor R2 are connected in series with the first relay, the first resistor R1 is arranged between the positive pole of the bypass auxiliary power supply and the first relay, and the second resistor R2 is arranged between the negative pole of the bypass auxiliary power supply and the first relay.

[0009] In one of the embodiments, the thyristor bypass module further comprises a third diode D3 arranged on the first relay and the super capacitor positive connection line, and a fourth diode D4 arranged on the first relay and the super capacitor negative connection line, the positive pole of the third diode D3 is connected with the positive pole of the super capacitor, the negative pole of the third diode D3 is connected with the first relay, the positive pole of the fourth diode D4 is connected with the first relay, and the negative pole of the fourth diode D4 is connected with the negative pole of the super capacitor.

[0010] In one of the embodiments, the bias maintaining circuit and the auxiliary power source are respectively connected in parallel on the connection line of the DC / DC power converter and the super capacitor.

[0011] In one of the embodiments, the second relay is arranged on the connection line of the auxiliary power source and the super capacitor.

[0012] In one of the embodiments, a third resistor R3 is connected between the second relay and the positive pole of the auxiliary power source, a fourth resistor R4 is connected between the second relay and the negative pole of the auxiliary power source, a fifth diode D5 is connected between the third resistor R3 and the positive pole of the auxiliary power source, a sixth diode D6 is connected between the fourth resistor R4 and the negative pole of the auxiliary power source, a third line is arranged between the third resistor R3 and the fifth diode D5, the third line is connected with the positive pole of the inverter bus, a fourth line is arranged between the fourth resistor R4 and the sixth diode D6, and the fourth line is connected with the negative pole of the inverter bus.

[0013] In one of the embodiments, the super capacitor comprises a plurality of super capacitor modules arranged in series.

[0014] In one of the embodiments, the timing circuit comprises a timer.

[0015] The direct current self-starting circuit for the voltage sag management device of the utility model has high multiplexing rate of system circuit, less new circuit, small volume, low cost, and will not cause power shortage or redundancy, without occupying the main power discharge circuit of the super capacitor, with small bus voltage limit of the main power conversion circuit, and with the thyristor bypass module and the soft starting device and auxiliary power circuit of the DVR module, the monitoring module and the self-checking and monitoring of the DVR module are introduced, the monitoring module detects and alarms, the reliability is improved, with interlocking and self-closing functions, the failure rate is reduced, the timing circuit is added, the direct current self-starting circuit is effectively cut off after the direct current self-starting function is completed, unnecessary loss and risk are avoided, and the service life is prolonged. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 The module connection diagram of the direct current self-starting circuit in one of the embodiments of the utility model;

[0017] Figure 2 The circuit principle block diagram of the direct current self-starting circuit in an embodiment of the utility model;

[0018] Figure 3 The logic block diagram of the direct current self-starting circuit when working in an embodiment of the utility model. DETAILED DESCRIPTION

[0019] In order to make the above object, features and advantages of the utility model more apparent, obvious and easy to understand, the specific embodiments of the utility model are described in detail below. In the following description, a lot of specific details are set forth in order to fully understand the utility model. But the utility model can be implemented in many other ways different from the description herein, and the person skilled in the art can make similar improvements without departing from the connotation of the utility model, so the utility model is not limited by the following disclosed specific embodiments.

[0020] The utility model discloses a kind of direct current self-starting circuit for voltage sag management device, the direct current self-starting circuit includes thyristor bypass module 100, monitoring module 200, DVR module 300 and super capacitor 400, with the starting threshold value lower than discharge termination voltage threshold value, can carry out fault alarm in direct current self-starting process, without being equipped with additional spare power supply device, and not with the advantages such as conflict when operating with ac system.

[0021] Specifically, please combine Figures 1-3 Thyristor bypass module 100 constitutes the main part of direct current self-starting circuit, and it needs to link monitoring module 200 and DVR module 300 to complete voltage sag management device direct current self-starting together. Thyristor bypass module 100 includes thyristor device for main power flow, DSP master control (i.e. Figure 2 In the DSP in DSP) for detection and control connected with thyristor device, drive circuit (i.e. Figure 2 In the SCR drive) for driving thyristor device action between thyristor device and DSP master control, bypass auxiliary power supply for power supply to DSP master control and drive circuit, overcurrent protection circuit for protecting bypass auxiliary power supply, starting unit for starting bypass auxiliary power supply, first relay (i.e. Figure 2 In the Relay-A) in connection with bypass auxiliary power supply, bias maintenance circuit for power supply to first relay and connected with super capacitor 400, switch (i.e. Figure 2 In the S1) for on-off direct current self-starting circuit connected with bias maintenance circuit, timing circuit connected with bias maintenance circuit and cutting off bias maintenance circuit, first optocoupler (i.e. Figure 2the second optocoupler (i.e. Figure 2 the second optocoupler 2) in the bypass auxiliary power supply, wherein the DC self-starting signal is provided by the bypass auxiliary power supply. The super capacitor 400 is connected with the first relay. In the embodiment, the first relay is connected between the super capacitor 400 and the bypass auxiliary power supply, and is used to directly power the bypass auxiliary power supply during the DC self-starting. The switch can be a push button switch or a dial switch, and the switch is used to turn on the DC self-starting function. The second optocoupler is used to provide an enable signal to the bypass auxiliary power supply, so that the bypass auxiliary power supply outputs the DC self-starting signal; the first optocoupler sends a signal to the bias maintaining circuit after the auxiliary power supply is started, so as to inhibit the generation of the enable signal of the second optocoupler, in other words, the first optocoupler is used to disable the DC self-starting after the auxiliary power supply is started. The monitoring module 200 is connected with the bypass auxiliary power supply, and the monitoring module 200 is used to complete self-checking and parameter issuing of the whole system during the DC self-starting.

[0022] The DVR module 300, also known as a dynamic voltage restorer (DVR) module, is used to monitor and quickly compensate voltage fluctuations in real time, and to ensure that sensitive loads always obtain stable power supply. The DVR module 300 includes a DC / DC power converter (i.e. Figure 2 DC / DC in the above), an inverter bus connected with the DC / DC power converter, an inverter used to convert the voltage of the inverter bus into a rated alternating voltage, an auxiliary power supply connected with the DC / DC power converter and the super capacitor 400, a second relay (i.e. Figure 2 Relay-B in the above) used to control the on-off of the auxiliary power supply and the super capacitor 400 and start the inverter bus, and the second relay is connected with the second optocoupler and the bypass auxiliary power supply. In the embodiment, the DC / DC power converter is used to transmit the energy of the super capacitor 400 to the inverter bus (inverter DC bus), and the second relay is used to power the auxiliary power supply of the DVR module 300 and soft-start the inverter bus during the DC self-starting.

[0023] In an embodiment, the thyristor device is an SCR electronic bypass, where SCR is Silicon Controlled Rectifier. The SCR electronic bypass is used as a low-loss bypass under normal working condition of the DVR module, fault or over-current protection for the DVR module, and fast switching for voltage sag compensation. Specifically, when the grid voltage is stable and no compensation is needed, the SCR electronic bypass (thyristor bypass) is turned on to directly transmit power to the load, bypassing the compensation circuit (such as inverter, transformer, etc.) of the DVR module. In this way, the loss (such as iron loss, copper loss) of the main circuit of the DVR module and the device aging can be reduced, and the overall energy efficiency can be improved. When an internal fault (such as overcurrent, short circuit) of the DVR module or an abnormality on the load side is detected, the SCR electronic bypass is quickly turned on to cut off the DVR module from the main circuit, so as to avoid equipment damage, while ensuring uninterrupted power supply to the load and enhancing system reliability. When the grid voltage is sagged or boosted, the SCR electronic bypass is turned off in milliseconds to make the DVR module immediately enter the compensation mode, so as to seamlessly switch to ensure sensitive loads (such as precision instruments, production lines) and eliminate the influence of voltage fluctuations on them. In the embodiment, the input end of the thyristor device is connected to the bypass AC input, and the output end of the thyristor device is connected to the bypass AC output.

[0024] The DSP master control is a digital signal processor (Digital Signal Processor, abbreviated as DSP) for realizing signal processing of the entire direct current self-starting circuit. The driving circuit is used to drive the thyristor device to act. In the embodiment, the driving circuit can be one of a resistance trigger circuit, an RC phase-shift trigger circuit, a zero-crossing detection trigger circuit, an optical coupling isolation driving circuit, and a PWM trigger circuit.

[0025] The starting unit comprises a first uncontrolled rectifier unit D1 connected with the bypass AC input and a second uncontrolled rectifier unit D2 connected with the bypass AC output; the negative pole of the first uncontrolled rectifier unit D1 is connected in parallel with the negative pole of the second uncontrolled rectifier unit D2 and connected with the positive pole of the bypass auxiliary power supply through a first line; the positive pole of the first uncontrolled rectifier unit D1 is connected in parallel with the positive pole of the second uncontrolled rectifier unit D2 and connected with the negative pole of the bypass auxiliary power supply through a second line. In the embodiment, the first uncontrolled rectifier unit D1 is actually a first diode and the second uncontrolled rectifier unit D2 is actually a second diode. The thyristor device and the bypass auxiliary power supply are connected through the first uncontrolled rectifier unit D1 and the second uncontrolled rectifier unit D2 so as to start the bypass auxiliary power supply. The overcurrent protection circuit comprises a first resistor R1 connected in series on the first line and a second resistor R2 connected in series on the second line; a first relay is connected in series with the positive pole of the super capacitor 400 and the first resistor R1 and connected in series with the negative pole of the super capacitor 400 and the second resistor R2, and the first resistor R1 is located between the positive pole of the bypass auxiliary power supply and the first relay and the second resistor R2 is located between the negative pole of the bypass auxiliary power supply and the first relay. By arranging the first resistor R1 and the second resistor R2 on the connection line of the thyristor device and the bypass auxiliary power supply, the voltage supplied by the super capacitor 400 to the bypass auxiliary power supply can be divided so as to realize the overcurrent protection of the bypass auxiliary power supply.

[0026] Further, in the embodiment, the thyristor bypass module 100 further comprises a third diode D3 arranged on the connection line of the first relay and the positive pole of the super capacitor 400 and a fourth diode D4 arranged on the connection line of the first relay and the negative pole of the super capacitor 400; the positive pole of the third diode D3 is connected with the positive pole of the super capacitor 400, the negative pole of the third diode D3 is connected with the first relay, the positive pole of the fourth diode D4 is connected with the first relay, and the negative pole of the fourth diode D4 is connected with the negative pole of the super capacitor 400. By arranging the third diode D3 and the fourth diode D4 on the connection line of the first relay and the super capacitor 400, the super capacitor 400 and the bypass auxiliary power supply can be prevented from being reversely connected, the circuit components can be prevented from being damaged, and the failure rate of the direct current self-starting circuit can be reduced.

[0027] The bias maintaining circuit makes the bypass auxiliary power supply maintain in an ideal bias state by providing a stable direct current voltage or current. In the embodiment, the bias maintaining circuit can be one of a voltage division type bias circuit, a collector feedback bias circuit, a current source bias circuit and an operational amplifier bias circuit. Further, the bias maintaining circuit and the auxiliary power supply are connected in parallel on the connection line of the DC / DC power converter and the super capacitor 400. In addition, in the embodiment, the timing circuit comprises a timer.

[0028] In an embodiment, the second relay is arranged on a connection line between the auxiliary power supply and the super capacitor 400, and in this embodiment, the second relay is in communication connection with the monitoring module 200 to receive parameters and alarm information sent by the monitoring module 200, and after confirming that there is no abnormality, the second relay works under the driving of the bypass auxiliary power supply to restore normal functions. In addition, in this embodiment, a third resistor R3 is connected between the second relay and the positive pole of the auxiliary power supply, and a fourth resistor R4 is connected between the second relay and the negative pole of the auxiliary power supply; a fifth diode D5 is connected between the third resistor R3 and the positive pole of the auxiliary power supply, and a sixth diode D6 is connected between the fourth resistor R4 and the negative pole of the auxiliary power supply; a third line is arranged between the third resistor R3 and the fifth diode D5, and the third line is connected with the positive pole of the inverter bus, and a fourth line is arranged between the fourth resistor R4 and the sixth diode D6, and the fourth line is connected with the negative pole of the inverter bus. The third resistor R3 and the fourth resistor R4 are used for soft starting of the inverter bus together, and the fifth diode D5 and the sixth diode D6 are used for distinguishing the case that the starting unit supplies power to the auxiliary power supply and the case that the inverter bus supplies power to the auxiliary power supply.

[0029] In an embodiment, the super capacitor 400 includes a plurality of super capacitor 400 modules arranged in series. The super capacitor 400 in this embodiment is the energy source of the voltage sag management device in the direct-current self-starting process.

[0030] In the working process of the direct-current self-starting circuit, first, the direct-current self-starting button (switch) is pressed to make the bias maintenance circuit temporarily obtain energy from the super capacitor 400, and after the button is released, the bias maintenance circuit still continuously outputs a 15V reference voltage, and at the same time, the timing circuit starts timing. In this process, the bias maintenance circuit outputs a 15V reference voltage and drives the Relay-A relay to be attracted, and the super capacitor 400 supplies power to the bypass auxiliary power supply of the thyristor bypass module 100 through the third diode D3 and the fourth diode D4, the first resistor R1 and the second resistor R2. After the bypass auxiliary power supply is powered on, it starts and outputs +24V / +18V / 5V / 3.3V voltage, so that the DSP master control and the driving circuit in the thyristor bypass module 100 are ready, and when the alternating current input is restored to normal power supply, it can work normally. At the same time, +24V output by the bypass auxiliary power supply is fed back to the bias maintenance circuit through the first optocoupler, thereby realizing the interlocking function, so that the direct-current self-starting function cannot be started when the voltage sag management device works normally, avoiding unnecessary loss caused by accidental touch.

[0031] When the first relay and the bypass auxiliary power supply are both validly started, the bias maintaining circuit sends an enable signal to the bypass auxiliary power supply through the second optocoupler, so as to enable the DC self-starting signal. Then, the +18V voltage output by the bypass auxiliary power supply supplies the monitoring module 200, the monitoring module 200 is started and performs self-checking and parameter issuing, and the whole machine system is ensured to have no other abnormal alarms. The DC self-starting signal generated by the bypass auxiliary power supply is transmitted to the DVR module 300, the second relay is driven to act and be attracted, after being attracted, the voltage of the super capacitor 400 flows through the third resistor R3 and the fourth resistor R4, so as to soft-start the inverter bus of the DVR module 300, and at the same time, the voltage of the super capacitor 400 flows through the third resistor R3, the fourth resistor R4, the fifth diode D5 and the sixth diode D6, so as to start the auxiliary power supply of the DVR module 300.

[0032] When the auxiliary power supply and the inverter bus of the DVR module 300 complete soft-starting, the DVR module 300 performs self-checking and communicates with the monitoring module 200 to receive parameters and alarm information, and after confirming that there is no abnormality, the DVR module 300 can restore normal functions. After the DVR module 300 restores normal functions, the DC / DC power converter is operated, at this time, the main energy can be obtained from the super capacitor 400 side through the DC / DC power converter, the normal working voltage of the bus is restored, the bus voltage flows through the fifth diode D5 and the sixth diode D6 to maintain the normal working of the auxiliary power supply, at this time, the DVR module 300 can normally start the inverter output to supply power to the load.

[0033] After the timing circuit completes timing, the bias maintaining circuit is pulled low, so that the first relay is disconnected, the bypass auxiliary power supply takes power from the second uncontrolled rectifier unit to maintain the working of the bypass auxiliary power supply. Because the bias maintaining circuit is pulled low, the DC self-starting signal is closed, and the second relay is also closed. Because the DC / DC power converter has normally worked and maintains the inverter bus voltage of the DVR module 300, the DVR module 300 can normally work, and thus the DC self-starting process is completed.

[0034] The DC self-starting circuit for the voltage sag management device of the utility model has the advantages that the DC self-starting circuit does not need to occupy the main power discharge circuit of the super capacitor 400, the bus voltage limit of the main power conversion circuit is small, the soft-starting device and the auxiliary power supply circuit of the thyristor bypass module 100 and the DVR module 300 are utilized to achieve high system circuit multiplexing rate, the newly-added circuit is small, the volume is small, the cost is low, power shortage or redundancy is not caused, the self-checking and monitoring of the monitoring module 200 and the DVR module 300 are introduced, the monitoring module 200 detects and alarms, the reliability is improved, the interlocking and self-closing functions are provided, the failure rate is reduced, the timing circuit is added, the DC self-starting circuit can be effectively cut off after the DC self-starting function is completed, unnecessary loss and risk are avoided, and the service life is prolonged.

[0035] Any combination of the technical features in the above-described embodiments can be made, and for the sake of brevity, not all possible combinations are described, however, as long as the combination of the technical features does not exist in contradiction, it shall be considered as the scope of the description.

[0036] The above-described embodiments only express several implementation manners of the utility model, the description is more specific and detailed, but it cannot be understood as the limitation of the utility model patent scope. It should be pointed out that for ordinary skilled person in the art, under the premise of not departing from the utility model concept, a number of modifications and improvements can be made, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be subject to the appended claims.

Claims

1. A DC self-starting circuit for a voltage sag mitigation device, characterized in that, The system includes a thyristor bypass module, a monitoring module, a DVR module, and a supercapacitor. The thyristor bypass module includes a thyristor device for main power flow, a DSP controller connected to the thyristor device for detection and control, a drive circuit positioned between the thyristor device and the DSP controller for driving the thyristor device, a bypass auxiliary power supply for powering the DSP controller and the drive circuit, an overcurrent protection circuit for protecting the bypass auxiliary power supply, a starting unit for starting the bypass auxiliary power supply, a first relay connected to the bypass auxiliary power supply, a bias sustaining circuit connected to the first relay for power supply and connected to the supercapacitor, a switch connected to the bias sustaining circuit to switch the DC self-starting circuit on and off, and a switch connected to the bias sustaining circuit to disconnect the bias sustaining circuit. The system includes a timing circuit, a first optocoupler connected to the bypass auxiliary power supply and the bias sustaining circuit and used to disable the DC self-starting function during normal operation, and a second optocoupler connected to the bypass auxiliary power supply and the bias sustaining circuit and used to enable the DC self-starting signal; the monitoring module is connected to the bypass auxiliary power supply; the DVR module includes a DC / DC power converter connected to the supercapacitor and the monitoring module, an inverter bus connected to the DC / DC power converter, an inverter for converting the voltage of the inverter bus to the rated AC voltage, an auxiliary power supply connected to the DC / DC power converter and the supercapacitor, and a second relay for controlling the switching of the auxiliary power supply and the supercapacitor and starting the inverter bus, the second relay being connected to the second optocoupler and the bypass auxiliary power supply; the supercapacitor is connected to the first relay.

2. The DC self-starting circuit according to claim 1, characterized in that, The thyristor device is an SCR electronic bypass.

3. The DC self-starting circuit according to claim 1, characterized in that, The input terminal of the thyristor device is connected to the bypass AC input, and the output terminal of the thyristor device is connected to the bypass AC output. The starting unit includes a first uncontrolled rectifier unit D1 connected to the bypass AC input and a second uncontrolled rectifier unit D2 connected to the bypass AC output. The negative terminal of the first uncontrolled rectifier unit D1 is connected in parallel with the negative terminal of the second uncontrolled rectifier unit D2, and is connected to the positive terminal of the bypass auxiliary power supply through a first line. The positive terminal of the first uncontrolled rectifier unit D1 is connected in parallel with the positive terminal of the second uncontrolled rectifier unit D2, and is connected to the negative terminal of the bypass auxiliary power supply through a second line.

4. The DC self-starting circuit according to claim 3, characterized in that, The overcurrent protection circuit includes a first resistor R1 connected in series on the first line and a second resistor R2 connected in series on the second line. A first relay is connected in series with the positive terminal of the supercapacitor and the first resistor R1. The first relay is connected in series with the negative terminal of the supercapacitor and the second resistor R2. The first resistor R1 is located between the positive terminal of the bypass auxiliary power supply and the first relay, and the second resistor R2 is located between the negative terminal of the bypass auxiliary power supply and the first relay.

5. The DC self-starting circuit according to claim 4, characterized in that, The thyristor bypass module also includes a third diode D3 disposed on the connection line between the first relay and the positive terminal of the supercapacitor, and a fourth diode D4 disposed on the connection line between the first relay and the negative terminal of the supercapacitor. The positive terminal of the third diode D3 is connected to the positive terminal of the supercapacitor, and the negative terminal of the third diode D3 is connected to the first relay. The positive terminal of the fourth diode D4 is connected to the first relay, and the negative terminal of the fourth diode D4 is connected to the negative terminal of the supercapacitor.

6. The DC self-starting circuit according to claim 1, characterized in that, The bias sustaining circuit and the auxiliary power supply are connected in parallel on the connection line between the DC / DC power converter and the supercapacitor.

7. The DC self-starting circuit according to claim 6, characterized in that, The second relay is installed on the connection line between the auxiliary power supply and the supercapacitor.

8. The DC self-starting circuit according to claim 7, characterized in that, A third resistor R3 is connected between the second relay and the positive terminal of the auxiliary power supply, and a fourth resistor R4 is connected between the second relay and the negative terminal of the auxiliary power supply. A fifth diode D5 is connected between the third resistor R3 and the positive terminal of the auxiliary power supply, and a sixth diode D6 is connected between the fourth resistor R4 and the negative terminal of the auxiliary power supply. A third line is provided between the third resistor R3 and the fifth diode D5, and the third line is connected to the positive terminal of the inverter bus. A fourth line is provided between the fourth resistor R4 and the sixth diode D6, and the fourth line is connected to the negative terminal of the inverter bus.

9. The DC self-starting circuit according to claim 1, characterized in that, The supercapacitor comprises several supercapacitor modules connected in series.

10. The DC self-starting circuit according to claim 1, characterized in that, The timing circuit includes a timer.

Images