Marine high-power DC-DC power converter

Abstract

The utility model discloses a marine high-power DC-DC power converter, which belongs to the technical field of power converters and comprises a pre-charging board, a power board and a control board, a pre-charging circuit is arranged on the pre-charging board, a soft start circuit, a boost output circuit and a drive circuit are arranged on the power board, and a control circuit is arranged on the control board. Capacitors are connected between two input ends and two output ends of the boost output circuit, a first branch and a second branch which are connected in parallel are arranged between one input end and one output end, each of the first branch and the second branch comprises a resistor, an inductor and a fly-wheel diode which are sequentially connected in series, and a first field effect transistor and a second field effect transistor are arranged between the two input ends. On one hand, a multi-board design is adopted, strong and weak current separation can be realized, and electromagnetic compatibility layout is satisfied; and on the other hand, the boost output circuit adopts a SiC MOSFET double-transistor interleaving parallel design, the power density is high, the number of power semiconductor devices can be reduced, and the overall efficiency is improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of power converters, and particularly relates to a marine high-power DC-DC power converter. Background Art

[0002] A DC-DC power converter can boost the low voltage output by a storage battery to the high voltage for the operation of an inverter, ensuring the continuous operation of a marine inverter to guarantee the continuous and stable operation of key equipment such as ship navigation and communication. It is an important bridge for the normal operation between the storage battery and the inverter. The working voltage of marine inverters in China is mostly DC650V - DC700V, and the output power is relatively large. However, since the output voltage of most storage batteries is DC300V - DC400V, which cannot meet the working voltage of the inverter, therefore, to meet the above requirements, a high-power DC-DC power converter needs to be provided. Summary of the Utility Model

[0003] The technical problem to be solved by the utility model is to provide a marine high-power DC-DC power converter to reduce the number of power semiconductor devices and improve the overall efficiency.

[0004] To solve the above technical problem, the utility model provides the following technical solutions:

[0005] A marine high-power DC-DC power converter includes a pre-charge board, a power board, and a control board, wherein:

[0006] A pre-charge circuit is provided on the pre-charge board. A soft start circuit, a boost output circuit, and a drive circuit for driving the boost output circuit are sequentially provided on the power board. A control circuit and a communication circuit are sequentially provided on the control board. The input end of the marine high-power DC-DC power converter is sequentially connected to the output end of the marine high-power DC-DC power converter through the pre-charge circuit, the soft start circuit, and the boost output circuit;

[0007] A first capacitor is connected between the two input ends of the boost output circuit. A second capacitor is connected between the two output ends of the boost output circuit. A first branch and a second branch in parallel are provided between one input end and one output end of the boost output circuit. The first branch includes a first resistor, a first inductor, and a first freewheeling diode connected in series in sequence. The second branch includes a second resistor, a second inductor, and a second freewheeling diode connected in series in sequence;

[0008] A first field-effect transistor and a second field-effect transistor are also provided between the two input terminals of the boost output circuit. Both the first field-effect transistor and the second field-effect transistor are PNP-type SiC MOSFETs. The gates of the first field-effect transistor and the second field-effect transistor are respectively connected to the drive circuit. The drains of the first field-effect transistor and the second field-effect transistor are respectively connected between the first inductor and the first freewheeling diode, and between the second inductor and the second freewheeling diode. The sources of the first field-effect transistor and the second field-effect transistor are both connected to the other input terminal of the boost output circuit.

[0009] Further, the overall circuit layout of the marine high-power DC-DC power converter adopts an L-shaped circuit design, with the upper left side for incoming line and the upper right side for outgoing line. The input interface and the output interface are on both sides of the whole machine.

[0010] Further, the control board is isolated and installed above the power board, and a radiator is provided below the power board, where:

[0011] The first inductor and the second inductor are installed on the radiator;

[0012] And / or, the first field-effect transistor and the second field-effect transistor are attached to the radiator;

[0013] And / or, the marine high-power DC-DC power converter adopts a standard 2U chassis design, and the radiator is embedded at the bottom of the chassis.

[0014] Further, the pre-charge circuit is arranged at the positive input terminal of the marine high-power DC-DC power converter to control the on / off of the whole device. The pre-charge circuit includes a pre-charge relay and a pre-charge resistor. The switch of the pre-charge relay is connected in parallel with the pre-charge resistor. The pre-charge relay is independently installed on the radiator, and the coil control circuit of the pre-charge relay and the pre-charge resistor are arranged on the pre-charge board.

[0015] Further, the coil control circuit of the pre-charge relay includes a triode and an opto-isolation chip, where:

[0016] The base of the triode receives the coil control signal sent by the control circuit through a resistor, and is connected to the emitter of the triode and grounded after passing through a parallel resistor and capacitor;

[0017] The positive pole of the opto-isolation chip is connected to the power supply, the negative pole is connected to the collector of the triode, and the output terminal is used to supply power to the coil of the pre-charge relay.

[0018] Further, the driving circuit includes two driving sub - circuits with the same structure to drive the first field - effect transistor and the second field - effect transistor respectively. Each driving sub - circuit includes an isolated driving chip, where:

[0019] The positive input terminal of the isolated driving chip receives the pulse - width modulation signal sent by the control circuit through one path via a resistor, and the other path is grounded after passing through a parallel - connected resistor and capacitor. The negative input terminal is grounded through a resistor, and the output terminal is grounded through a first voltage - dividing resistor and a second voltage - dividing resistor. The connection point between the first voltage - dividing resistor and the second voltage - dividing resistor is connected to the gate of the first field - effect transistor or the second field - effect transistor.

[0020] Further, the clamping input terminal of the isolated driving chip is also connected to the connection point between the first voltage - dividing resistor and the second voltage - dividing resistor, and is connected to the output terminal of the isolated driving chip through a resistor at the same time.

[0021] Further, a high - voltage - side signal sampling circuit for sampling the voltages at both ends of the first capacitor or the second capacitor is also provided on the power board. The high - voltage - side signal sampling circuit includes an isolated voltage amplifier chip, where:

[0022] The voltage across the first capacitor or the second capacitor is grounded through a third voltage - dividing resistor and a fourth voltage - dividing resistor;

[0023] The positive input terminal of the isolated voltage amplifier chip is connected to the connection point between the third voltage - dividing resistor and the fourth voltage - dividing resistor through a resistor, the negative input terminal is grounded through a resistor, and a capacitor is also connected between the positive input terminal and the negative input terminal;

[0024] The positive output terminal of the isolated voltage amplifier chip is used to output a high voltage to be measured, and the negative output terminal is used to output a low voltage to be measured.

[0025] Further, a low - voltage - side signal sampling circuit is also provided on the control board. The low - voltage - side signal sampling circuit includes a first operational amplifier and a second operational amplifier, where:

[0026] The inverting input terminal of the first operational amplifier is connected to the negative output terminal of the isolated voltage amplifier chip through a resistor, and the non - inverting input terminal of the first operational amplifier is connected to the positive output terminal of the isolated voltage amplifier chip through a resistor;

[0027] The non - inverting input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier through a resistor, the output terminal of the second operational amplifier is connected to the inverting input terminal of the second operational amplifier, and the output terminal of the second operational amplifier is used to output an analog voltage to be measured.

[0028] Furthermore, an isolated CAN interface and an isolated RS485 interface are provided on the power board, and the communication signal line is transferred and output through the digital signal interface of the control board to the power board.

[0029] The utility model has the following beneficial effects:

[0030] The marine high-power DC-DC power converter of the utility model, on the one hand, adopts a multi-board design, including a pre-charge board, a power board and a control board, which can realize the separation of strong and weak electricity and meet the electromagnetic compatibility layout; on the other hand, the boost output circuit adopts a SiC MOSFET dual-tube interleaved parallel design, with high power density, half of the power devices reduced, and half of the conduction losses reduced, which can reduce the number of power semiconductor devices and improve the overall efficiency. Description of the Drawings

[0031] The drawings described herein are used to provide a further understanding of the utility model, form a part of the utility model, and the schematic embodiments and descriptions thereof of the utility model are used to explain the present application and do not constitute an improper limitation of the utility model. In the drawings:

[0032] Figure 1 is the overall circuit structure block diagram of the marine high-power DC-DC power converter of the utility model;

[0033] Figure 2 is the top view of the overall circuit layout of the marine high-power DC-DC power converter of the utility model;

[0034] Figure 3 is the right view of the overall circuit layout of the marine high-power DC-DC power converter of the utility model;

[0035] Figure 4 is the schematic diagram of the pre-charge circuit in the utility model;

[0036] Figure 5 is the simulation waveform diagram of the pre-charge DC voltage and charging current in the utility model;

[0037] Figure 6 is the simulation result diagram of the soft start of the output voltage in the utility model;

[0038] Figure 7 is the partial schematic diagram of the drive circuit in the utility model;

[0039] Figure 8 is the partial schematic diagram of the boost output circuit in the utility model;

[0040] Figure 9 is the circuit steady-state and dynamic simulation result diagram in the utility model;

[0041] Figure 10This is the schematic diagram of the high-voltage side signal sampling circuit in the present utility model;

[0042] Figure 11 This is the schematic diagram of the low-voltage side signal sampling circuit in the present utility model;

[0043] Figure 12 This is the structure diagram of the boost control algorithm in the present utility model. Detailed implementation manners

[0044] In order to more clearly illustrate the overall concept of the present application, the following will be described in detail by way of examples in combination with the drawings in the specification.

[0045] In the following description, many specific details are set forth in order to fully understand the present utility model. However, the present utility model can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present utility model is not limited by the specific embodiments disclosed below.

[0046] In addition, in the description of the present utility model, it should be understood that the terms "top", "bottom", "inner", "outer", "axial", "radial", "circumferential", etc. indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention.

[0047] In the present utility model, unless otherwise clearly defined and limited, the terms "installation", "connection", "connection", "fixation", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection, an electrical connection, or a communication connection; it can be directly connected, or indirectly connected through an intermediate medium, and can be the internal communication of two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0048] In the present utility model, unless otherwise clearly specified and defined, the first feature being "on" or "under" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0049] The present utility model provides a marine high-power DC-DC power converter, as Figure 1 shown, which includes a pre-charge board 10, a power board 20, and a control board 30, wherein:

[0050] A pre-charge circuit is provided on the pre-charge board 10, a soft start circuit, a boost output circuit 201, and a drive circuit for driving the boost output circuit 201 are sequentially provided on the power board 20, a control circuit and a communication circuit are sequentially provided on the control board 30, and the input end of the marine high-power DC-DC power converter (i.e., Figure 1 at Vin herein) is sequentially connected to the output end of the marine high-power DC-DC power converter (i.e., Figure 1 at Vout herein) through the pre-charge circuit, the soft start circuit, and the boost output circuit 201;

[0051] A first capacitor C10 is connected between the two input ends of the boost output circuit 201, a second capacitor C20 is connected between the two output ends of the boost output circuit 201, and a first branch ( Figure 1 branch 1 herein) and a second branch ( Figure 1 branch 2 herein) are provided in parallel between one input end and one output end of the boost output circuit 201. The first branch includes a first resistor Rs1, a first inductor L1, and a first freewheeling diode D1 connected in series in sequence, and the second branch includes a second resistor Rs2, a second inductor L2, and a second freewheeling diode D2 connected in series in sequence;

[0052] A first field-effect transistor Q1 and a second field-effect transistor Q2 are also provided between two input terminals of the boost output circuit 201. Both the first field-effect transistor Q1 and the second field-effect transistor Q2 are PNP-type SiC MOSFET transistors. The gates of the first field-effect transistor Q1 and the second field-effect transistor Q2 are respectively connected to the drive circuit. The drains of the first field-effect transistor Q1 and the second field-effect transistor Q2 are respectively connected between the first inductor L1 and the first freewheeling diode D1, and between the second inductor L2 and the second freewheeling diode D2. The sources of the first field-effect transistor Q1 and the second field-effect transistor Q2 are both connected to the other input terminal of the boost output circuit 201.

[0053] For the marine high-power DC-DC power converter of the present invention, on the one hand, a multi-board design is adopted, including a pre-charge board, a power board and a control board, which can achieve the separation of strong and weak electricity and meet the electromagnetic compatibility layout. On the other hand, the boost output circuit adopts a SiC MOSFET dual-tube interleaved parallel design, with high power density, half the number of power devices reduced, and half the conduction loss reduced. It can reduce the number of power semiconductor devices and improve the overall efficiency.

[0054] The present invention can stabilize the input variable DC voltage of 300V to 400V of the marine high-power DC-DC power converter to DC650V - DC700V, providing a relatively stable DC power supply for the subsequent-stage inverter. The stable DC voltage can keep the gain within a reasonable range during the frequency modulation control of the subsequent-stage inverter. The present invention has a large output power, an output voltage of DC650V - DC700V, a maximum output current of 28.6A - 30A, and the rated capacity of the whole machine can reach 20kVA.

[0055] For the marine high-power DC-DC power converter of the present invention, the overall circuit layout of the whole machine can adopt the classic L-shaped circuit design, with the layout of incoming line on the upper left side and outgoing line on the upper right side. The input interface and the output interface are on both sides of the whole machine, meeting the process requirements of left-in and right-out. The L-shaped circuit layout can be in turn: input pre-charge circuit --- soft start circuit --- boost output circuit --- drive circuit --- signal sampling circuit --- control circuit --- communication circuit. The control circuit can be placed on the lower right side of the L-shaped circuit, and the overall adopts the separation of strong and weak electricity to meet the electromagnetic compatibility layout.

[0056] Figure 2 It is a top view of the overall layout of the marine high-power DC-DC power converter circuit design. Figure 3 It is a right view of the overall layout of the marine high-power DC-DC power converter circuit design, where 1 is an inductor (corresponding to Figure 1L1 and L2 therein), 2 is the input interface, 3 is the drive circuit, 4 is the output interface, 5 is the signal sampling circuit (corresponding to the subsequent high-voltage side signal sampling circuit), 6 is the control circuit, 7 is the SiC MOSFET (corresponding to Figure 1 Q1 and Q2 therein), and 8 is the radiator.

[0057] As Figure 2-3 shown, the control board 30 can be isolated and installed above the power board 20 to separate the strong and weak electricity and avoid signal interference; a radiator 8 can be provided below the power board 20 to improve the working stability of the whole machine. Moreover, the inductor 1 (i.e., the first inductor L1 and the second inductor L2) can be installed on the radiator 8, and the input interface 2, the drive circuit 3, the output interface 4, and the signal sampling circuit 5 can all be arranged on the power board 20. The SiC MOSFET 7 (i.e., the first field-effect transistor Q1 and the second field-effect transistor Q2) is attached / close to the bottom radiator 8. Through air cooling, the heat generated by the SIC MOSFET 7 can be quickly reduced, and the working efficiency of the boost output circuit 201 can be improved. The whole machine can adopt a standard 2U chassis design, and the radiator 8 can be embedded in the bottom of the chassis. In Figure 3 it, the pre-charge board 10 and the power board 20 are arranged at the same height and thus are blocked from view by the power board 20.

[0058] The following specifically describes each circuit involved in the present invention.

[0059] 1. Pre-charge circuit

[0060] As Figure 1 shown, the pre-charge circuit is arranged at the positive input end (i.e., the positive input interface) of the marine high-power DC-DC power converter and is used to control the on / off of the entire device. The pre-charge circuit can include a pre-charge relay J0 and a pre-charge resistor R0. The switch of the pre-charge relay J0 is connected in parallel with the pre-charge resistor R0. The pre-charge relay J0 is independently installed on the radiator 8, and the coil control circuit of the pre-charge relay J0 and the pre-charge resistor R0 are arranged on the pre-charge board 10. In specific implementation, the pre-charge board 10 can be installed on the rear panel of the module and is docked with the control board 30 through a control interface (in the embodiment shown in the figure, there is a pre-charge control interface on the power board 20, and the power board 20 routes to the pins of the control board 30, and the control board 30 controls the pre-charge circuit), controlling the working state of the pre-charge resistor R0. Specifically, the switch of the pre-charge relay J0 is default in the open state. After the input interface of the power converter is powered on, the current flows through the pre-charge resistor R0 for pre-charging. After meeting the set conditions, the pre-charge relay J0 is attracted and the switch is closed, and the current bypasses the pre-charge resistor R0, and the power converter starts the power conversion work.

[0061] To improve the circuit safety, as Figure 4As shown, the coil control circuit of the pre-charge relay J0 preferably includes a triode Q3 and an opto-isolation chip U1, where:

[0062] The base of the triode Q3 receives the coil control signal CHARGE sent by the control circuit via the resistor R11, and at the same time is connected to the emitter of the triode Q3 and grounded after passing through the parallel-connected resistors R12 and capacitor C3;

[0063] The positive pole A of the opto-isolation chip U1 is connected to the power supply, the negative pole C is connected to the collector of the triode Q3, and the output terminal Vo is used to supply power to the coil of the pre-charge relay J0 (see the label JDXO+ in the figure).

[0064] The model of the opto-isolation chip U1 can be flexibly selected according to needs, such as OR-314(B)-W. In Figure 4 Among them, the resistors R1-R14 between the right pads are used to form the pre-charge resistor R0 through series and parallel connections. The pre-charge simulation waveform is as Figure 5 , the voltage establishment time of the DC capacitor (including input and output) is about 2s. The maximum charging current is about 5A. The coil of the DC relay is driven by an opto-coupler (i.e., the opto-isolation chip U1), and the control voltage is +5V, which can realize the function of protecting against excessive instantaneous impact current at the input.

[0065] 2. Soft start circuit

[0066] The soft start circuit can be built using conventional techniques in the art, for example, composed of capacitors, resistors and comparators, which is not shown in the figure and will not be elaborated here. The soft start circuit is controlled by the control board 30. During the soft start process, the output voltage gradually rises from the starting voltage of 300V to the given value of 700V. The voltage change during the soft start process is stable without overshoot, and the duration of the soft start process is less than 100ms. The soft start simulation result of the output voltage is shown in Figure 6 . The soft start circuit can help start the electronic device in a progressive and stable manner, meeting the function of protecting the hardware during startup.

[0067] 3. Drive circuit

[0068] To improve the driving ability and safety of the circuit, preferably, the drive circuit includes two drive sub-circuits with the same structure to drive the first field effect transistor Q1 and the second field effect transistor Q2 respectively, as Figure 7 shown, each drive sub-circuit includes an isolation drive chip U6, where:

[0069] The positive input terminal IN+ of the isolated drive chip U6 receives the pulse-width modulation signal EPWM1A_5V sent by the control circuit through a path including the resistor R29, and another path is grounded after passing through the parallel-connected resistor R32 and capacitor C62. The negative input terminal IN- is grounded through the resistor R33. The output terminal OUT is grounded after passing through the first voltage-dividing resistor R28 and the second voltage-dividing resistor R31. The connection point between the first voltage-dividing resistor R28 and the second voltage-dividing resistor R31 (where the control signal G_Q1 or G_Q2 is formed) is connected to the gate of the first field-effect transistor Q1 or the second field-effect transistor Q2.

[0070] The model of the isolated drive chip U6 can be flexibly selected according to needs, such as NSI6601MBDSWVR. The drive circuit uses a domestically developed and self-developed isolated chip to amplify the pulse signal output by the control board 30. By controlling the duty cycle of the pulse signal, the SiC MOSFET tube in the boost output circuit is turned off to adjust the output voltage magnitude. Adopting isolated control can avoid the influence of the primary side signal by electromagnetic interference on the regulation effect of the SiC MOSFET tube, making the voltage regulation more stable and reliable.

[0071] Furthermore, the clamping input terminal CLAMP of the isolated drive chip U6 can also be connected between the first voltage-dividing resistor R28 and the second voltage-dividing resistor R31, and at the same time, it is connected to the output terminal OUT of the isolated drive chip U6 through the resistor R30 to improve the stability of the output drive signal.

[0072] 4. Boost Output Circuit

[0073] As Figure 1 and Figure 8 shown, the boost output circuit 201 adopts a two-stage interleaved parallel BOOST (boost) topology and uses an (isolated) drive circuit to perform PWM modulation on the SiC MOSFET tube, boosting the DC300V - DC400V voltage to DC650V - DC700V, with a rated capacity of up to 20kVA, and can achieve the characteristics of a wide input range / wide output adjustment range. At the same time, the high-heat-generating power devices are connected to the radiator 8 for air-cooling heat dissipation treatment of the power devices. In Figure 8 it, the first inductor L1 is connected between the left nodes PJ2 and PJ3, and the second inductor L2 is connected between the nodes PJ5 and PJ6; the two freewheeling diodes in the upper right corner (corresponding to Figure 1 D1 and D2 in

[0074] it) can be implemented by one device, such as B2DM100120N1. Figure 9The input voltage jumps from 300V to 400V at 2s and suddenly drops from 400V to 300V at 5s; the load current suddenly increases from half load to rated at 4s and suddenly drops from rated to half load at 6s. During the whole process, the output voltage can be stabilized at the given value of 700V, with the dynamic fluctuation not exceeding 40V and the transition time being short.

[0075] 5. Signal Sampling Circuit

[0076] For realizing circuit signal sampling and control, preferably, as Figure 1 and Figure 10 shown, a high-voltage side signal sampling circuit for sampling the voltages at both ends of the first capacitor C10 or the second capacitor C20 is further provided on the power board 20. The high-voltage side signal sampling circuit includes an isolation voltage amplifier chip U12, wherein:

[0077] The voltage VinP at both ends of the first capacitor C10 or the second capacitor C20 is grounded through a third voltage-dividing resistor ( Figure 10 formed by R49, R50, R51 and R52 together in

[0078] Figure 10 and a fourth voltage-dividing resistor R57. It can be understood that only one resistor can also be used); The positive input terminal VINP of the isolation voltage amplifier chip U12 is connected to the middle of the third voltage-dividing resistor (

[0079] formed by R49, R50, R51 and R52 together) and the fourth voltage-dividing resistor R57 through a resistor R53, the negative input terminal VINN is grounded through a resistor R62, and a capacitor C96 is also connected between the positive input terminal VINP and the negative input terminal VINN;

[0080] The positive output terminal VOUTP of the isolation voltage amplifier chip U12 is used to output the high voltage to be measured Uin_H, and the negative output terminal VOUTN is used to output the low voltage to be measured Uin_L.

[0081] Further, as Figure 11 shown, a low-voltage side signal sampling circuit can also be provided on the control board 30. The low-voltage side signal sampling circuit includes a first operational amplifier U9A and a second operational amplifier U9B, wherein:

[0082] The inverting input terminal of the first operational amplifier U9A is connected to the negative output terminal VOUTN of the isolation voltage amplifier chip U12 through a resistor R33 to introduce the low voltage to be measured Uin_L, and the non-inverting input terminal of the first operational amplifier U9A is connected to the positive output terminal VOUTP of the isolation voltage amplifier chip U12 through a resistor R37 to introduce the high voltage to be measured Uin_H;

[0083] The non-inverting input terminal of the second operational amplifier U9B is connected to the output terminal of the first operational amplifier U9A through a resistor R35. The output terminal of the second operational amplifier U9B is connected to the inverting input terminal of the second operational amplifier U9B. The output terminal of the second operational amplifier U9B is used to output the analog voltage Vin_AD to be measured.

[0084] In Figure 1 there are a total of 2 voltage detections (input and output voltage detections) and 3 current detections (branch 1 current detection, branch 2 current detection, and output current detection). The current sampling circuit can be designed with reference to the above voltage sampling circuit method and will not be elaborated here.

[0085] To improve the anti-interference ability of the sampling circuit, the signal sampling circuit is divided into two independent parts: the high-voltage side and the low-voltage side. The high-voltage side is located on the power board 20, and the low-voltage side is located on the control board 30. Isolation amplifiers are used for signal isolation, and all signals entering the analog interface of the control board 30 are differential signals, maximizing the common-mode rejection ratio of the sampling circuit. At the same time, when arranging the control board 30, it can be fully considered to separate the analog signals from the digital signals, and the analog ground and the digital ground are connected at a single point.

[0086] In terms of the control algorithm, it can be designed in combination with the common knowledge in the field. A brief description is as follows:

[0087] The control algorithm structure is as Figure 12 shown, mainly including output voltage filtering G fil (z), voltage loop regulation G vo (z), input voltage feedforward V in_FF (z), load current feedforward I out_FF (z), current sharing algorithm I bal (z), etc. Among them, V in_FF (z) and I out_FF (z) are used to improve the anti-disturbance performance of the BOOST output voltage, and Ibal(z) is used to achieve current sharing between two boosts, avoiding overheating and damage of the switching tubes due to uneven current sharing.

[0088] In this way, the utility model can sample the input voltage, output voltage, and output current, and apply voltage loop regulation, current loop regulation, input voltage feedforward, and current sharing algorithm, etc., to improve the anti-disturbance performance of the output voltage of the marine high-power DC-DC power converter, and achieve the functions of input undervoltage protection, input overvoltage protection, and output overvoltage protection. When the output power is less than the load power, current limiting output can be performed, that is, the output current remains unchanged and the output voltage automatically decreases to achieve the overcurrent protection function.

[0089] 6. Communication circuit

[0090] The marine high-power DC-DC power converter is the core of the entire module, and it is necessary to know the operating status, fault information, voltage and current sampling values, etc. of the marine high-power DC-DC power converter in real time. To realize the background monitoring of the working status of the marine high-power DC-DC power converter, 2 independent communication interfaces are designed, that is, an isolated CAN interface (which can be 1 or multiple) and an isolated RS485 interface (which can be 1 or multiple) are provided on the power board 20. The communication signal line is transferred and output through the digital signal interface of the control board 30 to the power board 20. It supports a variety of communication functions and performs data interaction in real time.

[0091] The utility model has the following progressive effects:

[0092] 1. The pre-charge circuit protects the whole machine module and avoids damage caused by excessive instantaneous impact current of the module during the switching conversion of high current, high voltage and high load;

[0093] 2. The marine high-power DC-DC power converter adopts a standard 2U chassis design, and a radiator is embedded at the bottom of the chassis, which is convenient for installation, maintenance and replacement;

[0094] 3. The sampling detection circuit uses differential signals to realize the acquisition of current and voltage analog quantities, improves the anti-interference ability of the sampling circuit, and maximizes the common-mode rejection ratio of the sampling circuit;

[0095] 4. Custom-designed flat inductive magnetic devices, selected small capacitors, multiple in parallel, and three-dimensional design comprehensively utilizes the overall space, reduces the thermal loss of power devices, and increases the high power density;

[0096] 5. It supports multiple communication functions such as CAN and RS485. Each communication function can work in parallel and perform data interaction with the client in real time. And CAN and RS485 are isolated communications, not affected by strong electric fields, the communication signal transmission is stable, and the disconnection reconnection function is supported. If the communication is disconnected for 3S, it will automatically alarm and block the PWM signal to stop boosting, preventing the situation of abnormal control of the DC-DC power converter caused by communication anomalies;

[0097] 6. The power devices in the power circuit, such as SiC MOSFET tubes, SiC Schottky diodes, inductors, capacitors, drive circuits, sampling circuits, communication circuits and control circuits, all use domestic components and domestic chips, and the entire high-power DC-DC power converter realizes 100% domestic design.

[0098] In summary, the utility model provides a marine high-power DC-DC power converter, which can meet the functions of protecting against excessive instantaneous impact current at the input, power-on hardware protection function, characteristics of wide input range / wide output adjustment range, input undervoltage, input overvoltage, output overvoltage protection functions, output overcurrent protection function; supports multiple communication functions; and the components are designed with all domestic products.

[0099] In the present utility model, those parts not described can be realized by adopting or referring to the prior art.

[0100] Each embodiment in this specification is described in a progressive manner. For the same or similar parts among the embodiments, reference can be made to each other, and the key points of each embodiment are the differences from other embodiments.

[0101] The above description is only for the embodiments of the present utility model and is not intended to limit the present utility model. For those skilled in the art, various modifications and changes can be made to the present utility model. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the scope of the claims of the present utility model.

Claims

1. A high-power DC-DC power converter for marine use, characterized in that, It includes a pre-charge board, a power board and a control board, where: A pre-charge circuit is provided on the pre-charge board. A soft start circuit, a boost output circuit and a drive circuit for driving the boost output circuit are sequentially provided on the power board. A control circuit and a communication circuit are sequentially provided on the control board. The input end of the marine high-power DC-DC power converter is sequentially connected to the output end of the marine high-power DC-DC power converter through the pre-charge circuit, the soft start circuit and the boost output circuit; A first capacitor is connected between the two input ends of the boost output circuit. A second capacitor is connected between the two output ends of the boost output circuit. A first branch and a second branch in parallel are provided between one input end and one output end of the boost output circuit. The first branch includes a first resistor, a first inductor and a first freewheeling diode connected in series in sequence. The second branch includes a second resistor, a second inductor and a second freewheeling diode connected in series in sequence; A first field effect transistor and a second field effect transistor are also provided between the two input ends of the boost output circuit. Both the first field effect transistor and the second field effect transistor are PNP-type SiC MOSFET tubes. The gates of the first field effect transistor and the second field effect transistor are respectively connected to the drive circuit. The drains of the first field effect transistor and the second field effect transistor are respectively connected between the first inductor and the first freewheeling diode, and between the second inductor and the second freewheeling diode. The sources of the first field effect transistor and the second field effect transistor are both connected to the other input end of the boost output circuit.

2. The marine high-power DC-DC power converter according to claim 1, characterized in that, The overall circuit layout of the marine high-power DC-DC power converter adopts an L-type circuit design, with the layout of incoming line on the upper left side and outgoing line on the upper right side. The input interface and the output interface are on both sides of the whole machine.

3. The marine high-power DC-DC power converter according to claim 1, characterized in that, The control board is isolated and installed above the power board. A radiator is provided below the power board, where: The first inductor and the second inductor are installed on the radiator; and / or, the first field effect transistor and the second field effect transistor are attached to the radiator; and / or, the marine high-power DC-DC power converter adopts a standard 2U chassis design, and the radiator is embedded at the bottom of the chassis.

4. The marine high-power DC-DC power converter according to claim 3, characterized in that, The pre-charge circuit is provided at the positive input end of the marine high-power DC-DC power converter and is used to control the on-off of the whole device. The pre-charge circuit includes a pre-charge relay and a pre-charge resistor. The switch of the pre-charge relay is connected in parallel with the pre-charge resistor. The pre-charge relay is independently installed on the radiator. The coil control circuit of the pre-charge relay and the pre-charge resistor are arranged on the pre-charge board.

5. The marine high-power DC-DC power converter according to claim 4, wherein, The coil control circuit of the pre-charge relay includes a triode and an opto-isolation chip, where: The base of the triode receives the coil control signal sent by the control circuit through a resistor, and is simultaneously connected to the emitter of the triode and grounded after passing through a resistor and a capacitor connected in parallel; The positive electrode of the optocoupler isolation chip is connected to the power supply, the negative electrode is connected to the collector of the triode, and the output terminal is used to supply power to the coil of the pre-charge relay.

6. The marine high-power DC-DC power converter according to claim 1, characterized in that, The drive circuit includes two drive sub-circuits with the same structure to drive the first field-effect transistor and the second field-effect transistor respectively. Each drive sub-circuit includes an isolated drive chip, where: The positive input terminal of the isolated drive chip receives the pulse-width modulation signal sent by the control circuit through one resistor, and the other path is grounded after passing through a parallel combination of a resistor and a capacitor. The negative input terminal is grounded through a resistor, and the output terminal is grounded after passing through a first voltage-dividing resistor and a second voltage-dividing resistor. The connection point between the first voltage-dividing resistor and the second voltage-dividing resistor is connected to the gate of the first field-effect transistor or the second field-effect transistor.

7. The marine high-power DC-DC power converter according to claim 6, characterized in that, The clamping input terminal of the isolated drive chip is also connected to the connection point between the first voltage-dividing resistor and the second voltage-dividing resistor, and is simultaneously connected to the output terminal of the isolated drive chip through a resistor.

8. The marine high-power DC-DC power converter according to any one of claims 1-7, characterized in that, The power board is also provided with a high-side signal sampling circuit for sampling the voltages at both ends of the first capacitor or the second capacitor. The high-side signal sampling circuit includes an isolated voltage amplifier chip, where: The voltages at both ends of the first capacitor or the second capacitor are grounded after passing through a third voltage-dividing resistor and a fourth voltage-dividing resistor; The positive input terminal of the isolated voltage amplifier chip is connected to the connection point between the third voltage-dividing resistor and the fourth voltage-dividing resistor through a resistor, the negative input terminal is grounded through a resistor, and a capacitor is also connected between the positive input terminal and the negative input terminal; The positive output terminal of the isolated voltage amplifier chip is used to output a high voltage to be measured, and the negative output terminal is used to output a low voltage to be measured.

9. The marine high-power DC-DC power converter according to claim 8, characterized in that, The control board is also provided with a low-side signal sampling circuit. The low-side signal sampling circuit includes a first operational amplifier and a second operational amplifier, where: The inverting input terminal of the first operational amplifier is connected to the negative output terminal of the isolated voltage amplifier chip through a resistor, and the non-inverting input terminal of the first operational amplifier is connected to the positive output terminal of the isolated voltage amplifier chip through a resistor; The non-inverting input terminal of the second operational amplifier is connected to the output terminal of the first operational amplifier through a resistor. The output terminal of the second operational amplifier is connected to the inverting input terminal of the second operational amplifier, and the output terminal of the second operational amplifier is used to output an analog voltage to be measured.

10. The marine high-power DC-DC power converter according to claim 8, characterized in that, The power board is provided with an isolated CAN interface and an isolated RS485 interface. The communication signal line is transferred and output through the digital signal interface of the control board to the power board.

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