Power supply conversion control device suitable for nuclear power emergency diesel generating set

Abstract

The invention relates to a power supply conversion control device suitable for a nuclear power emergency diesel generating set. The primary side conversion circuit comprises a power supply conversion main circuit and a power supply conversion controller, the primary side conversion circuit is adaptively connected with a primary side coil of the high-frequency transformer, the connected alternating current input voltage is chopped into a high-frequency input signal, and the high-frequency input signal generated by chopping is loaded to the primary side coil of the high-frequency transformer; and the secondary side conversion circuit is adaptively connected with a secondary side coil of the high-frequency transformer, converts the high-frequency voltage signal generated by the high-frequency transformer into a power supply voltage, and provides the power supply voltage to a connected load unit. According to the invention, the stability and reliability of load power supply can be improved.

Description

Technical Field

[0001] The invention relates to a power conversion control device, in particular to a power conversion control device suitable for nuclear power emergency diesel generator sets. Background Art

[0002] Regarding the quality of electric energy, the current power supply quality at home and abroad has problems such as voltage imbalance and grid interference, which is extremely unfavorable for power loads. Therefore, the reliability of power supply needs to be improved.

[0003] At present, in the application of diesel generator sets in nuclear power plants, there is no power conversion device for this usage scenario, which means that the stability and reliability of power supply cannot be effectively improved. Summary of the invention

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art and provide a power conversion control device suitable for a nuclear power emergency diesel generator set, which can improve the stability and reliability of power supply to a load.

[0005] According to the technical solution provided by the present invention, a power conversion control device suitable for a nuclear power emergency diesel generator set includes a power conversion main circuit and a power conversion controller for controlling the working state of the power conversion main circuit, wherein:

[0006] The power conversion main circuit includes a primary side conversion circuit, a high frequency transformer and a secondary side conversion circuit connected in sequence.

[0007] The primary conversion circuit is adaptively connected to the primary coil of the high-frequency transformer, and chops the connected AC input voltage into a high-frequency input signal, and loads the chopped high-frequency input signal to the primary coil of the high-frequency transformer;

[0008] The secondary side conversion circuit is adaptively connected to the secondary side coil of the high frequency transformer, converts the high frequency voltage signal generated by the high frequency transformer into a power supply voltage, and provides the power supply voltage to the connected load unit;

[0009] The power conversion controller is adaptively connected to the primary side conversion circuit and the secondary side conversion circuit, wherein:

[0010] Based on the power supply voltage provided to the load unit and the load current flowing through the load unit, the power conversion controller controls the corresponding working states of the primary conversion circuit and the secondary conversion circuit to provide a stable power supply voltage to the load circuit via the secondary conversion circuit.

[0011] The primary side conversion circuit at least includes an input filter and an input cycloconverter, wherein:

[0012] The input filter receives the AC input voltage and loads the filtered AC input voltage to the input cycloconverter;

[0013] The input frequency converter is adaptively connected to the primary coil of the high-frequency transformer, and is used to chop the filtered AC input voltage into a high-frequency input signal, and load the high-frequency input signal to the primary coil of the high-frequency transformer.

[0014] The input cycloconverter adopts a full-bridge conversion structure, and the input cycloconverter includes an input conversion first bridge arm and an input conversion second bridge arm, wherein:

[0015] The input conversion first bridge arm includes an input conversion first upper bridge arm unit and an input conversion first lower bridge arm unit, and the connection part of the input conversion first upper bridge arm unit and the input conversion first lower bridge arm unit is connected to the first end of the primary coil of the high-frequency transformer;

[0016] The input conversion second bridge arm includes an input conversion second upper bridge arm unit and an input conversion second lower bridge arm unit, and the connection part of the input conversion second upper bridge arm unit and the input conversion second lower bridge arm unit is connected to the second end of the primary coil of the high-frequency transformer;

[0017] The power conversion controller is adaptively connected to the first upper bridge arm unit of input conversion, the first lower bridge arm unit of input conversion, the second upper bridge arm unit of input conversion and the second lower bridge arm unit of input conversion to control the corresponding working states of the first upper bridge arm unit of input conversion, the first lower bridge arm unit of input conversion, the second upper bridge arm unit of input conversion and the second lower bridge arm unit of input conversion, and chop the AC input voltage into a high-frequency input signal.

[0018] The first upper bridge arm unit of the input conversion includes a switch tube S 1a And the switch tube S 1b ,in,

[0019] Switching tube S 1a The first switch end is connected to the input filter output, and the switch tube S 1a The second switch terminal and the switch tube S 1b The second switch terminal is connected to the switch tube S 1b The first switch end is connected to the first end of the high frequency transformer, and the switch tube S 1a The second switch end, the switch tube S 1b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 1a The first switch end, the switch tube S 1b The corresponding first switch terminal is connected, and the switch tube S 1a , switch tube S 1b The corresponding control terminal is connected to the output terminal of the power converter;

[0020] The second upper bridge arm unit of the input conversion includes a switch tube S 2a And the switch tube S 2b ,in,

[0021] Switching tube S 2a The first switch end is adapted to be connected to the input filter, and the switch tube S 2a The second switch terminal and the switch tube S 2b The second switch terminal is connected to the switch tube S 2b The first switch end is connected to the second end of the high frequency transformer, and the switch tube S 2a The second switch end, the switch tube S 2b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 2a The first switch end, the switch tube S 2b The corresponding first switch terminal is connected, and the switch tube S 2a , switch tube S 2b The corresponding control terminal is connected to the output terminal of the power converter;

[0022] The first lower bridge arm unit of the input conversion includes a switch tube S' 2a And the switch tube S' 2b ,in,

[0023] Switch tube S' 2a The first switch end is connected to the first end of the primary coil of the high-frequency transformer, and the switch tube S′ 2a The second switch end and the switch tube S' 2b The second switch end is connected to the switch tube S' 2b The first switch end is adapted to be connected to the input filter, and the switch tube S′ 2a The second switch end, the switch tube S' 2 ' b The second switch end of each of the two circuits is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S'. 2a The first switch end, the switch tube S' 2b The corresponding first switch terminal is connected to the switch tube S' 2a , switch tube S' 2b The corresponding control terminal is connected to the output terminal of the power converter;

[0024] The second lower bridge arm unit of the input conversion includes a switch tube S' 1a And the switch tube S' 1b ,in,

[0025] Switch tube S' 1a The first switch end is connected to the second end of the primary coil of the high-frequency transformer, and the switch tube S′1a The second switch end and the switch tube S' 1b The second switch end is connected to the switch tube S' 1b The first switch end is adapted to be connected to the input filter, and the switch tube S′ 1a The second switch end, the switch tube S' 1b The second switch end of each of the two circuits is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S'. 1a The first switch end, the switch tube S' 1b The corresponding first switch terminal is connected to the switch tube S' 1a , switch tube S' 1b The corresponding control terminal is connected to the output terminal of the power converter.

[0026] The input filter includes an input filter inductor and an input filter capacitor, wherein:

[0027] One end of the input filter inductor is connected to the first end of the input power supply, and the second end of the input filter inductor is connected to one end of the input filter capacitor and the switch tube S 1a The first switch end and the switch tube S 2a A first switch terminal is connected;

[0028] The other end of the input filter capacitor is connected to the other end of the input power supply and the switch tube S' 2b The first switch end and the switch tube S' 1b The first switch terminal is connected to

[0029] The input AC voltage is loaded to the input filter through the input power supply. When the AC input voltage of the input filter of the input power supply is in the positive half-wave, the switch tube S 1b , switch tube S 2b , switch tube S' 2b And the switch tube S' 1b Keep in closed conduction state.

[0030] The secondary side conversion circuit comprises an output cycloconverter and an output filter connected in sequence, wherein:

[0031] The output cycloconverter is adaptively connected to the secondary coil of the high-frequency transformer and provides a power supply voltage to the load unit through an output filter;

[0032] The output cycloconverter is adaptively connected to the power conversion controller so that the power conversion controller controls the working state of the output cycloconverter.

[0033] The output cycloconverter comprises an output first conversion unit and an output second conversion unit, wherein:

[0034] The output first conversion unit is adaptively connected to the first end of the secondary coil of the high-frequency transformer, the output filter and the second output second conversion unit;

[0035] The second conversion unit is adaptively connected to the second end of the secondary coil of the high-frequency transformer, and the center tap of the high-frequency transformer is adaptively connected to the output filter and the load unit.

[0036] The output first conversion unit includes a switch tube S 3a And the switch tube S 3b ,in,

[0037] Switching tube S 3a The first switch end of the high-frequency transformer is connected to the first end of the secondary coil of the high-frequency transformer. 3a The second switch terminal and the switch tube S 3b The second switch terminal is connected to the switch tube S 3b The first switch end is connected to the output filter and the switch tube S in the output second conversion unit 4b A first switch terminal is connected;

[0038] Switching tube S 4b The second switch terminal and the switch tube S 4a The second switch terminal is connected to the switch tube S 4a The first switch end is connected to the second end of the secondary coil of the high-frequency transformer;

[0039] Switching tube S 3a The second switch end, the switch tube S 3b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 3a The first switch end, the switch tube S 3b The corresponding first switch terminal is connected, and the switch tube S 3a , switch tube S 3b The corresponding control terminal is connected to the output terminal of the power converter;

[0040] Switching tube S 4a The second switch end, the switch tube S 4b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 4a The first switch end, the switch tube S 4b The corresponding first switch terminal is connected, and the switch tube S 4a , switch tube S 4b The corresponding control terminal is connected to the output terminal of the power converter.

[0041] The output filter includes an output filter inductor and an output filter capacitor connected to the output filter inductor, wherein:

[0042] One end of the output filter inductor is connected to the switch tube S 3b The first switch end and the switch tube S 4b The first switch terminal of the output filter inductor is connected, and the other end of the output filter inductor is connected to one end of the output filter capacitor.

[0043] The other end of the output filter capacitor is connected to the center tap of the high frequency transformer, and the load unit is connected in parallel with the output filter capacitor.

[0044] When the power conversion controller controls the corresponding working states of the primary side conversion circuit and the secondary side conversion circuit, it includes:

[0045] Repeatingly controlling the supply voltage provided to the load unit and generating a repeated control duty cycle signal after the repeated control;

[0046] At the same time, a voltage-current dual-loop PI control is performed on a power supply voltage provided to the load unit and a load current flowing through the load unit, so as to generate a dual-loop control duty cycle signal after the voltage-current dual-loop PI control;

[0047] An SPWM control signal is generated based on the repeated control chopping ratio signal and the dual-loop control duty cycle signal, and power conversion control information is generated based on the SPWM control signal to control the corresponding working states of the primary side conversion circuit and the secondary side conversion circuit based on the power conversion control information.

[0048] Advantages of the present invention: the power conversion main circuit includes a primary conversion circuit, a high-frequency transformer and a secondary conversion circuit connected in sequence. Based on the power supply voltage provided to the load unit and the load current flowing through the load unit, the power conversion controller controls the corresponding working states of the primary conversion circuit and the secondary conversion circuit to provide a stable power supply voltage to the load circuit via the secondary conversion circuit, thereby improving the stability and reliability of power supply to the load. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The figure is a structural block diagram of an embodiment of the power conversion main circuit of the present invention.

[0050] Figure 2 The topological schematic diagram is a schematic diagram of an embodiment of the power conversion main circuit of the present invention.

[0051] Figure 3 A schematic diagram of an embodiment of the power conversion controller of the present invention performing conversion control.

[0052] Figure 4 A schematic diagram of an embodiment of a power conversion controller of the present invention for performing conversion control trigger waveforms.

[0053] Figures 5 to 14The schematic diagram of the circuit working state of the power conversion controller of the present invention generating power conversion control information to control the power conversion main circuit for the positive half-wave AC input voltage is shown, wherein:

[0054] Figure 5 It is a schematic diagram corresponding to the first working state of the power conversion main circuit of the present invention;

[0055] Figure 6 It is a schematic diagram corresponding to the second working state of the power conversion main circuit of the present invention;

[0056] Figure 7 It is a schematic diagram corresponding to the third working state of the power conversion main circuit of the present invention;

[0057] Figure 8 It is a schematic diagram corresponding to the fourth working state of the power conversion main circuit of the present invention;

[0058] Fig. 9 It is a schematic diagram corresponding to the fifth working state of the power conversion main circuit of the present invention;.

[0059] Fig.10 It is a schematic diagram corresponding to the sixth working state of the power conversion main circuit of the present invention;

[0060] Fig.11 It is a schematic diagram corresponding to the seventh working state of the power conversion main circuit of the present invention;

[0061] Fig.12 It is a schematic diagram corresponding to the eighth working state of the power conversion main circuit of the present invention;

[0062] Fig.13 It is a schematic diagram corresponding to the ninth working state of the power conversion main circuit of the present invention;

[0063] Fig.14 It is a schematic diagram corresponding to the tenth working state of the power conversion main circuit of the present invention. DETAILED DESCRIPTION

[0064] The present invention will be further described below in conjunction with specific drawings and embodiments.

[0065] In order to improve the stability and reliability of power supply to loads, the present invention provides a power conversion control device suitable for nuclear power emergency diesel generator sets. Specifically, the power conversion control device includes a power conversion main circuit and a power conversion controller for controlling the working state of the power conversion main circuit, wherein:

[0066] The power conversion main circuit includes a primary side conversion circuit, a high frequency transformer and a secondary side conversion circuit connected in sequence.

[0067] The primary conversion circuit is adaptively connected to the primary coil of the high-frequency transformer, and chops the connected AC input voltage into a high-frequency input signal, and loads the chopped high-frequency input signal to the primary coil of the high-frequency transformer;

[0068] The secondary side conversion circuit is adaptively connected to the secondary side coil of the high frequency transformer, converts the high frequency voltage signal generated by the high frequency transformer into a power supply voltage, and provides the power supply voltage to the connected load unit;

[0069] The power conversion controller is adaptively connected to the primary side conversion circuit and the secondary side conversion circuit, wherein:

[0070] Based on the power supply voltage provided to the load unit and the load current flowing through the load unit, the power conversion controller controls the corresponding working states of the primary conversion circuit and the secondary conversion circuit to provide a stable power supply voltage to the load circuit via the secondary conversion circuit.

[0071] It can be understood that the power conversion main circuit is the main functional unit of voltage conversion. The power conversion main circuit can be used to change the AC input voltage into the power supply voltage required by the load unit. The working state of the power conversion main circuit can be configured through the power conversion controller so that the power supply voltage provided by the power conversion main circuit remains stable. In one implementation of the present invention, the AC input voltage conversion is the AC power generated by the nuclear power emergency diesel generator set.

[0072] Figure 1 An embodiment of a power conversion main circuit is shown in the figure. It should be noted that the power conversion controller is not shown in the figure. Figure 1 In the invention, the power conversion main circuit generally includes a high-frequency transformer, wherein the high-frequency transformer can be connected to the AC input voltage through a primary-side conversion circuit, and the high-frequency transformer can generate a power supply voltage through a secondary-side conversion circuit. Figure 1 In the figure, T1 is a high frequency transformer. The high frequency transformer can adopt an existing commonly used form. The function of the high frequency transformer is also consistent with the existing technology, which is based on the ability to realize power conversion and provide power supply voltage to the load unit.

[0073] When the power conversion main circuit includes a primary conversion circuit, a high-frequency transformer and a secondary conversion circuit, the power conversion controller should at least be adaptively connected to the primary conversion circuit and the secondary conversion circuit, and can control the corresponding working states of the primary conversion circuit and the secondary conversion circuit, wherein the corresponding working states of the primary conversion circuit and the secondary conversion circuit are controlled so as to provide a power supply voltage to the load unit and keep the power supply voltage stable.

[0074] The specific method and process of the primary side conversion circuit, the secondary side conversion circuit, and the power conversion controller controlling the primary side conversion circuit and the secondary side conversion circuit are described in detail below.

[0075] In one embodiment of the present invention, the primary side conversion circuit at least includes an input filter and an input cycloconverter, wherein:

[0076] The input filter receives the AC input voltage and loads the filtered AC input voltage to the input cycloconverter;

[0077] The input frequency converter is adaptively connected to the primary coil of the high-frequency transformer, and is used to chop the filtered AC input voltage into a high-frequency input signal, and load the high-frequency input signal to the primary coil of the high-frequency transformer.

[0078] Figure 1 An embodiment of the primary side conversion circuit is shown in FIG. As can be seen from the figure, the primary side conversion circuit may include an input filter and an input cyclotron converter, wherein BH1 is the input cyclotron converter, the input filter may filter the AC input voltage to improve the quality of the AC input voltage after filtering, and the filtered AC input voltage may be chopped into a high-frequency input signal through the input cyclotron converter.

[0079] In one embodiment of the present invention, the input cycloconverter adopts a full-bridge conversion structure, and the input cycloconverter includes an input conversion first bridge arm and an input conversion second bridge arm, wherein:

[0080] The input conversion first bridge arm includes an input conversion first upper bridge arm unit and an input conversion first lower bridge arm unit, and the connection part of the input conversion first upper bridge arm unit and the input conversion first lower bridge arm unit is connected to the first end of the primary coil of the high-frequency transformer;

[0081] The input conversion second bridge arm includes an input conversion second upper bridge arm unit and an input conversion second lower bridge arm unit, and the connection part of the input conversion second upper bridge arm unit and the input conversion second lower bridge arm unit is connected to the second end of the primary coil of the high-frequency transformer;

[0082] The power conversion controller is adaptively connected to the first upper bridge arm unit of input conversion, the first lower bridge arm unit of input conversion, the second upper bridge arm unit of input conversion and the second lower bridge arm unit of input conversion to control the corresponding working states of the first upper bridge arm unit of input conversion, the first lower bridge arm unit of input conversion, the second upper bridge arm unit of input conversion and the second lower bridge arm unit of input conversion, and chop the AC input voltage into a high-frequency input signal.

[0083] Specifically, the input cyclotron converter adopts a full-bridge conversion structure. Therefore, the input cyclotron converter may include an input conversion first bridge arm and an input conversion second bridge arm. The input conversion first bridge arm and the input conversion second bridge arm may adopt the same structural form. For example, the input conversion first bridge arm includes an input conversion first upper bridge arm unit and an input conversion first lower bridge arm unit. At the same time, the input conversion second bridge arm includes an input conversion second upper bridge arm unit and an input conversion second lower bridge arm unit.

[0084] Generally, the first upper bridge arm unit of input conversion, the first lower bridge arm unit of input conversion, the second upper bridge arm unit of input conversion and the second lower bridge arm unit of input conversion are all controllable, that is, the corresponding working states of the first upper bridge arm unit of input conversion, the first lower bridge arm unit of input conversion, the second upper bridge arm unit of input conversion and the second lower bridge arm unit of input conversion can be controlled by the power converter.

[0085] Combine the following Figure 2 The specific form of the input cycloconverter is described, specifically:

[0086] In one embodiment of the present invention, the input conversion first upper bridge arm unit includes a switch tube S 1a And the switch tube S 1b ,in,

[0087] Switching tube S 1a The first switch end is connected to the input filter output, and the switch tube S 1a The second switch terminal and the switch tube S 1b The second switch terminal is connected to the switch tube S 1b The first switch end is connected to the first end of the high frequency transformer, and the switch tube S 1a The second switch end, the switch tube S 1b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 1a The first switch end, the switch tube S 1b The corresponding first switch terminal is connected, and the switch tube S 1a , switch tube S 1b The corresponding control terminal is connected to the output terminal of the power converter;

[0088] The second upper bridge arm unit of the input conversion includes a switch tube S 2a And the switch tube S 2b ,in,

[0089] Switching tube S 2a The first switch end is adapted to be connected to the input filter, and the switch tube S 2a The second switch terminal and the switch tube S 2b The second switch terminal is connected to the switch tube S 2bThe first switch end is connected to the second end of the high frequency transformer, and the switch tube S 2a The second switch end, the switch tube S 2b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 2a The first switch end, the switch tube S 2b The corresponding first switch terminal is connected, and the switch tube S 2a , switch tube S 2b The corresponding control terminal is connected to the output terminal of the power converter;

[0090] The first lower bridge arm unit of the input conversion includes a switch tube S' 2a And the switch tube S' 2b ,in,

[0091] Switch tube S' 2a The first switch end is connected to the first end of the primary coil of the high-frequency transformer, and the switch tube S′ 2a The second switch end and the switch tube S' 2b The second switch end is connected to the switch tube S' 2b The first switch end is adapted to be connected to the input filter, and the switch tube S′ 2a The second switch end, the switch tube S' 2b The second switch end of each of the two circuits is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S'. 2a The first switch end, the switch tube S' 2b The corresponding first switch terminal is connected to the switch tube S' 2a , switch tube S' 2b The corresponding control terminal is connected to the output terminal of the power converter;

[0092] The second lower bridge arm unit of the input conversion includes a switch tube S' 1a And the switch tube S' 1b ,in,

[0093] Switch tube S' 1a The first switch end is connected to the second end of the primary coil of the high-frequency transformer, and the switch tube S′ 1a The second switch end and the switch tube S' 1b The second switch end is connected to the switch tube S' 1b The first switch end is adapted to be connected to the input filter, and the switch tube S′ 1a The second switch end, the switch tube S' 1b The second switch end of each of the two circuits is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S'. 1a The first switch end, the switch tube S' 1bThe corresponding first switch terminal is connected to the switch tube S' 1a , switch tube S' 1b The corresponding control terminal is connected to the output terminal of the power converter.

[0094] Specifically, the switch tube S 1a , switch tube S 1b , switch tube S 2a And the switch tube S 2b , switch tube S' 2a , switch tube S' 2b , switch tube S' 1a And the switch tube S' 1b The same controllable switch tube can be used, such as a MOSFET device. When a MOSFET device is used as the switch tube, the first switch terminal of the switch tube is the drain terminal of the MOSFET device, the second switch terminal of the switch tube is the source terminal of the MOSFET device, and the control terminal of the switch tube is the gate terminal of the MOSFET device. When the switch tube adopts other controllable forms, the corresponding first switch terminal, second switch terminal and control terminal type can be specifically determined, which will not be repeated here.

[0095] Depend on Figure 2 It can be seen that the first end of the primary coil of the high-frequency transformer is the same as the primary coil of the high-frequency transformer. The connection form between the input frequency converter and the primary coil of the high-frequency transformer can be referred to. Figure 2 illustrate.

[0096] In one embodiment of the present invention, the input filter includes an input filter inductor and an input filter capacitor, wherein:

[0097] One end of the input filter inductor is connected to the first end of the input power supply, and the second end of the input filter inductor is connected to one end of the input filter capacitor and the switch tube S 1a The first switch end and the switch tube S 2a A first switch terminal is connected;

[0098] The other end of the input filter capacitor is connected to the other end of the input power supply and the switch tube S' 2b The first switch end and the switch tube S' 1b The first switch terminal is connected to

[0099] The input AC voltage is loaded to the input filter through the input power supply. When the AC input voltage of the input filter of the input power supply is in the positive half-wave, the switch tube S 1b , switch tube S 2b , switch tube S' 2b And the switch tube S' 1b Keep in closed conduction state.

[0100] Figure 1 and Figure 2 In the figure, Lin is the input filter inductor, Cin is the input filter capacitor, and the input power supply in the figure is the nuclear power emergency diesel generator set. i Of course, the input filter can also adopt other forms, which shall be based on whether it can filter the AC input voltage.

[0101] In one embodiment of the present invention, the secondary side conversion circuit comprises an output cycloconverter and an output filter connected in sequence, wherein:

[0102] The output cycloconverter is adaptively connected to the secondary coil of the high-frequency transformer and provides a power supply voltage to the load unit through an output filter;

[0103] The output cycloconverter is adaptively connected to the power conversion controller so that the power conversion controller controls the working state of the output cycloconverter.

[0104] Figure 1 An embodiment of a secondary converter is shown in FIG. 1 . As can be seen from the figure, the secondary conversion circuit may include an output cycloconverter and an output filter. The output cycloconverter is used to convert the high-frequency voltage conversion signal output by the high-frequency transformer, and after filtering by the output filter, it can provide a power supply voltage to the load unit. Figure 1 and Figure 2 In, R L That is the load unit.

[0105] In one embodiment of the present invention, the output cycloconverter comprises an output first conversion unit and an output second conversion unit, wherein:

[0106] The output first conversion unit is adaptively connected to the first end of the secondary coil of the high-frequency transformer, the output filter and the second output second conversion unit;

[0107] The second conversion unit is adaptively connected to the second end of the secondary coil of the high-frequency transformer, and the center tap of the high-frequency transformer is adaptively connected to the output filter and the load unit.

[0108] Specifically, the output cycloconverter may include an output first conversion unit and an output second conversion unit. Generally, the output first conversion unit and the output second conversion unit may be in a controllable form, that is, the output first conversion unit and the output second conversion unit may be controlled by a power conversion controller.

[0109] In one embodiment of the present invention, the output first conversion unit includes a switch tube S 3a And the switch tube S 3b ,in,

[0110] Switching tube S 3aThe first switch end of the high-frequency transformer is connected to the first end of the secondary coil of the high-frequency transformer. 3a The second switch terminal and the switch tube S 3b The second switch terminal is connected to the switch tube S 3b The first switch end is connected to the output filter and the switch tube S in the output second conversion unit 4b A first switch terminal is connected;

[0111] Switching tube S 4b The second switch terminal and the switch tube S 4a The second switch terminal is connected to the switch tube S 4a The first switch end is connected to the second end of the secondary coil of the high-frequency transformer;

[0112] Switching tube S 3a The second switch end, the switch tube S 3b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 3a The first switch end, the switch tube S 3b The corresponding first switch terminal is connected, and the switch tube S 3a , switch tube S 3b The corresponding control terminal is connected to the output terminal of the power converter;

[0113] Switching tube S 4a The second switch end, the switch tube S 4b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 4a The first switch end, the switch tube S 4b The corresponding first switch terminal is connected, and the switch tube S 4a , switch tube S 4b The corresponding control terminal is connected to the output terminal of the power converter.

[0114] Figure 2 An embodiment of the output cyclotron filter is shown in FIG. 3a , switch tube S 3b , switch tube S 4a , switch tube S 4b Generally, the same form can be adopted, such as the above-mentioned switch tube S 1a When the same type and the same form are adopted, the corresponding first switch end, the second switch end and the corresponding control end can refer to the above description and will not be repeated here.

[0115] In one embodiment of the present invention, the output filter comprises an output filter inductor and an output filter capacitor connected to the output filter inductor, wherein:

[0116] One end of the output filter inductor is connected to the switch tube S 3b The first switch end and the switch tube S 4b The first switch terminal of the output filter inductor is connected, and the other end of the output filter inductor is connected to one end of the output filter capacitor.

[0117] The other end of the output filter capacitor is connected to the center tap of the high frequency transformer, and the load unit is connected in parallel with the output filter capacitor.

[0118] Figure 1 and Figure 2 In, L f That is the output filter inductor, C f That is the output filter capacitor. Figure 2 in,i Lf That is, the load current flowing through the load unit, u o This is the supply voltage.

[0119] In one embodiment of the present invention, when the power conversion controller controls the corresponding working states of the primary side conversion circuit and the secondary side conversion circuit, it includes:

[0120] Repeatingly controlling the supply voltage provided to the load unit and generating a repeated control duty cycle signal after the repeated control;

[0121] At the same time, a voltage-current dual-loop PI control is performed on a power supply voltage provided to the load unit and a load current flowing through the load unit, so as to generate a dual-loop control duty cycle signal after the voltage-current dual-loop PI control;

[0122] An SPWM control signal is generated based on the repeated control chopping ratio signal and the dual-loop control duty cycle signal, and power conversion control information is generated based on the SPWM control signal to control the corresponding working states of the primary side conversion circuit and the secondary side conversion circuit based on the power conversion control information.

[0123] It should be noted that the power conversion control information is a switch control signal for controlling the input cycloconverter and the output cycloconverter. Figure 4 An embodiment of power conversion control information for AC input voltage at different half-waves is shown in FIG. Figure 4 In, S 3 That is, the output first conversion unit includes a switch tube S 3a And the switch tube S 3b , S 4 That is, the output first conversion unit includes a switch tube S 4a And the switch tube S 4b , that is, when working, the switch tube S 3a And the switch tube S 3bIn the on state or in the off state at the same time, the situation of S4 is consistent with that of S3. In order to improve reliability, S3 and S4 should not be in the on state at the same time.

[0124] Figure 4 middle, That is, the voltage difference between the first end of the secondary coil of the high-frequency transformer and the center tap, or the voltage difference between the center tap and the second end of the secondary coil of the high-frequency transformer, u AB is the voltage difference between node A and node B, Figure 2 In the output filter inductor and the switch tube S 3b The first end of the switch, the switch tube S 4b The first ends of the switches are connected to form a node, and node B is the voltage difference between the output filter capacitor and the center tap of the secondary coil of the high-frequency transformer.

[0125] Figure 3 The converter is the main power conversion circuit of the present invention, which consists of Figure 3 It can be seen that when the power conversion controller generates power conversion control information, a dual closed-loop method is adopted, that is, an outer loop feedback control including repetitive control and an inner loop feedback control of voltage and current dual loop PI control. Figure 3 A method of generating power conversion control information will be described.

[0126] Depend on Figure 3 It can be seen that during repeated control, the corresponding phase voltage is obtained after sampling the power supply voltage, and thereafter, the phase voltage is transformed into αβ coordinates to obtain at least the α-axis phase voltage after the αβ coordinate transformation. Of course, the β-axis phase voltage can also be obtained. Generally, the β-axis phase voltage is a voltage delayed by 1 / 4 cycle relative to the α-axis phase voltage, that is, the corresponding β-axis phase voltage can be obtained according to the α-axis phase voltage. In one embodiment of the present invention, during repeated control, only the α-axis phase voltage can be used, and the method of transforming the phase voltage into αβ coordinates to obtain the α-axis phase voltage can be consistent with the prior art.

[0127] After the α-axis phase voltage is obtained, the α-axis phase reference voltage is subtracted from the α-axis phase voltage to obtain a repeatedly controlled error voltage after the subtraction. Thereafter, the error voltage is repeatedly controlled. It should be noted that the essence of repetitive control is to add the dynamic model of the external reference signal to the controller to form a high-precision feedback control system, thereby achieving zero-static tracking of the reference signal. When the error value between the feedback signal and the reference signal is zero, the same control amount as the previous moment can be continuously output, which is similar to a signal generator, and finally outputs a repetitively controlled duty cycle signal.

[0128] Specifically, the repetitive control duty cycle signal is generated because in the αβ coordinate system, the corresponding repetitive control duty cycle signal can be obtained according to the corresponding space state equation. The situation of calculating the repetitive control duty cycle signal according to the space state equation is consistent with the prior art and will not be repeated here.

[0129] Depend on Figure 3 It can be seen that when the voltage and current dual-loop PI control is adopted, the supply voltage is first sampled to obtain the corresponding phase voltage, and then the phase voltage is transformed into dq coordinates to obtain at least the d-axis phase voltage after the dq coordinate transformation. The method of obtaining the d-axis phase voltage is consistent with the prior art. Similarly, the load current is transformed into dq coordinates to obtain the d-axis inductor current, which is obtained by Figure 2 It can be seen that the load current passes through the output filter inductor, so, Figure 3 The inductor current in is the load current.

[0130] After obtaining the d-axis phase voltage, the d-axis phase voltage is subtracted from the reference phase voltage on the dq axis and used as the voltage error of voltage PI control. Voltage PI control is performed on the voltage error, and the output of the voltage PI control is used as the reference current value of current PI control. When performing current PI control, the reference current value is subtracted from the d-axis inductor current. After that, the dual-loop control duty cycle signal can be obtained through current PI control.

[0131] Depend on Figure 3 It can be seen that after obtaining the repeated control duty cycle signal and the dual-loop control duty cycle signal, the repeated control duty cycle signal and the dual-loop control duty cycle signal are added to obtain the duty cycle signal cumulative value after addition. Thereafter, the duty cycle signal cumulative value is input into the SPWM modulation module, so that the SPWM modulation module generates a PWM modulation wave, i.e., power conversion control information. The SPWM modulation module can adopt an existing commonly used form. The SPWM modulation module generates a PWM modulation wave according to the duty cycle signal cumulative value in a manner consistent with the prior art. For example, the duty cycle signal cumulative value can be converted into a delay time to generate a square wave and achieve the purpose of controlling the switch tube. Specifically, it can generate Figure 4 The power conversion control information in the table shall prevail.

[0132] It can be understood that the power conversion control information is an SPWM wave, and the corresponding working states of the input cycloconverter and the output cycloconverter can be controlled by the SPWM wave. It should be noted that the α-axis phase reference voltage and the dq-axis reference phase voltage can generally be set according to the power supply requirements of the load unit, such as generally being set to 220V, which will not be repeated here.

[0133] Combine the following Figure 4When the positive half-wave AC input voltage is converted into power, the corresponding working processes of the input cycloconverter and the output cycloconverter are explained in detail.

[0134] When the AC input voltage is in the positive half-wave, Figure 4 When the polarity of the AC input voltage is “⊕”, Figure 4 It can be seen that the power conversion control information makes the switch tube S 1b , switch tube S 2b , switch tube S′ 1b , switch tube S' 2b It is always in the state of being triggered and turned on.

[0135] Figure 5 FIG. 1 is a schematic diagram showing the first working state of the power conversion main circuit. It should be noted that before the power conversion main circuit enters the first working state, the voltage across the primary coil of the high-frequency transformer should be 0. Thereafter, the switch tube S′ 1a , switch tube S 1a Triggering conduction, at this time it is full voltage hard open, the current flow path is as follows Figure 5 As shown, u N1 =u i At the same time, on the secondary side of the high-frequency transformer, the secondary current flows through the switch tube S 3a , switch tube S 3b , and the switch tube S 3b The anti-parallel diode and the output filter are connected to the load unit.

[0136] Figure 6 FIG. 1 shows a schematic diagram of the second working state of the power conversion main circuit. When entering the second working state, the switch tube S 1a Zero voltage shutdown, at this time, the primary current of the high-frequency transformer passes through the switch tube S' 1a , switch tube S′ 1b , and the switch tube S′ 1b Anti-parallel diode, switch tube S' 2b , switch tube S' 2a The anti-parallel diode is connected to the Figure 6 At this time, the voltage of the primary coil of the high-frequency transformer is 0, and the secondary current of the high-frequency transformer still flows through the switch S 3a , switch tube S 3b , and the switch tube S 3b The anti-parallel diode and the output filter are connected to the load unit, u AB = 0. At this time, the switch tube S' 2a The terminal voltage it bears will drop to zero, creating conditions for it to be turned on under zero voltage conditions.

[0137] Figure 7FIG. 1 shows a schematic diagram of the third working state of the power conversion main circuit. When entering the third working state, the switch tube S' 2a Zero voltage switching, the primary current flows as follows Figure 7 At this time, the output first conversion unit and the output second conversion unit in the output cycloconverter start to commutate, and then the switch tube S 4a And switch tube S 4b Zero voltage trigger conduction. Due to the commutation overlap time, at this time, the switch tube S 3a , switch tube S 3b , switch tube S 4a , switch tube S 4b will be turned on at the same time. Since the commutation time is very short, it is not specifically marked in the figure. To ensure that the output cycloconverter can successfully complete ZVS, its commutation time t 0 Should meet (D / 2) max ≤0.5-t 0 F S , F S is the switching frequency.

[0138] Figure 8 FIG. 1 shows a schematic diagram of the fourth working state of the power conversion main circuit. When the fourth working state is entered, the commutation process of the output cycloconverter ends, and the switch tube S 3a and S 3b Zero voltage shutdown, load current i Lf The direction remains unchanged. The secondary current flows through the switch tube S 4a , switch tube S 4b , and the switch tube S 4b The anti-parallel diode, output filter and load unit flow, u AB = 0. The primary current i of the high-frequency transformer N1 The flow direction will change, and its flow path will be Figure 8 As shown; at this time, the voltage of the primary coil of the high-frequency transformer is still 0.

[0139] Fig. 9 FIG. 1 shows a schematic diagram of the fifth working state of the power conversion main circuit. When entering the fifth working state, the switch tube S′ 1a Zero voltage shutdown, the primary current flows as follows Fig. 9 As shown in The secondary side state remains unchanged, u AB =0.

[0140] Fig.10 FIG. 1 shows a schematic diagram of the sixth working state of the power conversion main circuit. When entering the sixth working state, the switch tube S 2a is triggered to conduct, and the switch tube S 2aThe state is full voltage hard open. The primary current flows as follows Fig.10 As shown in N1 =-u i The states of the corresponding switches in the first conversion unit and the output second conversion unit remain unchanged, and the output cycloconverter back-end voltage u AB =(N 2 / N 1 ) i At this time, the input AC voltage is chopped and transmitted to the secondary side through a high-frequency transformer, providing energy to the energy storage element and the load unit.

[0141] Fig.11 FIG. 1 shows a schematic diagram of the seventh working state of the power conversion main circuit. When entering the seventh working state, the switch tube S' 2a Zero voltage shutdown, at this time, the primary current flows through the switch tube S 2a , switch tube S 2b , and the switch tube S 2b Anti-parallel diode, switch tube S 1b And switch tube S 1a The anti-parallel diode flows, such as Fig.11 As shown. The voltage of the primary coil of the high-frequency transformer drops to zero again; the secondary current still flows through the switch tube S 4a , switch tube S 4b , and the switch tube S 4b The anti-parallel diode, output filter and load unit flow, u AB = 0. At this time, the switch tube S 1a The terminal voltage will drop to zero, which is the switching tube S 1a This creates the conditions for opening under zero voltage conditions.

[0142] Fig.12 FIG. 1 shows a schematic diagram of the eighth working state of the power conversion main circuit. When entering the eighth working state, the switch tube S 1a Zero voltage switching, the primary current flows as follows Fig.12 As shown, after that, the output cycloconverter also starts its commutation process again. During the commutation overlap time, the switch tube S 3a , switch tube S 3b , switch tube S 4a , switch tube S 4b They will be turned on at the same time. To achieve ZVS, the conditions that must be met by the commutation conduction time are the same as before.

[0143] Fig.13 FIG. 1 shows a schematic diagram of the ninth working state of the power conversion main circuit. When the ninth working state is entered, the commutation process of the output cycloconverter ends, and the switch tube S 4a , switch tube S 4bZero voltage shutdown, switch tube S 3a , switch tube S 3b , zero voltage trigger conduction. Load current i Lf The direction remains unchanged. The secondary current flows through the switch tube S 3a , switch tube S 3b , and the switch tube S 3b The anti-parallel diode, output filter and load unit flow, u AB = 0. The primary current i of the high-frequency transformer N1 The flow direction changes. Fig.13 At this time, the voltage of the primary coil of the high-frequency transformer has not changed and remains at 0.

[0144] Fig.14 FIG. 1 shows a schematic diagram of the tenth working state of the power conversion main circuit. When the tenth working state is entered, the switch tube S 2a Zero voltage shutdown, the primary current flows as follows Fig.14 As shown, The secondary side state remains unchanged, u AB = 0. At this time, a switching process ends, and from the next moment, it will return to the starting moment and enter the next cycle.

[0145] From the above analysis of the switching process, it can be seen that the corresponding switch tube in the output cycloconverter can be turned on and off under zero voltage conditions. At the same time, in the positive half-wave, when the output filter inductor current and the supply voltage are both greater than zero, the switch tube S in the input cycloconverter 1a And switch tube S' 2a It can also be turned on and off under zero voltage conditions.

[0146] It can be understood that when the AC input voltage is in the negative half-wave, the operation process of the power conversion controller controlling the input cycloconverter and the output cycloconverter can refer to the positive half-wave and Figure 4 The corresponding instructions will not be repeated here.

[0147] In addition, by Figure 4 It can be seen that when the AC input voltage is in the positive half-wave, the switch tube S 1a The conduction time of the switch tube S' 1a There is a phase difference of θ; when the AC input voltage is in the positive half-wave, the switch tube S 1b The conduction time of the switch tube S' 1b There is a phase difference of θ. At this time, the amplitude of the high-frequency input signal input to the frequency converter can be adjusted.

Claims

1. A power conversion control device suitable for nuclear power emergency diesel generator sets, characterized in that: The power conversion control device includes a power conversion main circuit and a power conversion controller for controlling the working state of the power conversion main circuit, wherein: The power conversion main circuit includes a primary side conversion circuit, a high frequency transformer and a secondary side conversion circuit connected in sequence. The primary conversion circuit is adaptively connected to the primary coil of the high-frequency transformer, and chops the connected AC input voltage into a high-frequency input signal, and loads the chopped high-frequency input signal to the primary coil of the high-frequency transformer; The secondary side conversion circuit is adaptively connected to the secondary side coil of the high frequency transformer, converts the high frequency voltage signal generated by the high frequency transformer into a power supply voltage, and provides the power supply voltage to the connected load unit; The power conversion controller is adaptively connected to the primary side conversion circuit and the secondary side conversion circuit, wherein: Based on the power supply voltage provided to the load unit and the load current flowing through the load unit, the power conversion controller controls the corresponding working states of the primary conversion circuit and the secondary conversion circuit to provide a stable power supply voltage to the load circuit via the secondary conversion circuit.

2. The power conversion control device suitable for nuclear power emergency diesel generator set according to claim 1 is characterized in that: The primary side conversion circuit at least includes an input filter and an input cycloconverter, wherein: The input filter receives the AC input voltage and loads the filtered AC input voltage to the input cycloconverter; The input frequency converter is adaptively connected to the primary coil of the high-frequency transformer, and is used to chop the filtered AC input voltage into a high-frequency input signal, and load the high-frequency input signal to the primary coil of the high-frequency transformer.

3. The power conversion control device suitable for nuclear power emergency diesel generator set according to claim 2 is characterized in that: The input cycloconverter adopts a full-bridge conversion structure, and the input cycloconverter includes an input conversion first bridge arm and an input conversion second bridge arm, wherein: The input conversion first bridge arm includes an input conversion first upper bridge arm unit and an input conversion first lower bridge arm unit, and the connection part of the input conversion first upper bridge arm unit and the input conversion first lower bridge arm unit is connected to the first end of the primary coil of the high-frequency transformer; The input conversion second bridge arm includes an input conversion second upper bridge arm unit and an input conversion second lower bridge arm unit, and the connection part of the input conversion second upper bridge arm unit and the input conversion second lower bridge arm unit is connected to the second end of the primary coil of the high-frequency transformer; The power conversion controller is adaptively connected to the first upper bridge arm unit of input conversion, the first lower bridge arm unit of input conversion, the second upper bridge arm unit of input conversion and the second lower bridge arm unit of input conversion to control the corresponding working states of the first upper bridge arm unit of input conversion, the first lower bridge arm unit of input conversion, the second upper bridge arm unit of input conversion and the second lower bridge arm unit of input conversion, and chop the AC input voltage into a high-frequency input signal.

4. The power conversion control device suitable for nuclear power emergency diesel generator set according to claim 3 is characterized in that: The first upper bridge arm unit of the input conversion includes a switch tube S 1a And the switch tube S 1b ,in, Switching tube S 1a The first switch end is connected to the input filter output, and the switch tube S 1a The second switch terminal and the switch tube S 1b The second switch terminal is connected to the switch tube S 1b The first switch end is connected to the first end of the high frequency transformer, and the switch tube S 1a The second switch end, the switch tube S 1b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 1a The first switch end, the switch tube S 1b The corresponding first switch terminal is connected, and the switch tube S 1a , switch tube S 1b The corresponding control terminal is connected to the output terminal of the power converter; The second upper bridge arm unit of the input conversion includes a switch tube S 2a And the switch tube S 2b ,in, Switching tube S 2a The first switch end is adapted to be connected to the input filter, and the switch tube S 2a The second switch terminal and the switch tube S 2b The second switch terminal is connected to the switch tube S 2b The first switch end is connected to the second end of the high frequency transformer, and the switch tube S 2a The second switch end, the switch tube S 2b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 2a The first switch end, the switch tube S 2b The corresponding first switch terminal is connected, and the switch tube S 2a , switch tube S 2b The corresponding control terminal is connected to the output terminal of the power converter; The first lower bridge arm unit of the input conversion includes a switch tube S2' a And switch tube S2' b ,in, Switch tube S2' a The first switch end is connected to the first end of the primary coil of the high-frequency transformer, and the switch tube S2′ a The second switch end and the switch tube S2′ b The second switch end is connected to the switch tube S2′ b The first switch end is adapted to be connected to the input filter, and the switch tube S2′ a The second switch end, switch tube S2' b The second switch end of each of the two circuits is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S2′. a The first switch end, the switch tube S2' b The corresponding first switch terminal is connected to the switch tube S2′ a , switch tube S2' b The corresponding control terminal is connected to the output terminal of the power converter; The second lower bridge arm unit of the input conversion includes a switch tube S1' a And switch tube S1' b ,in, Switch tube S1' a The first switch end is connected to the second end of the primary coil of the high-frequency transformer, and the switch tube S1′ a The second switch terminal and the switch tube S1′ b The second switch end is connected to the switch tube S1′ b The first switch end is adapted to be connected to the input filter, and the switch tube S1′ a The second switch end, switch tube S1' b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S1′ a The first switch end, the switch tube S1' b The corresponding first switch terminal is connected to the switch tube S1′ a , switch tube S1′ b The corresponding control terminal is connected to the output terminal of the power converter.

5. The power conversion control device suitable for nuclear power emergency diesel generator set according to claim 4 is characterized in that: The input filter includes an input filter inductor and an input filter capacitor, wherein: One end of the input filter inductor is connected to the first end of the input power supply, and the second end of the input filter inductor is connected to one end of the input filter capacitor and the switch tube S 1a The first switch end and the switch tube S 2a A first switch terminal is connected; The other end of the input filter capacitor is connected to the other end of the input power supply and the switch tube S2' b The first switch end and the switch tube S1′ b The first switch terminal is connected to The input AC voltage is loaded to the input filter through the input power supply. When the AC input voltage of the input filter of the input power supply is in the positive half-wave, the switch tube S 1b , switch tube S 2b , switch tube S2' b And switch tube S1' b Keep in closed conduction state.

6. The power conversion control device suitable for nuclear power emergency diesel generator set according to claim 4 is characterized in that: The secondary side conversion circuit comprises an output cycloconverter and an output filter connected in sequence, wherein: The output cycloconverter is adaptively connected to the secondary coil of the high-frequency transformer and provides a power supply voltage to the load unit through an output filter; The output cycloconverter is adaptively connected to the power conversion controller so that the power conversion controller controls the working state of the output cycloconverter.

7. The power conversion control device suitable for nuclear power emergency diesel generator set according to claim 6 is characterized in that: The output cycloconverter comprises an output first conversion unit and an output second conversion unit, wherein: The output first conversion unit is adaptively connected to the first end of the secondary coil of the high-frequency transformer, the output filter and the second output second conversion unit; The second conversion unit is adaptively connected to the second end of the secondary coil of the high-frequency transformer, and the center tap of the high-frequency transformer is adaptively connected to the output filter and the load unit.

8. The power conversion control device suitable for nuclear power emergency diesel generator set according to claim 7 is characterized in that: The output first conversion unit includes a switch tube S 3a And the switch tube S 3b ,in, Switching tube S 3a The first switch end of the high-frequency transformer is connected to the first end of the secondary coil of the high-frequency transformer. 3a The second switch terminal and the switch tube S 3b The second switch terminal is connected to the switch tube S 3b The first switch end is connected to the output filter and the switch tube S in the output second conversion unit 4b A first switch terminal is connected; Switching tube S 4b The second switch terminal and the switch tube S 4a The second switch terminal is connected to the switch tube S 4a The first switch end is connected to the second end of the secondary coil of the high-frequency transformer; Switching tube S 3a The second switch end, the switch tube S 3b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 3a The first switch end, the switch tube S 3b The corresponding first switch terminal is connected, and the switch tube S 3a , switch tube S 3b The corresponding control terminal is connected to the output terminal of the power converter; Switching tube S 4a The second switch end, the switch tube S 4b The second switch end is connected to the anode end of a freewheeling diode, and the cathode end of the corresponding freewheeling diode is connected to the switch tube S 4a The first switch end, the switch tube S 4b The corresponding first switch terminal is connected, and the switch tube S 4a , switch tube S 4b The corresponding control terminal is connected to the output terminal of the power converter.

9. The power conversion control device suitable for nuclear power emergency diesel generator set according to claim 8 is characterized in that: The output filter includes an output filter inductor and an output filter capacitor connected to the output filter inductor, wherein: One end of the output filter inductor is connected to the switch tube S 3b The first switch end and the switch tube S 4b The first switch terminal of the output filter inductor is connected, and the other end of the output filter inductor is connected to one end of the output filter capacitor. The other end of the output filter capacitor is connected to the center tap of the high frequency transformer, and the load unit is connected in parallel with the output filter capacitor.

10. The power conversion control device suitable for nuclear power emergency diesel generator set according to claim 8 is characterized in that: When the power conversion controller controls the corresponding working states of the primary side conversion circuit and the secondary side conversion circuit, it includes: Repeatingly controlling the supply voltage provided to the load unit and generating a repeated control duty cycle signal after the repeated control; At the same time, a voltage-current dual-loop PI control is performed on a power supply voltage provided to the load unit and a load current flowing through the load unit, so as to generate a dual-loop control duty cycle signal after the voltage-current dual-loop PI control; An SPWM control signal is generated based on the repeated control chopping ratio signal and the dual-loop control duty cycle signal, and power conversion control information is generated based on the SPWM control signal to control the corresponding working states of the primary side conversion circuit and the secondary side conversion circuit based on the power conversion control information.

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