A method for regulating pre-charging of power electronic switches of a ship power system

Abstract

The application discloses a kind of power electronic switch pre-charging regulation and control method of ship power system, first by voltage sensor measurement power electronic switch on / off time's bus voltage, by current sensor measurement bus current, and voltage and current signal are transferred to signal processing module, signal processing module is filtered and amplified to processor with voltage and current signal pre-processing, processor judges voltage and current signal, and the on / off frequency of power electronic switch is calculated, and the on / off of power electronic switch is output PWM wave control, processor collects voltage / current signal fed back by voltage sensor and current sensor, the on / off frequency of power electronic switch is changed in real time, and the on / off of power electronic switch is controlled, and pre-charging is completed;The application meets the high reliability requirement of pre-charging requirement of ship field user, can be used for project modification upgrade, with good market prospect.

Description

Technical Field

[0001] The present invention belongs to the field of electricity consumption and control of marine electrical equipment, and in particular relates to a method for implementing a pre-charging control strategy through a power electronic switch in a marine power system. Background Art

[0002] The power electronic switch is the most critical electrical equipment in the ship's power supply system. It connects the port / starboard DC busbar to realize the pre-charging function.

[0003] Precharging is the process of applying a small current to a capacitor before charging. This gradually charges the capacitor to prevent sudden current surges during the charging moment, potentially impacting circuit components. This also reduces circuit noise and improves circuit stability and reliability. Precharge control strategies are particularly important in power electronics systems, effectively protecting equipment and optimizing performance. Summary of the Invention

[0004] The object of the present invention is to provide a method for implementing a pre-charging control strategy through a power electronic switch in response to the deficiencies of the prior art.

[0005] The technical solution adopted by the present invention to solve its technical problems is: a pre-charging control method for a power electronic switch of a ship power system, based on a ship power system consisting of a power module ZK1, a port DC positive busbar, a port DC negative busbar, a starboard DC positive busbar and a starboard DC negative busbar, wherein DC contactors KM1 and KM2 are respectively installed on the port DC positive and negative busbars, and DC contactors KM3 and KM4 are respectively installed on the starboard DC positive and negative busbars, the port DC positive and negative busbars on one side of the DC contactors KM1 and KM2 are connected to a voltage sensor TV3, and the other side is connected to a voltage sensor TV1, the port DC positive and negative busbars on one side of the DC contactors KM3 and KM4 are connected to a voltage sensor TV4, and the other side is connected to a voltage sensor TV2, A pre-charging resistor RCH1 is connected between the port DC positive busbar and the voltage sensor TV1, and a pre-charging resistor RCH2 is connected between the starboard DC positive busbar and the voltage sensor TV2. The power module ZK1 includes a signal processing module connected to the voltage sensors TV1 to TV4 and the current sensor TA, and a processor connected to the signal processing module. The processor is connected to the IGBT module 1 and the IGBT module 2 via an optical fiber transmission line. The IGBT module 1 and the IGBT module 2 are connected to the IGBT module 3 and the IGBT module 4, as well as the capacitors C1 and C2 and the current sensor TA to form an H-bridge structure. Each IGBT module is connected to an anti-parallel diode. The current sensor TA senses the measured current and converts it into a usable output signal. The process includes the following steps:

[0006] Step one, measure the bus voltage when the power electronic switch is on / off by voltage sensor TV1~TV4, measure the bus current by current sensor TA, and transmit the voltage and current signals to the signal processing module;

[0007] Step two, the signal processing module filters and amplifies the voltage and current signals for preprocessing, and transmits the processed voltage and current signals to the processor;

[0008] Step three, after the processor judges the voltage and current signals, the on / off frequency of the power electronic switch is calculated by the voltage and current signals collected on the line, and the PWM wave is output to control the on / off of the power electronic switch;

[0009] Step four, the processor collects the voltage / current signals fed back by the voltage sensor TV1~TV4 and the current sensor TA, judges the charging condition of the left / right DC positive / negative bus, changes the on / off frequency of the power electronic switch in real time, controls the on / off of the power electronic switch, and completes the whole pre-charging process.

[0010] Further, the processor issues a pre-charging instruction to charge the capacitors C1~C2 in the power module and controls the closing of the left / right DC contactors KM1~KM4: if the initial state of the left DC positive / negative bus is charged, the capacitor C1 is charged first; if the initial state of the right DC positive / negative bus is charged, the capacitor C2 is charged first.

[0011] Further, the processor judges the charging condition of the capacitors C1~C2 through the voltage on the left DC positive / negative bus where the voltage sensors TV1 and TV2 are located, and sets a threshold value in the software. After the voltage of the capacitors C1~C2 meets the condition, the on / off of the IGBT module 1~2 is controlled.

[0012] Further, the processor calculates the voltage difference between the left and right DC buses through the voltage on the right DC positive / negative bus where the voltage sensors TV3 and TV4 are located. Since the IGBT module 1 or the IGBT module 2 is controlled to close at the beginning, according to the formula , the voltage difference between the left and right DC buses is large, and the di / dt current rise rate changes greatly. In order to avoid overcurrent caused by excessive current, the duty cycle of the PWM wave needs to be set to in the software to control the on time of the IGBT module 1~2, where u1 is the voltage value of the left DC positive / negative bus, u2 is the voltage value of the right DC positive / negative bus, and u is the rated DC bus voltage value of the system. Through repeated on / off of the IGBT, the left / right voltage will tend to be consistent. When the voltage difference between the left and right is within a certain threshold range, the IGBT module 1 or the IGBT module 2 will be in a constant on state, and the whole pre-charging process is completed.

[0013] The method for pre-charging control of power electronic switches in a ship power system adopts an AD sampling chip in its signal processing module, which performs "peak shaving and valley filling" and pre-processes the sampled signal before sending it to the analog-to-digital chip AD7606. The processor adopts a DSP2812 chip for control algorithm processing.

[0014] In the method for controlling pre-charging of a power electronic switch in a ship power system, the pre-charging resistor is a resistor with a fixed resistance.

[0015] The beneficial effects of the present invention are as follows: the entire pre-charging process is a process of charging the voltage from the voltage-side bus to the non-voltage-side bus by controlling the power electronic switch; the processor processes the voltage and current signals in real time, calculates the power electronic switch frequency, and continuously regulates the on / off state of the power electronic switch, so that after the voltage difference across the power electronic switch reaches a voltage less than a certain threshold, the switch will remain in the on state and the pre-charging process is completed.

[0016] The control method of the present invention meets the high reliability, easy maintenance and intelligent requirements of users in the ship field for pre-charging. It only requires a processor, a sensor, a power electronic switch, a resistor, and a DC contactor to realize the pre-charging function. It saves costs while having a stable and reliable communication method and logic algorithm. The implementation plan is simple and can also be used for the transformation and upgrading of existing projects. It has good market prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic diagram of the electrical circuit of the ship power system of the present invention;

[0018] Figure 2 It is a schematic structural diagram of the power module of the present invention;

[0019] Figure 3 This is a schematic diagram of the main circuit of the power module of the present invention.

[0020] The reference numerals are: ZK1—power module, TV1 / TV2 / TV3 / TV4—voltage sensor, ZK1—power electronic switch, KM1 / KM2 / KM3 / KM4—DC contactor, RCH1 / RCH2—resistor, C1 / C2—capacitor, TA—current sensor. DETAILED DESCRIPTION

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0022] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort shall fall within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or physical connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0024] Reference Figure 1 、 Figure 2 and Figure 3As shown, the ship power system disclosed in the present invention consists of a power module ZK1, a port DC positive busbar, a port DC negative busbar, a starboard DC positive busbar and a starboard DC negative busbar. The port DC positive and negative busbars are respectively installed with DC contactors KM1 and KM2. The left / starboard DC positive and negative busbars are DC side power supply busbars. The DC contactors KM1 and KM2 are electronic components for controlling the DC path. The starboard DC positive and negative busbars are respectively installed with DC contactors KM3 and KM4. The port DC positive and negative busbars on one side of the DC contactors KM1 and KM2 are connected to a voltage sensor TV3, and the other side is connected to a voltage sensor TV1. The port DC positive and negative busbars on one side of the DC contactors KM3 and KM4 are connected to a voltage sensor TV4, and the other side is connected to a voltage sensor TV2. The voltage sensors TV1 to TV4 sense the measured voltage and convert it into a usable output signal. A pre-charging resistor RCH1 is connected between the port DC positive busbar and the voltage sensor TV1, and a pre-charging resistor RCH2 is connected between the starboard DC positive busbar and the voltage sensor TV2. The power module ZK1 includes a signal processing module connected to the voltage sensors TV1 to TV4 and the current sensor TA, and a processor connected to the signal processing module. The processor is connected to IGBT module 1 and IGBT module 2 via an optical fiber transmission line. IGBT module 1 and IGBT module 2, IGBT module 3 and IGBT module 4, as well as capacitors C1 and C2 and the current sensor TA form an H-bridge structure. Each IGBT module is connected to an anti-parallel diode. The current sensor TA senses the measured current and converts it into a usable output signal. The two ends of capacitor C1 are respectively connected to the port and starboard DC positive busbars, and one end of C2 is connected to the port / starboard DC positive busbars and the other end is connected to the port and starboard DC negative busbars.

[0025] The present invention discloses a method for controlling precharging of a power electronic switch of a ship power system, which is used to realize the precharging function of the left / starboard DC busbar in the ship power supply system. The voltage of the left / starboard DC busbar is measured by a voltage sensor, and the busbar current is measured by a current sensor. The voltage and current signals are transmitted to a signal processing module, and then the voltage signal is filtered, amplified and pre-processed by the signal processing module. After AD sampling processing, the signal is transmitted to a processor. The processor then calculates the voltage difference of the left / starboard DC busbar and the current on the line based on the voltage signal. Finally, the processor judges the real-time voltage and current of the left / starboard DC busbar based on the voltage difference and current on the line, controls the PWM wave, and changes the switching frequency in real time to control the power electronic switch to perform precharging. The method specifically includes the following steps.

[0026] Step one, measure the bus voltage when the power electronic switch is on / off by voltage sensor TV1~TV4, measure the bus current by current sensor TA, and transmit the voltage and current signals to the signal processing module.

[0027] Step two, the signal processing module filters and amplifies the voltage and current signals for preprocessing, and transmits the processed voltage and current signals to the processor.

[0028] Step three, the processor calculates the on / off frequency of the power electronic switch by the voltage and current signals obtained on the line, and outputs the PWM wave to control the on / off of the power electronic switch.

[0029] Step four, the processor judges the charging condition of the left / right DC positive and negative bus bars according to the voltage / current signals fed back by the voltage sensor TV1~TV4 and the current sensor TA, changes the on / off frequency of the power electronic switch in real time, controls the on / off of the power electronic switch, and completes the whole pre-charging process.

[0030] The processor issues a pre-charging instruction to charge the capacitors C1~C2 in the power module and controls the left / right DC contactors KM1~KM4 to close: if the initial state of the left DC positive and negative bus bars is charged, charge the capacitor C1 first; if the initial state of the right DC positive and negative bus bars is charged, charge the capacitor C2 first.

[0031] The processor judges the charging condition of the capacitors C1~C2 by the voltage on the left DC positive and negative bus bars where the voltage sensors TV1 and TV2 are located, and sets a threshold value in the software. When the voltage of the capacitors C1~C2 meets the condition, control the on / off of the IGBT module 1~2.

[0032] The processor calculates the voltage difference between the left and right DC bus bars by the voltage on the right DC positive and negative bus bars where the voltage sensors TV3 and TV4 are located. Since the IGBT module 1 or the IGBT module 2 is controlled to close at the beginning, according to the formula , the voltage difference between the left and right DC bus bars is large, and the di / dt current rise rate changes greatly. To avoid overcurrent caused by excessive current, the duty cycle of the PWM wave needs to be set to , control the conduction time of IGBT modules 1~2, where u1 is the port DC positive and negative busbar voltage value, u2 is the starboard DC positive and negative busbar voltage value, and u is the system rated DC busbar voltage value; the processor collects the current from the current sensor TA. Each time the IGBT module is turned on, the current on the line increases. After it is turned off, the current flows through the diode in parallel with the IGBT. After the current drops to a certain threshold, the PWM wave is output to control the conduction of the IGBT module. Through the repeated on and off of the IGBT, the port / starboard voltages will tend to be consistent. When the port / starboard voltage difference is within a certain threshold range, IGBT module 1 or IGBT module 2 will be in the on state, completing the entire pre-charging process.

[0033] The signal processing module uses an AD sampling chip to perform peak-shaving and valley-filling on the sampled signal, and then pre-processes it before sending it to the analog-to-digital chip AD7606. The processor uses a DSP2812 chip for control algorithm processing. The pre-charge resistor is a fixed-value resistor.

[0034] The above embodiments are merely illustrative of the principles and effects of the present invention, as well as some embodiments of its application. A person skilled in the art may make several modifications and improvements without departing from the inventive concept of the present invention, and all of these modifications and improvements fall within the scope of protection of the present invention.

Claims

1. A method for controlling pre-charging of a power electronic switch in a ship power system, characterized by: Based on the ship power system composed of power module ZK1, port DC positive busbar, port DC negative busbar, starboard DC positive busbar and starboard DC negative busbar, DC contactors KM1 and KM2 are installed on the port DC positive and negative busbars respectively, and DC contactors KM3 and KM4 are installed on the starboard DC positive and negative busbars respectively. The port DC positive and negative busbars on one side of DC contactors KM1 and KM2 are connected to voltage sensor TV3, and the other side is connected to voltage sensor TV1. The port DC positive and negative busbars on one side of DC contactors KM3 and KM4 are connected to voltage sensor TV4, and the other side is connected to voltage sensor TV2. A pre-charging resistor RCH1 is connected between the port DC positive busbar and voltage sensor TV1, and a pre-charging resistor RCH2 is connected between the starboard DC positive busbar and voltage sensor TV2. The power module ZK1 The method includes a signal processing module connected to voltage sensors TV1 to TV4 and a current sensor TA, and a processor connected to the signal processing module. The processor is connected to IGBT module 1 and IGBT module 2 via an optical fiber transmission line. IGBT module 1 and IGBT module 2, IGBT module 3 and IGBT module 4, capacitor C1 and capacitor C2, current sensor TA and reactor form an H-bridge structure. The H-bridge includes two left and right bridge arms and a current sensor TA and a reactor connected in series between the two bridge arms. The left bridge arm is formed by connecting IGBT module 1 and IGBT module 3 in upper and lower parts, and the right bridge arm is formed by connecting IGBT module 2 and IGBT module 4 in upper and lower parts. The left bridge arm and the right bridge arm are respectively connected in parallel with capacitor C1 and capacitor C2. Capacitor C1 and capacitor C2 are respectively connected in series between the positive and negative busbars on the left and right sides. A diode is connected in reverse parallel to each IGBT module. The method includes the following steps: Step 1: Voltage sensors TV1 to TV4 measure the bus voltage when the power electronic switch is turned on / off, and current sensor TA measures the bus current. The voltage and current signals are transmitted to the signal processing module. Step 2: The signal processing module performs filtering and amplification preprocessing on the voltage and current signals, and transmits the processed voltage and current signals to the processor; Step 3: After evaluating the voltage and current signals, the processor calculates the on / off frequency of the power electronic switch and outputs a PWM wave to control the on / off of the power electronic switch. The processor then issues a pre-charge instruction to charge capacitors C1-C2 in the power module and control the closing of DC contactors KM1-KM4. If the port DC positive and negative busbars are initially charged, capacitor C1 is charged first. If the starboard DC positive and negative busbars are initially charged, capacitor C2 is charged first. Step 4: The processor changes the on / off frequency of the power electronic switch in real time according to the voltage / current signals fed back by the voltage sensors TV1~TV4 and the current sensor TA, controls the on / off of the power electronic switch, and completes pre-charging: the processor judges the current charging status of the capacitors C1~C2 through the voltage of the voltage sensors TV1 and TV2, and sets the threshold in the software to control the on / off of the IGBT modules 1~2 after the voltage of the capacitors C1~C2 meets the conditions; the processor calculates the voltage difference between the left and right DC busbars through the voltage of the voltage sensors TV3 and TV4; and sets the duty cycle of the PWM wave to , controls the on-time of IGBT modules 1 and 2, where u1 is the port DC positive and negative busbar voltage value, u2 is the starboard DC positive and negative busbar voltage value, and u is the system rated DC busbar voltage value.

2. The method for controlling pre-charging of a power electronic switch of a ship power system according to claim 1, characterized in that: The signal processing module adopts an AD sampling chip, and the processor adopts a DSP2812 chip.

3. The method for controlling pre-charging of a power electronic switch of a ship power system according to claim 1, characterized in that: The pre-charging resistor is a resistor with a fixed resistance.

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