A system for reducing the speed of an internal combustion engine in the low-power range of a generator set and the generator set itself.

Abstract

The present invention discloses a system and a generator set for reducing the speed of an internal combustion engine in a low-power section of a generator set, wherein the generator set includes an internal combustion engine, a permanent magnet synchronous motor, an AC-DC rectifier unit and a DC-AC inverter unit, and the system includes a power detection unit, a speed control unit, a boost unit and a boost control unit; the power detection unit is used to detect the output power of the AC output end of the DC-AC inverter unit, the speed control unit is used to control the working state of the speed control actuator of the internal combustion engine according to the detected output power, so that the internal combustion engine works at a target speed, the boost control unit is used to collect the voltage signal of the DC bus, and control the working state of the boost unit according to the collected voltage signal, and the boost unit is used to increase the input voltage of the DC-AC inverter unit to the target voltage value under the control of the boost control unit. The present invention can increase the power of the permanent magnet synchronous motor at low speed, thereby reducing the speed of the internal combustion engine at low power output, and reducing fuel consumption and noise.

Description

Technical Field

[0001] The invention relates to the technical field of internal combustion engine generator sets, and in particular to a system for reducing the rotation speed of an internal combustion engine in a low-power range of the generator set and the generator set. Background Art

[0002] In the speed-power characteristic curve of a gasoline internal combustion engine, the slope of the curve gradually decreases as the speed increases, while the slope of the speed-power characteristic curve of the matching permanent magnet synchronous motor at rated voltage gradually increases as the speed increases.

[0003] In current generator sets, gasoline internal combustion engines and permanent magnet synchronous motors are usually matched in power at rated speed during design and selection. This results in the internal combustion engine having surplus power at low speeds, while the permanent magnet synchronous motor has insufficient power at rated voltage. This mismatch requires the internal combustion engine to maintain a higher speed when the generator set is outputting low power, which in turn results in higher fuel consumption and noise, reducing the efficiency of the generator set and the user experience. Summary of the invention

[0004] The present invention provides a system for reducing the speed of an internal combustion engine in a low-power range of a generator set and a generator set, aiming to solve the problems of high speed of the internal combustion engine, high fuel consumption and high noise when the generator set outputs low power.

[0005] A first object of the present invention is to provide a system for reducing the speed of an internal combustion engine in a low power range of a generator set.

[0006] The above-mentioned application objective of the present invention is achieved through the following technical solutions:

[0007] A system for reducing the speed of an internal combustion engine in a low-power range of a generator set, the generator set comprising an internal combustion engine, a permanent magnet synchronous motor, an AC-DC rectifier unit and a DC-AC inverter unit, the internal combustion engine is drivingly connected to the permanent magnet synchronous motor to drive the permanent magnet synchronous motor to generate electricity, the power output end of the permanent magnet synchronous motor is connected to the AC input end of the AC-DC rectifier unit, the DC output end of the AC-DC rectifier unit is connected to the DC input end of the DC-AC inverter unit through a DC bus, and the AC output end of the DC-AC inverter unit is used to connect a load to supply power to the load;

[0008] The system includes a power detection unit, a speed control unit, a boost unit and a boost control unit, wherein the signal input end of the power detection unit is connected to the AC output end of the DC-AC inverter unit, the signal output end of the power detection unit is connected to the signal input end of the speed control unit, the signal output end of the speed control unit is connected to the speed control actuator of the internal combustion engine, the input end of the boost unit is connected to one end of the DC bus close to the AC-DC rectifier unit, the output end of the boost unit is connected to one end of the DC bus close to the DC-AC inverter unit, the control end of the boost unit is connected to the signal output end of the boost control unit, and the signal input end of the boost control unit is connected to the DC bus, wherein:

[0009] The power detection unit is used to detect the output power of the AC output end of the DC-AC inverter unit;

[0010] The speed control unit is used to control the working state of the speed control actuator of the internal combustion engine according to the detected output power, so that the internal combustion engine operates at a target speed;

[0011] The boost control unit is used to collect the voltage signal of the DC bus and control the working state of the boost unit according to the collected voltage signal;

[0012] The boost unit is used to increase the voltage transmitted from the DC bus to the DC input terminal of the DC-AC inverter unit to a target voltage value under the control of the boost control unit.

[0013] Preferably, the boost control unit includes a voltage detection module and a boost control module, the signal input end of the voltage detection module is connected to the DC bus as the signal input end of the boost control unit, the signal output end of the voltage detection module is connected to the signal input end of the boost control module, and the signal output end of the boost control module is connected to the control end of the boost unit as the signal output end of the boost control unit, wherein:

[0014] The voltage detection module is used to detect the voltage signal of the DC bus and transmit the detected voltage signal to the boost control module;

[0015] The boost control module is used to control the boost unit to be turned on or off according to the voltage signal detected by the voltage detection module.

[0016] Preferably, the voltage detection module includes a first voltage acquisition circuit and a second voltage acquisition circuit, wherein:

[0017] The signal input end of the first voltage acquisition circuit is connected to one end of the DC bus close to the AC-DC rectifier unit, and the signal output end of the first voltage acquisition circuit is connected to the first signal input end of the boost control module. The first voltage acquisition circuit is used to detect the voltage signal of the DC output end of the AC-DC rectifier unit in real time, and transmit the detected voltage signal to the boost control module;

[0018] The signal input end of the second voltage acquisition circuit is connected to an end of the DC bus close to the DC-AC inverter unit, and the signal output end of the second voltage acquisition circuit is connected to the second signal input end of the boost control module. The second voltage acquisition circuit is used to detect the voltage signal of the DC input end of the DC-AC inverter unit when the boost unit is turned on, and transmit the detected voltage signal to the boost control module.

[0019] Preferably, the boost control module is used to control the boost unit to be turned on or off according to the voltage signal detected by the first voltage acquisition circuit and the voltage signal detected by the second voltage acquisition circuit.

[0020] Preferably, when the boost control module controls the boost unit to be turned on or off according to the voltage signal detected by the first voltage acquisition circuit and the voltage signal detected by the second voltage acquisition circuit, it is specifically used to:

[0021] The boost control module compares the voltage signal collected by the first voltage collection circuit with the target voltage value. When the voltage signal collected by the first voltage collection circuit is less than the target voltage value, the boost control module outputs a high level, and the control end of the boost unit enables the boost unit to be turned on and enter a working state, so as to increase the voltage of the DC bus near the input end of the DC-AC inverter unit through the boost unit.

[0022] In the process of the boost unit boosting the voltage of the DC bus near the input end of the DC-AC inverter unit, the boost control module compares the voltage signal collected by the second voltage collection circuit with the target voltage value. When the voltage signal collected by the second voltage collection circuit is greater than or equal to the target voltage value, the boost control module outputs a low level, and the control end of the boost unit is powered off to shut down the boost unit and exit the working state.

[0023] Preferably, the voltage detection module further includes a first filtering circuit and a second filtering circuit, the first filtering circuit is connected in parallel with the first voltage collection circuit, and the second filtering circuit is connected in parallel with the second voltage collection circuit.

[0024] Preferably, the boost control module adopts an MCU controller or a voltage comparison circuit.

[0025] Preferably, the DC bus includes a DC positive bus and a DC negative bus, one end of the DC positive bus is connected to the positive electrode of the DC output terminal of the AC-DC rectifier unit, the other end of the DC positive bus is connected to the positive electrode of the DC input terminal of the DC-AC inverter unit, one end of the DC negative bus is connected to the negative electrode of the DC output terminal of the AC-DC rectifier unit, and the other end of the DC negative bus is connected to the negative electrode of the DC input terminal of the DC-AC inverter unit.

[0026] The positive pole of the input end of the boost unit is connected to one end of the DC positive bus bar close to the AC-DC rectifier unit, the negative pole of the input end of the boost unit is connected to one end of the DC negative bus bar close to the AC-DC rectifier unit, the positive pole of the output end of the boost unit is connected to one end of the DC positive bus bar close to the DC-AC inverter unit, and the negative pole of the output end of the boost unit is connected to one end of the DC negative bus bar close to the DC-AC inverter unit.

[0027] The system also includes an anti-backflow diode, which is connected to the DC positive bus, and the positive electrode of the anti-backflow diode is connected to the positive electrode of the input end of the boost unit, and the negative electrode of the anti-backflow diode is connected to the positive electrode of the output end of the boost unit.

[0028] Preferably, the boost unit adopts a Boost boost circuit.

[0029] A second object of the present invention is to provide a generator set.

[0030] The second application objective of the present invention is achieved through the following technical solutions:

[0031] A generator set comprises the system for reducing the speed of an internal combustion engine in a low power range of the generator set as described in the first object of the present invention.

[0032] The beneficial effects of the present invention are as follows:

[0033] 1. By increasing the power of the permanent magnet synchronous motor at low speed, the internal combustion engine does not need to maintain a high speed when the power output is low, thereby effectively reducing fuel consumption and improving the fuel economy of the generator set;

[0034] 2. The reduction in the speed of the internal combustion engine directly reduces the noise generated during operation, providing users with a quieter operating environment and improving user experience;

[0035] 3. The matching performance between permanent magnet synchronous motor and internal combustion engine in the low power range is optimized, making the operation of the entire generator set more stable and reliable, and reducing the possibility of system fluctuations and failures caused by power mismatch. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 It is a principle block diagram of a system for reducing the speed of an internal combustion engine in a low power range of a generator set in one embodiment of the present invention;

[0038] Figure 2 It is the power characteristic curve of the generator set under various working conditions. DETAILED DESCRIPTION

[0039] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0040] In the embodiments provided by the present invention, it should be understood that the disclosed methods and systems can be implemented in other ways. The system embodiments described below are only schematic. For example, the division of units and modules is only a logical function division. There may be other division methods in actual implementation, such as: multiple units or modules can be combined, or can be integrated into another system, or some features can be ignored or not executed. In addition, the coupling, direct coupling, or communication connection between the components shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or modules, which can be electrical, mechanical or other forms.

[0041] In addition, all functional units in the embodiments of the present invention may be integrated into one processor, or each unit may be a separate device, or two or more units may be integrated into one device; each functional unit in the embodiments of the present invention may be implemented in the form of hardware or in the form of hardware plus software functional units.

[0042] A person skilled in the art can understand that all or part of the steps of the following method embodiments can be completed by program instructions and related hardware. The aforementioned program instructions can be stored in a computer-readable storage medium. When the program instructions are executed, the steps of the following method embodiments are executed; and the aforementioned storage medium includes: a mobile storage device, a read-only memory (ROM), a magnetic disk or an optical disk, and other media that can store program codes.

[0043] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "multiple" and "several" is two or more, unless otherwise clearly and specifically defined.

[0044] like Figure 1 As shown, an embodiment of the present invention provides a system for reducing the speed of an internal combustion engine in a low power range of a generator set.

[0045] Specifically, the generator set includes an internal combustion engine 100, a permanent magnet synchronous motor 200, an AC-DC rectifier unit 300 and a DC-AC inverter unit 400. The internal combustion engine 100 is driven and connected to the permanent magnet synchronous motor 200 to drive the permanent magnet synchronous motor 200 to generate electricity. The power output end of the permanent magnet synchronous motor 200 is connected to the AC input end of the AC-DC rectifier unit 300. The DC output end of the AC-DC rectifier unit 300 is connected to the DC input end of the DC-AC inverter unit 400 through a DC bus. The AC output end of the DC-AC inverter unit 400 is used to connect a load to supply power to the load.

[0046] Specifically, the system for reducing the speed of an internal combustion engine in a low-power stage of a generator set includes a power detection unit 1, a speed control unit 2, a boost unit 3 and a boost control unit, wherein the signal input end of the power detection unit 1 is connected to the AC output end of a DC-AC inverter unit 400, the signal output end of the power detection unit 1 is connected to the signal input end of the speed control unit 2, the signal output end of the speed control unit 2 is connected to a speed control actuator of the internal combustion engine 100, the input end of the boost unit 3 is connected to an end of the DC bus close to the AC-DC rectifier unit 300, the output end of the boost unit 3 is connected to an end of the DC bus close to the DC-AC inverter unit 400, the control end of the boost unit 3 is connected to the signal output end of the boost control unit, and the signal input end of the boost control unit is connected to the DC bus, wherein:

[0047] The power detection unit 1 is used to detect the output power of the AC output end of the DC-AC inverter unit 400;

[0048] The speed control unit 2 is used to control the working state of the speed control actuator of the internal combustion engine 100 according to the detected output power, so that the internal combustion engine 100 operates at a target speed;

[0049] The boost control unit is used to collect the voltage signal of the DC bus and control the working state of the boost unit 3 according to the collected voltage signal;

[0050] The boost unit 3 is used to boost the voltage transmitted from the DC bus to the DC input terminal of the DC-AC inverter unit 400 to a target voltage value under the control of the boost control unit.

[0051] The working principle of the system for reducing the speed of the internal combustion engine in the low power range of the generator set in this embodiment is as follows:

[0052] When the generator set is working, the internal combustion engine 100 drives the permanent magnet synchronous motor 200 to rotate, and the permanent magnet synchronous motor 200 outputs three-phase alternating current to the AC-DC rectifier unit 300. The AC-DC rectifier unit 300 converts the alternating current into direct current and outputs it to the DC-AC inverter unit 400. The DC-AC inverter unit 400 converts the direct current into the alternating current required by the load. During the operation of the generator set, the power detection unit 1 detects the output power of the AC output end of the DC-AC inverter unit 400, and the speed control unit 2 controls the working state of the speed control actuator (such as the throttle, injector, etc.) of the internal combustion engine 100 according to the detected output power, so that the internal combustion engine 100 operates at a target speed to avoid excessive speed of the internal combustion engine 100, which leads to higher fuel consumption and greater noise. In order to keep the output power of the generator set at a lower speed to meet the load demand, the boost control unit collects the voltage signal of the DC bus and controls the working state of the boost unit 3 according to the collected voltage signal. Under the control of the boost control unit, the boost unit 3 increases the voltage transmitted from the DC bus to the DC input end of the DC-AC inverter unit 400 to the target voltage value.

[0053] Because the permanent magnet synchronous motor 200 can output more electric power at the same speed when the output voltage is lower; for example, when the output voltage is T1, the output power is P1, and when the output voltage is adjusted to T1*70%, the output power is P1*130%.

[0054] like Figure 2 As shown, in order to ensure that the output voltage of the entire generator set does not drop, for example, when the rated voltage of the motor (i.e., the permanent magnet synchronous motor 200) is designed to be 150V, when the engine (i.e., the internal combustion engine 100) / motor speed (horizontal axis) drops below 2600rpm, the motor output power does not meet the required power when the voltage is maintained at not less than 150V, while the engine power can be met and has surplus. At this time, when the motor output voltage reaches 110V, the motor output power can meet the required power.

[0055] In order to solve the problem that the output voltage of the whole generator set is too low due to the low output voltage of the above-mentioned motor, the present invention adds a boost unit 3. When it is detected that the output voltage of the AC-DC rectifier unit 300 is lower than the target voltage, the boost control unit is enabled, so that the output voltage of the AC-DC rectifier unit 300 is increased to the target voltage through the boost unit 3, thereby making the output voltage of the DA-AC inverter unit reach the rated value.

[0056] It should be noted that, in this embodiment, the output power of the AC output end of the DC-AC inverter unit 400 (i.e., the output power of the generator set) is detected by the power detection unit 1, and the speed control unit 2 controls the working state of the speed control actuator of the internal combustion engine 100 according to the detected output power, so that the internal combustion engine 100 operates at the target speed. Specifically, when the power detection unit 1 detects that the output power of the generator set is lower than the preset power threshold (i.e., when the generator set enters the preset low power section), the speed control unit 2 controls the working state of the speed control actuator of the internal combustion engine 100 according to the pre-constructed power-speed curve of the low power section, so that the speed of the internal combustion engine 100 is lower than the speed at the same power in the prior art, so as to avoid the internal combustion engine 100 from having too high a speed when the generator set outputs low power, thereby effectively reducing the fuel consumption and noise of the internal combustion engine 100.

[0057] The decrease in engine speed will cause the output voltage of the permanent magnet synchronous motor 200 to drop, which will cause the output voltage of the entire generator set to the load to be lower than the rated voltage and affect the normal operation of the load. Therefore, in order to ensure that the output voltage of the entire generator set of the internal combustion engine 100 can meet the load demand at low speed, after the speed of the internal combustion engine 100 is lowered according to the preset power-speed curve, the voltage signal of the DC bus is collected through the boost control unit. When it is detected that the output voltage of the AC-DC rectifier unit 300 is lower than the target voltage, the boost control unit is enabled, so that the output voltage of the AC-DC rectifier unit 300 is increased to the target voltage through the boost unit 3, thereby making the output voltage of the DA-AC inverter unit reach the rated voltage.

[0058] This embodiment increases the power output to the load by the permanent magnet synchronous motor 200 at low speed, so that the internal combustion engine 100 does not need to maintain a high speed when outputting low power, thereby effectively reducing fuel consumption and improving the fuel economy of the generator set.

[0059] In one embodiment, the boost control unit includes a voltage detection module and a boost control module 42, the signal input end of the voltage detection module is connected to the DC bus as the signal input end of the boost control unit, the signal output end of the voltage detection module is connected to the signal input end of the boost control module 42, and the signal output end of the boost control module 42 is connected to the control end of the boost unit 3 as the signal output end of the boost control unit, wherein:

[0060] The voltage detection module is used to detect the voltage signal of the DC bus and transmit the detected voltage signal to the boost control module 42;

[0061] The boost control module 42 is used to control the boost unit 3 to turn on or off according to the voltage signal detected by the voltage detection module.

[0062] In this embodiment, the boost control unit is provided with a voltage detection module and a boost control module 42. The voltage detection module detects the voltage signal of the DC bus in real time, and transmits the detected voltage signal to the boost control module 42. The boost control module 42 controls the boost unit 3 to be turned on or off according to the voltage signal detected by the voltage detection module, thereby realizing automatic control of the opening and closing of the boost unit 3 according to the voltage of the DC bus.

[0063] In one embodiment, the voltage detection module includes a first voltage acquisition circuit 411 and a second voltage acquisition circuit 412, wherein:

[0064] The signal input end of the first voltage acquisition circuit 411 is connected to one end of the DC bus close to the AC-DC rectifier unit 300, and the signal output end of the first voltage acquisition circuit 411 is connected to the first signal input end of the boost control module 42. The first voltage acquisition circuit 411 is used to detect the voltage signal of the DC output end of the AC-DC rectifier unit 300 in real time, and transmit the detected voltage signal to the boost control module 42;

[0065] The signal input end of the second voltage acquisition circuit 412 is connected to one end of the DC bus close to the DC-AC inverter unit 400, and the signal output end of the second voltage acquisition circuit 412 is connected to the second signal input end of the boost control module 42. The second voltage acquisition circuit 412 is used to detect the voltage signal of the DC input end of the DC-AC inverter unit 400 when the boost unit 3 is turned on, and transmit the detected voltage signal to the boost control module 42;

[0066] The boost control module 42 is used to control the boost unit 3 to be turned on or off according to the voltage signal detected by the first voltage acquisition circuit 411 and the voltage signal detected by the second voltage acquisition circuit 412 .

[0067] In this embodiment, the voltage detection module is provided with a first voltage acquisition circuit 411 and a second voltage acquisition circuit 412, and detects the voltage signal at the DC output end of the AC-DC rectifier unit 300 in real time through the first voltage acquisition circuit 411, and transmits the detected voltage signal to the boost control module 42, and detects the voltage signal at the DC input end of the DC-AC inverter unit 400 through the second voltage acquisition circuit 412 when the boost unit 3 is turned on, and transmits the detected voltage signal to the boost control module 42, so that the boost control module controls the boost unit 3 to be turned on or off according to the voltage signal detected by the first voltage acquisition circuit 411 and the voltage signal detected by the second voltage acquisition circuit 412.

[0068] In one embodiment, the boost control module 42 is specifically used to control the boost unit 3 to be turned on or off according to the voltage signal detected by the first voltage acquisition circuit 411 and the voltage signal detected by the second voltage acquisition circuit 412:

[0069] The boost control module 42 compares the voltage signal collected by the first voltage collection circuit 411 with the target voltage value. When the voltage signal collected by the first voltage collection circuit 411 is less than the target voltage value (indicating that after the generator set enters the low power stage, the speed is controlled to be reduced, so that the output voltage of the permanent magnet synchronous motor 200 is too low, and the output voltage of the generator set cannot meet the demand, and a boost is required), at this time, the boost control module 42 outputs a high level, and the control end of the boost unit 3 enables the boost unit 3 to be turned on and enter the working state, so as to increase the voltage of the DC bus near the input end of the DC-AC inverter unit 400 through the boost unit 3.

[0070] In the process of the boost unit 3 boosting the voltage of the DC bus near the input end of the DC-AC inverter unit 400, the boost control module 42 compares the voltage signal collected by the second voltage acquisition circuit 412 with the target voltage value. When the voltage signal collected by the second voltage acquisition circuit 412 is greater than or equal to the target voltage value (indicating that after the boost unit 3 boosts the voltage, the output voltage of the entire generator set reaches the target voltage that meets the demand), at this time, the boost control module 42 outputs a low level, and the control end of the boost unit 3 is powered off to shut down the boost unit 3 and exit the working state.

[0071] It should be noted that, in this embodiment, the boost control module 42 adopts an MCU controller or a voltage comparison circuit. The boost control module 42 controls the control process when the boost unit 3 is turned on or off according to the voltage signal detected by the first voltage acquisition circuit 411 and the voltage signal detected by the second voltage acquisition circuit 412, which does not involve the improvement of the computer program itself, and can be realized by controlling the comparison device or the comparator in the comparison circuit by the MCU. Hardware modules such as the comparator are implemented.

[0072] In one embodiment, the voltage detection module further includes a first filter circuit 413 and a second filter circuit 414, wherein the first filter circuit 413 is connected in parallel with the first voltage acquisition circuit 411, and the second filter circuit 414 is connected in parallel with the second voltage acquisition circuit 412. By providing the first filter circuit 413 and the second filter circuit 414, the voltage signals collected by the first voltage acquisition circuit 411 and the second voltage acquisition circuit 412 are more accurate and reliable, thereby ensuring accurate switching of the boost unit 3. Specifically, in this embodiment, the first filter circuit 413 and the second filter circuit 414 are both implemented using filter capacitors.

[0073] In one embodiment, the DC bus includes a DC positive bus and a DC negative bus, one end of the DC positive bus is connected to the positive electrode of the DC output terminal of the AC-DC rectifier unit 300, the other end of the DC positive bus is connected to the positive electrode of the DC input terminal of the DC-AC inverter unit 400, one end of the DC negative bus is connected to the negative electrode of the DC output terminal of the AC-DC rectifier unit 300, and the other end of the DC negative bus is connected to the negative electrode of the DC input terminal of the DC-AC inverter unit 400.

[0074] The positive pole of the input end of the boost unit 3 is connected to one end of the DC positive bus close to the AC-DC rectifier unit 300, the negative pole of the input end of the boost unit 3 is connected to one end of the DC negative bus close to the AC-DC rectifier unit 300, the positive pole of the output end of the boost unit 3 is connected to one end of the DC positive bus close to the DC-AC inverter unit 400, and the negative pole of the output end of the boost unit 3 is connected to one end of the DC negative bus close to the DC-AC inverter unit 400.

[0075] The system further includes an anti-backflow diode 5, which is connected to the DC positive busbar, and the positive electrode of the anti-backflow diode 5 is connected to the positive electrode of the input end of the boost unit 3, and the negative electrode of the anti-backflow diode 5 is connected to the positive electrode of the output end of the boost unit 3. By providing the anti-backflow diode 5, the electricity output through the output end of the boost unit 3 after boosting is prevented from backflowing to the input end, thereby better ensuring the normal and stable operation of the system.

[0076] In one embodiment, the boost unit 3 adopts a Boost boost circuit. The Boost boost circuit uses the energy storage element inductor as an intermittent power source, which is connected in series with the input power source to achieve boost. The Boost boost circuit includes components such as an inductor, a capacitor, and a power switch tube. When the voltage output by the AC-DC rectifier unit 300 is boosted by the Boost boost circuit, the voltage output to the DC bus can be controlled by controlling the conduction time of the power switch tube. The specific circuit structure of the Boost boost circuit belongs to the prior art and will not be repeated here.

[0077] An embodiment of the present invention further provides a generator set, comprising the generator set transient power compensation system in any of the above embodiments.

[0078] The generator set in this embodiment has the same working principle and technical effect as the transient power compensation system of the generator set in the above embodiment, which will not be described in detail here.

[0079] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0080] Professionals may further appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians may use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0081] The steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be implemented directly using hardware, software modules executed by a processor, or a combination of the two. The software modules may be placed in a random access memory (RAM), a memory, a read-only memory (ROM), an electrically programmable ROM, an electrically erasable programmable ROM, a register, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art.

[0082] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A system for reducing the speed of an internal combustion engine in a low power range of a generator set, characterized in that: The generator set includes an internal combustion engine, a permanent magnet synchronous motor, an AC-DC rectifier unit and a DC-AC inverter unit. The internal combustion engine is drivingly connected to the permanent magnet synchronous motor to drive the permanent magnet synchronous motor to generate electricity. The power output end of the permanent magnet synchronous motor is connected to the AC input end of the AC-DC rectifier unit. The DC output end of the AC-DC rectifier unit is connected to the DC input end of the DC-AC inverter unit through a DC bus. The AC output end of the DC-AC inverter unit is used to connect a load to supply power to the load. The system includes a power detection unit, a speed control unit, a boost unit and a boost control unit, wherein the signal input end of the power detection unit is connected to the AC output end of the DC-AC inverter unit, the signal output end of the power detection unit is connected to the signal input end of the speed control unit, the signal output end of the speed control unit is connected to the speed control actuator of the internal combustion engine, the input end of the boost unit is connected to one end of the DC bus close to the AC-DC rectifier unit, the output end of the boost unit is connected to one end of the DC bus close to the DC-AC inverter unit, the control end of the boost unit is connected to the signal output end of the boost control unit, and the signal input end of the boost control unit is connected to the DC bus, wherein: The power detection unit is used to detect the output power of the AC output end of the DC-AC inverter unit; The speed control unit is used to control the working state of the speed control actuator of the internal combustion engine according to the detected output power, so that the internal combustion engine operates at a target speed; The boost control unit is used to collect the voltage signal of the DC bus and control the working state of the boost unit according to the collected voltage signal; The boost unit is used to increase the voltage transmitted from the DC bus to the DC input terminal of the DC-AC inverter unit to a target voltage value under the control of the boost control unit.

2. The system for reducing the speed of an internal combustion engine in a low power range of a generator set according to claim 1, characterized in that: The boost control unit includes a voltage detection module and a boost control module, the signal input end of the voltage detection module is connected to the DC bus as the signal input end of the boost control unit, the signal output end of the voltage detection module is connected to the signal input end of the boost control module, and the signal output end of the boost control module is connected to the control end of the boost unit as the signal output end of the boost control unit, wherein: The voltage detection module is used to detect the voltage signal of the DC bus and transmit the detected voltage signal to the boost control module; The boost control module is used to control the boost unit to be turned on or off according to the voltage signal detected by the voltage detection module.

3. The system for reducing the speed of the internal combustion engine in the low power range of the generator set according to claim 2, characterized in that: The voltage detection module includes a first voltage acquisition circuit and a second voltage acquisition circuit, wherein: The signal input end of the first voltage acquisition circuit is connected to one end of the DC bus close to the AC-DC rectifier unit, and the signal output end of the first voltage acquisition circuit is connected to the first signal input end of the boost control module. The first voltage acquisition circuit is used to detect the voltage signal of the DC output end of the AC-DC rectifier unit in real time, and transmit the detected voltage signal to the boost control module; The signal input end of the second voltage acquisition circuit is connected to an end of the DC bus close to the DC-AC inverter unit, and the signal output end of the second voltage acquisition circuit is connected to the second signal input end of the boost control module. The second voltage acquisition circuit is used to detect the voltage signal of the DC input end of the DC-AC inverter unit when the boost unit is turned on, and transmit the detected voltage signal to the boost control module.

4. The system for reducing the speed of an internal combustion engine in a low power range of a generator set according to claim 3, characterized in that: The boost control module is used to control the boost unit to be turned on or off according to the voltage signal detected by the first voltage acquisition circuit and the voltage signal detected by the second voltage acquisition circuit.

5. The system for reducing the speed of an internal combustion engine in a low power range of a generator set according to claim 4, characterized in that: When the boost control module controls the boost unit to be turned on or off according to the voltage signal detected by the first voltage acquisition circuit and the voltage signal detected by the second voltage acquisition circuit, it is specifically used to: The boost control module compares the voltage signal collected by the first voltage collection circuit with the target voltage value. When the voltage signal collected by the first voltage collection circuit is less than the target voltage value, the boost control module outputs a high level, and the control end of the boost unit enables the boost unit to be turned on and enter a working state, so as to increase the voltage of the DC bus near the input end of the DC-AC inverter unit through the boost unit. In the process of the boost unit boosting the voltage of the DC bus near the input end of the DC-AC inverter unit, the boost control module compares the voltage signal collected by the second voltage collection circuit with the target voltage value. When the voltage signal collected by the second voltage collection circuit is greater than or equal to the target voltage value, the boost control module outputs a low level, and the control end of the boost unit is powered off to shut down the boost unit and exit the working state.

6. The system for reducing the speed of an internal combustion engine in a low power range of a generator set according to claim 3, characterized in that: The voltage detection module further includes a first filtering circuit and a second filtering circuit, wherein the first filtering circuit is connected in parallel with the first voltage collection circuit, and the second filtering circuit is connected in parallel with the second voltage collection circuit.

7. The system for reducing the speed of an internal combustion engine in a low power range of a generator set according to claim 2, characterized in that: The boost control module adopts an MCU controller or a voltage comparison circuit.

8. The system for reducing the speed of an internal combustion engine in a low power range of a generator set according to claim 1, characterized in that: The DC bus includes a DC positive bus and a DC negative bus, one end of the DC positive bus is connected to the positive pole of the DC output end of the AC-DC rectifier unit, the other end of the DC positive bus is connected to the positive pole of the DC input end of the DC-AC inverter unit, one end of the DC negative bus is connected to the negative pole of the DC output end of the AC-DC rectifier unit, and the other end of the DC negative bus is connected to the negative pole of the DC input end of the DC-AC inverter unit. The positive pole of the input end of the boost unit is connected to one end of the DC positive bus bar close to the AC-DC rectifier unit, the negative pole of the input end of the boost unit is connected to one end of the DC negative bus bar close to the AC-DC rectifier unit, the positive pole of the output end of the boost unit is connected to one end of the DC positive bus bar close to the DC-AC inverter unit, and the negative pole of the output end of the boost unit is connected to one end of the DC negative bus bar close to the DC-AC inverter unit. The system also includes an anti-backflow diode, which is connected to the DC positive bus, and the positive electrode of the anti-backflow diode is connected to the positive electrode of the input end of the boost unit, and the negative electrode of the anti-backflow diode is connected to the positive electrode of the output end of the boost unit.

9. The system for reducing the speed of an internal combustion engine in a low power range of a generator set according to any one of claims 1 to 8, characterized in that: The voltage boost unit adopts a Boost voltage boost circuit.

10. A generator set, characterized in that: A system for reducing the speed of an internal combustion engine in a low power range of a generator set as described in any one of claims 1 to 9.

Images