Bus voltage control method for a power generation system and related apparatus

Abstract

The application discloses a bus voltage control method of a power generation system and related devices, and relates to the field of voltage control, which comprises the following steps: acquiring a bus voltage demand value and a bus voltage actual value of the power generation system, determining a voltage deviation direction based on the bus voltage demand value and the bus voltage actual value, executing a first control branch in response to the voltage deviation direction being a first deviation direction, controlling the bus voltage to change to the bus voltage demand value by adjusting the mechanical torque of a motor in the power generation system, executing a second control branch in response to the voltage deviation direction being a second deviation direction, and controlling the bus voltage to change to the bus voltage demand value by adjusting the field weakening current of the motor. According to the application, the control branch is dynamically selected according to the bus voltage deviation direction, the electric energy is supplemented by torque adjustment when the voltage is low, the excess electric energy is consumed by field weakening power consumption when the voltage is high, bidirectional active adjustment is realized, the bus voltage is ensured to stably converge to the demand value under all working conditions, and overvoltage or undervoltage faults are avoided.

Description

Technical Field

[0001] This invention relates to the field of voltage control technology, and more specifically, to a method and related apparatus for controlling the bus voltage of a power generation system. Background Technology

[0002] Range-extended electric vehicle (REEV) power generation systems, as a crucial technological solution in the fields of new energy vehicles and independent power supply, primarily rely on an engine-driven generator to produce electricity to maintain the battery's charge or directly power the load. In existing range extender control systems, the stability of the bus voltage directly affects the safe operation of the vehicle's high-voltage electrical equipment and the responsiveness of the power system. Typically, such systems rely on large-capacity batteries or supercapacitors as buffers for the DC bus, utilizing the enormous energy throughput of energy storage components to smooth voltage oscillations caused by sudden load changes or fluctuations in power generation. Conventional control strategies often employ closed-loop voltage control based on PI (Proportional-Integral) algorithms. By monitoring the deviation between the actual bus voltage value and the target demand value in real time, the output torque or speed of the generator is adjusted, thereby adjusting the power generation to track load changes and ensure that the bus voltage remains within a preset safety window.

[0003] However, with increasing demands for system integration and growing cost control pressures, battery-free / micro-battery range extender architectures that eliminate large-capacity battery packs or only configure extremely small-capacity capacitors are gradually becoming an industry trend. In scenarios lacking large-capacity energy storage buffers, or when a battery system failure necessitates a direct connection between the range extender and the load, the system's inertia decreases significantly, placing extremely high demands on the dynamic response speed and steady-state accuracy of voltage control.

[0004] While existing voltage loop control schemes generally employ PI regulators to achieve closed-loop regulation of bus voltage, most lack specific voltage regulation control logic adapted to low-inertia systems without batteries or with micro-batteries. Simply applying conventional PI control to such systems is insufficient due to the lack of buffering effect from large-capacity energy storage components; a single PI regulator struggles to balance dynamic response and steady-state accuracy across the entire operating range. Especially under extreme conditions such as drastic load fluctuations or instantaneous power mismatch between the generator and consumer, conventional PI control is prone to integral saturation, response lag, or inappropriate control output, leading to severe overshoot or voltage dips in the bus voltage. This can trigger overvoltage or undervoltage protection, causing shutdowns and even damaging high-voltage electrical components, becoming a key bottleneck restricting the reliable application of such lightweight range-extending systems. Summary of the Invention

[0005] In view of this, the present invention discloses a bus voltage control method and related device for a power generation system, in order to solve the technical problem that in scenarios lacking large-capacity energy storage buffers, when faced with drastic load changes or instantaneous power mismatch, the bus voltage is prone to overshoot or drop, leading to system protection shutdown or even damage to electrical components.

[0006] A method for controlling bus voltage in a power generation system includes:

[0007] Obtain the required bus voltage and the actual bus voltage of the power generation system;

[0008] Based on the required bus voltage value and the actual bus voltage value, the voltage deviation direction is determined. The voltage deviation direction includes a first deviation direction and a second deviation direction, and the first deviation direction is opposite to the second deviation direction.

[0009] In response to the voltage deviation direction being the first deviation direction, the first control branch is executed, and the bus voltage is controlled to change towards the bus voltage demand value by adjusting the mechanical torque of the motor in the power generation system;

[0010] In response to the voltage deviation direction being the second deviation direction, a second control branch is executed, which controls the bus voltage to change towards the required bus voltage value by adjusting the field weakening current of the motor.

[0011] Optionally, determining the direction of voltage deviation based on the required bus voltage value and the actual bus voltage value includes:

[0012] If the actual value of the bus voltage is less than or equal to the required value of the bus voltage, the direction of the voltage deviation is determined to be the first deviation direction.

[0013] If the actual value of the bus voltage is greater than the required value of the bus voltage, the direction of the voltage deviation is determined to be the second deviation direction.

[0014] Optionally, executing the first control branch, by adjusting the mechanical torque of the motor in the power generation system to control the bus voltage to change towards the bus voltage demand value, includes:

[0015] Based on the bus voltage difference between the required bus voltage value and the actual bus voltage value, the foundation mechanical torque is calculated using a proportional-integral controller.

[0016] Obtain the feedforward torque and / or feedback torque used to compensate for the basic mechanical torque, and superimpose the feedforward torque and / or the feedback torque with the basic mechanical torque to obtain the torque required for power generation;

[0017] The torque required for power generation is subjected to amplitude limiting and / or gradient processing to obtain the target mechanical torque;

[0018] Based on the target mechanical torque and the equivalent speed of the motor, direct-axis current command and quadrature-axis current command of the motor are generated to control the motor to output the target mechanical torque.

[0019] Optionally, generating the direct-axis current command and quadrature-axis current command of the motor based on the target mechanical torque and the equivalent speed of the motor includes:

[0020] Based on the target mechanical torque and the equivalent speed of the motor, the direct-axis current command and the quadrature-axis current command are obtained by looking up a table using either a maximum torque-to-current ratio control strategy or a maximum torque-to-voltage ratio control strategy; or...

[0021] Based on the target mechanical torque and the equivalent speed of the motor, the direct-axis current command and the quadrature-axis current command are obtained by looking up a table through current mapping.

[0022] Optionally, executing the second control branch, by adjusting the field weakening current of the motor to control the bus voltage to change towards the required bus voltage value, includes:

[0023] Based on the bus voltage difference between the required bus voltage value and the actual bus voltage value, the direct-axis current adjustment is calculated using a proportional-integral controller.

[0024] The direct-axis current adjustment amount is limited, and the limited direct-axis current adjustment amount is superimposed on the basic direct-axis current command to obtain the target direct-axis current command.

[0025] Control signals are generated based on the target direct-axis current command and quadrature-axis current command to drive the motor.

[0026] Wherein, the direct-axis current adjustment amount is a magnetic weakening current, and / or, the quadrature-axis current command is set to zero to consume bus power by increasing the copper loss of the motor.

[0027] Optionally, generating the control signal based on the target direct-axis current command and quadrature-axis current command includes:

[0028] When the motor is in a power-consuming state, the quadrature-axis current command is set to zero, and the control signal is generated based on the target direct-axis current command and the quadrature-axis current command set to zero;

[0029] When the motor is not in a power-consuming state, the control signal is generated based on the target direct-axis current command and the current quadrature-axis current command.

[0030] Optionally, the bus voltage control method further includes:

[0031] In the event that a system state switch is detected or a fault signal is received, a zeroing operation is performed on the integral element in the first control branch or the second control branch.

[0032] And / or,

[0033] Amplitude limiting is performed on the output signal of the first control branch or the second control branch.

[0034] A bus voltage control device for a power generation system, comprising:

[0035] The acquisition unit is used to acquire the required bus voltage value and the actual bus voltage value of the power generation system.

[0036] The voltage deviation direction determination unit is used to determine the voltage deviation direction based on the bus voltage demand value and the actual bus voltage value. The voltage deviation direction includes a first deviation direction and a second deviation direction, wherein the first deviation direction is opposite to the second deviation direction.

[0037] The first control branch execution unit is used to execute the first control branch in response to the voltage deviation direction being the first deviation direction, and to control the bus voltage to change to the bus voltage demand value by adjusting the mechanical torque of the motor in the power generation system.

[0038] The second control branch execution unit is used to execute the second control branch in response to the voltage deviation direction being the second deviation direction, and to control the bus voltage to change towards the bus voltage demand value by adjusting the field weakening current of the motor.

[0039] A computer-readable storage medium storing at least one instruction that, when executed by a processor, implements the bus voltage control method for a power generation system described above.

[0040] A motor controller, the motor controller comprising: a memory and a processor;

[0041] The memory is used to store at least one instruction;

[0042] The processor is used to execute the at least one instruction to implement the bus voltage control method of the power generation system described above.

[0043] As can be seen from the above technical solution, the present invention discloses a bus voltage control method and related device for a power generation system. By acquiring the actual value and the demand value of the bus voltage and determining the direction of the voltage deviation between the two, when the deviation direction is the first deviation direction, the first control branch is executed to adjust the mechanical torque of the motor to raise the voltage. When the deviation direction is the second deviation direction, the second control branch is executed to adjust the magnetic field weakening current of the motor to consume electricity and lower the voltage. Thus, the corresponding control branch is dynamically selected according to the voltage deviation direction, enabling the system to supplement electrical energy through torque adjustment when the voltage is low and consume excess electrical energy through magnetic field weakening when the voltage is high, forming a bidirectional active adjustment mechanism. Without relying on large-capacity energy storage elements for buffering, it can still effectively suppress voltage oscillations caused by load changes, ensuring that the bus voltage stably converges to the demand value within the entire operating range, avoiding overvoltage or undervoltage faults, and ensuring reliable system operation. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of the present 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 only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the published drawings without creative effort.

[0045] Figure 1 This is a flowchart of a bus voltage control method for a power generation system disclosed in an embodiment of the present invention;

[0046] Figure 2 This is a flowchart illustrating a specific implementation method for executing the first control branch according to an embodiment of the present invention.

[0047] Figure 3 This is a flowchart illustrating a specific implementation method for executing a second control branch according to an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of a bus voltage control process for a power generation system disclosed in an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the structure of a bus voltage control device for a power generation system disclosed in an embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram of the structure of a motor controller disclosed in an embodiment of the present invention. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] See Figure 1 The present invention discloses a flowchart of a bus voltage control method for a power generation system, the method comprising:

[0053] Step S101: Obtain the required bus voltage value and the actual bus voltage value of the power generation system.

[0054] The actual bus voltage value refers to the real-time measured voltage value on the DC bus of the power generation system. This value can be acquired through voltage sampling sensors or circuits configured on the bus side, and after analog-to-digital conversion and filtering, reflects the true voltage level on the bus at the current moment. The required bus voltage value refers to the target voltage value set according to the operating requirements of the load equipment or the system's preset strategy; it is the stable voltage reference that the system expects to maintain. This step aims to monitor the voltage status of the power generation system in real time, providing a data foundation for subsequent deviation calculations and control decisions.

[0055] When a voltage sampling circuit or sensor is available, the motor controller acquires the voltage signal at both ends of the DC bus in real time through the sampling circuit. After filtering, conditioning and analog-to-digital conversion, the actual value of the bus voltage is obtained. At the same time, the bus voltage demand value corresponding to the current operating condition is read from the host computer, energy management system or preset memory.

[0056] Step S102: Determine the direction of voltage deviation based on the required bus voltage value and the actual bus voltage value.

[0057] The voltage deviation direction characterizes the deviation trend of the actual bus voltage value relative to the required bus voltage value, specifically including a first deviation direction and a second deviation direction. The first and second deviation directions are opposite to each other, corresponding to two states: low voltage and high voltage, respectively. This step is used to convert the numerical value of the voltage deviation into a directional logical judgment in order to select the corresponding control strategy.

[0058] Based on the acquired bus voltage demand value and the actual bus voltage value, the motor controller calculates the difference between the two and determines the direction of voltage deviation according to the sign or magnitude of the difference. For example, the deviation direction can be determined by comparing the magnitude of the bus voltage demand value and the actual bus voltage value; alternatively, it can be determined by calculating the voltage deviation value and judging its sign. If the deviation direction is determined to be the first deviation direction, it indicates that the current voltage is trending or in a state lower than the demand value; if the deviation direction is determined to be the second deviation direction, it indicates that the current voltage is trending or in a state higher than the demand value.

[0059] Step S103: In response to the voltage deviation direction being the first deviation direction, execute the first control branch, and control the bus voltage to change towards the bus voltage demand value by adjusting the mechanical torque of the motor in the power generation system.

[0060] The first control branch is a control logic path designed for low voltage conditions. Its core lies in changing the power generation by adjusting the mechanical torque of the motor, thereby regulating the bus voltage. Mechanical torque refers to the torque acting on the motor shaft, which determines the amount of mechanical power output or absorbed by the motor.

[0061] This step aims to increase the bus voltage by increasing the generator torque, bringing it back to the required value. When the voltage deviation direction is determined to be the first deviation direction, the bus voltage control device triggers the first control branch. This process could, for example, involve controlling the motor controller to increase the motor's mechanical torque, causing the motor to absorb more mechanical power from the engine and convert it into electrical energy output to the DC bus, thereby raising the bus voltage. By adjusting the mechanical torque of the motor in the generator system, the actual bus voltage value gradually approaches the required bus voltage value, achieving voltage boosting under low-voltage conditions.

[0062] Step S104: In response to the voltage deviation direction being the second deviation direction, execute the second control branch, and control the bus voltage to change towards the bus voltage demand value by adjusting the field weakening current of the motor.

[0063] The second control branch is a control logic path designed for situations with excessively high voltage. Its core lies in consuming bus power by adjusting the motor's field-weakening current. The field-weakening current typically refers to the motor's direct-axis negative current, used to weaken the motor's air-gap magnetic field. In this scheme, the resulting motor copper losses are used to consume excess energy on the DC bus.

[0064] This step aims to reduce the bus voltage and prevent overvoltage faults by increasing the internal losses of the motor. When the voltage deviation direction is determined to be the second deviation direction, the bus voltage control device triggers the second control branch. This process can be, for example, by injecting a direct-axis field-weakening current into the motor. This current generates Joule heat on the internal resistance of the motor windings, converting the electrical energy on the DC bus into heat energy, thereby lowering the bus voltage. Alternatively, the equivalent load of the motor can be dynamically adjusted by controlling the magnitude of the field-weakening current, thus controlling the rate of decrease in the bus voltage. By adjusting the motor's field-weakening current, the actual bus voltage value gradually returns to the required bus voltage value, achieving voltage suppression under high-voltage conditions.

[0065] In summary, this invention discloses a bus voltage control method for a power generation system. By acquiring the actual and demand values ​​of the bus voltage and determining the direction of the voltage deviation between them, a first control branch is executed when the deviation direction is the first deviation direction to adjust the mechanical torque of the motor to raise the voltage. When the deviation direction is the second deviation direction, a second control branch is executed to adjust the field weakening current of the motor to consume electricity and lower the voltage. Thus, the corresponding control branch is dynamically selected according to the direction of the voltage deviation, enabling the system to supplement electrical energy through torque adjustment when the voltage is low and consume excess electrical energy through field weakening when the voltage is high, forming a bidirectional active regulation mechanism. Without relying on large-capacity energy storage components for buffering, it can still effectively suppress voltage oscillations caused by load changes, ensuring that the bus voltage stably converges to the demand value across the entire operating range, avoiding overvoltage or undervoltage faults, and ensuring reliable system operation.

[0066] In one embodiment, step S102 may specifically include:

[0067] If the actual value of the bus voltage is less than or equal to the required value of the bus voltage, the direction of the voltage deviation is determined to be the first deviation direction.

[0068] If the actual value of the bus voltage is greater than the required value of the bus voltage, the direction of the voltage deviation is determined to be the second deviation direction.

[0069] When the actual bus voltage value Udc_act is determined to be less than or equal to the required bus voltage value Udc_ref, the bus voltage difference Udc_diff is greater than or equal to 0, indicating that the current bus voltage level is lower than or equal to the target value. Based on this, this state is defined as the first deviation direction, and the system enters the power generation state. The first deviation direction characterizes the situation where the bus voltage needs to be increased, triggering the first control branch to enter the working mode. The bus voltage difference Udc_diff, along with the proportional coefficient Kp and integral coefficient Ki obtained from a table based on the current bus voltage difference Udc_diff and the current operating conditions, are input into the PI controller. After amplitude limiting and / or integral zeroing, the torque required for power generation is adjusted to raise the bus voltage to the required value. This embodiment, by introducing specific numerical comparison logic, can transform the abstract voltage deviation trend into a Boolean logic judgment that can be accurately executed by the controller, ensuring accurate identification and corrective measures when the voltage is insufficient.

[0070] When the actual bus voltage value is detected to be greater than the required bus voltage value, it usually means that the range extender has excessive generating power, the load is suddenly shedding, or the regenerative braking energy is causing the bus voltage to rise. For this condition, the voltage deviation direction is determined as the second deviation direction. The second deviation direction is logically mutually exclusive and opposite to the first deviation direction, clearly indicating that the current bus voltage is at risk of being too high. This determination process provides a clear status flag for the control strategy, enabling the system to switch to either power consumption or field weakening control mode accordingly.

[0071] This embodiment, by setting up a direction determination method based on numerical magnitude, enables the control system to distinguish whether the voltage needs to be raised or lowered within milliseconds. This avoids the problem that a single control loop cannot adapt to bidirectional adjustment requirements, and provides a reliable preliminary decision-making basis for subsequent precise adjustment of the motor's mechanical torque or field weakening current.

[0072] In one embodiment, see Figure 2 The flowchart of a specific implementation method for executing the first control branch disclosed in this embodiment of the invention, specifically step S103 may include:

[0073] Step S201: Based on the bus voltage difference between the required bus voltage value and the actual bus voltage value, calculate the foundation mechanical torque using a proportional-integral controller.

[0074] The bus voltage differential reflects the deviation between the actual current bus voltage value and the target demand value. During the execution of the first control branch, the bus voltage differential is determined first. In one optional implementation, the bus voltage differential is equal to the demand value of the bus voltage minus the actual value of the bus voltage. The bus voltage differential serves as an input error signal for the control system, and its sign and magnitude characterize the direction and degree of voltage deviation, respectively.

[0075] The proportional-integral (PI) controller, as the core regulating unit, calculates the basic mechanical torque based on the bus voltage difference. Unlike simple proportional control, the PPI controller not only focuses on the current error magnitude but also considers the cumulative error history, thus effectively eliminating steady-state errors and ensuring that the bus voltage tracks the bus voltage demand value without steady-state error. Specifically, in the calculation process, the proportional term multiplies the current bus voltage difference by a proportionality coefficient for rapid response to voltage fluctuations; the integral term integrates the bus voltage difference over time and multiplies it by an integral coefficient for continuous deviation correction. This calculation process can be formalized as follows:

[0076] T base =Kp⋅(Udc_ref−Udc_act)+Ki⋅∫(Udc_ref−Udc_act)dt;

[0077] In the formula, T base Udc_ref represents the calculated basic mechanical torque, Udc_act represents the bus voltage demand value, Udc_act represents the actual bus voltage value, Kp represents the proportional coefficient, and Ki represents the integral coefficient.

[0078] In practical applications, by setting the proportional and integral coefficients appropriately, proportional-integral control can maintain system stability while ensuring response speed, and output the basic mechanical torque that meets the voltage regulation requirements.

[0079] Step S202: Obtain the feedforward torque and / or feedback torque used to compensate for the base mechanical torque, and superimpose the feedforward torque and / or feedback torque with the base mechanical torque to obtain the torque required for power generation.

[0080] Feedforward torque is calculated based on the system's physical model or a pre-defined operating condition mapping relationship. Feedforward torque is primarily used to predict the torque demand caused by load changes or speed fluctuations, enabling feedforward control and completing torque reserve and response preparation before sudden load changes. In one optional implementation, the feedforward torque can be calculated based on the range extender's current speed and target power output, either through a lookup table or using an efficiency-optimized algorithm. This feedforward torque is then superimposed on the base mechanical torque, allowing the system to provide necessary torque support at the moment of load change, thereby improving the system's dynamic response performance. The efficiency-optimized algorithm can be Maximum Torque Per Ampere (MTPA) control, which optimizes the distribution of direct-axis and quadrature-axis currents to minimize the current required by the motor to output the same torque, thus achieving optimal efficiency.

[0081] Feedback torque is calculated based on real-time measurements of other system states and is used for closed-loop correction of model errors or external disturbances. For example, feedback torque can be calculated based on the generator's actual output power fluctuations, speed oscillation amplitudes, or the rate of change of bus voltage.

[0082] After obtaining the feedforward torque and / or feedback torque, the feedforward torque and / or feedback torque are used as compensation values ​​and superimposed on the obtained base mechanical torque. The superposition operation can be, for example, a simple algebraic summation. Through this superposition process, the generated torque required for power generation includes not only the adjustment amount needed to eliminate voltage errors, but also the prediction and correction amounts needed to cope with dynamic changes in the system, thereby improving the robustness and response speed of voltage control.

[0083] Step S203: Perform amplitude limiting and / or gradient processing on the torque required for power generation to obtain the target mechanical torque.

[0084] Considering the limitations of physical actuators and the safety of system operation, this embodiment performs constraint processing on the calculated torque required for power generation to ensure that it is within the safe operating range of the motor and power generation system. This step includes amplitude limiting processing and gradient processing.

[0085] Limiting is designed to restrict the absolute value of the torque required for power generation to between the system's maximum and minimum allowable torque. When the required torque exceeds a preset upper threshold, it is clamped to the upper threshold; when it falls below a preset lower threshold, it is clamped to the lower threshold. For example, for a generator with a rated power of 30kW, the maximum generating torque may be limited to 200Nm. The specific value of the limiting threshold can be set based on physical parameters such as the motor's thermal capacity, the inverter's current carrying capacity, and the mechanical strength of the drive system, to prevent device damage or system instability due to excessive torque.

[0086] Gradient processing is used to limit the rate of change of torque, that is, to control the magnitude of torque change per unit time, avoiding system shocks caused by drastic jumps in torque command. In one optional implementation, gradient processing calculates the difference between the torque required for power generation at the current moment and the actual torque output at the previous moment. If the difference exceeds a preset gradient threshold, the torque output is gradually adjusted according to the maximum allowable rate of change. For example, the preset gradient threshold can be set to a change of no more than 50 Nm per second. Through gradient processing, the output trajectory of the torque command can be smoothed, the impact load on the mechanical transmission system can be reduced, and the ripple fluctuations of the bus voltage can be suppressed.

[0087] The torque value after amplitude limiting and / or gradient processing is determined as the target mechanical torque, so that the target mechanical torque meets the bus voltage regulation requirements while also meeting the system's safety constraints and stability requirements.

[0088] Step S204: Based on the target mechanical torque and the equivalent speed of the motor, generate the direct-axis current command and quadrature-axis current command of the motor to control the motor to output the target mechanical torque.

[0089] Equivalent speed refers to the real-time speed of the motor under current operating conditions, and it is an important variable that determines the torque-current mapping relationship of the motor. In motor control theory, the magnitude of torque is closely related to the direct-axis current id and the quadrature-axis current iq, and this relationship changes with the speed, especially after entering the field weakening region.

[0090] Generating current commands based on target mechanical torque and equivalent speed can be achieved through methods such as lookup tables or analytical calculations. In the lookup table method, the optimal id and iq values ​​for the motor under different speed and torque combinations are pre-tested using bench tests, creating a two-dimensional or three-dimensional current map, i.e., a current mapping table. During operation, based on the target mechanical torque and equivalent speed, the corresponding direct-axis and quadrature-axis current commands are obtained by interpolating and querying the current map. In the analytical calculation method, the required id and iq values ​​can be solved in real-time based on the motor's mathematical model, such as voltage equations and flux linkage equations, combined with the current speed and torque target.

[0091] In this embodiment, the generated direct-axis current command and quadrature-axis current command are sent to the motor's current loop controller, driving the inverter to output the corresponding three-phase current, thereby controlling the motor to output the target mechanical torque. Through this torque regulation, the generator's load characteristics are changed, thereby regulating the bus voltage to change towards the required bus voltage value.

[0092] This embodiment utilizes the bus voltage difference as the drive signal, combined with proportional-integral control, feedforward feedback compensation, and amplitude-limiting gradient constraints, to achieve accurate calculation and smooth control of the target mechanical torque. Based on this, current command mapping using equivalent speed ensures that the motor can accurately output the required mechanical torque, thereby effectively raising the bus voltage in generator mode and guaranteeing voltage stability of the battery-less or small-capacity battery range extender system under all operating conditions.

[0093] In one embodiment, the process of generating the direct-axis current command and quadrature-axis current command of the motor based on the target mechanical torque and the equivalent speed of the motor may specifically include:

[0094] Based on the target mechanical torque and the equivalent speed of the motor, the direct-axis current command and the quadrature-axis current command are obtained by looking up a table using either a maximum torque-to-current ratio control strategy or a maximum torque-to-voltage ratio control strategy; or...

[0095] Based on the target mechanical torque and the equivalent speed of the motor, the direct-axis current command and the quadrature-axis current command are obtained by looking up a table through current mapping.

[0096] In practical applications, after determining the target mechanical torque and the equivalent speed of the motor, these parameters need to be mapped to the motor's direct-axis current command and quadrature-axis current command to drive the motor to operate according to the target mechanical torque. This mapping process is a key step in achieving precise torque control, and its core lies in quickly determining the corresponding current combination based on the motor's optimal operating curve under different operating conditions or a preset mapping relationship.

[0097] Maximum Torque Per Ampere (MTPA) control strategy refers to a control strategy that, while maintaining the same output electromagnetic torque, optimizes the space vector of the stator current to minimize the stator current amplitude, thereby reducing motor copper losses and improving system efficiency. In this embodiment, the implementation of the MTPA control strategy is typically based on a pre-calculated and stored two-dimensional data table. This table uses the motor's equivalent speed and target mechanical torque as indexes, and the optimal direct-axis current and quadrature-axis current as stored values. During the offline calculation phase, based on the motor's mathematical model and parameters, for each speed point and torque demand point, the current combination that minimizes the current amplitude is solved, thus constructing a complete MTPA data table.

[0098] The Maximum Torque Per Voltage (MTPV) control strategy is mainly applied during the high-speed operation of the motor. When the back electromotive force approaches the inverter's output voltage limit, the phase of the current vector is adjusted to output the maximum possible electromagnetic torque while satisfying voltage constraints, thereby extending the motor's constant power operating range. Similar to the aforementioned strategies, the MTPV strategy also obtains a mapping table covering speed, torque, and optimal current command through offline calculation.

[0099] When performing a lookup operation, the target mechanical torque and the equivalent motor speed detected by sensors are first obtained. Then, these two parameters are used as index keys to access the maximum torque-to-current ratio (MTPA) or maximum torque-to-voltage ratio (MTV) data tables pre-stored in the controller's memory. For example, when the motor is in the low-to-medium speed constant torque operating region, by querying the MTPA table, the direct-axis current command and quadrature-axis current command that minimize the stator current can be obtained, thus achieving the most efficient torque output. When the motor speed increases to enter the deep field-weakening region, the query switches to the MTPV table, obtaining the optimal combination of current commands based on voltage boundary constraints to ensure that the required torque can still be output under voltage saturation conditions. If the speed or torque corresponding to the index value is located between table nodes, bilinear interpolation or other interpolation algorithms can be used to calculate the accurate direct-axis current command and quadrature-axis current command based on the current values ​​of the surrounding four nodes.

[0100] As an alternative implementation, a method for obtaining current commands through current mapping lookup tables is also provided. Current mapping lookup tables can refer to directly establishing a full-condition mapping relationship between the motor's equivalent speed, target mechanical torque, and direct-axis and quadrature-axis current commands. This mapping relationship covers the entire operating range of the motor from startup and loading to field-weakening operation. It can be based on measured data obtained from motor bench testing and calibration, or theoretical data obtained from motor model simulation calculations. This method is not limited to a specific optimal control theory, but constructs a mapping table according to the actual control requirements of the system, such as balancing efficiency, response speed, or stability under specific operating conditions. During the lookup process, the target mechanical torque and equivalent speed are used as inputs, and the corresponding direct-axis and quadrature-axis current commands are directly output through lookup tables or interpolation calculations. Through a pre-set current mapping table, the controller can quickly respond to changes in torque commands, simplifying the complexity of real-time calculations and meeting the needs of engineering applications with high real-time requirements.

[0101] In summary, this embodiment converts the target mechanical torque and equivalent speed into specific direct-axis and quadrature-axis current commands, providing precise input for subsequent current closed-loop control and ensuring a high degree of consistency between the motor output torque and the target mechanical torque. This command generation method based on lookup tables not only avoids complex online iterative calculations and reduces the computational load on the controller, but also guarantees the motor's operating performance across the entire operating range through pre-calibrated or calculated optimal data.

[0102] In one embodiment, see Figure 3 The flowchart of a specific implementation method for executing a second control branch disclosed in this embodiment of the invention, specifically step S104, may include:

[0103] Step S301: Based on the bus voltage difference between the required bus voltage value and the actual bus voltage value, calculate the direct-axis current adjustment amount using a proportional-integral controller.

[0104] When the actual bus voltage is higher than the required bus voltage, the system enters a second control branch to consume excess energy. First, the required bus voltage is compared with the actual bus voltage, and the difference is calculated as the bus voltage differential. This bus voltage differential serves as the input error signal for the proportional-integral (PI) controller. Based on this error signal, the PI controller performs calculations according to preset proportional and integral coefficients, outputting a direct-axis current adjustment. This process aims to convert the voltage error into a corresponding current regulation command, dynamically adjusting the motor's direct-axis current component, utilizing the motor's field weakening effect and internal copper losses to consume excess energy on the bus side, thereby reducing the bus voltage to the target value. The parameters of the PI controller (such as the proportional and integral coefficients) can be calibrated according to the specific power level of the power generation system, motor parameters, and load characteristics to ensure the response speed and stability of the regulation process.

[0105] Step S302: Limit the direct-axis current adjustment amount and superimpose the limited direct-axis current adjustment amount onto the basic direct-axis current command to obtain the target direct-axis current command.

[0106] To prevent excessive current surges during adjustment that could lead to system overload or loss of control, the calculated direct-axis current adjustment needs to be limited. This limiting process sets allowable upper and lower limits for current adjustment to ensure that the direct-axis current adjustment remains within the safe range that the motor and its controller can withstand. After limiting, the limited direct-axis current adjustment is superimposed on the basic direct-axis current command.

[0107] The basic direct-axis current command is typically determined by the motor's basic operating conditions, such as a default direct-axis current value obtained by looking up a table based on motor speed and torque requirements. Through a superposition operation, the field-weakening current component required for voltage loop regulation is injected into the basic control command, generating the final target direct-axis current command for current loop control. This target direct-axis current command includes not only the current component necessary to maintain normal motor operation but also the field-weakening current component used to consume bus power, thus achieving precise regulation of the bus voltage.

[0108] Step S303: Generate a control signal based on the target direct-axis current command and quadrature-axis current command to drive the motor.

[0109] The system uses the target direct-axis current command and quadrature-axis current command to generate the final control signal. This signal is typically generated as a pulse-width modulated wave using techniques such as Space Vector Pulse Width Modulation (SVPWM) to drive the motor. The method provided in this application increases the copper loss of the motor through a specific current configuration strategy, thereby consuming bus power.

[0110] Wherein, the direct-axis current adjustment amount is a magnetic weakening current, and / or, the quadrature-axis current command is set to zero to consume bus power by increasing the copper loss of the motor.

[0111] Specifically, the direct-axis current regulation, acting as a field-weakening current, generates a demagnetizing effect and increases the current component in the stator windings. Since copper losses are proportional to the square of the current, increasing the direct-axis current component significantly increases the resistive heating of the motor stator windings. Simultaneously, by setting the quadrature-axis current command to zero, the motor does not generate effective electromagnetic torque output, thus primarily converting the input electrical energy into heat energy for consumption, rather than into mechanical energy output. This zero-torque, high-current operating state can actively and rapidly absorb energy from the bus, effectively suppressing bus voltage surges and ensuring the bus voltage remains stable near the required value, preventing the system protection mechanism from being triggered due to excessive voltage.

[0112] In summary, this embodiment enables the power generation system to actively dissipate energy by adjusting the field weakening current of the motor when the bus voltage is too high. It achieves rapid response to voltage deviations through proportional-integral control, ensures system safety through amplitude limiting, achieves precise control of the field weakening depth through the superposition of target commands, and maximizes copper loss by combining a quadrature-axis current zeroing strategy. Thus, it achieves efficient bus voltage stability control without the need for energy storage devices such as batteries.

[0113] In one embodiment, the process of generating control signals based on target direct-axis current commands and quadrature-axis current commands may specifically include:

[0114] When the motor is in a power-consuming state, the quadrature-axis current command is set to zero, and the control signal is generated based on the target direct-axis current command and the quadrature-axis current command set to zero;

[0115] When the motor is not in a power-consuming state, the control signal is generated based on the target direct-axis current command and the current quadrature-axis current command.

[0116] When the power generation system determines that the actual bus voltage is higher than the required bus voltage, and needs to consume excess electrical energy through a weakening magnetic current to reduce the bus voltage, the motor enters a power-consuming state. This state signifies that the system's operating mode has changed from energy output to energy consumption. Under this condition, the quadrature-axis current command is forcibly set to zero to cut off the quadrature-axis magnetic field component that generates electromagnetic torque, ensuring that the motor does not output mechanical power during rotation and avoiding reverse drag on the prime mover or causing mechanical vibration.

[0117] The target direct-axis current command is generated by superimposing the direct-axis current regulation obtained through voltage closed-loop control with the basic direct-axis current command. Its value is typically negative, used to generate a demagnetizing effect and increase internal copper losses in the motor. A control signal is generated by combining the quadrature-axis current command (set to zero) with the target direct-axis current command to drive the inverter switching transistors, allowing the motor to absorb excess energy from the bus using only the resistive losses generated by the direct-axis current. This method achieves a stable drop in bus voltage without generating mechanical work, effectively preventing load disturbances caused by uncontrolled quadrature-axis current, and improving the system's stability and safety during energy dissipation.

[0118] If the motor is not in a power-consuming state, it indicates that the system is operating in normal power generation, drive, or other non-pure power-consuming modes. In this case, normal torque output or voltage support functions must be maintained. Under these conditions, the current quadrature-axis current command is retained and participates in the generation of control signals. This quadrature-axis current command is usually calculated based on torque requirements (including the torque required for power generation) using strategies such as maximum torque-to-current ratio or maximum torque-to-voltage ratio, and is used to establish the magnetic field that generates rotating torque. Simultaneously, the target direct-axis current command is superimposed with a corresponding field-weakening adjustment component according to voltage regulation requirements, to help suppress voltage rise when the voltage is high, or to optimize the magnetic field distribution when the voltage is low. Combining the target direct-axis current command and the current quadrature-axis current command, control signals are generated using coordinate transformation and SVPWM techniques to drive the motor. This process satisfies the closed-loop regulation requirements of the bus voltage and ensures the electromagnetic torque output characteristics of the motor under non-power-consuming conditions, ensuring the continuity and smooth transition of current commands when the system switches between different operating conditions, and avoiding control oscillations or torque shocks caused by sudden command changes.

[0119] In summary, the method provided by this invention dynamically adjusts the assignment strategy of the quadrature-axis current command based on real-time identification of the motor's operating state: in the power-consuming state, it forces the value to zero to isolate the mechanical torque path, ensuring the purity and safety of the field weakening power consumption process; in the non-power-consuming state, it retains the original command logic to maintain the system's multi-condition adaptability and dynamic response performance. This state-branch-based control signal generation mechanism enables the power generation system to quickly switch to a voltage-stabilized power consumption mode when the voltage is too high, and seamlessly switch to a high-efficiency power generation or drive mode when the voltage is normal or low, thereby achieving precise and stable control of the bus voltage across the entire operating range.

[0120] In one embodiment, the bus voltage control method may further include:

[0121] In the event of a system state switch or a fault signal being received, a zeroing operation is performed on the integral element in the first control branch or the second control branch; and / or, amplitude limiting processing is performed on the output signal of the first control branch or the second control branch.

[0122] System state switching refers to a scenario where the operating mode of a power generation system changes abruptly during operation, such as switching from standby mode to generation mode, from generation mode to power consumption mode, or switching between different load levels. Such changes in operating conditions are often accompanied by instantaneous changes in the characteristics of the control target or the controlled object. Fault signals refer to abnormal status messages detected by the system's internal diagnostic mechanisms, such as communication packet loss, sensor value overflow, or over-temperature protection. These sudden situations can all disturb the bus voltage control loop. This process aims to eliminate the adverse cumulative effects of state transitions or faults through specific protection logic, maintaining stable system operation.

[0123] When the system state changes or a fault signal is received, the original control logic is no longer applicable to the new operating conditions. The accumulated historical error value in the integral term becomes a source of interference, causing a large overshoot or violent oscillation in the control output, leading to voltage runaway. Therefore, a forced zeroing operation is performed to reset the historical accumulated value of the integral term to zero. This action instantly cuts off the inertial influence of the past state on the current control, allowing the controller to respond to the new operating conditions with a completely new initial state. This effectively avoids voltage surges during mode switching and ensures a smooth transition of the bus voltage.

[0124] Simultaneously or alternatively, amplitude limiting processing is performed on the output signals of the first or second control branch. The output signal can refer to the calculated control quantity used to drive the actuator (such as a motor torque command or current command). Under system state switching or fault disturbances, the feedback mechanism may experience short-term abnormal feedback, causing the control loop to calculate extreme control commands exceeding the physical device's carrying capacity. By using preset upper and lower boundaries, the amplitude of the output signal is physically constrained, clamping it within a safe range. For example, for the target mechanical torque output by the first control branch, amplitude limiting processing can prevent the motor output torque from exceeding the mechanical strength limit; for the direct-axis current regulation output by the second control branch, amplitude limiting processing can prevent the current from exceeding the thermal withstand limit of the inverter or motor windings. Through this boundary constraint mechanism, excessive actuator movement caused by abnormal feedback can be prevented, thus keeping the bus voltage and critical equipment parameters within the safe operating range when the system encounters sudden situations.

[0125] In summary, when a system state switch or fault signal is detected, this invention eliminates the interference of historical control inertia on the current state by resetting the integral stage. Simultaneously, output signal limiting processing constructs a final safety barrier, constraining extreme control quantities within physically feasible ranges. The combination of these two methods effectively solves the problem of drastic voltage fluctuations caused by integral saturation or output overshoot in range-extended power generation systems during mode switching or fault triggering, ensuring the safe and stable operation of the system under complex dynamic conditions.

[0126] For ease of understanding, see [link to relevant documentation]. Figure 4 The present invention discloses a schematic diagram of a bus voltage control process for a power generation system. The bus voltage control principle is as follows:

[0127] The bus voltage demand value Udc_ref and the actual bus voltage value Udc_act are used to calculate the difference and output the bus voltage difference Udc_diff.

[0128] The bus voltage difference Udc_diff serves as the basis for selecting the control branch. When the bus voltage difference Udc_diff ≥ 0, the first control branch is triggered. In the first control branch, the bus voltage difference Udc_diff is fed into the proportional branch and the integral branch of the proportional-integral controller. The proportional branch multiplies the bus voltage difference Udc_diff by the proportional coefficient Kp, and the integral branch multiplies the bus voltage difference Udc_diff by the integral coefficient Ki and then performs integration. The outputs of the proportional branch and the integral branch are superimposed to obtain the basic mechanical torque. This basic mechanical torque is superimposed with the feedforward torque and / or feedback torque obtained based on torque signals and speed signals to obtain the torque required for power generation. The torque required for power generation is then subjected to amplitude limiting and / or gradient processing to obtain the target mechanical torque. The target mechanical torque and the equivalent speed of the motor are input together to MTPA, MTPV or current MAP. MTPA, MTPV or current MAP performs a lookup based on the target mechanical torque and the equivalent lookup speed, and outputs the corresponding direct-axis current command id_ref and quadrature-axis current command iq_ref to control the motor to output the target mechanical torque.

[0129] When the actual bus voltage value Udc_act is greater than the required bus voltage value Udc_ref, i.e., when the bus voltage difference Udc_diff < 0, the second control branch is triggered. In the second branch, the bus voltage difference Udc_diff is input to the proportional-integral controller, and after proportional-integral calculation and limiting processing, the direct-axis current adjustment Δid is output. The direct-axis current adjustment Δid is superimposed on the basic direct-axis current command obtained from the current MAP lookup table to obtain the target direct-axis current command id_ref and the target quadrature-axis current command iq_ref, which drive the motor to run.

[0130] The proportional-integral controller performs integral zeroing processing under input conditions such as amplitude limit value and fault status signal; the amplitude limit processing is subject to boundary constraints such as preset amplitude limit value and system status signal.

[0131] Corresponding to the above method embodiments, the present invention also discloses a bus voltage control device for a power generation system.

[0132] See Figure 5 The present invention discloses a schematic diagram of a bus voltage control device for a power generation system, which may include:

[0133] The acquisition unit 401 is used to acquire the bus voltage demand value and the actual bus voltage value of the power generation system.

[0134] The voltage deviation direction determination unit 402 is used to determine the voltage deviation direction based on the bus voltage demand value and the actual bus voltage value.

[0135] The voltage deviation direction includes a first deviation direction and a second deviation direction, wherein the first deviation direction is opposite to the second deviation direction.

[0136] The first control branch execution unit 403 is used to execute a first control branch in response to the voltage deviation direction being the first deviation direction, and to control the bus voltage to change to the bus voltage demand value by adjusting the mechanical torque of the motor in the power generation system.

[0137] The second control branch execution unit 404 is used to execute the second control branch in response to the voltage deviation direction being the second deviation direction, and to control the bus voltage to change to the bus voltage demand value by adjusting the field weakening current of the motor.

[0138] In summary, this invention discloses a bus voltage control device for a power generation system. By acquiring the actual and required values ​​of the bus voltage and determining the direction of the voltage deviation between them, a first control branch is executed when the deviation direction is the first deviation direction to adjust the mechanical torque of the motor to raise the voltage. When the deviation direction is the second deviation direction, a second control branch is executed to adjust the field weakening current of the motor to consume electricity and lower the voltage. Thus, the corresponding control branch is dynamically selected according to the direction of the voltage deviation, enabling the system to supplement electrical energy through torque adjustment when the voltage is low and consume excess electrical energy through field weakening when the voltage is high, forming a bidirectional active adjustment mechanism. Without relying on large-capacity energy storage elements for buffering, it can still effectively suppress voltage oscillations caused by load changes, ensuring that the bus voltage stably converges to the required value across the entire operating range, avoiding overvoltage or undervoltage faults, and ensuring reliable system operation.

[0139] In one embodiment, the voltage deviation direction determination unit 402 can be specifically used for:

[0140] If the actual value of the bus voltage is less than or equal to the required value of the bus voltage, the direction of the voltage deviation is determined to be the first deviation direction.

[0141] If the actual value of the bus voltage is greater than the required value of the bus voltage, the direction of the voltage deviation is determined to be the second deviation direction.

[0142] In one embodiment, the first control branch execution unit 403 can be specifically used for:

[0143] Based on the bus voltage difference between the required bus voltage value and the actual bus voltage value, the foundation mechanical torque is calculated using a proportional-integral controller.

[0144] Obtain the feedforward torque and / or feedback torque used to compensate for the basic mechanical torque, and superimpose the feedforward torque and / or the feedback torque with the basic mechanical torque to obtain the torque required for power generation;

[0145] The torque required for power generation is subjected to amplitude limiting and / or gradient processing to obtain the target mechanical torque;

[0146] Based on the target mechanical torque and the equivalent speed of the motor, direct-axis current command and quadrature-axis current command of the motor are generated to control the motor to output the target mechanical torque.

[0147] In one embodiment, the first control branch execution unit 403 can also be used for:

[0148] Based on the target mechanical torque and the equivalent speed of the motor, the direct-axis current command and the quadrature-axis current command are obtained by looking up a table using either a maximum torque-to-current ratio control strategy or a maximum torque-to-voltage ratio control strategy; or...

[0149] Based on the target mechanical torque and the equivalent speed of the motor, the direct-axis current command and the quadrature-axis current command are obtained by looking up a table through current mapping.

[0150] In one embodiment, the second control branch execution unit 404 can be specifically used for:

[0151] Based on the bus voltage difference between the required bus voltage value and the actual bus voltage value, the direct-axis current adjustment is calculated using a proportional-integral controller.

[0152] The direct-axis current adjustment amount is limited, and the limited direct-axis current adjustment amount is superimposed on the basic direct-axis current command to obtain the target direct-axis current command.

[0153] Control signals are generated based on the target direct-axis current command and quadrature-axis current command to drive the motor.

[0154] Wherein, the direct-axis current adjustment amount is a magnetic weakening current, and / or, the quadrature-axis current command is set to zero to consume bus power by increasing the copper loss of the motor.

[0155] In one embodiment, the second control branch execution unit 404 can also be used for:

[0156] When the motor is in a power-consuming state, the quadrature-axis current command is set to zero, and the control signal is generated based on the target direct-axis current command and the quadrature-axis current command set to zero;

[0157] When the motor is not in a power-consuming state, the control signal is generated based on the target direct-axis current command and the current quadrature-axis current command.

[0158] In one embodiment, the bus voltage control device may further include:

[0159] The execution unit is used to perform a zeroing operation on the integral element in the first control branch or the second control branch when a system state switch is detected or a fault signal is received.

[0160] And / or,

[0161] Amplitude limiting is performed on the output signal of the first control branch or the second control branch.

[0162] It should be noted that the specific working principles of each component in the device embodiment can be found in the corresponding section of the method embodiment, and will not be repeated here.

[0163] Corresponding to the above embodiments, the present invention also discloses a computer-readable storage medium that stores at least one instruction, which, when executed by a processor, implements the steps shown in the embodiments of the bus voltage control method for a power generation system.

[0164] Corresponding to the above embodiments, such as Figure 6 As shown, the present invention also provides a schematic diagram of the structure of a motor controller, which may include: a processor 1 and a memory 2;

[0165] The processor 1 and memory 2 communicate with each other via communication bus 3.

[0166] Processor 1, for executing at least one instruction;

[0167] Memory 2 is used to store at least one instruction;

[0168] Processor 1 may be a central processing unit (CPU), an application specific integrated circuit (ASIC), or one or more integrated circuits configured to implement embodiments of the present invention.

[0169] Memory 2 may include high-speed RAM memory, and may also include non-volatile memory, such as at least one disk storage device.

[0170] In this embodiment, processor 1 executes at least one instruction to implement the steps shown in the method embodiment for controlling the bus voltage of a power generation system.

[0171] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0172] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0173] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for controlling bus voltage in a power generation system, characterized in that, include: Obtain the required bus voltage and the actual bus voltage of the power generation system; Based on the required bus voltage value and the actual bus voltage value, the voltage deviation direction is determined. The voltage deviation direction includes a first deviation direction and a second deviation direction, and the first deviation direction is opposite to the second deviation direction. In response to the voltage deviation direction being the first deviation direction, the first control branch is executed, and the bus voltage is controlled to change towards the bus voltage demand value by adjusting the mechanical torque of the motor in the power generation system; In response to the voltage deviation direction being the second deviation direction, a second control branch is executed, which controls the bus voltage to change towards the required bus voltage value by adjusting the field weakening current of the motor.

2. The bus voltage control method according to claim 1, characterized in that, Determining the direction of voltage deviation based on the required bus voltage value and the actual bus voltage value includes: If the actual value of the bus voltage is less than or equal to the required value of the bus voltage, the direction of the voltage deviation is determined to be the first deviation direction. If the actual value of the bus voltage is greater than the required value of the bus voltage, the direction of the voltage deviation is determined to be the second deviation direction.

3. The bus voltage control method according to claim 1 or 2, characterized in that, The execution of the first control branch, by adjusting the mechanical torque of the motor in the power generation system to control the bus voltage to change towards the bus voltage demand value, includes: Based on the bus voltage difference between the required bus voltage value and the actual bus voltage value, the foundation mechanical torque is calculated using a proportional-integral controller. Obtain the feedforward torque and / or feedback torque used to compensate for the basic mechanical torque, and superimpose the feedforward torque and / or the feedback torque with the basic mechanical torque to obtain the torque required for power generation; The torque required for power generation is subjected to amplitude limiting and / or gradient processing to obtain the target mechanical torque; Based on the target mechanical torque and the equivalent speed of the motor, direct-axis current command and quadrature-axis current command of the motor are generated to control the motor to output the target mechanical torque.

4. The bus voltage control method according to claim 3, characterized in that, The step of generating the direct-axis current command and quadrature-axis current command of the motor based on the target mechanical torque and the equivalent speed of the motor includes: Based on the target mechanical torque and the equivalent speed of the motor, the direct-axis current command and the quadrature-axis current command are obtained by looking up a table using either a maximum torque-to-current ratio control strategy or a maximum torque-to-voltage ratio control strategy; or... Based on the target mechanical torque and the equivalent speed of the motor, the direct-axis current command and the quadrature-axis current command are obtained by looking up a table through current mapping.

5. The bus voltage control method according to claim 1 or 2, characterized in that, The execution of the second control branch, by adjusting the field weakening current of the motor to control the bus voltage to change towards the required bus voltage value, includes: Based on the bus voltage difference between the required bus voltage value and the actual bus voltage value, the direct-axis current adjustment is calculated using a proportional-integral controller. The direct-axis current adjustment amount is limited, and the limited direct-axis current adjustment amount is superimposed on the basic direct-axis current command to obtain the target direct-axis current command. Control signals are generated based on the target direct-axis current command and quadrature-axis current command to drive the motor. Wherein, the direct-axis current adjustment amount is a magnetic weakening current, and / or, the quadrature-axis current command is set to zero to consume bus power by increasing the copper loss of the motor.

6. The bus voltage control method according to claim 5, characterized in that, The generation of control signals based on the target direct-axis current command and quadrature-axis current command includes: When the motor is in a power-consuming state, the quadrature-axis current command is set to zero, and the control signal is generated based on the target direct-axis current command and the quadrature-axis current command set to zero; When the motor is not in a power-consuming state, the control signal is generated based on the target direct-axis current command and the current quadrature-axis current command.

7. The bus voltage control method according to claim 1, characterized in that, The bus voltage control method further includes: In the event that a system state switch is detected or a fault signal is received, a zeroing operation is performed on the integral element in the first control branch or the second control branch. And / or, Amplitude limiting is performed on the output signal of the first control branch or the second control branch.

8. A bus voltage control device for a power generation system, characterized in that, include: The acquisition unit is used to acquire the required bus voltage value and the actual bus voltage value of the power generation system. The voltage deviation direction determination unit is used to determine the voltage deviation direction based on the bus voltage demand value and the actual bus voltage value. The voltage deviation direction includes a first deviation direction and a second deviation direction, wherein the first deviation direction is opposite to the second deviation direction. The first control branch execution unit is used to execute the first control branch in response to the voltage deviation direction being the first deviation direction, and to control the bus voltage to change to the bus voltage demand value by adjusting the mechanical torque of the motor in the power generation system. The second control branch execution unit is used to execute the second control branch in response to the voltage deviation direction being the second deviation direction, and to control the bus voltage to change towards the bus voltage demand value by adjusting the field weakening current of the motor.

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores at least one instruction, which, when executed by a processor, implements the bus voltage control method for a power generation system as described in any one of claims 1 to 7.

10. A motor controller, characterized in that, The motor controller includes: a memory and a processor; The memory is used to store at least one instruction; The processor is used to execute the at least one instruction to implement the bus voltage control method for a power generation system as described in any one of claims 1 to 7.

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