Emergency seamless switching system and method for full water-cooled permanent magnet synchronous diesel generator set

Abstract

The present invention discloses an emergency seamless switching system and method for a fully water-cooled permanent magnet synchronous diesel generator set, comprising a diesel generator set, an AC-DC bidirectional inverter main circuit, and a DC-DC bidirectional converter main circuit. The AC-DC bidirectional inverter main circuit is provided with three voltage lines L1, L2, L3 and a zero line N for providing a three-phase voltage to a load. The DC-DC bidirectional converter main circuit is connected to an energy storage battery pack. The permanent magnet synchronous generator outputs a DC bus voltage U through the AC-DC bidirectional inverter main circuit. C And three-phase voltage, DC bus voltage U C The energy storage battery pack is charged through the DC-DC bidirectional converter main circuit. When the load suddenly increases and the DC bus voltage U C When the voltage drops, the energy storage battery pack will boost the voltage through the DC-DC bidirectional converter main circuit to make the DC bus voltage U C Increases to maintain the DC bus voltage U C The present invention improves the adaptability of the diesel generator set under sudden load conditions, the emergency response capability under abnormal conditions and the stable power supply capability during the startup phase.

Description

Technical Field

[0001] The present invention relates to the technical field of diesel generator sets, and in particular to an emergency seamless switching system and method for a full water-cooled permanent magnet synchronous diesel generator set. Background Art

[0002] Permanent magnet synchronous diesel generator set is a kind of power generation equipment which uses diesel as the main fuel. It uses the diesel engine as the motive force to drive the generator to generate electricity, and is a mechanical equipment which converts kinetic energy into electrical energy and thermal energy.

[0003] The existing permanent magnet synchronous diesel generator sets have the following problems when in use:

[0004] First, the adaptability to sudden load in energy-saving mode is poor. In energy-saving mode, the control system of the diesel generator set can adjust the engine speed in real time according to the output power of the generator to achieve energy saving and emission reduction. However, in an environment with a sudden large load, due to the limited power output of the engine at a low speed, the engine needs 2 to 3 seconds to speed up, so it cannot provide the required power instantly, which causes the engine to stop due to a large load.

[0005] Second, the emergency response capability is poor in abnormal situations. Diesel generator sets cannot provide power to equipment through seamless switching under abnormal circumstances, and will also cause damage and irreparable losses to electrical equipment.

[0006] Third, the unit cannot be powered during the startup phase. Since it takes a certain amount of time for a diesel generator set to start running, it is impossible to provide stable power supply to the equipment during the startup phase of the diesel generator set. Summary of the invention

[0007] In order to solve the above problems, the present invention proposes an emergency seamless switching system and method for a fully water-cooled permanent magnet synchronous diesel generator set, aiming to improve the adaptability of the diesel generator set under sudden load conditions, the emergency response capability under abnormal conditions, and the stable power supply capability of the unit during the startup phase. The specific technical solution is as follows:

[0008] A fully water-cooled permanent magnet synchronous diesel generator set emergency seamless switching system comprises a fully water-cooled permanent magnet synchronous diesel generator set consisting of an engine and a permanent magnet synchronous generator, an AC-DC bidirectional inverter main circuit connected to the permanent magnet synchronous generator, and a DC-DC bidirectional converter main circuit connected to the AC-DC bidirectional inverter main circuit through a pair of DC buses, wherein the AC-DC bidirectional inverter main circuit is provided with three voltage lines L1, L2, L3 and a zero line N for providing three-phase voltage to a load, and the DC-DC bidirectional converter main circuit is connected to an energy storage battery pack; the permanent magnet synchronous generator outputs a DC bus voltage UC and a three-phase voltage respectively through the AC-DC bidirectional inverter main circuit, the DC bus voltage UC charges the energy storage battery pack through the DC-DC bidirectional converter main circuit, and the three-phase voltage supplies power to the load, and when the load suddenly increases and causes the DC bus voltage UC to drop, the energy storage battery pack performs voltage boosting through the DC-DC bidirectional converter main circuit to increase the DC bus voltage UC so as to maintain the stability of the DC bus voltage UC.

[0009] Preferably, an emergency seamless switching system for a fully water-cooled permanent magnet synchronous diesel generator set of the present invention also includes a unit controller, an integrated energy management system and a battery management system, wherein the unit controller is connected to the integrated energy management system, and the integrated energy management system is respectively connected to the AC-DC bidirectional inverter main circuit, the DC-DC bidirectional converter main circuit and the battery management system, and the battery management system is connected to the energy storage battery pack.

[0010] Preferably, the AC-DC bidirectional inverter main circuit includes an AC-DC conversion module and a DC-AC conversion module, and the AC-DC conversion module is connected to the DC-AC conversion module through a pair of DC bus bars; the AC-DC conversion module includes three groups of IGBTs arranged in parallel between the pair of DC bus bars, each group of IGBTs is composed of a pair of IGBTs with damping diodes connected in series in the same direction, and phase line connection points are respectively arranged on the connecting lines between each pair of IGBTs with damping diodes connected in series in the same direction, and the three phase lines of the permanent magnet synchronous generator are respectively connected to the phase line connection points, and a filter capacitor C1 is arranged between the pair of DC bus bars located between the AC-DC conversion module and the DC-AC conversion module.

[0011] Preferably, the DC-AC conversion module includes four groups of IGBTs arranged in parallel between the pair of DC bus bars, each group of IGBTs consists of a pair of IGBTs connected in series in the same direction; and load power supply lines are respectively led out from the connecting lines between each pair of IGBTs connected in series in the same direction, the load power supply lines include the three voltage lines L1, L2, L3 and a neutral line N, and capacitors C2, C3, C4 are respectively arranged between each of the voltage lines and the neutral line.

[0012] Preferably, the DC-DC bidirectional converter main circuit includes three groups of IGBTs arranged in parallel between a pair of DC busbars, each group of IGBTs is composed of a pair of IGBTs with damping diodes connected in series in the opposite direction, and three voltage lines with inductance are respectively led out from the connecting lines between each pair of IGBTs with damping diodes connected in series in the opposite direction, and the three voltage lines with inductance are connected in parallel to the positive electrode of the energy storage battery pack, and a capacitor is arranged between the parallel connection point of the three voltage lines with inductance and the negative busbar of the pair of DC busbars.

[0013] In the present invention, an LC filtering device is provided in the main circuit of the DC-DC bidirectional converter, and the LC filtering device includes a pair of series capacitors and a pair of series inductors respectively arranged in parallel between a pair of DC bus bars, and the connection part between the pair of series capacitors and the connection part between the pair of series inductors are interconnected.

[0014] An emergency seamless switching method for an emergency seamless switching system of a full water-cooled permanent magnet synchronous diesel generator set, comprising the following switching method:

[0015] (1) When the engine is in energy-saving mode with a relatively low speed and the load is suddenly increased, the AC-DC bidirectional inverter detects the sudden increase in load, and the AC-DC bidirectional inverter contacts the DC-DC bidirectional converter through the field bus to connect the energy storage battery pack. The energy storage battery pack provides power to the DC bus of the AC-DC bidirectional inverter, thereby providing a certain amount of power supplement for the load. Subsequently, the engine speed increases. When the engine speed increases to the speed corresponding to the load size, the AC-DC bidirectional inverter notifies the DC-DC bidirectional converter to disconnect the DC bus through the field bus;

[0016] (2) When the engine voltage is abnormal, the AC-DC bidirectional inverter supplies power to the DC bus through the DC-DC bidirectional converter. At the same time, the controller of the diesel generator set issues an alarm and prompts the user to save relevant data as soon as possible. At the same time, it prompts the user that the energy storage battery pack will be disconnected after a certain period of time. The power supply time of the energy storage battery pack depends on the battery capacity of the energy storage battery pack.

[0017] Preferably, an emergency power supply switch is provided to enable the energy storage battery group to supply power to the load first when the diesel generator set is not started, or to provide stable power to the load by the energy storage battery group in the initial stage of starting the diesel generator set.

[0018] In the present invention, the field bus is an RS485 bus or a CAN bus.

[0019] Furthermore, the present invention provides power to the DC bus of the AC-DC bidirectional inverter when the diesel generator set is used for power supply, and at the same time considers providing the best charging performance for the energy storage battery pack, and a battery charging characteristic curve is built into the DC-DC bidirectional converter to maximize the battery life and performance.

[0020] The beneficial effects of the present invention are:

[0021] First, the present invention provides a fully water-cooled permanent magnet synchronous diesel generator set emergency seamless switching system and method, which realizes the engine's ability to carry sudden loads in energy-saving mode by setting an AC-DC bidirectional inverter, a DC-DC bidirectional converter and an emergency energy storage battery pack.

[0022] Second, the present invention provides a fully water-cooled permanent magnet synchronous diesel generator set emergency seamless switching system and method, which can seamlessly switch to the energy storage battery pack to power the equipment and ensure the continuous operation of the equipment within a certain period of time when the diesel generator set is in an abnormal condition.

[0023] Third, the emergency seamless switching system and method of a fully water-cooled permanent magnet synchronous diesel generator set of the present invention can reduce the capacity and number of batteries of the energy storage battery pack by setting a DC-DC bidirectional converter. Compared with the conventional solution of using a DC500-600V energy storage battery pack to directly power the set, its volume is greatly reduced, and the reliability of battery charging and system is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a general architecture diagram of an emergency seamless switching system for a fully water-cooled permanent magnet synchronous diesel generator set of the present invention;

[0025] Figure 2 This is a schematic diagram of the implementation of an emergency seamless switching system for a fully water-cooled permanent magnet synchronous diesel generator set of the present invention;

[0026] Figure 3 yes Figure 1 and Figure 2 The main circuit diagram of the AC-DC bidirectional inverter;

[0027] Figure 4 yes Figure 1 and Figure 2 The main circuit diagram of the DC-DC bidirectional converter.

[0028] In the figure: BUS+ and BUS- are a pair of DC bus bars. DETAILED DESCRIPTION

[0029] The specific implementation of the present invention is further described below in conjunction with the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0030] Embodiment 1:

[0031] like Figures 1 to 4 The present invention shows an embodiment of an emergency seamless switching system of a fully water-cooled permanent magnet synchronous diesel generator set, comprising a fully water-cooled permanent magnet synchronous diesel generator set consisting of an engine and a permanent magnet synchronous generator, an AC-DC bidirectional inverter main circuit connected to the permanent magnet synchronous generator, and a DC-DC bidirectional converter main circuit connected to the AC-DC bidirectional inverter main circuit through a pair of DC buses, wherein the AC-DC bidirectional inverter main circuit is provided with three voltage lines L1, L2, L3 and a zero line N for providing a three-phase voltage to a load, and the DC-DC bidirectional converter main circuit is connected to an energy storage battery pack; the permanent magnet synchronous generator outputs a DC bus voltage UC and a three-phase voltage respectively through the AC-DC bidirectional inverter main circuit, the DC bus voltage UC charges the energy storage battery pack through the DC-DC bidirectional converter main circuit, and the three-phase voltage supplies power to the load, and when the load suddenly increases and causes the DC bus voltage UC to drop, the energy storage battery pack performs voltage boosting through the DC-DC bidirectional converter main circuit to increase the DC bus voltage UC, thereby maintaining the stability of the DC bus voltage UC.

[0032] Preferably, an emergency seamless switching system for a fully water-cooled permanent magnet synchronous diesel generator set in this embodiment also includes a unit controller, an integrated energy management system and a battery management system, wherein the unit controller is connected to the integrated energy management system, and the integrated energy management system is respectively connected to the AC-DC bidirectional inverter main circuit, the DC-DC bidirectional converter main circuit and the battery management system, and the battery management system is connected to the energy storage battery pack.

[0033] Preferably, the AC-DC bidirectional inverter main circuit includes an AC-DC conversion module and a DC-AC conversion module, and the AC-DC conversion module is connected to the DC-AC conversion module through a pair of DC bus bars; the AC-DC conversion module includes three groups of IGBTs arranged in parallel between the pair of DC bus bars, each group of IGBTs is composed of a pair of IGBTs with damping diodes connected in series in the same direction, and phase line connection points are respectively arranged on the connecting lines between each pair of IGBTs with damping diodes connected in series in the same direction, and the three phase lines of the permanent magnet synchronous generator are respectively connected to the phase line connection points, and a filter capacitor C1 is arranged between the pair of DC bus bars located between the AC-DC conversion module and the DC-AC conversion module.

[0034] Preferably, the DC-AC conversion module includes four groups of IGBTs arranged in parallel between the pair of DC bus bars, each group of IGBTs consists of a pair of IGBTs connected in series in the same direction; and load power supply lines are respectively led out from the connecting lines between each pair of IGBTs connected in series in the same direction, the load power supply lines include the three voltage lines L1, L2, L3 and a neutral line N, and capacitors C2, C3, C4 are respectively arranged between each of the voltage lines and the neutral line.

[0035] Preferably, the DC-DC bidirectional converter main circuit includes three groups of IGBTs arranged in parallel between a pair of DC busbars, each group of IGBTs is composed of a pair of IGBTs with damping diodes connected in series in the opposite direction, and three voltage lines with inductance are respectively led out from the connecting lines between each pair of IGBTs with damping diodes connected in series in the opposite direction, and the three voltage lines with inductance are connected in parallel to the positive electrode of the energy storage battery pack, and a capacitor is arranged between the parallel connection point of the three voltage lines with inductance and the negative busbar of the pair of DC busbars.

[0036] In this embodiment, an LC filtering device is provided in the main circuit of the DC-DC bidirectional converter, and the LC filtering device includes a pair of series capacitors and a pair of series inductors respectively arranged in parallel between a pair of DC bus bars, and the connection part between the pair of series capacitors and the connection part between the pair of series inductors are interconnected.

[0037] Embodiment 2:

[0038] An emergency seamless switching method of the emergency seamless switching system of the full water-cooled permanent magnet synchronous diesel generator set using Example 1 includes the following switching method:

[0039] (1) When the engine is in energy-saving mode with a relatively low speed and the load is suddenly increased, the AC-DC bidirectional inverter detects the sudden increase in load, and the AC-DC bidirectional inverter contacts the DC-DC bidirectional converter through the field bus to connect the energy storage battery pack. The energy storage battery pack provides power to the DC bus of the AC-DC bidirectional inverter, thereby providing a certain amount of power supplement for the load. Subsequently, the engine speed increases. When the engine speed increases to the speed corresponding to the load size, the AC-DC bidirectional inverter notifies the DC-DC bidirectional converter to disconnect the DC bus through the field bus;

[0040] (2) When the engine voltage is abnormal, the AC-DC bidirectional inverter supplies power to the DC bus through the DC-DC bidirectional converter. At the same time, the controller of the diesel generator set issues an alarm and prompts the user to save relevant data as soon as possible. At the same time, it prompts the user that the energy storage battery pack will be disconnected after a certain period of time. The power supply time of the energy storage battery pack depends on the battery capacity of the energy storage battery pack.

[0041] Preferably, an emergency power supply switch is provided to enable the energy storage battery group to supply power to the load first when the diesel generator set is not started, or to provide stable power to the load by the energy storage battery group in the initial stage of starting the diesel generator set.

[0042] In this embodiment, the field bus is an RS485 bus or a CAN bus.

[0043] Furthermore, this embodiment provides power to the DC bus of the AC-DC bidirectional inverter when the diesel generator set is used for power supply. At the same time, in order to provide the best charging performance for the energy storage battery pack, a battery charging characteristic curve is built into the DC-DC bidirectional converter to maximize the battery life and performance.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. An emergency seamless switching system for a fully water-cooled permanent magnet synchronous diesel generator set, characterized in that: The invention comprises a fully water-cooled permanent magnet synchronous diesel generator set consisting of an engine and a permanent magnet synchronous generator, an AC-DC bidirectional inverter main circuit connected to the permanent magnet synchronous generator, and a DC-DC bidirectional converter main circuit connected to the AC-DC bidirectional inverter main circuit through a pair of DC buses. The AC-DC bidirectional inverter main circuit is provided with three voltage lines L1, L2, L3 and a zero line N for providing a three-phase voltage to a load. The DC-DC bidirectional converter main circuit is connected to an energy storage battery pack. The permanent magnet synchronous generator outputs a DC bus voltage U through the AC-DC bidirectional inverter main circuit. C and three-phase voltage, the DC bus voltage U C The energy storage battery pack is charged through the DC-DC bidirectional converter main circuit, and the three-phase voltage is used to supply power to the load. When the load suddenly increases, the DC bus voltage U C When the voltage drops, the energy storage battery pack is used to boost the voltage through the DC-DC bidirectional converter main circuit so that the DC bus voltage U C Increases to maintain the DC bus voltage U C stability; The AC-DC bidirectional inverter main circuit includes an AC-DC conversion module and a DC-AC conversion module, wherein the AC-DC conversion module is connected to the DC-AC conversion module via a pair of DC bus bars; the AC-DC conversion module includes three groups of IGBTs arranged in parallel between the pair of DC bus bars, each group of IGBTs is composed of a pair of IGBTs with damping diodes connected in series in the same direction, and phase line connection points are respectively arranged on the connection lines between each pair of IGBTs with damping diodes connected in series in the same direction, and the three phase lines of the permanent magnet synchronous generator are respectively connected to the phase line connection points, and a filter capacitor C1 is arranged between the pair of DC bus bars between the AC-DC conversion module and the DC-AC conversion module; The DC-DC bidirectional converter main circuit includes three groups of IGBTs arranged in parallel between a pair of DC busbars. Each group of IGBTs is composed of a pair of IGBTs with damping diodes connected in series in the opposite direction. Three voltage lines with inductance are respectively led out from the connecting lines between each pair of IGBTs with damping diodes connected in series in the opposite direction. The three voltage lines with inductance are connected in parallel to the positive electrode of the energy storage battery pack. A capacitor is arranged between the parallel connection point of the three voltage lines with inductance and the negative busbar of the pair of DC busbars.

2. According to claim 1, a fully water-cooled permanent magnet synchronous diesel generator set emergency seamless switching system is characterized in that: It also includes a unit controller, an integrated energy management system and a battery management system. The unit controller is connected to the integrated energy management system, and the integrated energy management system is respectively connected to the AC-DC bidirectional inverter main circuit, the DC-DC bidirectional converter main circuit and the battery management system, and the battery management system is connected to the energy storage battery pack.

3. The emergency seamless switching system of a fully water-cooled permanent magnet synchronous diesel generator set according to claim 1 is characterized in that: The DC-AC conversion module includes four groups of IGBTs arranged in parallel between the pair of DC busbars, each group of IGBTs is composed of a pair of IGBTs connected in series in the same direction; and load power supply lines are respectively led out from the connecting lines between each pair of IGBTs connected in series in the same direction, and the load power supply lines include the three voltage lines L1, L2, L3 and a neutral line N, and capacitors C2, C3, C4 are respectively arranged between each of the voltage lines and the neutral line.

4. The emergency seamless switching system of a fully water-cooled permanent magnet synchronous diesel generator set according to claim 1 is characterized in that: An LC filtering device is provided in the main circuit of the DC-DC bidirectional converter, and the LC filtering device includes a pair of series capacitors and a pair of series inductors respectively arranged in parallel between a pair of DC bus bars, and the connection part between the pair of series capacitors and the connection part between the pair of series inductors are interconnected.

5. An emergency seamless switching method for an emergency seamless switching system of a fully water-cooled permanent magnet synchronous diesel generator set according to any one of claims 1 to 4, characterized in that: The following switching methods are included: (1) When the engine suddenly increases the load in the energy-saving mode at a lower speed, the AC-DC bidirectional inverter detects the sudden increase in load. The AC-DC bidirectional inverter contacts the DC-DC bidirectional converter through the field bus to connect the energy storage battery pack. The energy storage battery pack provides power to the DC bus of the AC-DC bidirectional inverter, thereby providing a certain amount of power supplement for the load. Then the engine speed increases. When the engine speed increases to the speed corresponding to the load size, the AC-DC bidirectional inverter informs the DC-DC bidirectional converter to disconnect the DC bus through the field bus. (2) When the engine voltage is abnormal, the AC-DC bidirectional inverter supplies power to the DC bus through the DC-DC bidirectional converter. At the same time, the controller of the diesel generator set issues an alarm and prompts the user to save relevant data as soon as possible. At the same time, it prompts the user that the energy storage battery pack will be disconnected after a certain period of time. The power supply time of the energy storage battery pack depends on the battery capacity of the energy storage battery pack.

6. The emergency seamless switching method of the emergency seamless switching system of a fully water-cooled permanent magnet synchronous diesel generator set according to claim 5, characterized in that: By setting an emergency power supply switch, the energy storage battery group can first supply power to the load when the diesel generator set is not started, or the energy storage battery group can provide stable power supply to the load in the initial stage of starting and running of the diesel generator set.

7. The emergency seamless switching method of the emergency seamless switching system of a full water-cooled permanent magnet synchronous diesel generator set according to claim 5, characterized in that: The field bus is RS485 bus or CAN bus.

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