Flexible chopping type direct-current energy consumption device and online energy-taking power supply, method and system thereof

Abstract

The embodiment of the invention relates to the technical field of direct-current power transmission, and discloses a flexible chopping type direct-current energy consumption device and an online energy taking power supply, method and system thereof, and the online energy taking power supply comprises an input end, a starting circuit, a PWM controller, a switching tube Q, a transformer T and a photoelectric coupler OC; the first end of the input end is connected to a direct current capacitor C of the power module; the second end of the input end is connected to the input end of the starting circuit; the output end of the starting circuit is connected to the first input end of the PWM controller; the output end of the PWM controller is connected to the first pole of the switching tube Q; the second pole of the switching tube Q is connected to the primary side of the transformer T; the secondary side of the transformer T is connected to the input end of the photoelectric coupler OC; and the output end of the photoelectric coupler OC is connected to the second input end of the PWM controller. According to the embodiment of the invention, the energy required by the control circuit can be conveniently obtained, and an industrial frequency transformer is not needed.

Description

TECHNICAL FIELD

[0001] Embodiments of the present disclosure relate to the technical field of direct current power transmission, in particular to a flexible chopper type direct current energy consumption device, an online energy taking power supply, method and system thereof. BACKGROUND

[0002] As shown in the flexible direct current power transmission system is a main technical means to solve the offshore wind power grid connection. But when the receiving end AC power grid fails, the wind farm energy that cannot be consumed in time will cause the direct current voltage to rise rapidly, which threatens the safety of the converter valve and the whole system. Therefore, a direct current energy consumption device is needed to consume the energy that the system cannot normally transmit, to achieve the purpose of stabilizing the direct current voltage and assisting the system to complete the fault ride through. Figure 1

[0003] Controllable high-power semiconductor switching devices are an important part of direct current energy consumption device research. Currently, integrated gate-commutated thyristors (IGCT) and insulated gate bipolar transistors (IGBT) are mainly used as controllable switching devices in direct current energy consumption device schemes.

[0004] There are two main technical routes for direct current energy consumption devices. One is a centralized energy consumption device with resistors. The other is a distributed energy consumption device with resistors. The centralized energy consumption device mainly concentrates the energy consumption resistors on both sides of the poles and is arranged outside the valve hall in actual application. The energy consumption resistors meet the natural cooling requirements. The distributed energy consumption device distributes the energy consumption resistors in each module between the poles. The energy consumption resistors need water cooling devices for cooling.

[0005] How to design sub-modules to realize the energy taking function of the flexible chopper energy consumption device is a problem to be solved at present. SUMMARY

[0006] Embodiments of the present disclosure provide a flexible chopper type direct current energy consumption device, an online energy taking power supply, method and system thereof, to solve or alleviate one or more of the above technical problems in the prior art.

[0007] According to one aspect of the present disclosure, an online energy taking power supply of a flexible chopper type direct current energy consumption device is provided, comprising:

[0008] an input end, a starting circuit, a PWM controller, a switch tube Q, a transformer T and an optoelectronic coupler OC;

[0009] a first end of the input end is connected to a direct current capacitor C of a power module;

[0010] a second end of the input end is connected to an input end of the starting circuit;​

[0011] The output end of the starting circuit is connected to the first input end of the PWM controller;

[0012] The output end of the PWM controller is connected to the first pole of the switch tube Q;

[0013] The second pole of the switch tube Q is connected to the primary side of the transformer T;

[0014] The secondary side of the transformer T is connected to the input end of the photoelectric coupler OC;

[0015] The output end of the photoelectric coupler OC is connected to the second input end of the PWM controller.

[0016] In a possible implementation, it comprises:

[0017] A current sampling circuit is connected in series to the third pole of the switch tube Q, and the output end of the current sampling circuit is connected to the third input end of the PWM controller.

[0018] In a possible implementation, a diode D1 and a common mode inductor L are connected between the input end and the starting circuit, the diode D1 is used for isolating the input source, and the common mode inductor L is used for filtering the input source.

[0019] In a possible implementation, the starting circuit comprises a direct current support capacitor C1, a resistor R1 and a starting capacitor C2; the direct current support capacitor C1 is used for storing the energy input by the input end; the direct current support capacitor C1 charges the starting capacitor C2 to the starting voltage of the PWM controller through the resistor R1.

[0020] In a possible implementation, a rectification filtering circuit and a sampling circuit are connected between the transformer T and the photoelectric coupler OC, the rectification filtering circuit comprises a rectification diode D4 and a filtering capacitor C6, and the sampling circuit comprises a sampling resistor R10 and a sampling resistor R12 connected in series;

[0021] The rectification diode D4 is used for rectifying the square wave voltage induced to the secondary side of the transformer T;

[0022] The filtering capacitor C6 is used for filtering the rectified voltage;

[0023] The sampling resistor R10 and the sampling resistor R12 connected in series are used for sampling the filtered voltage to form an input signal isolated by the photoelectric coupler.

[0024] According to one aspect of the present disclosure, there is provided a flexible chopper DC energy consumption device, comprising a plurality of cascaded power modules, each power module comprising a DC capacitor; and further comprising an online energy extraction power supply of the flexible chopper DC energy consumption device according to any one of claims 1-5, wherein the input end of the energy extraction power supply is connected to both ends of the DC capacitor C.

[0025] According to one aspect of the present disclosure, there is provided an online energy extraction method of a flexible chopper DC energy consumption device, comprising:

[0026] obtaining the voltage of the DC capacitor C of the power module as an input source;

[0027] starting the PWM controller according to the input source;

[0028] outputting a PWM signal from the started PWM controller to the switch tube Q;

[0029] controlling the primary side charging of the transformer T according to the PWM signal, forming a square wave voltage and inducing a square wave voltage to the secondary side of the transformer T;

[0030] processing the square wave voltage induced to the secondary side of the transformer T to form an optocoupler isolation input signal;

[0031] performing optocoupler isolation processing on the optocoupler isolation input signal to form an output signal, and feeding back to the PWM controller to form a closed-loop voltage control.

[0032] In one possible implementation, the method comprises:

[0033] obtaining the third electrode voltage of the switch tube Q;

[0034] feeding back the third electrode voltage of the switch tube Q to the PWM controller to form a current closed-loop control.

[0035] In one possible implementation, after obtaining the voltage of the DC capacitor C of the power module as an input source, the method comprises:

[0036] performing isolation and filtering processing on the input source.

[0037] In one possible implementation, starting the PWM controller according to the input source comprises:

[0038] storing the isolation and filtering processed input source to a DC support capacitor C1;

[0039] charging a starting capacitor C2 of the PWM controller to a starting voltage of the PWM controller;

[0040] starting the PWM controller according to the starting voltage.

[0041] In a possible implementation, processing the square wave voltage induced to the secondary side of the transformer T to form an opto-isolated input signal comprises:

[0042] rectifying and filtering the square wave voltage induced to the secondary side of the transformer T;

[0043] sampling the rectified and filtered square wave voltage to form the opto-isolated input signal.

[0044] According to one aspect of the present disclosure, an online energy taking system of a flexible chopper DC energy consumption device is provided, comprising:

[0045] a first obtaining unit configured to obtain a voltage of a DC capacitor C of a power module as an input source;

[0046] a starting unit configured to start a PWM controller according to the input source;

[0047] a PWM controller configured to output a PWM signal to a switch tube Q;

[0048] the switch tube Q configured to control charging of a primary side of a transformer T according to the PWM signal, form a square wave voltage, and induce the square wave voltage to a secondary side of the transformer T;

[0049] a first processing unit configured to process the square wave voltage induced to the secondary side of the transformer T to form an opto-isolated input signal;

[0050] an opto-isolation unit configured to perform opto-isolation processing on the opto-isolated input signal, form an output signal, and feed back to the PWM controller to form a closed-loop voltage control.

[0051] In a possible implementation, the system comprises:

[0052] a second obtaining unit configured to obtain an emitter voltage of the switch tube Q;

[0053] a feedback unit configured to feed back the emitter voltage of the switch tube Q to the PWM controller to form a current closed-loop control.

[0054] In a possible implementation, the system comprises:

[0055] a second processing unit configured to perform isolation and filtering processing on the input source.

[0056] In a possible implementation, the starting unit comprises:

[0057] a storage module configured to store the input source after the isolation and filtering processing to a DC support capacitor C1;

[0058] a charging module configured to charge a starting capacitor C2 of the PWM controller to a starting voltage of the PWM controller.

[0059] A startup module is used to start the PWM controller according to the startup voltage.

[0060] In one possible implementation, the first processing unit includes:

[0061] The processing module is used to rectify and filter the square wave voltage sensed on the secondary side of transformer T; the sampling module is used to sample the rectified and filtered square wave voltage to form an optocoupler-isolated input signal.

[0062] The exemplary embodiments of this disclosure have the following beneficial effects: In the exemplary embodiments of this disclosure, the voltage of the DC capacitor of the power module is used as the input source of the power supply. After isolating and filtering the input source, the DC support capacitor charges the start-up capacitor of the PWM control chip to the start-up voltage of the PWM control chip. Then, the PWM control chip is started, and the PWM signal is output to the switching transistor Q. The switching transistor Q controls the high-frequency transformer T to form a square wave voltage on its primary side and senses its secondary side. After high-frequency rectification, filtering and sampling, and after optocoupler isolation, the signal is fed back to the PWM control chip to form a closed-loop voltage control. The voltage of the emitter of the switching transistor connected in series is fed back to the PWM controller to form a current closed-loop control. In summary, the conversion of the input source is completed, which can conveniently obtain the energy required for the control circuit. There is no need for a power frequency transformer. Moreover, it is small in size, easy to be arranged in the power module, and has high conversion efficiency and low cost.

[0063] Details of one or more embodiments of this application are set forth in the following drawings and description. Other features and advantages of this application will become apparent from the accompanying drawings. It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not intended to limit this disclosure. Attached Figure Description

[0064] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure. It is obvious that the drawings described below are merely some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0065] Figure 1 This is a schematic diagram of a flexible DC transmission system;

[0066] Figure 2 This is a topology diagram of the online power source for a flexible chopper-type DC power consumption device according to an exemplary embodiment of the present invention;

[0067] Figure 3 This is a topology diagram of the flexible chopper energy dissipation device of this exemplary embodiment;

[0068] Figure 4 is a flow chart of an on-line energy harvesting method of a flexible chopper DC energy sink device of the present exemplary embodiment;

[0069] Figure 5 is a block diagram of an on-line energy harvesting system of a flexible chopper DC energy sink device of the present exemplary embodiment;

[0070] Figure 6 is a first waveform schematic of the present exemplary embodiment;

[0071] Figure 7 is a second waveform schematic of the present exemplary embodiment;

[0072] Figure 8 is a third waveform schematic of the present exemplary embodiment. DETAILED DESCRIPTION

[0073] Example implementations will now be described more fully with reference to the accompanying drawings. Example implementations can be implemented in any

[0074] Moreover, the drawings represent a simplified schematic of the present disclosure and are not necessarily to scale. Like reference numerals in different drawings denote the same or similar functionalities; thus, their repetitive description will be omitted. Some of the block diagrams shown in the drawings are functional entities that do not necessarily have to correspond to physically or logically independent entities. These functional entities can be implemented in software, or in one or more hardware units or integrated circuits, or in different network and / or processor devices and / or microcontroller devices.

[0075] The flow charts shown in the drawings are only exemplary illustrations and do not necessarily include all the steps. For example, some steps can be further broken down, and some steps can be combined or partially combined, so that the actual execution order can be changed according to the actual situation.

[0076] The terms "first", "second", and the like, as used in the specification and in the claims of the application, and in the above Description of Embodiments, unless otherwise specified, are used for distinguishing between similar objects talking about the same or similar embodiments, and do not necessarily indicate a required or a preferred order of engaging in or performing activities thereof.

[0077] In addition, the terms "comprise", "comprising", "have", "having", "include", "including", "contain", "containing", and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, product, or apparatus that comprises, has, includes, contains one or more steps or components does not exclude other steps or components not expressly listed or inherent to such process, method, system, product, or apparatus.

[0078] Figure 2 is a topology diagram of an online energy-taking power supply of a flexible chopper DC energy consumption device according to an example embodiment of the present application; as shown in Figure 2 The example embodiment of the present disclosure provides an online energy-taking power supply of a flexible chopper DC energy consumption device, comprising: an input end, a starting circuit, a PWM (Pulse Width Modulation) controller, a switch tube Q, a transformer T, and an opto-coupler OC.

[0079] A first end of the input end is connected to a DC capacitor C of a power module.

[0080] A second end of the input end is connected to an input end of the starting circuit.

[0081] An output end of the starting circuit is connected to a first input end of the PWM controller.

[0082] An output end of the PWM controller is connected to a first pole (base pole) of the switch tube Q.

[0083] A second pole (collector pole) of the switch tube Q is connected to a primary side of the transformer T.

[0084] A secondary side of the transformer T is connected to an input end of the opto-coupler OC.

[0085] An output end of the opto-coupler OC is connected to a second input end of the PWM controller.

[0086] Specifically, the energy-taking power supply further comprises:

[0087] A current sampling circuit in series with a third pole (emitter pole) of the switch tube Q, an output end of the current sampling circuit being connected to a third input end of the PWM controller.

[0088] Specifically, the input end is connected with a diode D1 and a common mode inductor L, the diode D1 is used for isolating the input source, and the common mode inductor L is used for filtering the input source.

[0089] Specifically, the starting circuit comprises a direct current support capacitor C1, a resistor R1 and a starting capacitor C2, the direct current support capacitor C1 is used for storing the energy input by the input end, and the direct current support capacitor C1 charges the starting capacitor C2 to the starting voltage of the PWM controller through the resistor R1.

[0090] Specifically, the transformer T is connected with a rectification filter circuit and a sampling circuit between the optocoupler OC, the rectification filter circuit comprises a rectification diode D4 and a filter capacitor C6, and the sampling circuit comprises a sampling resistor R10 and a sampling resistor R12 connected in series.

[0091] The rectification diode D4 is used for rectifying the square wave voltage induced to the secondary side of the transformer T.

[0092] The filter capacitor C6 is used for filtering the rectified voltage.

[0093] The sampling resistor R10 and the sampling resistor R12 connected in series are used for sampling the filtered voltage to form an input signal isolated by the optocoupler.

[0094] The working principle of the embodiment is that the voltage of a direct current capacitor C of a power module in a flexible chopper type direct current energy consumption device is taken as an input source of an energy taking power supply, the input source is isolated through a diode D1, is subjected to EMC (electromagnetic compatibility) filtering through a common mode inductor L, a starting capacitor C2 of a PWM controller is charged to a starting voltage by a resistor R1 through a direct current support capacitor C1, a PWM signal is output to a switch tube Q by the PWM controller, the transformer T (the transformer T is a high frequency transformer) is controlled by the switch tube Q, a square wave voltage is formed at a primary side of the transformer T and is induced to a secondary side of the transformer T, signals are fed back to the PWM controller after high frequency rectification, filtering and optocoupler isolation of a sampling circuit, a closed loop voltage control is formed, and the purpose of voltage stabilization is achieved, the size of a load current when the switch tube Q works is reflected on a primary current of the transformer T, and the voltage between the two ends of the resistor R6 connected in series at an emitter of the switch tube Q is fed back to the PWM controller, so that current closed loop control is formed.

[0095] In the embodiment, a high voltage MOSFET is selected as the switch tube Q of the energy taking power supply, the Vce voltage is 3000V, two MOSFET devices with a Ve voltage of 3000V are connected in series, and the direct current support capacitor C1 is connected in series by two film capacitors.

[0096] Because the module input voltage range is wide, fluctuation is large, the power supply output voltage is required to be stable and high, the input and output isolation voltage is high, the partial discharge is small, the high frequency transformer ratio in the power supply is large, the primary and secondary side insulation voltage is high, the switching tube duty cycle conversion range is wide, and all of these are factors restricting the reliable operation of the power supply.

[0097] It is worth mentioning that, Figure 2 The diode D1 in the circuit is a reverse prevention diode, which is used to prevent external input from causing circuit loss; the resistor R1 and the capacitor C2 form a soft start circuit, the resistor R1 limits the current to slowly charge the capacitor C2, and the PWM controller starts after reaching the threshold; the diode D2 and the resistor R2 form a rectifier circuit, which mainly charges the capacitor C2; the resistor R3 is the driving resistor of the switching tube Q; the capacitor C3 and the resistor R5 are current sampling filter circuits; the resistor R4 is a switching-off protection resistor of the switching tube Q; the resistor R6 is a current sampling resistor, which is used to collect the current flowing through the switching tube Q; the resistor R7, the capacitor C4 and the diode D3 form an RCD absorption circuit, which protects the transformer T; the diode D5 is a rectifier diode of output 1; the capacitor C5 is a filter capacitor of output 1; the diode D4 is a rectifier diode of output 2; the capacitor C6 is a filter capacitor of output 2; the resistor R8 is a current limiting resistor, which limits the current flowing into the optocoupler OC; the resistor R8 is a current limiting resistor, which limits the cathode current flowing through the voltage stabilizing tube D6; the resistor R11 and the capacitor C7 form an RC integration circuit, which is used to control the turn-on delay time of the voltage stabilizing tube D6; the voltage stabilizing tube D6 is used to provide a reference voltage for the output circuit; the resistor R10 and the resistor R12 are voltage dividing resistors.

[0098] Figure 3 is a flexible chopper energy consumption device topology of the present exemplary embodiment; as shown in Figure 3 The present exemplary embodiment provides a flexible chopper DC energy consumption device, which includes a plurality of cascaded power modules, each power module including a DC capacitor; and an online power supply as described above, the input end of the power supply being connected to both ends of the DC capacitor C.

[0099] In the present embodiment, the working DC voltage of the flexible chopper energy consumption device is 1000kV, the number of cascaded modules is 520, the voltage level is high, and the number of power modules is large; the device and power module topology are as shown in Figure 3 As can be seen from Figure 3 Each module is designed with a DC capacitor, and the system DC voltage is divided by the cascaded power modules; if the inconsistency of voltage distribution is ignored, the average DC voltage of each module is about 2kV, which is 1000kV / 494 (it is worth mentioning that 520 is the design number including redundancy; 494 is the design number without redundancy), which creates favorable conditions for power taking from the module.

[0100] Figure 4 is a flow chart of an online energy harvesting method of a flexible chopper DC energy sink device according to an example embodiment of the present disclosure; as shown in Figure 4 the present disclosure provides an online energy harvesting method of a flexible chopper DC energy sink device, comprising steps of:

[0101] acquiring a voltage of a DC capacitor C of a power module as an input source;

[0102] starting a PWM controller according to the input source;

[0103] the started PWM controller outputs a PWM signal to a switch tube Q;

[0104] the switch tube Q controls a primary side charging of a transformer T according to the PWM signal, forms a square wave voltage and induces to a secondary side of the transformer T;

[0105] processing the square wave voltage induced to the secondary side of the transformer T to form an optocoupler isolation input signal;

[0106] processing the optocoupler isolation input signal to form an output signal and feeding back to the PWM controller to form a closed loop voltage control.

[0107] Specifically, the online energy harvesting method further comprises steps of:

[0108] acquiring a third pole voltage of the switch tube Q;

[0109] feeding back the third pole voltage of the switch tube Q to the PWM controller to form a current closed loop control.

[0110] Specifically, after acquiring the voltage of the DC capacitor C of the power module as the input source, the method comprises:

[0111] isolating and filtering processing the input source.

[0112] Specifically, starting the PWM controller according to the input source comprises:

[0113] storing the isolated and filtered input source to a DC support capacitor C1;

[0114] charging a starting capacitor C2 of the PWM controller to a starting voltage of the PWM controller;

[0115] starting the PWM controller according to the starting voltage.

[0116] Specifically, processing the square wave voltage induced to the secondary side of the transformer T to form the optocoupler isolation input signal comprises:

[0117] rectifying and filtering processing the square wave voltage induced to the secondary side of the transformer T;

[0118] The sampled square wave voltage after the rectification and filtering processing forms an optocoupler isolated input signal.

[0119] Figure 5 is a block diagram of an online energy taking system of a flexible chopper DC energy consumption device according to an example embodiment of the present disclosure, as shown, the example embodiment of the present disclosure provides an online energy taking system of a flexible chopper DC energy consumption device, comprising: Figure 5

[0120] The first acquisition unit 10 is configured to acquire the voltage of the DC capacitor C of the power module as an input source;

[0121] The starting unit 20 is configured to start the PWM controller according to the input source;

[0122] The PWM controller 30 is configured to output a PWM signal to the switch tube Q;

[0123] The switch tube Q 40 is configured to control the primary side charging of the transformer T according to the PWM signal, form a square wave voltage and induce to the secondary side of the transformer T;

[0124] The first processing unit 50 is configured to process the square wave voltage induced to the secondary side of the transformer T to form an optocoupler isolated input signal;

[0125] The optocoupler isolation unit 60 is configured to perform optocoupler isolation processing on the optocoupler isolated input signal to form an output signal, and feedback to the PWM controller to form a closed-loop voltage control.

[0126] Specifically, the online energy taking system further comprises:

[0127] The second acquisition unit is configured to acquire the emitter voltage of the switch tube Q;

[0128] The feedback unit is configured to feedback the emitter voltage of the switch tube Q to the PWM controller to form a current closed-loop control.

[0129] Specifically, the online energy taking system further comprises:

[0130] The second processing unit is configured to perform isolation and filtering processing on the input source.

[0131] Specifically, the starting unit comprises:

[0132] The storage module is configured to store the isolated and filtered input source to the DC support capacitor C1;

[0133] The charging module is configured to charge the starting capacitor C2 of the PWM controller to the starting voltage of the PWM controller;

[0134] The starting module is configured to start the PWM controller according to the starting voltage.​

[0135] In particular, the first processing unit comprises:

[0136] a processing module for rectifying and filtering the square wave voltage induced on the secondary side of the transformer T;

[0137] a sampling module for sampling the rectified and filtered square wave voltage to form an opto-isolated input signal.

[0138] The power sub-module of the flexible chopper energy consumption device does not work before and at the initial stage of starting because the module capacitor has no voltage or low voltage and the power supply does not meet the starting voltage, so the power sub-module unit controller and the driver cannot work, and the control electrode of the switching device has no control voltage and is in an uncontrolled state. The input voltage of the power supply rises rapidly at the initial stage of starting, and the capacitor voltage rises linearly as the starting time extends. After the starting voltage is met, the power supply starts and begins to establish the control voltage. The lower the starting voltage of the power supply and the shorter the time to establish the control voltage, the more conducive to the switching device, the module control circuit and the control protection system of the device. After the power supply establishes the control voltage, the further rise of the capacitor voltage significantly improves the working condition of the power supply until the soft start ends and the energy consumption valve enters the steady state running condition. Figure 6 The test waveform of the power supply 350V starting to the complete establishment of the output 35V voltage is shown. The 35V load is the 3000uF capacitor for the power-on of the IGCT driver and the analog unit controller, and the 400V load is the external bypass switch 470uF. From the test waveform, it can be known that the time from the start of the power supply to the establishment of the 35V control voltage is about 65ms, and the maximum starting current is about 1.6A.

[0139] During the soft start process, attention should be paid to the rising rate of the capacitor voltage, the resistance value of the soft start resistor, and the power of the starting loop to prevent the capacitor voltage from rapidly dropping due to the impact of the instantaneous starting current of the power supply, causing the voltage of the starting pin of the power supply controller to drop and exit the starting, and waiting for the capacitor voltage to meet the starting voltage again before restarting, resulting in repeated hiccup starting of the energy supply and inability to function normally. The occurrence of this situation will be accompanied by uneven voltage between cascaded modules, and with the increase of the number of repeated starts, the voltage difference will become more and more obvious, so the soft start resistor should be reasonably configured to match the rising speed of the module capacitor voltage and the starting voltage of the power supply, and the DC bus voltage value of the power module after the control voltage of the power supply is established should not be too high to provide protection for the safe starting and running of the device.

[0140] To avoid the above problems, the DC bus voltage of the power module is controlled at a relatively low and appropriate voltage when the energy supply establishes the 35V control power supply, so that the power supply does not hiccup during the starting process and the DC voltage between the control modules is well balanced.

[0141] The power module switch device is selected as a 4500V voltage level device. The upper limit of the input voltage of the power supply is usually determined according to the voltage resistance requirement of the switch device, so as to ensure that the switch device has a reliable control power supply within its full voltage resistance range. When the power supply works at this highest voltage, the duty cycle of the switch tube is the smallest, and the high-voltage side inside the power supply is prone to a higher surge voltage when the tube is off, which increases the loss of the absorption circuit, and the power supply is prone to unstable operation, the failure rate of the switch tube increases, and the working condition needs to be tested and checked. Figure 7 The working waveform of the switch tube is shown when the input voltage of the power supply is 4500V, the output is 35V / 4A load. Channel 1 (CH1) is the input voltage (limited probe measurement range, the voltage is 1 / 2 of the support capacitor voltage), channel 2 (CH2) and channel 3 (CH3) are the switch tube Vce, and channel 4 (CH4) is the output current. From the test waveform, it can be seen that the switch tube working waveform is normal, and the tube Vce voltage margin is sufficient.

[0142] The power supply has a fault detection circuit to detect the output voltage. If the power supply output is abnormal, an alarm signal can be sent to the outside through the fault output port. After the fault is recovered, the alarm port can cancel the alarm information.

[0143] Any electronic component may have an abnormality, so how to deal with the abnormality and the processing method after the abnormality occurs is particularly important. Through analysis of a large number of faulty switch power supplies, it is found that the high-voltage end of the power supply accounts for the highest proportion in all faults. In order to deal with the failure of the power supply, an energy storage element is designed on the low-voltage side of the power supply. When the power supply fails, the energy stored in the energy storage element can support the power module unit controller to work for 20ms, so that there is sufficient time for protection processing, and the energy storage element is in an isolated state in the power supply. After energy storage, it can only provide energy to the unit controller in one direction. Figure 8 ( Figure 8 The Tek in the figure represents an oscilloscope, Acq Complete represents capture completion, M POS10.00ms indicates that each large grid of the horizontal axis (time axis) of the oscilloscope is 10.00ms, and MEASURE represents the measured value.

[0144] Figures 6-8 The Tek in the figure represents an oscilloscope, Acq Complete represents capture completion, M POS10.00ms indicates that each large grid of the horizontal axis (time axis) of the oscilloscope is 10.00ms, and MEASURE represents the measured value.

[0145] In order to meet the safety requirements of the power module, a resistance R6 is connected in series between the high-voltage input side DC support capacitor C and the high-voltage switch tube MOSFET of the high-frequency transformer primary, the resistance R is a 5W / 0.5R metal oxide film resistance, which can ensure the MOSFET to be fused quickly in the case of short circuit; a 0.3mm wide and 15mm long PCB printed wire is used as a fuse (the connecting wire on both sides of the diode D1) between the high-voltage side input terminal and the DC support capacitor, which can ensure the fuse to be fused quickly in the case of short circuit of the rear-stage circuit.

[0146] The above is only the preferred embodiment of the present disclosure, and the protection scope of the present disclosure is not limited to the above-mentioned embodiments only. Any technical solution falling within the concept of the present disclosure shall fall within the protection scope of the present disclosure. It should be noted that, for ordinary skilled persons in the art, some improvements and refinements without departing from the principles of the present disclosure shall be considered as falling within the protection scope of the present disclosure.

Claims

1. An online power source for a flexible chopper-type DC power dissipation device, characterized in that, include: Input terminal, startup circuit, PWM controller, switching transistor Q, transformer T, and optocoupler OC; The first end of the input terminal is connected to the DC capacitor C of the power module; The second end of the input terminal is connected to the input terminal of the startup circuit; The output of the startup circuit is connected to the first input of the PWM controller. The output terminal of the PWM controller is connected to the first terminal of the switching transistor Q; The second terminal of the switching transistor Q is connected to the primary side of the transformer T; The secondary side of the transformer T is connected to the input terminal of the optocoupler OC; The output of the optocoupler OC is connected to the second input of the PWM controller.

2. The online power source for the flexible chopper-type DC power dissipation device according to claim 1, characterized in that, include: A current sampling circuit is connected in series with the third terminal of the switching transistor Q, and the output terminal of the current sampling circuit is connected to the third input terminal of the PWM controller.

3. The online power source for the flexible chopper-type DC power dissipation device according to claim 2, characterized in that, A diode D1 and a common-mode inductor L are connected between the input terminal and the startup circuit. The diode D1 is used to isolate the input source, and the common-mode inductor L is used to filter the input source.

4. The online power source for the flexible chopper-type DC power dissipation device according to claim 2, characterized in that, The startup circuit includes: a DC support capacitor C1, a resistor R1, and a startup capacitor C2; the DC support capacitor C1 is used to store the energy input at the input terminal; the DC support capacitor C1 charges the startup capacitor C2 through the resistor R1 to the startup voltage of the PWM controller.

5. The online power source for the flexible chopper-type DC power dissipation device according to claim 2, characterized in that, A rectifier filter circuit and a sampling circuit are connected between the transformer T and the optocoupler OC. The rectifier filter circuit includes a rectifier diode D4 and a filter capacitor C6. The sampling circuit includes a sampling resistor R10 and a sampling resistor R12 connected in series. The rectifier diode D4 is used to rectify the square wave voltage induced on the secondary side of transformer T; The filter capacitor C6 is used to filter the rectified voltage; The series-connected sampling resistors R10 and R12 are used to sample the filtered voltage to form an optocoupler-isolated input signal.

6. A flexible chopper-type DC power dissipation device, characterized in that, It includes several cascaded power modules, each power module including a DC capacitor; it also includes an online power source for the flexible chopper-type DC power consumption device according to any one of claims 1-5, the input terminal of the power source being connected to both ends of the DC capacitor C.

7. An online energy harvesting method for a flexible chopper-type DC energy dissipation device, characterized in that, include: The voltage of the DC capacitor C of the power module is obtained as the input source; The PWM controller is started according to the input source; After startup, the PWM controller outputs a PWM signal to the switching transistor Q; The switching transistor Q controls the primary side of the transformer T to charge according to the PWM signal, forming a square wave voltage and sensing the secondary side of the transformer T. The square wave voltage sensed on the secondary side of transformer T is processed to form an optocoupler-isolated input signal; The optocoupler-isolated input signal is optically isolated to form an output signal, which is then fed back to the PWM controller to form a closed-loop voltage control.

8. The online energy harvesting method for the flexible chopper-type DC energy dissipation device according to claim 7, characterized in that, include: Obtain the voltage at the third terminal of the switching transistor Q; The voltage of the third electrode of the switching transistor Q is fed back to the PWM controller to form a current closed-loop control.

9. The online energy harvesting method for the flexible chopper-type DC energy dissipation device according to claim 8, characterized in that, After obtaining the voltage of the DC capacitor C of the power module as the input source, the following steps are included: The input source is isolated and filtered.

10. The online energy harvesting method for the flexible chopper-type DC energy dissipation device according to claim 8, characterized in that, Starting the PWM controller based on the input source includes: The isolated and filtered input source is stored in DC support capacitor C1; Charge the PWM controller's startup capacitor C2 to the PWM controller's startup voltage; The PWM controller is started according to the start-up voltage.

11. The online energy harvesting method for the flexible chopper-type DC energy dissipation device according to claim 8, characterized in that, The square wave voltage induced on the secondary side of transformer T is processed to form an optocoupler-isolated input signal, including: The square wave voltage induced on the secondary side of transformer T is rectified and filtered. The square wave voltage after rectification and filtering is sampled to form an optically isolated input signal.

12. An online energy harvesting system for a flexible chopper-type DC energy dissipation device, characterized in that, include: The first acquisition unit is used to acquire the voltage of the DC capacitor C of the power module as an input source; A startup unit is used to start the PWM controller according to the input source; The PWM controller is used to output a PWM signal to the switching transistor Q; The switching transistor Q is used to control the primary side of the transformer T to charge according to the PWM signal, forming a square wave voltage and sensing the secondary side of the transformer T. The first processing unit is used to process the square wave voltage sensed on the secondary side of transformer T to form an optocoupler-isolated input signal; The optocoupler isolation unit is used to perform optocoupler isolation processing on the optocoupler isolation input signal, form an output signal, and feed it back to the PWM controller to form closed-loop voltage control.

13. The online energy harvesting system of the flexible chopper-type DC energy dissipation device according to claim 12, characterized in that, include: The second acquisition unit is used to acquire the emitter voltage of the switching transistor Q; The feedback unit is used to feed back the emitter voltage of the switching transistor Q to the PWM controller to form a current closed-loop control.

14. The online energy harvesting system of the flexible chopper-type DC energy dissipation device according to claim 13, characterized in that, include: The second processing unit is used to isolate and filter the input source.

15. The online energy harvesting system of the flexible chopper-type DC energy dissipation device according to claim 13, characterized in that, The startup unit includes: The storage module is used to store the isolated and filtered input source into the DC support capacitor C1; The charging module is used to charge the PWM controller's startup capacitor C2 to the PWM controller's startup voltage. A startup module is used to start the PWM controller according to the startup voltage.

16. The online energy harvesting system of the flexible chopper-type DC energy dissipation device according to claim 13, characterized in that, The first processing unit includes: The processing module is used to rectify and filter the square wave voltage sensed on the secondary side of transformer T. The sampling module is used to sample the rectified and filtered square wave voltage to form an optically isolated input signal.

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