Parallel hybrid system control method, system and parallel hybrid system

Abstract

This invention provides a control method, system, and parallel hybrid system for a parallel hybrid system, belonging to the field of engineering equipment technology. The method includes: determining whether the operating mode of the parallel hybrid system is a hybrid power mode; when the operating mode is hybrid power mode and the parallel hybrid system has no power generation demand, controlling the speeds of the motor and engine based on a first target speed and a second target speed, respectively. The first target speed is the target speed of the parallel hybrid system, and the second target speed is equal to the difference between the first target speed and a speed correction value, which is determined based on the difference between the actual speed of the motor and the actual speed of the engine. This invention addresses the shortcomings of existing technologies that use separate speed and torque control for different power components in parallel hybrid systems, resulting in easy speed loss under transient conditions and significant energy consumption losses.

Description

Technical Field

[0001] This invention relates to a control method, system, and parallel hybrid system for a parallel hybrid system. Background Technology

[0002] Currently, hybrid powertrains are becoming increasingly common in the fields of engineering equipment and commercial vehicles. Among them, the parallel hybrid configuration has more prominent advantages and is particularly favored by various companies.

[0003] Parallel hybrid systems mechanically connect the engine and electric motor via a clutch mechanism to achieve power superposition. However, although parallel hybrid systems are mechanically connected via the same driveshaft, during dual-power control, the different response speeds of the controllers for the power components and the differences in the speeds they acquire are significant factors. Therefore, the vehicle controller typically uses a mode where one power component is controlled by speed and the other by torque.

[0004] This control mode has certain advantages when the machine is in a steady state, but for transient conditions, the dynamic response of torque control is far slower than that of speed control, which makes this mode also have significant drawbacks. For example, when the system power changes drastically, it will cause excessive speed surges and drops, resulting in excessive energy loss, increased fuel and electricity consumption; it will also cause the motor to frequently switch between discharging and generating modes, leading to a reduction in the lifespan of the motor controller and battery. Summary of the Invention

[0005] This invention provides a control method, system, and parallel hybrid system for a parallel hybrid system, which solves the defects in the prior art, where different power components in a parallel hybrid system are controlled by speed and torque respectively, resulting in easy speed loss and large energy consumption loss under transient conditions.

[0006] This invention provides a control method for a parallel hybrid system, comprising:

[0007] Determine whether the operating mode of the parallel hybrid system is hybrid mode;

[0008] When the operating mode is the hybrid mode and the parallel hybrid system has no power generation requirement, the motor and engine speeds are controlled based on a first target speed and a second target speed, respectively. The first target speed is the target speed of the parallel hybrid system, and the second target speed is equal to the difference between the first target speed and a speed correction value. The speed correction value is determined based on the difference between the actual speed of the motor and the actual speed of the engine.

[0009] According to the control method of the parallel hybrid system of the present invention, the speed correction value is determined based on the difference between the actual speed of the motor and the actual speed of the engine, including:

[0010] Determine whether the difference between the actual speed of the motor and the actual speed of the engine is within a preset threshold range;

[0011] If it is within the preset threshold range, the difference between the actual speed of the motor and the actual speed of the engine is used as the speed correction value;

[0012] If the value is less than the lower limit of the preset threshold range, the lower limit value will be used as the speed correction value.

[0013] If the value is greater than the upper limit of the preset threshold range, the upper limit value will be used as the speed correction value.

[0014] The control method for the parallel hybrid system according to the present invention further includes:

[0015] When the difference between the actual speed of the motor and the actual speed of the engine is less than the lower limit or greater than the upper limit, a first fault alarm is triggered. The first fault alarm is used to warn that the speed of the motor and the speed of the engine are out of sync.

[0016] According to the control method of the parallel hybrid system of the present invention, the step of controlling the speed of the motor and the engine based on a first target speed and a second target speed respectively includes:

[0017] After receiving the commutation signal, the actual speed of the motor and the actual speed of the engine remain unchanged for a first preset time period;

[0018] Based on the third target speed and the fourth target speed, the motor and the engine are controlled for speed within a second preset time during the commutation process, respectively. The third target speed is the difference between the first target speed and the preset speed fluctuation value, and the fourth target speed is the difference between the third target speed and the speed correction value.

[0019] Based on the first target speed and the second target speed, the motor and the engine are respectively controlled within a third preset time period during the commutation process;

[0020] Based on the fifth target speed and the sixth target speed, the motor and the engine are controlled for speed within the fourth preset time of the commutation process, respectively. The fifth target speed is the sum of the first target speed and the preset speed fluctuation value, and the sixth target speed is the difference between the fifth target speed and the speed correction value.

[0021] After the commutation process is completed, determine whether the output power of the motor is greater than the target power of the motor;

[0022] If the output power of the motor is less than or equal to the target power of the motor, the motor and the engine are controlled by speed based on the first target speed and the second target speed, respectively, until the sum of the output power of the motor and the output power of the engine is greater than the target power of the parallel hybrid system. Then, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0023] According to the control method of the parallel hybrid system of the present invention, the step of controlling the speed of the motor and the engine respectively within a fourth preset time period of the commutation process based on a fifth target speed and a sixth target speed further includes:

[0024] Determine whether the output power of the motor is greater than the target power of the motor;

[0025] If the output power of the motor is less than or equal to the target power of the motor, the speed control of the motor and the engine shall continue to be performed based on the fifth target speed and the sixth target speed, respectively.

[0026] If the output power of the motor is greater than the target power of the motor, the motor and the engine are controlled by speed based on the actual speed of the motor and the second target speed, respectively, until the output power of the engine is greater than the difference between the target power of the engine and the preset power correction value. Then, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0027] According to the control method of the parallel hybrid system of the present invention, the step of controlling the speed of the motor and the engine based on a first target speed and a second target speed respectively further includes:

[0028] If the output power of the motor is greater than the target power of the motor, the motor and the engine are controlled by speed based on the actual speed of the motor and the second target speed, respectively, until the output power of the engine is greater than the difference between the target power of the engine and the preset power correction value. Then, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0029] According to the control method of the parallel hybrid system of the present invention, the step of controlling the speed of the motor and the engine based on a first target speed and a second target speed respectively includes:

[0030] Obtain the target power of the engine;

[0031] Based on the target power and correction coefficient of the engine, the corrected power of the engine is determined as the first corrected power;

[0032] Based on the first corrected power and the actual power of the engine, a first power difference is determined;

[0033] If the absolute value of the first power difference is less than the preset power correction value, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0034] If the absolute value of the first power difference is greater than or equal to the preset power correction value, the motor and the engine are controlled by speed based on the first target speed and the seventh target speed, respectively. The seventh target speed is the sum of the second target speed and the correction speed of the engine determined based on the first power difference.

[0035] The control method for the parallel hybrid system according to the present invention further includes:

[0036] Obtain the target total power of the parallel hybrid system;

[0037] Based on the target total power and the correction coefficient, the corrected power of the parallel hybrid system is determined as the second corrected power;

[0038] The second power difference is determined based on the second corrected power and the actual total power of the parallel hybrid system;

[0039] If the absolute value of the second power difference is greater than or equal to the preset power correction value, it is determined whether the parallel hybrid system has a power fault.

[0040] If the aforementioned power failure exists, the preset fault handling mechanism will be executed;

[0041] If the power failure does not exist, determine whether the absolute value of the correction coefficient is less than a preset coefficient threshold.

[0042] If the absolute value of the correction coefficient is less than the preset coefficient threshold, a new correction coefficient is determined, and based on the new correction coefficient and the target total power of the parallel hybrid system, the corrected power of the parallel hybrid system is determined.

[0043] If the absolute value of the correction coefficient is greater than or equal to the preset coefficient threshold, a second fault alarm is triggered. The second fault alarm is used to warn that the parallel hybrid system has the power fault and to execute the preset fault handling mechanism.

[0044] The present invention also provides a control system for a parallel hybrid system, comprising:

[0045] The determination module is used to determine whether the operating mode of the parallel hybrid system is hybrid mode;

[0046] The control module is configured to control the speed of the motor and the engine based on a first target speed and a second target speed when the operating mode is the hybrid mode and the parallel hybrid system has no power generation requirement. The first target speed is the target speed of the parallel hybrid system, and the second target speed is equal to the difference between the first target speed and a speed correction value. The speed correction value is determined based on the difference between the actual speed of the motor and the actual speed of the engine.

[0047] The present invention also provides a control system including the parallel hybrid system as described above, or a parallel hybrid system controlled by the control method of the parallel hybrid system as described above.

[0048] The present invention also provides an engineering device comprising the parallel hybrid system described above.

[0049] This invention provides a control method, system, and parallel hybrid system for a parallel hybrid system. By determining that the operating mode of the parallel hybrid system is a hybrid power mode and there is no power generation requirement, the motor and engine are controlled at their respective speeds based on a first target speed and a second target speed. This achieves a dual-speed control mode for the parallel hybrid system when both the engine and motor are outputting net power. Compared to the control method that uses torque and speed to control the engine and motor separately, this effectively improves the system's power response, reduces speed fluctuations and noise, and enables the parallel hybrid system to respond quickly and maintain stable speed changes even when facing transient conditions with rapid changes in system power. At the same time, it reduces system energy consumption and improves system lifespan. Attached Figure Description

[0050] To more clearly illustrate the technical solutions in this invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0051] Figure 1 This is a flowchart illustrating the control method for a parallel hybrid system provided in an embodiment of the present invention.

[0052] Figure 2 This is a schematic diagram of the system configuration of the parallel hybrid system provided in an embodiment of the present invention;

[0053] Figure 3 This is a schematic diagram of the control logic for determining the control mode of a parallel hybrid system provided in an embodiment of the present invention;

[0054] Figure 4 This is a schematic diagram of the control logic for dual-speed control of a parallel hybrid system provided in an embodiment of the present invention;

[0055] Figure 5 This is a schematic diagram of the control logic for determining the speed correction value provided in an embodiment of the present invention;

[0056] Figure 6 This is a schematic diagram of the control logic for dual-speed control of the engine and motor during commutation provided in an embodiment of the present invention;

[0057] Figure 7 This is a schematic diagram of the control logic for power distribution under dual-speed control of the engine and motor provided in an embodiment of the present invention;

[0058] Figure 8 This is a schematic diagram of the control logic for target power correction and fault assessment under dual-speed control of the engine and motor provided in an embodiment of the present invention;

[0059] Figure 9 This is a schematic diagram of the control system of the parallel hybrid system provided in an embodiment of the present invention;

[0060] Figure 10 This is a schematic diagram of the structure of the electronic device provided by the present invention;

[0061] Figure label:

[0062] 1: Engine; 2: Clutch; 3: Motor; 4: Load. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0064] The following is combined with Figures 1 to 10 This invention describes a control method, system, and hybrid system for a parallel hybrid system.

[0065] Figure 1 This is a flowchart illustrating the control method for a parallel hybrid system provided in an embodiment of the present invention.

[0066] like Figure 1 As shown in the figure, the control method for a parallel hybrid system provided by this invention can be executed by software and / or hardware in the hybrid vehicle's vehicle control unit (HCU), and mainly includes the following steps:

[0067] 101. Determine whether the operating mode of the parallel hybrid system is hybrid mode;

[0068] It is understandable that the system configuration of a parallel hybrid system is as follows: Figure 2 As shown, the system includes: engine 1, clutch 2, motor 3, and load 4. Engine 1 is controlled by an Electronic Control Unit (ECU), clutch 2 by a Clutch Control Unit (CCU), motor 3 by a Motor Control Unit (MCU), and load 4 by a motion controller. Additionally, the parallel hybrid system may also include a battery controller, a multi-function controller, etc. The HCU, as the hybrid vehicle controller, coordinates and controls the above controllers, acting as the main controller in the parallel hybrid system.

[0069] Furthermore, the operating modes of a parallel hybrid system generally include range-extending power generation, shutdown, pure electric motor drive, pure engine drive, and hybrid power mode driven by both the electric motor and the engine. Among these, the shutdown, pure electric motor drive, and pure engine drive modes do not involve simultaneous speed requirements for both the electric motor and the engine; therefore, speed control of these modes is unnecessary. Range-extending power generation refers to the process of charging the battery by driving the electric motor through the engine. This can be viewed as a process where the engine acts as the power source and the electric motor as the load. Because the electric motor acts as a relatively stable load during range-extending power generation, and the required power output is generally also relatively fixed, it is only necessary to stabilize the engine speed at a fixed rate, without the need for repeated adjustments to the engine and / or electric motor speeds. Therefore, when controlling a parallel hybrid system, the first step is to determine whether the operating mode of the parallel hybrid system is a hybrid power mode.

[0070] Specifically, the following can be adopted: Figure 3 The control logic shown determines the control mode for the parallel hybrid system, where, for example... Figure 3As shown, when the parallel hybrid system operates in range-extending power generation mode, or when there is a power generation demand in hybrid mode, a control mode that controls the engine speed and the motor torque can be adopted. When the parallel hybrid system operates in other modes besides range-extending power generation and hybrid mode, the current control mode of the parallel hybrid system can be maintained. At the same time, when the parallel hybrid system is under dual-speed control, for example, when the upper structure fault level triggers a shutdown, the clutch has disengaged, the system operating mode switches from hybrid mode to other modes, or when there is a power generation demand in hybrid mode, the exit condition for exiting dual-speed control of the parallel hybrid system is met. At this time, the dual-speed control mode can be exited, and then the adapted control mode is re-executed based on the current operating mode of the parallel hybrid system.

[0071] More specifically, it can be done as follows: Figure 4 The control logic shown is used to perform dual-speed control on the parallel hybrid system. If the motor or engine was under speed control in the previous sampling period, speed control is maintained, and the requested speed value, i.e., the target speed, is set to the previous target speed value. Conversely, if the control mode for the engine or motor was not speed control in the previous sampling period, speed control is switched, and the requested speed value for the engine or motor is set to the actual speed of the engine or motor, thereby avoiding excessive speed fluctuations and improving system operational stability. Simultaneously, if... Figure 4 As shown, the requested engine or motor speed can also be set to be limited by the upper and lower deviation values ​​of the system target speed, so as to further ensure the safety and stability of system operation.

[0072] 102. When the operating mode is the hybrid mode and the parallel hybrid system has no power generation requirement, the motor and engine are controlled based on a first target speed and a second target speed, respectively. The first target speed is the target speed of the parallel hybrid system, and the second target speed is equal to the difference between the first target speed and the speed correction value. The speed correction value is determined based on the difference between the actual speed of the motor and the actual speed of the engine.

[0073] It is understandable that in a parallel hybrid system, the engine and motor are arranged coaxially. In theory, the engine speed and the motor speed should be the same. However, in practical applications, due to differences in the sampling methods and sampling frequencies of the motor and engine speeds, as well as differences in the interaction process between the engine and motor on the bus, there will be some differences between the obtained engine speed and motor speed.

[0074] Specifically, after entering the dual-speed control mode, which controls the speed of the motor and the engine based on the first target speed and the second target speed respectively, the first target speed used to control the speed of the motor is the target speed of the parallel hybrid system, while the second target speed used to control the speed of the engine is the difference between the first target speed and the speed correction value determined based on the difference between the actual speed of the motor and the actual speed of the engine. This allows the motor and engine to be controlled with the same target speed, thereby enabling the parallel hybrid system to operate in the economic zone and reducing energy consumption loss.

[0075] More specifically, when the parallel hybrid system is in hybrid mode and there is no need for power generation, the load is driven by both the engine and the motor. At this time, the motor and engine are controlled by speed control based on the first target speed and the second target speed, respectively. This means that the system enters a dual-speed control mode, which ensures that the control of the engine and motor has a fast response when the parallel hybrid system is in transient conditions. This avoids excessive speed surges and drops, thus reducing speed fluctuations and energy loss.

[0076] Based on the above embodiments, the speed correction value is determined based on the difference between the actual speed of the motor and the actual speed of the engine, including:

[0077] Determine whether the difference between the actual speed of the motor and the actual speed of the engine is within a preset threshold range;

[0078] If it is within the preset threshold range, the difference between the actual speed of the motor and the actual speed of the engine is used as the speed correction value;

[0079] If the value is less than the lower limit of the preset threshold range, the lower limit value will be used as the speed correction value.

[0080] If the value is greater than the upper limit of the preset threshold range, the upper limit value will be used as the speed correction value.

[0081] It is understandable that after the actual speed of the motor and the actual speed of the engine are obtained by the speed sensor, the actual speed can be filtered, and then the speed correction value can be determined based on the relationship between the difference between the actual speed of the motor and the actual speed of the engine and a preset threshold range.

[0082] Specifically, the upper and lower limits of the preset threshold range can be set as speed threshold value 1 and speed threshold value 2, respectively. The speed threshold value refers to the maximum possible difference between the motor speed and the engine speed when the speed sensor, clutch and other functions are normal. For example, if the speed difference between the motor speed and the engine speed is generally no more than 5 revolutions, then speed threshold value 1 and speed threshold value 2 can be set to 6 revolutions and -6 revolutions, respectively, that is, the preset threshold range is [-6, 6].

[0083] More specifically, by the speed difference between the actual speed of the motor and the engine. When within the preset threshold range, As speed correction value 修 ,exist When the value is less than the lower limit of the preset threshold range, the lower limit of the preset threshold range, i.e., the speed threshold value 2, is used as the speed correction value. 修 , and When the value exceeds the upper limit of the preset threshold range, the upper limit of the preset threshold range, i.e., the speed threshold value 1, is used as the speed correction value. 修 On the one hand, it can quickly determine the speed correction value, and on the other hand, it can limit the speed correction value to upper and lower threshold values, thus facilitating the speed control of the engine and motor.

[0084] Based on the above embodiments, the control method for a parallel hybrid system further includes:

[0085] When the difference between the actual speed of the motor and the actual speed of the engine is less than the lower limit or greater than the upper limit, a first fault alarm is triggered. The first fault alarm is used to warn that the speed of the motor and the speed of the engine are out of sync.

[0086] Specifically, because the upper and lower limits of the preset threshold range are the maximum possible speed difference between the engine and the electric motor when the speed sensor, clutch, and other functions are normal, therefore, when the speed difference... If the value is greater than the upper limit or less than the lower limit, it indicates that the parallel hybrid system may have a power-related fault, such as a faulty speed sensor or clutch. Therefore, it can be determined by... Figure 5 The control logic shown determines the speed correction value while simultaneously adjusting the speed difference. When the value exceeds the upper limit or falls below the lower limit, the first fault alarm is triggered, promptly informing the user that there is a fault in the parallel hybrid system where the motor speed and engine speed are out of sync, and providing guidance to the user to troubleshoot the fault in a timely manner.

[0087] It should be noted that the reversal process of engineering equipment using a parallel hybrid system is a load change process. Specifically, during the reversal, all loads are initially removed, and then restored to the pre-reversal load in the later stages. If the engine and motor speeds are not adjusted when the parallel hybrid system removes all loads, the engine and motor speeds will surge significantly, resulting in fuel and electricity consumption. Simultaneously, due to the load removal, the engine will reduce or even stop fuel injection, and the motor will reduce, or even shut down, or reverse charge. Subsequently, when the parallel hybrid system restores the load to the pre-reversal load, the reduced or stopped fuel injection and the reduced, shut-down, or reverse-charging current output of the motor will cause the engine and motor speeds to be too low to respond to the load.

[0088] Based on this, the control method for the parallel hybrid system described in this embodiment of the invention provides a method for controlling the speed of the motor and engine during the commutation process, so as to avoid large fluctuations in speed and energy loss during the commutation process, while effectively ensuring the response speed of the parallel hybrid system when facing load changes.

[0089] Based on the above embodiments, the step of controlling the speed of the motor and the engine based on the first target speed and the second target speed respectively includes:

[0090] After receiving the commutation signal, the actual speed of the motor and the actual speed of the engine remain unchanged for a first preset time period;

[0091] Based on the third target speed and the fourth target speed, the motor and the engine are controlled for speed within a second preset time during the commutation process, respectively. The third target speed is the difference between the first target speed and the preset speed fluctuation value, and the fourth target speed is the difference between the third target speed and the speed correction value.

[0092] Based on the first target speed and the second target speed, the motor and the engine are respectively controlled within a third preset time period during the commutation process;

[0093] Based on the fifth target speed and the sixth target speed, the motor and the engine are controlled for speed within the fourth preset time of the commutation process, respectively. The fifth target speed is the sum of the first target speed and the preset speed fluctuation value, and the sixth target speed is the difference between the fifth target speed and the speed correction value.

[0094] After the commutation process is completed, determine whether the output power of the motor is greater than the target power of the motor;

[0095] If the output power of the motor is less than or equal to the target power of the motor, the motor and the engine are controlled by speed based on the first target speed and the second target speed, respectively, until the sum of the output power of the motor and the output power of the engine is greater than the target power of the parallel hybrid system. Then, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0096] Specifically, the first preset duration is the time from receiving the commutation signal to the start of the commutation process in the parallel hybrid system. By keeping the actual speed of the motor and the actual speed of the engine constant within the first preset duration after receiving the commutation signal, the speed fluctuation of the parallel hybrid system before all loads are removed can be maintained. The second, third, and fourth preset durations are the durations during which the load of the parallel hybrid system drops sharply, remains basically constant, and rises sharply during the commutation process, respectively. In other words, the entire commutation process can be divided into three stages according to time: the second preset duration, the third preset duration, and the fourth preset duration. Therefore, by controlling the motor speed at a third target speed (the difference between the first target speed and the preset speed fluctuation value) within a second preset time period, and controlling the engine speed at a fourth target speed (the difference between the third target speed and the speed correction value), torque can be quickly reduced by lowering the target speed when the load drops sharply. Similarly, by controlling the motor speed at the first target speed (the target speed of the parallel hybrid system) within a third preset time period, and controlling the engine speed at a second target speed, speed stability can be maintained when the torque of the parallel hybrid system is basically stable. Furthermore, by controlling the motor speed at a fifth target speed (the sum of the first target speed and the preset speed fluctuation value) within a fourth preset time period, and controlling the engine speed at a sixth target speed (the difference between the fifth target speed and the speed correction value), torque response can be improved by raising the target speed when the load increases sharply. Thus, based on the preset speed fluctuation value, control of the motor and engine based on floating target speeds during commutation is achieved, effectively improving power response speed and avoiding sudden changes in motor and engine speeds, thereby reducing fuel and electricity consumption.

[0097] More specifically, after the commutation process is completed, when the motor's output power is less than or equal to the motor's target power, it indicates that the motor's actual speed has not yet reached the first target speed. At this point, the speed control of the motor and engine continues based on the first and second target speeds until the sum of the motor's output power and the engine's output power exceeds the target power of the parallel hybrid system. This indicates that the total output power of the engine and motor meets the load requirements. At this point, the speed control of the motor and engine can be maintained separately based on the first target speed and the engine's actual speed. This allows the motor to cope with small fluctuations in the load of the parallel hybrid system, while the engine maintains a stable power output. This avoids the simultaneous fine-tuning of the engine and motor speeds, which would cause the engine's power distribution to gradually increase or decrease, thereby improving the operational stability of the parallel hybrid system.

[0098] It should be noted that the preset value for speed fluctuation is determined based on the actual debugging effect of the parallel hybrid system.

[0099] Based on the above embodiments, the step of controlling the speed of the motor and the engine respectively within a fourth preset time period of the commutation process based on the fifth target speed and the sixth target speed further includes:

[0100] Determine whether the output power of the motor is greater than the target power of the motor;

[0101] If the output power of the motor is less than or equal to the target power of the motor, the speed control of the motor and the engine shall continue to be performed based on the fifth target speed and the sixth target speed, respectively.

[0102] If the output power of the motor is greater than the target power of the motor, the motor and the engine are controlled by speed based on the actual speed of the motor and the second target speed, respectively, until the output power of the engine is greater than the difference between the target power of the engine and the preset power correction value. Then, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0103] Specifically, during the fourth preset time period of the commutation process, based on the fifth and sixth target speeds, the motor and engine speeds are controlled separately. The system determines whether the motor's output power is greater than its target power. If the motor's output power is less than or equal to its target power, the system continues to control the motor and engine speeds based on the fifth and sixth target speeds to quickly reach their target speeds. When the motor's output power exceeds its target power, it indicates that the motor's actual speed has reached the first target speed. At this point, the system controls the motor and engine speeds based on the actual speed and the second target speed, effectively exiting the upward adjustment of the motor's target speed. This facilitates safe speed control and a smooth speed transition. Simultaneously, it allows the engine's output power to gradually approach its target power. Then, when the engine's output power exceeds the difference between its target power and the preset power correction value (i.e., the sum of the engine's output power and the motor's output power exceeds the target power of the parallel hybrid system), the system controls the motor and engine speeds based on the first target speed and the engine's actual speed. This allows the motor to handle small fluctuations in the parallel hybrid system's load, while the engine maintains a stable power output.

[0104] Furthermore, when calculating the output power of a parallel hybrid system, environmental factors and other influences can cause the calculated total power to differ from the actual power. By setting a preset power correction value and then comparing the difference between the engine's output power and the target engine power with the preset power correction value, the impact of the error between the calculated and actual output power on the control logic during commutation can be overcome. This improves the stability and power distribution accuracy of the parallel hybrid system that performs dual-speed control of the motor and engine during commutation.

[0105] Based on the above embodiments, the step of controlling the speed of the motor and the engine based on the first target speed and the second target speed respectively further includes:

[0106] If the output power of the motor is greater than the target power of the motor, the motor and the engine are controlled by speed based on the actual speed of the motor and the second target speed, respectively, until the output power of the engine is greater than the difference between the target power of the engine and the preset power correction value. Then, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0107] Specifically, when the motor's output power is greater than its target power, it indicates that the motor's actual speed has reached the first target speed. At this point, the motor and engine speeds are controlled based on the motor's actual speed and the second target speed, respectively. This allows the engine's output power to gradually approach its target power. Then, when the engine's output power exceeds the difference between its target power and the preset power correction value, i.e., when the sum of the engine's output power and the motor's output power exceeds the target power of the parallel hybrid system, the motor and engine speeds are controlled based on the first target speed and the engine's actual speed, respectively. This allows the motor to cope with small fluctuations in the load of the parallel hybrid system, while the engine maintains a stable power output.

[0108] In one specific embodiment, pre-control can be performed by self-learning the commutation cycle after the commutation signal has been filtered. That is, using... Figure 6 The control logic shown is used to control the dual speeds of the engine and motor during the commutation process. It is assumed that a commutation signal is received or a calculation is performed... The reversal will begin after time t1, then... Within time t1, the current control mode and target mechanism are maintained, the engine output power is frozen, and the engine speed follows the change in motor speed. During the commutation process... In time t2, assuming at the initial... The load drops sharply within time t2 / 2, therefore, after timer T2 is triggered, the load is quickly unloaded by lowering the target motor speed. t2 / 2 to During the t2 / 4 time period, the load remains basically constant. The motor target speed is controlled to be the system target speed, and the engine target speed is the difference between the motor target speed and the speed correction value to maintain speed stability. However, in the later stage of commutation, from 0 to... During the t1 / 4 time period, the load increases rapidly. The torque response is improved by increasing the target motor speed. Subsequently, when the motor's output power exceeds the target power, the target speed becomes the motor's actual speed. At this point, the motor's output power is frozen, maintaining the motor speed at its current speed while waiting for the engine to approach the target power. When time t2 ends, the target speeds of the motor and engine are calculated by determining whether the motor and engine have reached their respective target power allocations.

[0109] Based on the above embodiments, the step of controlling the speed of the motor and the engine based on the first target speed and the second target speed respectively includes:

[0110] Obtain the target power of the engine;

[0111] Based on the target power and correction coefficient of the engine, the corrected power of the engine is determined as the first corrected power;

[0112] Based on the first corrected power and the actual power of the engine, a first power difference is determined;

[0113] If the absolute value of the first power difference is less than the preset power correction value, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0114] If the absolute value of the first power difference is greater than or equal to the preset power correction value, the motor and the engine are controlled by speed based on the first target speed and the seventh target speed, respectively. The seventh target speed is the sum of the second target speed and the correction speed of the engine determined based on the first power difference.

[0115] Specifically, when controlling the speed of the motor and the engine based on the first target speed and the second target speed respectively, since the response speed of the motor is faster than that of the engine, the target power of the engine with a relatively slower response is compared with the actual power of the engine. Thus, when the deviation between the actual power of the engine and the target power is large, the target power of the motor-motor parallel hybrid system is taken as a premise, and the engine output power is adjusted by dynamically adjusting the target speed of the engine, thereby achieving the purpose of power distribution.

[0116] More specifically, it can be done as follows: Figure 7 The control logic shown is used for power distribution under dual-speed control. First, the target power of the engine is corrected using a correction coefficient to avoid power calculation deviations caused by environmental factors, thus obtaining a more accurate target power for the engine. Then, the corrected target power is calculated, which is the power difference between the corrected power and the actual engine power. When the absolute value of the power difference is less than the preset power correction value, the target total power of the parallel hybrid system is considered to be equivalent to the actual total power. Therefore, the motor and engine speeds are controlled separately based on the first target speed and the actual engine speed to keep the engine output power stable and use the motor to handle small fluctuations outside the parallel hybrid system. When the absolute value of the power difference is greater than or equal to the preset power correction value, the motor and engine speeds are controlled separately based on the sum of the first target speed and the seventh target speed (i.e., the second target speed) and the engine correction speed determined based on the power difference. This achieves the goal of stabilizing the target power of the parallel hybrid system with the motor and dynamically adjusting the target engine speed to adjust the engine output power, thereby making the power allocated to the motor and engine more reasonable.

[0117] Based on the above embodiments, the control method for a parallel hybrid system further includes:

[0118] Obtain the target total power of the parallel hybrid system;

[0119] Based on the target total power and the correction coefficient, the corrected power of the parallel hybrid system is determined as the second corrected power;

[0120] The second power difference is determined based on the second corrected power and the actual total power of the parallel hybrid system;

[0121] If the absolute value of the second power difference is greater than or equal to the preset power correction value, it is determined whether the parallel hybrid system has a power fault.

[0122] If the aforementioned power failure exists, the preset fault handling mechanism will be executed;

[0123] If the power failure does not exist, determine whether the absolute value of the correction coefficient is less than a preset coefficient threshold.

[0124] If the absolute value of the correction coefficient is less than the preset coefficient threshold, a new correction coefficient is determined, and based on the new correction coefficient and the target total power of the parallel hybrid system, the corrected power of the parallel hybrid system is determined.

[0125] If the absolute value of the correction coefficient is greater than or equal to the preset coefficient threshold, a second fault alarm is triggered. The second fault alarm is used to warn that the parallel hybrid system has the power fault and to execute the preset fault handling mechanism.

[0126] Specifically, such as Figure 8 The control logic shown corrects the target total power of the parallel hybrid system to obtain a second corrected power, and then calculates the difference between the second corrected power and the actual total power of the motor and engine. When the absolute value of the difference between the second corrected power and the actual total power of the motor and engine is less than the preset power correction value, the target total power is considered to be equivalent to the actual total power, and the power distribution between the motor and engine can proceed directly. If it is greater than or equal to the preset power correction value, and there is no power-related fault at this time, and the absolute value of the correction coefficient λ is less than the preset coefficient threshold, then a new correction coefficient is determined, and the target total power is corrected again based on the new correction coefficient. When the absolute value of the correction coefficient is greater than or equal to the preset coefficient threshold, a power-related fault is established, such as damage to a cylinder of the engine, and the fault handling mechanism is activated, such as exiting the dual-speed control mode, or a single power source or system shutdown action.

[0127] More specifically, the initial value of the correction coefficient is 0. When the difference between the actual total power of the parallel hybrid system and the power correction value of the parallel hybrid system is greater than or equal to the preset power correction value, a new correction coefficient is determined by increasing the preset step size based on the original correction coefficient. Conversely, when the difference between the power correction value of the parallel hybrid system and the actual total power of the parallel hybrid system is greater than or equal to the preset power correction value, a new correction coefficient is determined by decreasing the preset step size based on the original correction coefficient.

[0128] Furthermore, the preset coefficient threshold is determined based on the actual debugging effect, experiments, etc.

[0129] Based on the same general inventive concept, this invention also protects a control system for a parallel hybrid system. The control system for the parallel hybrid system provided by this invention will be described below. The control system for the parallel hybrid system described below and the control method for the parallel hybrid system described above can be referred to in correspondence.

[0130] Figure 9 This is a schematic diagram of the control system of the parallel hybrid system provided by the present invention. Figure 9 As shown, the system includes a determination module 910 and a control module 920; wherein:

[0131] The determination module 910 is used to determine whether the operating mode of the parallel hybrid system is a hybrid mode;

[0132] The control module 920 is used to control the speed of the motor and the engine based on a first target speed and a second target speed when the operating mode is the hybrid mode and the parallel hybrid system has no power generation demand. The first target speed is the target speed of the parallel hybrid system, and the second target speed is equal to the difference between the first target speed and the speed correction value. The speed correction value is determined based on the difference between the actual speed of the motor and the actual speed of the engine.

[0133] The control system for the parallel hybrid system provided in this invention, by determining that the operating mode of the parallel hybrid system is hybrid mode and there is no demand for power generation, controls the speed of the motor and engine based on a first target speed and a second target speed respectively. This achieves a dual-speed control mode for the parallel hybrid system when both the engine and motor are outputting net power. Compared with the control method of controlling the engine and motor separately by torque and speed, this effectively improves the system's power response, reduces speed fluctuations and noise, and enables the parallel hybrid system to respond quickly and maintain stable speed changes when facing transient conditions with rapid changes in system power. At the same time, it reduces system energy consumption and improves system lifespan.

[0134] Optionally, the speed correction value is determined based on the difference between the actual speed of the motor and the actual speed of the engine, including:

[0135] Determine whether the difference between the actual speed of the motor and the actual speed of the engine is within a preset threshold range;

[0136] If it is within the preset threshold range, the difference between the actual speed of the motor and the actual speed of the engine is used as the speed correction value;

[0137] If the value is less than the lower limit of the preset threshold range, the lower limit value will be used as the speed correction value.

[0138] If the value is greater than the upper limit of the preset threshold range, the upper limit value will be used as the speed correction value.

[0139] Optionally, the control system of the parallel hybrid system also includes: a first alarm module;

[0140] The aforementioned first alarm module is used to trigger a first fault alarm when the difference between the actual speed of the motor and the actual speed of the engine is less than the lower limit or greater than the upper limit. The first fault alarm is used to warn that the speed of the motor and the speed of the engine are out of sync.

[0141] Optionally, the control module 920 is specifically used for:

[0142] After receiving the commutation signal, the actual speed of the motor and the actual speed of the engine remain unchanged for a first preset time period;

[0143] Based on the third target speed and the fourth target speed, the motor and the engine are controlled for speed within a second preset time during the commutation process, respectively. The third target speed is the difference between the first target speed and the preset speed fluctuation value, and the fourth target speed is the difference between the third target speed and the speed correction value.

[0144] Based on the first target speed and the second target speed, the motor and the engine are respectively controlled within a third preset time period during the commutation process;

[0145] Based on the fifth target speed and the sixth target speed, the motor and the engine are controlled for speed within the fourth preset time of the commutation process, respectively. The fifth target speed is the sum of the first target speed and the preset upward speed value, and the sixth target speed is the difference between the fifth target speed and the speed correction value.

[0146] After the commutation process is completed, determine whether the output power of the motor is greater than the target power of the motor;

[0147] If the output power of the motor is less than or equal to the target power of the motor, the motor and the engine are controlled by speed based on the first target speed and the second target speed, respectively, until the sum of the output power of the motor and the output power of the engine is greater than the target power of the parallel hybrid system. Then, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0148] Optionally, the control module 920 is more specifically used for:

[0149] Determine whether the output power of the motor is greater than the target power of the motor;

[0150] If the output power of the motor is less than or equal to the target power of the motor, the speed control of the motor and the engine shall continue to be performed based on the fifth target speed and the sixth target speed, respectively.

[0151] If the output power of the motor is greater than the target power of the motor, the motor and the engine are controlled by speed based on the actual speed of the motor and the second target speed, respectively, until the output power of the engine is greater than the difference between the target power of the engine and the preset power correction value. Then, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0152] Optionally, the control module 920 is also specifically used for:

[0153] When the output power of the motor is greater than the target power of the motor, the motor and the engine are controlled by speed based on the actual speed of the motor and the second target speed, respectively, until the output power of the engine is greater than the difference between the target power of the engine and the preset power correction value. Then, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0154] Optionally, the control module 920 is also specifically used for:

[0155] Obtain the target power of the engine;

[0156] Based on the target power and correction coefficient of the engine, the corrected power of the engine is determined as the first corrected power;

[0157] Based on the first corrected power and the actual power of the engine, a first power difference is determined;

[0158] If the absolute value of the first power difference is less than the preset power correction value, the motor and the engine are controlled by speed based on the first target speed and the actual speed of the engine, respectively.

[0159] If the absolute value of the first power difference is greater than or equal to the preset power correction value, the motor and the engine are controlled by speed based on the first target speed and the seventh target speed, respectively. The seventh target speed is the sum of the second target speed and the correction speed of the engine determined based on the first power difference.

[0160] Optionally, the control module 920 is also specifically used for:

[0161] Obtain the target total power of the parallel hybrid system;

[0162] Based on the target total power and the correction coefficient, the corrected power of the parallel hybrid system is determined as the second corrected power;

[0163] The second power difference is determined based on the second corrected power and the actual total power of the parallel hybrid system;

[0164] If the absolute value of the second power difference is greater than or equal to the preset power correction value, it is determined whether the parallel hybrid system has a power fault.

[0165] If the aforementioned power failure exists, the preset fault handling mechanism will be executed;

[0166] If the power failure does not exist, determine whether the absolute value of the correction coefficient is less than a preset coefficient threshold.

[0167] If the absolute value of the correction coefficient is less than the preset coefficient threshold, a new correction coefficient is determined, and based on the new correction coefficient and the target total power of the parallel hybrid system, the corrected power of the parallel hybrid system is determined.

[0168] If the absolute value of the correction coefficient is greater than or equal to the preset coefficient threshold, a second fault alarm is triggered. The second fault alarm is used to warn that the parallel hybrid system has the power fault and to execute the preset fault handling mechanism.

[0169] Based on the same general inventive concept, the present invention also protects a parallel hybrid system, which includes a control system for a parallel hybrid system as described in any of the above embodiments, or is controlled by a control method for a parallel hybrid system as described in any of the above embodiments.

[0170] Based on the same general inventive concept, the present invention also protects an engineering device comprising a parallel hybrid system as described in the above embodiments.

[0171] Specifically, engineering equipment may include heavy trucks, trailers, excavators, roadheaders, bulldozers, road rollers and concrete pump trucks, or mechanical operating equipment such as tower cranes, construction hoists and material hoists.

[0172] Figure 10 An example is a schematic diagram of the physical structure of an electronic device, such as... Figure 10 As shown, the electronic device may include a processor 110, a communication interface 120, a memory 130, and a communication bus 140, wherein the processor 110, the communication interface 120, and the memory 130 communicate with each other through the communication bus 140. The processor 110 can call logic instructions in the memory 130 to execute a control method for a parallel hybrid system. The method includes: determining whether the operating mode of the parallel hybrid system is a hybrid power mode; when the operating mode is the hybrid power mode and the parallel hybrid system has no power generation demand, controlling the speed of the motor and the engine based on a first target speed and a second target speed, respectively. The first target speed is the target speed of the parallel hybrid system, and the second target speed is equal to the difference between the first target speed and a speed correction value, wherein the speed correction value is determined based on the difference between the actual speed of the motor and the actual speed of the engine.

[0173] Furthermore, the logical instructions in the aforementioned memory 130 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, essentially, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0174] On the other hand, the present invention also provides a computer program product, the computer program product including a computer program stored on a non-transitory computer-readable storage medium, the computer program including program instructions, when the program instructions are executed by a computer, the computer is able to execute the control method for the parallel hybrid system provided by the above methods, the method including: determining whether the operating mode of the parallel hybrid system is a hybrid mode; when the operating mode is the hybrid mode and the parallel hybrid system has no power generation demand, controlling the speed of the motor and the engine based on a first target speed and a second target speed respectively, the first target speed being the target speed of the parallel hybrid system, the second target speed being equal to the difference between the first target speed and a speed correction value, the speed correction value being determined based on the difference between the actual speed of the motor and the actual speed of the engine.

[0175] In another aspect, the present invention also provides a non-transitory computer-readable storage medium storing a computer program thereon, which, when executed by a processor, implements the control methods for the parallel hybrid systems provided above. The method includes: determining whether the operating mode of the parallel hybrid system is a hybrid power mode; and when the operating mode is the hybrid power mode and the parallel hybrid system has no power generation demand, controlling the speeds of the motor and the engine based on a first target speed and a second target speed, respectively. The first target speed is the target speed of the parallel hybrid system, and the second target speed is equal to the difference between the first target speed and a speed correction value, wherein the speed correction value is determined based on the difference between the actual speed of the motor and the actual speed of the engine.

[0176] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0177] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus necessary general-purpose hardware platforms, and of course, it can also be implemented by hardware. Based on this understanding, the above technical solutions, in essence or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0178] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A control method of a parallel hybrid system, characterized by, The method comprises the following steps: determining whether the working mode of a parallel hybrid system is a hybrid mode; when the working mode is the hybrid mode and the parallel hybrid system has no power generation demand, controlling the rotating speed of the motor and the engine based on a first target rotating speed and a second target rotating speed respectively, the first target rotating speed being a target rotating speed of the parallel hybrid system, the second target rotating speed being equal to the difference between the first target rotating speed and a rotating speed correction value, the rotating speed correction value being determined based on the difference between the actual rotating speed of the motor and the actual rotating speed of the engine; the step of controlling the rotating speed of the motor and the engine based on the first target rotating speed and the second target rotating speed respectively comprises the following steps: after receiving a switching signal, keeping the actual rotating speed of the motor and the actual rotating speed of the engine unchanged within a first preset time length; controlling the rotating speed of the motor and the engine based on a third target rotating speed and a fourth target rotating speed within a second preset time length of the switching process, the third target rotating speed being the difference between the first target rotating speed and a rotating speed floating preset value, the fourth target rotating speed being the difference between the third target rotating speed and the rotating speed correction value; controlling the rotating speed of the motor and the engine based on the first target rotating speed and the second target rotating speed within a third preset time length of the switching process; controlling the rotating speed of the motor and the engine based on a fifth target rotating speed and a sixth target rotating speed within a fourth preset time length of the switching process, the fifth target rotating speed being the sum of the first target rotating speed and the rotating speed floating preset value, the sixth target rotating speed being the difference between the fifth target rotating speed and the rotating speed correction value; after the switching process ends, determining whether the output power of the motor is greater than the target power of the motor; if the output power of the motor is less than or equal to the target power of the motor, controlling the rotating speed of the motor and the engine based on the first target rotating speed and the second target rotating speed respectively until the sum of the output power of the motor and the output power of the engine is greater than the target power of the parallel hybrid system, and then controlling the rotating speed of the motor and the engine based on the first target rotating speed and the actual rotating speed of the engine respectively.

2. The control method of a parallel type hybrid system according to claim 1, characterized by, the step of determining the rotating speed correction value based on the difference between the actual rotating speed of the motor and the actual rotating speed of the engine comprises the following steps: determining whether the difference between the actual rotating speed of the motor and the actual rotating speed of the engine is within a preset threshold range; if the difference is within the preset threshold range, taking the difference between the actual rotating speed of the motor and the actual rotating speed of the engine as the rotating speed correction value; if the difference is less than a lower limit value of the preset threshold range, taking the lower limit value as the rotating speed correction value; if the difference is greater than an upper limit value of the preset threshold range, taking the upper limit value as the rotating speed correction value.

3. The control method of a parallel type hybrid system according to claim 2, characterized by, The method further comprises the following steps: when the difference between the actual rotating speed of the motor and the actual rotating speed of the engine is less than the lower limit value or greater than the upper limit value, triggering a first fault alarm, the first fault alarm being used to warn that the rotating speed of the motor and the rotating speed of the engine are out of synchronization.

4. The control method of a parallel type hybrid system according to claim 1, characterized by, The speed control of the motor and the engine based on the fifth target speed and the sixth target speed respectively in the fourth preset time length of the commutation process further comprises: determining whether the output power of the motor is greater than the target power of the motor; if the output power of the motor is less than or equal to the target power of the motor, continuing to control the speed of the motor and the engine based on the fifth target speed and the sixth target speed respectively; if the output power of the motor is greater than the target power of the motor, controlling the speed of the motor and the engine based on the actual speed of the motor and the second target speed respectively until the output power of the engine is greater than the difference between the target power of the engine and the preset power correction value, and then controlling the speed of the motor and the engine based on the first target speed and the actual speed of the engine respectively.

5. The control method of a parallel type hybrid system according to claim 4, characterized by, The speed control of the motor and the engine based on the first target speed and the second target speed respectively further comprises: if the output power of the motor is greater than the target power of the motor, controlling the speed of the motor and the engine based on the actual speed of the motor and the second target speed respectively until the output power of the engine is greater than the difference between the target power of the engine and the preset power correction value, and then controlling the speed of the motor and the engine based on the first target speed and the actual speed of the engine respectively.

6. The control method of a parallel type hybrid system according to claim 4, characterized by, The speed control of the motor and the engine based on the first target speed and the second target speed respectively comprises: obtaining the target power of the engine; determining the correction power of the engine as a first correction power based on the target power of the engine and a correction coefficient; determining a first power difference based on the first correction power and the actual power of the engine; if the absolute value of the first power difference is less than the preset power correction value, controlling the speed of the motor and the engine based on the first target speed and the actual speed of the engine respectively; if the absolute value of the first power difference is greater than or equal to the preset power correction value, controlling the speed of the motor and the engine based on the first target speed and a seventh target speed respectively, the seventh target speed being the sum of the second target speed and the correction speed of the engine determined based on the first power difference.

7. The control method of a parallel type hybrid system according to claim 6, characterized by, Further comprising: obtaining the target total power of the parallel hybrid system; determining the correction power of the parallel hybrid system as a second correction power based on the target total power and the correction coefficient; determining a second power difference based on the second correction power and the actual total power of the parallel hybrid system; if the absolute value of the second power difference is greater than or equal to the preset power correction value, determining whether there is a power failure in the parallel hybrid system; if there is the power failure, executing a preset failure handling mechanism; if there is no power failure, determining whether the absolute value of the correction coefficient is less than a preset coefficient threshold. If the absolute value of the correction coefficient is less than the preset coefficient threshold, a new correction coefficient is determined, and based on the new correction coefficient and a target total power of the parallel hybrid system, a corrected power of the parallel hybrid system is determined; If the absolute value of the correction coefficient is greater than or equal to the preset coefficient threshold, a second fault alarm is triggered, the second fault alarm is used to alert that the parallel hybrid system has the power failure, and the preset fault handling mechanism is executed.

8. A control system of a parallel hybrid system, characterized by, Comprise: A determination module is configured to determine whether the working mode of a parallel hybrid system is a hybrid mode; A control module is configured to, when the working mode is the hybrid mode and the parallel hybrid system has no power generation demand, perform speed control on a motor and an engine based on a first target speed and a second target speed respectively, the first target speed being a target speed of the parallel hybrid system, the second target speed being equal to the difference between the first target speed and a speed correction value, the speed correction value being determined based on the difference between the actual speed of the motor and the actual speed of the engine; The control module is specifically configured to, after receiving a switching signal, keep the actual speed of the motor and the actual speed of the engine unchanged within a first preset time period; Perform speed control on the motor and the engine based on a third target speed and a fourth target speed within a second preset time period of the switching process, the third target speed being the difference between the first target speed and a speed floating preset value, the fourth target speed being the difference between the third target speed and the speed correction value; Perform speed control on the motor and the engine based on the first target speed and the second target speed within a third preset time period of the switching process; Perform speed control on the motor and the engine based on a fifth target speed and a sixth target speed within a fourth preset time period of the switching process, the fifth target speed being the sum of the first target speed and the speed floating preset value, the sixth target speed being the difference between the fifth target speed and the speed correction value; After the switching process ends, determine whether the output power of the motor is greater than the target power of the motor; If the output power of the motor is less than or equal to the target power of the motor, perform speed control on the motor and the engine based on the first target speed and the second target speed respectively, until the sum of the output power of the motor and the output power of the engine is greater than the target power of the parallel hybrid system, and then perform speed control on the motor and the engine based on the first target speed and the actual speed of the engine respectively.

9. A parallel hybrid system, characterized by A control system of a parallel hybrid system as claimed in claim 8, or a control method as claimed in any one of claims 1 to 7.

10. An engineering apparatus characterised by A parallel hybrid system as claimed in claim 9.

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