Transport refrigeration system

Abstract

The invention is entitled "Transport refrigeration system". A method of controlling a transport refrigeration system (1), wherein the transport refrigeration system comprises a refrigeration unit (7) comprising a compressor (8), and a refrigerated chamber (6) operably coupled to the refrigeration unit (7), and wherein the transport refrigeration system is operable in a standby mode in which the transport refrigeration system (1) is connected to and powered by a main power supply (2), the method comprising: providing a first compressor speed, wherein the first compressor speed is less than a maximum speed of the compressor (8) of the refrigeration unit (7); determining when the transport refrigeration system (1) is operating in the standby mode; determining whether a current time is within a first time period; and when it is determined that the transport refrigeration system (1) is operating in the standby mode, and when it is determined that the current time is within the first time period: operating the compressor (8) of the refrigeration unit (7) in accordance with the first compressor speed.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to transport refrigeration systems, and more particularly, to apparatuses and methods for controlling such transport refrigeration systems. BACKGROUND

[0002] Generally, cold chain distribution systems are used to transport and distribute goods, or more particularly, perishable goods and environmentally sensitive goods that can be susceptible to temperature, humidity, and other environmental factors (herein referred to as perishable goods). Perishable goods can include, but are not limited to, fruits, vegetables, grains, legumes, nuts, eggs, dairy products, seeds, flowers, meats, poultry, fish, ice, and pharmaceuticals. Advantageously, cold chain distribution systems allow perishable goods to be effectively transported and distributed without damage or other undesirable effects.

[0003] Refrigerated vehicles and trailers are commonly used to transport perishable goods in cold chain distribution systems. Transport refrigeration systems are operatively installed to the vehicles or trailers with a cargo space within the vehicle or trailer for maintaining a controlled temperature environment within the cargo space.

[0004] Conventionally, transport refrigeration systems used in conjunction with refrigerated vehicles and refrigerated trailers include a refrigeration unit having a refrigerant compressor, a condenser with one or more associated condenser fans, an expansion device, and an evaporator with one or more associated evaporator fans, connected via appropriate refrigerant lines in a closed refrigerant flow circuit. The refrigerant compressor operates as a pump, pressurizing and controlling the circulation of refrigerant. Air or air / gas mixture is drawn from the interior volume of the cargo space by means of the evaporator-associated evaporator fan(s) through the air side of the evaporator in heat exchange relationship with the refrigerant, whereby the refrigerant absorbs heat from the air, thereby cooling the air. The cooled air is then supplied back to the cargo space.

[0005] On commercially available transport refrigeration systems used in conjunction with refrigerated vehicles and refrigerated trailers, the compressor, and generally the other components of the refrigeration unit, are powered by a prime mover (e.g., a diesel engine) during the course of a shipment.

[0006] It is often desirable that the refrigerated compartment also be cooled when the vehicle is not moving and / or the prime mover (e.g., a diesel engine) is inactive, for example, to ensure that temperature-sensitive goods are not damaged or spoiled. Accordingly, in some conventional refrigeration units, an electrical architecture is provided such that the refrigeration unit can be connected to and powered by a main power source, so that the unit can cool the refrigerated compartment when the vehicle is, for example, parked in a warehouse loading bay on standby.

[0007] Transport refrigeration systems can generate significant levels of noise, especially when multiple transport refrigeration vehicles are on standby at the same warehouse. Warehouses are increasingly likely to be located in areas where local noise regulations are enforced, and it would be advantageous to provide a system that can manage those noise levels. SUMMARY

[0008] Viewed from a first aspect, the present invention provides a method of controlling a transport refrigeration system, wherein the transport refrigeration system comprises a refrigeration unit comprising a compressor, and a refrigerated chamber operably coupled to the refrigeration unit, and wherein the transport refrigeration system is operable in a standby mode in which the transport refrigeration system is connected to and powered by a mains power supply, the method comprising:

[0009] providing a first compressor speed, wherein the first compressor speed is less than a maximum speed of the compressor of the refrigeration unit;

[0010] determining when the transport refrigeration system is operating in the standby mode;

[0011] determining whether a current time is within a first time period; and

[0012] when it is determined that the transport refrigeration system is operating in the standby mode, and when it is determined that the current time is within the first time period:

[0013] operating the compressor of the refrigeration unit in accordance with the first compressor speed.

[0014] The Applicant has recognised that transport refrigeration systems, when operating in a standby mode, can be located in the same area as a plurality of other transport refrigeration systems, such as at a warehouse. Furthermore, these areas can be subject to local noise regulation. Advantageously, the method provided allows the speed of the compressor of a transport refrigeration system to be constrained when in standby mode and during a first time period, i.e. a period when noise constraints can be in place. Thereby, the noise generated by the refrigeration system can be appropriately mitigated during the period when it can be necessary to do so.

[0015] Operating the compressor in accordance with a first compressor speed comprises running the compressor at a speed that does not exceed the first compressor speed, i.e. the first compressor speed can be considered to be a compressor speed limit. Thereby, operating the compressor in accordance with a first compressor speed can comprise running the compressor at any suitable speed that is less than or equal to the first speed, including non-zero speeds and 0 RPM (i.e. the compressor is off).

[0016] Operating the compressor according to the first compressor speed during the first time period can include operating the compressor according to a speed profile. The speed profile can be uniform, i.e. the compressor is operated at a constant speed (not exceeding the first compressor speed) during the first time period. The speed profile can be continuously varying, wherein at any time during the first time period, the speed profile can vary between, for example, 0 RPM and the first compressor speed (i.e. the compressor speed limit).

[0017] By providing a method of varying the compressor speed during the first time period, it is possible to meet the cooling demand of the refrigerated chamber while limiting the noise generated during this time period.

[0018] The speed profile can include discrete“on” and“off” periods arranged during the first time period. During the“off” periods, the compressor is turned off (i.e. runs at 0 RPM). During the“on” periods, the compressor is operated at a non-zero speed not exceeding the first compressor speed (i.e. the compressor speed limit).

[0019] The maximum speed of the compressor can be the fastest possible operating speed of the compressor.

[0020] Alternatively, the maximum speed of the compressor can be a compressor speed that has been selected for standard operation. In this case, the standard operating speed of the compressor is selected to be the maximum speed at which the compressor can be run without compromising the durability and / or reliability of the transport refrigeration system.

[0021] The first compressor speed (the compressor speed limit) can be any suitable (non-zero) speed less than the maximum speed of the compressor, such as, for example, (i) less than 10% of the maximum speed of the compressor; (ii) 10-20% of the maximum speed of the compressor; (iii) 20-30% of the maximum speed of the compressor; (iv) 30-40% of the maximum speed of the compressor; (v) 40-50% of the maximum speed of the compressor; (vi) 50-60% of the maximum speed of the compressor; (vii) 60-70% of the maximum speed of the compressor; (viii) 70-80% of the maximum speed of the compressor; (ix) 80-90% of the maximum speed of the compressor; or (x) more than 90% of the maximum speed of the compressor.

[0022] The compressor can be operated by a controller of the transport refrigeration system, e.g. a control.

[0023] The compressor can comprise an AC electric motor, and the transport refrigeration system can comprise an electric power supply system configured to be connected to a mains power supply and configured to supply power to the AC electric motor. The electric motor and the electric power supply system together can form a variable frequency drive.

[0024] Accordingly, the power supply system can be configured to convert and / or transform the AC power supplied to the electric motor and can include at least one power conversion component. The power supply system can include at least one of an AC-to-AC voltage / frequency converter, an AC-to-DC rectifier, a DC-to-AC inverter, and a DC-to-DC voltage converter.

[0025] The speed and torque of the compressor can be controlled by the power supply system by adjusting the frequency and / or voltage of the AC power supplied to the electric motor. When the compressor is turned off, the power supply system can not supply power to the electric motor. The controller can command the power supply system to adjust the frequency of the AC power supplied to the compressor.

[0026] The method can include providing, e.g., obtaining, measuring, or otherwise determining, information about the transport refrigeration system. The information can include an interior temperature of the refrigerated chamber (e.g., as monitored by a temperature sensor in the refrigerated chamber) and / or a target interior temperature (e.g., a“setpoint”) of the refrigerated chamber. The setpoint can be manually provided (e.g., entered into a user interface of the transport refrigeration system) by a user, e.g., a driver. The information can include a specification of the refrigeration unit (e.g., a cooling capacity of the refrigeration unit) and / or a specification of the compressor (e.g., a maximum speed of the compressor).

[0027] The method can include communicating at least some of the information to a remote server, such as the transport refrigeration system communicating information indicative of at least the interior temperature of the refrigerated chamber, optionally along with some of all of the other information, to the remote server. The information can be communicated only once, e.g., before the first time period begins. Alternatively, the information can be communicated periodically, e.g., while the transport refrigeration unit is in a standby mode.

[0028] The method can include determining (e.g., calculating) a first compressor speed (for the first time period) by the remote server and based on the information.

[0029] The method can include communicating the first compressor speed from the remote server to the transport refrigeration system.

[0030] The transport refrigeration system can receive the first compressor speed and operate the compressor of the refrigeration unit in accordance with the first compressor speed.

[0031] Additionally or alternatively, the method can include determining (e.g., calculating) a speed profile (for the first time period) by the remote server and based on the information. Determining the speed profile can include determining on-periods and off-periods arranged during the first time period by the speed profile. The method can include communicating the speed profile (optionally including the on-periods and off-periods) to the transport refrigeration system and can further include operating the compressor of the refrigeration unit in accordance with the speed profile.

[0032] This information can be used to check, for example, control operation of the transport refrigeration unit and adjust operation of the compressor.

[0033] For example, if the remote server determines that the internal temperature of the refrigerated chamber is outside of a safety margin of the setpoint (e.g., in the case that the door of the refrigerated chamber has been inadvertently left open), the first compressor speed (and / or speed profile) can be adjusted in accordance with this information.

[0034] In other embodiments, the method can include operating the compressor in an override mode in which the compressor can be run at any desired speed, including a speed greater than the first compressor speed. In a normal operating mode, the compressor is operated in accordance with the first compressor speed received from the remote server (as described above). However, if the internal temperature of the refrigerated chamber is outside of a safety margin of the setpoint, the transport refrigeration system can need to respond before the remote server is updated with information indicating the problem. Accordingly, the transport refrigeration system is able to operate the compressor in an override mode in which the operating instructions from the remote server are overridden. The compressor can be run in the override mode until the information indicates that the compressor can be operated in accordance with the first compressor speed, i.e., the internal temperature of the refrigerated chamber is within the safety margin of the setpoint.

[0035] Although in the above-described embodiments the remote server provides the first compressor speed, in alternative embodiments the first compressor speed, optionally together with the first time period, can be manually provided (e.g., entered into a user interface of the transport refrigeration system) by a user, e.g., a driver.

[0036] In various embodiments, the first time period can be the entire period in which the transport refrigeration system is in standby mode, i.e., when the transport refrigeration system is connected to the mains power supply. Alternatively, the first time period can be a period in which it is desired to reduce the noise level, e.g., during night time, and / or during a period in which local noise constraints are in place.

[0037] The transport refrigeration system comprises a plurality of refrigerated chambers, each of the plurality of refrigerated chambers being operatively coupled to a respective refrigeration unit, and the method of controlling the transport refrigeration system can comprise:

[0038] obtaining information comprising an internal temperature and / or a target internal temperature of each of the plurality of refrigerated chambers;

[0039] determining, based on the information, a set of first compressor speeds comprising a first compressor speed (e.g., a compressor speed limit) of the compressor of each refrigeration unit; and

[0040] operating each compressor in accordance with a corresponding first compressor speed of the set of first compressor speeds when the current time is within the first time period.

[0041] Advantageously, the speed of each compressor of the transport refrigeration system can be independently limited in order to reduce the overall noise generated by the transport refrigeration system. This information can be used to calculate the cooling requirements of the respective refrigerated compartment and determine how each compressor should operate in accordance with the set of compressor speed limits in order to reduce the overall noise of the transport refrigeration system while ensuring that the cooling demand is met.

[0042] Operating the compressor(s) in accordance with the set of first compressor speeds (the set of compressor speed limits) can include operating the compressor(s) in accordance with a set of speed profiles. One or more or each speed profile can be determined to be complementary to one or more or each other speed profile in the set of speed profiles. For example, the“off’ period (or low speed operation period) of one or more (e.g., a subset) of the plurality of compressors can coincide with the“on’ period (or high speed operation period) of a different one or more (e.g., a different subset) of the plurality of compressors.

[0043] Viewed from a second aspect, the present application provides a transport refrigeration system operable in a standby mode in which the transport refrigeration system is connected to and powered by a main power supply, the transport refrigeration system comprising:

[0044] a refrigeration unit comprising a compressor;

[0045] a refrigerated compartment operably coupled to the refrigeration unit; and

[0046] a controller, wherein the controller is configured to:

[0047] receive a first compressor speed, wherein the first compressor speed is less than a maximum speed of the compressor of the refrigeration unit;

[0048] determine when the transport refrigeration system is operating in the standby mode;

[0049] determine whether a current time is within a first time period; and

[0050] when it is determined that the transport refrigeration system is operating in the standby mode and when it is determined that the current time is within the first time period:

[0051] operate the compressor of the refrigeration unit in accordance with the first compressor speed.

[0052] The controller can be configured to operate the compressor according to the first compressor speed by operating the compressor at a speed that does not exceed the first compressor speed, i.e., the first compressor speed can be considered a compressor speed limit. Thus, operating the compressor according to the first compressor speed can include operating the compressor at any suitable speed less than or equal to the first speed, including non-zero speeds and 0 RPM (i.e., the compressor is off).

[0053] During the first time period, operating the compressor according to the first compressor speed can include operating the compressor according to a speed profile. The speed profile can be uniform, i.e., the compressor is operated at a constant speed (not exceeding the first compressor speed) during the first time period. The speed profile can be continuously variable, where at any time during the first time period, the speed profile can vary between, for example, 0 RPM and the first compressor speed (i.e., the compressor speed limit).

[0054] The speed profile can include discrete“on” and“off” periods arranged during the first time period. During the“off” periods, the compressor is off (i.e., operating at 0 RPM). During the“on” periods, the compressor is operated at a speed greater than 0 RPM but not exceeding the first compressor speed (i.e., the compressor speed limit).

[0055] The maximum speed of the compressor can be the fastest possible operating speed of the compressor.

[0056] Alternatively, the maximum speed of the compressor can be a compressor speed that has been selected for standard operation. In this case, the standard operating speed of the compressor is selected to be the maximum speed at which the compressor can operate without compromising the durability and / or reliability of the transport refrigeration system.

[0057] The first compressor speed (compressor speed limit) can be any suitable (non-zero) speed less than the maximum speed of the compressor, such as, for example, (i) less than 10% of the maximum speed of the compressor; (ii) 10-20% of the maximum speed of the compressor; (iii) 20-30% of the maximum speed of the compressor; (iv) 30-40% of the maximum speed of the compressor; (v) 40-50% of the maximum speed of the compressor; (vi) 50-60% of the maximum speed of the compressor; (vii) 60-70% of the maximum speed of the compressor; (viii) 70-80% of the maximum speed of the compressor; (ix) 80-90% of the maximum speed of the compressor; or (x) greater than 90% of the maximum speed of the compressor.

[0058] The compressor can include an AC electric motor, and the transport refrigeration system can include an electric power supply system configured to be connected to a main power source and configured to supply power to the electric motor. Together, the electric motor and the electric power supply system can form a variable frequency drive.

[0059] Thus, the power supply system can be configured to convert and / or transform the AC power supplied to the electric motor and can comprise at least one power conversion component. The power supply system can preferably comprise an AC-to-AC voltage / frequency converter, but additionally can comprise an AC-to-DC rectifier, a DC-to-AC inverter, or a DC-to-DC voltage converter.

[0060] The speed and torque of the compressor can be controlled by the power supply system by adjusting the frequency and / or voltage of the AC power supplied to the electric motor. When the compressor is to be turned off, the power supply system can not supply power to the electric motor. The controller can be configured to command the power supply system to adjust the frequency of the AC power supplied to the compressor.

[0061] The controller can be configured to obtain information about the transport refrigeration system, e.g., measured or otherwise determined. The information can include an internal temperature of the refrigerated chamber and / or a target internal temperature (e.g., a“setpoint”) of the refrigerated chamber. The transport refrigeration system can include a sensor for monitoring the internal temperature of the refrigerated chamber. The setpoint can be manually provided (e.g., input into a user interface of the transport refrigeration system) by a user (e.g., a driver). The information can include a specification of the refrigeration unit (e.g., a cooling capacity of the refrigeration unit) and / or a specification of the compressor (e.g., a maximum speed of the compressor).

[0062] The controller can be configured to communicate at least some of the information to a remote server, e.g., information indicating at least the internal temperature of the refrigerated chamber, optionally along with some of all of the other information, to the remote server. The controller can be configured to communicate at least some of the information only once, e.g., before the first time period begins. Alternatively, the controller can be configured to periodically communicate the information, e.g., while the transport refrigeration unit is in a standby mode.

[0063] The controller can be configured to receive the first compressor speed from the remote server, optionally along with the first time period.

[0064] Additionally or alternatively, the controller can be configured to receive a speed profile from the remote server, which optionally includes the on-period and the off-period. The controller can be configured to operate the compressor of the refrigeration unit during the first time period in accordance with the speed profile received from the remote server.

[0065] Although in the above-described embodiments the remote server provides the first compressor speed, in alternative embodiments the controller can be configured to manually receive the first time period and / or the first compressor speed, e.g., manually input into a user interface of the transport refrigeration system by a driver or other user.

[0066] The controller can be configured to operate the compressor in an override mode, in which the compressor can run at any desired speed, including speeds greater than the first compressor speed. In a normal operating mode, the compressor operates according to the first compressor speed received from the remote server (as described above). However, if the internal temperature of the refrigerated chamber is outside a safe range of the setpoint, the transport refrigeration system can need to respond before updating the remote server with information indicating the problem. Accordingly, the controller can be configured to operate the compressor in an override mode, in which operating instructions from the remote server are overridden. The compressor can run in the override mode until the information indicates that the compressor can operate according to the first compressor speed, i.e., the internal temperature of the refrigerated chamber is within the safe range of the setpoint.

[0067] In various embodiments, the first time period can be the entire time period that the transport refrigeration system is in standby mode, i.e., when the transport refrigeration system is connected to a main power supply. Alternatively, the first time period can be a time period during which it is desirable to reduce noise levels, e.g., during nighttime, and / or during a time period in which local noise constraints are in place.

[0068] The transport refrigeration system can include a plurality of refrigeration units, each operably coupled to a respective refrigerated chamber of the transport refrigeration system. The controller can be configured to obtain (e.g., measure) information including an internal temperature and / or a target internal temperature of each refrigerated chamber of the plurality of refrigerated chambers; determine a set of first compressor speeds (e.g., compressor speed limits) including a first compressor speed of the compressor of each refrigeration unit based on the information (or receive such a set of first compressor speeds from a remote server); and operate each compressor according to a corresponding first compressor speed of the set of first compressor speeds when the current time is within a first time period.

[0069] Operating the compressor(s) according to the set of first compressor speeds (the set of compressor speed limits) can include operating the compressor(s) according to the set of speed profiles. One or more or each speed profile can be determined to be complementary to one or more or each other speed profile of the set of speed profiles. For example, an“off’ period (or low speed operation period) of one or more (e.g., a subset) of the plurality of compressors can coincide with an“on’ period (or high speed operation period) of a different one or more (e.g., a different subset) of the plurality of compressors.

[0070] Viewed from a third aspect, the present application provides a method of controlling a plurality of transport refrigeration systems, each transport refrigeration system including a refrigeration unit including a compressor, and a refrigerated chamber operably coupled to the refrigeration unit, the method including: obtaining information including an internal temperature and / or a target internal temperature of the refrigerated chamber of each transport refrigeration system of the plurality of transport refrigeration systems;

[0071] determining a set of compressor speeds based on the information, the set of compressor speeds comprising a compressor speed of the compressor of the refrigeration unit of each of the plurality of transport refrigeration systems;

[0072] operating the compressor of the refrigeration unit of each of the plurality of transport refrigeration systems according to a corresponding compressor speed from the set of compressor speeds for the compressor.

[0073] Applicants have recognized that conventionally, in situations where a plurality of transport refrigeration systems are gathered together in the same area, such as a warehouse, noise peaks can be generated when a large number of compressors are operating at the same time. Advantageously, the method provided allows the speed of each compressor of the plurality of transport refrigeration systems to be constrained and / or controlled in a coordinated manner. Thus, the peak noise generated by the plurality of refrigeration systems in the same area can be limited by operating each compressor independently according to a corresponding compressor speed from the set of compressor speeds for the compressor.

[0074] The temperature information of each refrigerated chamber can be used to help coordinate the operation of the transport refrigeration systems. For example, if the internal temperature of a refrigerated chamber is close to or within a safety range of a target internal temperature (i.e. setpoint), the compressor speed of the corresponding compressor can be limited. If the internal temperature of a different refrigerated chamber is far from the target internal temperature or outside the safety range of the target internal temperature, the compressor speed of the corresponding compressor can need to be changed, for example, increased. The method can balance the compressor speed increases / decreases across the set of compressor speeds, thereby ensuring that the total noise generated at any given time can be reduced or minimized.

[0075] Similarly, the method can be implemented to allow the speed of each compressor of the plurality of transport refrigeration systems to be constrained and / or controlled in a coordinated manner to avoid power consumption peaks. Thus, the method can be used to limit the peak power consumption of the plurality of transport refrigeration systems at any given time. Advantageously, the maximum power rating of the electrical infrastructure of the warehouse can be reduced, thereby saving costs.

[0076] operating the compressor of the refrigeration unit of each of the plurality of transport refrigeration systems according to a corresponding compressor speed from the set of compressor speeds for the compressor comprises operating each compressor at a speed that does not exceed the corresponding compressor speed, i.e. the compressor speed can be considered a compressor speed limit. Thus, operating the compressor according to the compressor speed of the compressor can comprise operating the compressor at any suitable speed that is less than or equal to the corresponding compressor speed, including non-zero speeds and 0 RPM (i.e. the compressor is off).

[0077] The method can comprise obtaining a first time period, such as an operating period. The first time period can be a time period during which a reduced noise level is desired, for example during night time, and / or during a time period in which local noise constraints are in place.

[0078] The set of compressor speeds can comprise or can form part of a set of compressor speed profiles. Thus, the method can comprise determining, based on the information, a set of compressor speed profiles comprising a compressor speed profile for a compressor of a refrigeration unit of each of the plurality of transport refrigeration systems.

[0079] Operating each compressor during the first time period (operating period) in accordance with a corresponding compressor speed from the set of compressor speeds for that compressor can comprise operating each compressor in accordance with a corresponding speed profile from the set of speed profiles for that compressor.

[0080] At least one of the speed profiles can be uniform, i.e. the compressor is operated at a constant speed (which does not exceed the corresponding compressor speed (i.e. the corresponding compressor speed limit)) over the first time period. At least one of the speed profiles can vary continuously, wherein at any time during the first time period, the speed profile(s) can take a value between 0 RPM and the corresponding compressor speed (i.e. the corresponding compressor speed limit).

[0081] At least one of the set of speed profiles can comprise discrete“on” and“off” sub-periods arranged during the first time period. During the“off’ sub-periods, the compressor is turned off (i.e. runs at 0 RPM). During the“on” sub-periods, the compressor is operated at a non-zero speed which does not exceed the corresponding compressor speed (i.e. the corresponding compressor speed limit).

[0082] Advantageously, one or more or each speed profile can be determined to be complementary (e.g. out of phase) with at least one other speed profile in the set of speed profiles. Thus, when operating each compressor of a refrigeration unit of the plurality of transport refrigeration systems in accordance with a corresponding speed profile from the set of speed profiles for that compressor, one or more or each speed profile can be complementary (e.g. out of phase) with at least one other speed profile in the set of speed profiles. For example, the“off’ sub-periods (or low speed operating periods) of one or more (e.g. a subset) of the plurality of compressors can coincide with the“on” sub-periods (or high speed operating periods) of a different one or more (e.g. a different subset) of the plurality of compressors. Advantageously, by coordinating the operation of the plurality of compressors, noise peaks can be avoided and the total noise produced at any given time can be reduced or minimised.

[0083] Each transport refrigeration system is operable in a standby mode in which the transport refrigeration system is connected to and powered by a main power supply. The method can include determining when each of the plurality of transport refrigeration systems is operating in the standby mode. In this way, the method can control only those transport refrigeration systems that are in the standby mode, as it is likely that the plurality of transport refrigeration systems that are in the standby mode will be located in the same area, e.g., in a warehouse. In this way, the compressor speed can be limited only when necessary, e.g., when a large number of transport refrigeration systems are gathered together in the same area, and the generated noise can be significant.

[0084] Each transport refrigeration system can include a controller configured to control operation of a compressor of the transport refrigeration system.

[0085] Each compressor can include an AC electric motor, and each transport refrigeration system can include a power supply system configured to be connected to a main power supply and configured to supply power to the AC electric motor. Together, the electric motor and the power supply system can form a variable frequency drive.

[0086] The power supply system can thus be configured to convert and / or transform the AC power supplied to the electric motor, and can include at least one power conversion component. The power supply system can include at least one of an AC-to-AC voltage / frequency converter, an AC-to-DC rectifier, a DC-to-AC inverter, and a DC-to-DC voltage converter.

[0087] The speed and torque of the compressor can be controlled by the power supply system by adjusting the frequency and / or voltage of the AC power supplied to the electric motor. When the compressor is turned off, the power supply system can not supply power to the electric motor. The controller can command the power supply system to adjust the frequency of the AC power supplied to the compressor.

[0088] The method includes obtaining, e.g., measuring or otherwise determining, information about one or more or each of the plurality of transport refrigeration systems. The information can include the specifications of one or more or each of the plurality of refrigeration units (e.g., the cooling capacity of the refrigeration unit) and / or the specifications of one or more or each of the plurality of compressors (e.g., the maximum speed of the compressor).

[0089] The method can include communicating at least some of the information to a remote server, such as a controller of one or more or each of the transport refrigeration systems, at least communicating information indicative of an interior temperature of a refrigerated compartment of the transport refrigeration system to the remote server. A target interior temperature of the refrigerated compartment can also be communicated to the remote server. Alternatively, the remote server can obtain the target interior temperature from elsewhere, such as a database of the remote server. The information can be communicated only once, for example, before the start of the first time period (operating period). Alternatively, the information can be communicated periodically, for example, when the transport refrigeration unit is in a standby mode. The communication between the remote server and the controller of each of the plurality of transport refrigeration systems can be over a wireless network, such as a telematics network, and / or a wired connection(s).

[0090] Determining the set of compressor speeds based on the information can be performed by the remote server. The remote server can calculate the set of compressor speeds based on the information and optionally the first time period (operating period). Thus, the remote server can be provided with computing power (i.e., one or more processors and one or more databases) to process the information received from each of the plurality of transport refrigeration systems and determine the set of compressor speeds.

[0091] The method can include the remote server communicating the set of compressor speeds to the plurality of transport refrigeration systems, i.e., by communicating the compressor speed for the compressor of each transport refrigeration system to the corresponding transport refrigeration system. Each transport refrigeration system can receive its corresponding compressor speed and operate its compressor in accordance with the received compressor speed.

[0092] As described above, the method can include determining (e.g., calculating) the set of speed profiles (for the operating period) by the remote server and based on the information. Determining the set of speed profiles can include determining the on and off sub-periods of one or more of the speed profiles in the set of speed profiles. The method can include the remote server communicating the set of compressor speed profiles to the plurality of transport refrigeration systems, i.e., by communicating each speed profile (optionally including on and off sub-periods) for the compressor of each transport refrigeration system to the transport refrigeration system. The method can further include each transport refrigeration system receiving its corresponding compressor speed profile and can include operating the compressor of the refrigeration unit of the corresponding transport refrigeration system in accordance with the speed profile.

[0093] The information can be used to check, for example, the operation of controlling the plurality of transport refrigeration systems and adjust the operation of at least one compressor accordingly.

[0094] For example, if it is determined that the internal temperature of one of the refrigerated compartments is outside of a safety margin of the set point for the refrigerated compartment (e.g., in the event that the door to the refrigerated compartment has been inadvertently left open), the corresponding compressor speed (and / or speed profile) of the set of compressor speeds can be adjusted in accordance with this information.

[0095] In other embodiments, the method can include operating the compressor in an override mode, where the compressor can operate at any desired speed, including a speed greater than the corresponding compressor speed determined for the compressor. In the normal operating mode, the compressor operates in accordance with the compressor speed received from the remote server (as described above). However, if the internal temperature of the associated refrigerated compartment is outside of a safety range of the set point, the transport refrigeration system can need to respond as quickly as possible, i.e., before the remote server is updated with information indicating the problem. Accordingly, each transport refrigeration system is capable of operating its compressor in an override mode, where the operating instructions from the remote server are overridden. Each compressor can operate in the override mode until information indicates that the compressor can operate in accordance with the corresponding compressor speed, i.e., the internal temperature of the refrigerated compartment is within the safety range of the set point.

[0096] The remote server can be configured to receive an indication that a compressor is operating in an override mode. When calculating the set of compressor speeds, the remote server can include this indication in its consideration. For example, one or more of the set of compressor speeds can be decreased in response to determining that one of the compressors is operating in an override mode, i.e., operating at a maximum speed. Thereby, even though one of the compressors of the plurality of transport refrigeration systems must operate at an increased (e.g., maximum) speed, the total peak noise generated by the plurality of transport refrigeration systems can be maintained at a reduced level.

[0097] Viewed from a fourth aspect, the present application provides a system comprising:

[0098] a plurality of transport refrigeration systems, each transport refrigeration system comprising:

[0099] a refrigeration unit comprising a compressor;

[0100] a refrigerated compartment operably coupled to the refrigeration unit; and

[0101] a controller configured to monitor an internal temperature of the refrigerated compartment and control operation of the compressor; and

[0102] a remote server configured to:

[0103] obtain information comprising the internal temperature of the refrigerated compartment of each of the plurality of transport refrigeration systems and a target internal temperature;

[0104] determining, based on the information, a set of compressor speeds, the set of compressor speeds comprising a compressor speed of the compressor of the refrigeration unit of each of the plurality of transport refrigeration systems; and

[0105] communicating each compressor speed of the set of compressor speeds to a corresponding transport refrigeration system;

[0106] wherein the controller of each of the plurality of transport refrigeration systems is configured to operate the compressor of the refrigeration unit of the transport refrigeration system in accordance with a corresponding compressor speed for the compressor from the set of compressor speeds.

[0107] The system of the fourth aspect of the application provides the advantages provided by the method of the third aspect of the application.

[0108] Operating the compressor of the refrigeration unit of each of the plurality of transport refrigeration systems in accordance with a corresponding compressor speed for the compressor from the set of compressor speeds comprises operating each compressor at no more than the corresponding compressor speed, i.e. the compressor speed can be considered to be a compressor speed limit. Thus, operating the compressor in accordance with the compressor speed of the compressor can comprise operating the compressor at any suitable speed less than or equal to the corresponding compressor speed, including a non-zero speed and 0 RPM (i.e. the compressor is off).

[0109] The remote server can be configured to obtain a first time period, such as an operating time period. The first time period can be a time period during which it is desirable to reduce the noise level, for example during night time, and / or during a time period in which local noise constraints are in place.

[0110] The set of compressor speeds can comprise or can form part of a set of compressor speed profiles. Thus, the remote server can be configured to determine (e.g. calculate) a set of compressor speed profiles based on the information, the set of compressor speed profiles comprising a compressor speed profile of the compressor of the refrigeration unit of each of the plurality of transport refrigeration systems.

[0111] During the first time period (operating time period), operating each compressor in accordance with a corresponding compressor speed for the compressor from the set of compressor speeds can comprise operating each compressor in accordance with a corresponding speed profile for the compressor from the set of speed profiles.

[0112] At least one of the speed profiles can be uniform, i.e., the compressor operates at a constant speed (which does not exceed the corresponding compressor speed (i.e., the corresponding compressor speed limit)) over the first time period. At least one of the speed profiles can vary continuously, wherein at any time during the first time period, the speed profile(s) can take a value between 0 RPM and the corresponding compressor speed (i.e., the corresponding compressor speed limit).

[0113] At least one of the set of speed profiles can include discrete“on” and“off” sub-periods arranged during the first time period. During the“off’ sub-period, the compressor is turned off (i.e., operates at 0 RPM). During the“on” sub-period, the compressor operates at a non-zero speed which does not exceed the corresponding compressor speed (i.e., the corresponding compressor speed limit).

[0114] Advantageously, one or more or each speed profile can be determined to be complementary (e.g., out of phase) with at least one other speed profile in the set of speed profiles. Thereby, when operating the compressors of the refrigeration units of each transport refrigeration system according to the corresponding speed profile for that compressor from the set of speed profiles, one or more or each speed profile can be complementary (e.g., out of phase) with at least one other speed profile in the set of speed profiles. For example, the“off’ sub-periods (or low speed operation periods) of one or more (e.g., a subset) of the plurality of compressors can coincide with the“on” sub-periods (or high speed operation periods) of a different one or more (e.g., a different subset) of the plurality of compressors. Advantageously, by coordinating the operation of the plurality of compressors, noise peaks can be avoided, and the total noise generated at any given time can be reduced or minimized.

[0115] Each transport refrigeration system can be operable in a standby mode in which the transport refrigeration system is connected to and powered by a main power supply. The remote server can be configured to determine when each transport refrigeration system of the plurality of transport refrigeration systems is operating in the standby mode. In this way, the remote server can only control those transport refrigeration systems which are in the standby mode, as it is likely that the plurality of transport refrigeration systems which are in the standby mode will be located in the same area, e.g., in a warehouse (in which the remote server can be located). In this way, the compressor speeds can only be limited when necessary, e.g., when a large number of transport refrigeration systems are gathered together in the same area, and the noise generated can be significant.

[0116] Each compressor can comprise an AC electric motor, and each transport refrigeration system can comprise an electric power supply system configured to be connected to a main power supply, and configured to supply power to the AC electric motor. The electric motor and the electric power supply system together can form a variable frequency drive.

[0117] Accordingly, the power supply system can be configured to convert and / or transform the AC power supplied to the electric motor and can include at least one power conversion component. The power supply system can include at least one of an AC-to-AC voltage / frequency converter, an AC-to-DC rectifier, a DC-to-AC inverter, and a DC-to-DC voltage converter.

[0118] The speed and torque of the compressor can be controlled by the power supply system by adjusting the frequency and / or voltage of the AC power supplied to the electric motor. When the compressor is turned off, the power supply system can not supply power to the electric motor. The controller can command the power supply system to adjust the frequency of the AC power supplied to the compressor.

[0119] The information can include specifications (e.g., cooling capacity of the refrigeration unit) of one or more or each of the plurality of refrigeration units and / or specifications (e.g., maximum speed of the compressor) of one or more or each of the plurality of compressors.

[0120] The controller of one or more or each of the transport refrigeration systems can be configured to communicate at least some information of the respective refrigerated compartment to a remote server. For example, the controller can communicate at least information indicative of an internal temperature of the corresponding refrigerated compartment to the remote server. A target internal temperature of the refrigerated compartment can also be communicated to the remote server. Alternatively, the remote server can obtain the target internal temperature(s) from elsewhere (e.g., a database of the remote server). The information can be communicated only once, for example, before the start of a first time period (operating period). Alternatively, the information can be communicated periodically, for example, when the transport refrigeration unit is in a standby mode. The communication between the remote server and the controller of each refrigeration system of the plurality of transport refrigeration systems can be over a wireless network, such as a telematics network, and / or wired connection(s).

[0121] The remote server can be configured to calculate the set of compressor speeds based on the information and optionally the first time period (operating period). As such, the remote server can include one or more processors and one or more databases, the remote server being capable of processing the information received from each of the plurality of transport refrigeration systems and determining the set of compressor speeds.

[0122] The remote server can be configured to communicate the set of compressor speeds to the plurality of transport refrigeration systems, i.e., to communicate the compressor speed of the compressor of each transport refrigeration system to the corresponding transport refrigeration system. Each transport refrigeration system can receive its corresponding compressor speed and operate its compressor in accordance with the received compressor speed.

[0123] As described above, the remote server can be configured to determine (e.g., calculate) the set of speed profiles (for an operating period) based on the information. The remote server can be configured to determine the on and off sub-periods of one or more or each speed profile in the set of speed profiles. The remote server can be configured to transmit the set of compressor speed profiles to the plurality of transport refrigeration systems, i.e., to transmit each speed profile (optionally including the on and off sub-periods) of the compressor of each transport refrigeration system to that transport refrigeration system. Each controller can be configured to receive its corresponding compressor speed profile and can be configured to operate the compressor of the refrigeration unit of the corresponding transport refrigeration system according to the speed profile.

[0124] The information can be used to check, for example, the operation of controlling the plurality of transport refrigeration systems and to adjust the operation of at least one compressor accordingly.

[0125] For example, if it is determined that the interior temperature of one of the refrigerated compartments is outside a safety margin of the setpoint of the refrigerated compartment (e.g., in the case that the door of the refrigerated compartment has been inadvertently left open), the corresponding compressor speed (and / or speed profile) of the set of compressor speeds can be adjusted according to the information.

[0126] In other embodiments, the controller can be configured to operate the corresponding compressor in an override mode in which the compressor can be run at any desired speed, including speeds greater than the compressor speed determined for the compressor. In a normal operating mode, the compressor can be operated according to the compressor speed received from the remote server (as described above). However, if the interior temperature of the associated refrigerated compartment is outside a safety range of the setpoint, the transport refrigeration system can need to respond as quickly as possible, i.e., before the remote server is updated with information indicating the problem. Accordingly, the controller of each transport refrigeration system is able to operate its compressor in an override mode in which the operating instructions from the remote server are overridden. Each compressor can be run in the override mode until the information indicates that the compressor can be operated according to the corresponding compressor speed, i.e., the interior temperature of the refrigerated compartment is within the safety range of the setpoint.

[0127] The remote server can be configured to receive an indication that a compressor is being run in an override mode. The remote server can include this indication in its consideration when calculating the set of compressor speeds. For example, one or more of the set of compressor speeds can be reduced in response to determining that one of the compressors is operating in an override mode, i.e., running at a maximum speed. Thereby, even though one of the compressors of the plurality of transport refrigeration systems has to be run at an increased, e.g., maximum, speed, the total peak noise generated by the plurality of transport refrigeration systems can be maintained at a reduced level.

[0128] Viewed from a fifth aspect, the present application provides a server for coordinating control of a plurality of transport refrigeration systems, each transport refrigeration system comprising a refrigeration unit including a compressor and a refrigerated chamber operably coupled to the refrigeration unit, the server being configured to:

[0129] obtain information comprising an internal temperature and / or a target internal temperature of the refrigerated chamber of each of the plurality of transport refrigeration systems;

[0130] determine a set of compressor speeds based on the information, the set of compressor speeds comprising a compressor speed of the compressor of the refrigeration unit of each of the plurality of transport refrigeration systems; and

[0131] communicate each compressor speed of the set of compressor speeds to a corresponding transport refrigeration system.

[0132] The server of the fifth aspect of the present application provides the advantages provided by the method of the third aspect of the present application. The server of the fifth aspect of the present application can suitably comprise any one or more or each of the above-mentioned optional features.

[0133] The server can be a remote server, i.e. a server remote from the plurality of transport refrigeration systems. BRIEF DESCRIPTION OF DRAWINGS

[0134] Preferred embodiments of the present application will now be described in more detail, by way of example only, with reference to the accompanying drawings in which:

[0135] Figure 1 a transport refrigeration system connected to a mains power supply is shown; and

[0136] Figure 2 a plurality of transport refrigeration systems connected to a mains power supply and in communication with a remote server. Figure 1 DETAILED DESCRIPTION

[0137] Figure 1 A transport refrigeration system 1 connected to a mains power supply 2 is shown.

[0138] The transport refrigeration system 1 is shown in combination with a vehicle 3. The transport refrigeration system 1 comprises a transport container 4. The vehicle 3 comprises a vehicle engine 5, and can comprise an engine controller configured to control operation of the vehicle engine. The engine controller can be an electronic controller comprising a processor and an associated memory containing computer executable instructions which, when executed by the processor, cause the processor to perform various operations.

[0139] ​The transport container 4 includes at least one refrigerated compartment 6. The refrigerated compartment 6 is operably coupled to a refrigeration unit 7 of the transport refrigeration system 1, i.e., in use, the refrigeration unit 7 cools the refrigerated compartment 6. The refrigeration unit 7 is operated to maintain and / or control an internal temperature of the refrigerated compartment 6.

[0140] The refrigeration unit 7 includes a refrigerant compression device 8, a refrigerant heat rejection heat exchanger (not shown), an expansion device (not shown), and a refrigerant heat absorption heat exchanger 9, which are connected in a closed loop refrigerant circuit in refrigerant flow communication, and are arranged in a conventional refrigeration cycle.

[0141] The refrigeration unit 7 can also include one or more fans (not shown) associated with the refrigerant heat rejection heat exchanger 9 and / or the refrigerant heat absorption heat exchanger.

[0142] The refrigerant compression device 8 can include a single stage or multi-stage compressor, such as, for example, a reciprocating compressor or a scroll compressor. The compression device 8 has a compression mechanism (not shown) that is driven by an AC electric motor (not shown). The AC electric motor of the compression device 8 receives supplied electrical power via an electrical power supply system 11.

[0143] The electrical power supply system 11 is configured to be connected to a power source, and to draw electrical power for supply to the compression device 8 (and other components of the refrigeration unit 7). During the road operating mode, the electrical power supply system 11 is configured to draw electrical power from an electrical generator that is operably associated with a prime mover (e.g., a diesel engine). When the transport refrigeration system 1 is connected to the main power source 2, i.e., when the transport refrigeration system 1 enters the standby operating mode, the electrical power supply system 11 is configured to draw electrical power from the main power source 2.

[0144] The electrical power supply system 11 is configured to convert and / or transform electrical power so that it is suitable for use by the AC electric motor of the compression device 8. Thus, it is to be understood that the electrical power supply system 11 can include various power conversion components, such as an AC to AC voltage / frequency converter, an AC to DC rectifier, a DC to AC inverter, and a DC to DC voltage converter.

[0145] The transport refrigeration system 1 also includes a controller 10 that is configured for controlling operation of the transport refrigeration system 1, including but not limited to operation of the various components of the refrigeration unit 7, to provide and maintain a desired thermal environment within the refrigerated compartment 6.

[0146] In particular, the controller 10 is configured to operate the compression device 8 at a variable speed. For example, during the standby mode, the controller 10 is configured to operate the compression device 8 according to a first compressor speed. To exert such control, the controller 10 instructs the power supply system 11 to adjust the frequency and / or the voltage of the AC power supplied to the motor of the compression device 8. Thereby, the AC motor 8 and the power supply system 11 together can be considered as a variable frequency drive.

[0147] A method of controlling the refrigeration system 1 will now be described.

[0148] Initially, the controller determines whether the transport refrigeration system 1 is operating in a standby mode, i.e. whether the transport refrigeration system 1 is connected to the mains power supply 2. For example, the transport refrigeration system 1 can be operated in the standby mode when parked in a loading bay of a warehouse. In response to determining that the transport refrigeration system 1 is connected to the mains power supply 2, the controller 10 is configured to determine whether the current time is within a first time period. At the same time (or in advance), the controller 10 provides a first compressor speed. The first compressor speed is determined to be less than a maximum speed of the compressor 8.

[0149] When it is determined that the transport refrigeration system is operating in the standby mode, and when it is determined that the current time is within the first time period, the controller 10 continues to operate the compressor 8 according to the first compressor speed, i.e. the compressor speed limit.

[0150] To meet the cooling demand of the refrigerated compartment 6 of the transport refrigeration system 1, the compressor 8 can run for a longer time during the first time period, but at a reduced speed that does not exceed the compressor speed limit. Thereby, while there can be operational benefits of the compressor 8 running at its maximum speed (e.g. the internal temperature of the refrigerated compartment 6 reaches the target internal temperature in less time), by limiting the speed at which the compressor 8 can run during the first time period, the peak noise generated by the compressor 8 is also constrained.

[0151] Thereby, when there are a large number of transport refrigeration systems in standby in the same local area (e.g. in a loading bay of a warehouse, which can be located in a city or residential area where local noise regulations are enforced), the peak noise generated by the transport refrigeration systems can be constrained.

[0152] Operating the compressor 8 according to the first compressor speed can include operating the compressor 8 according to a speed profile. The compressor speed profile (i.e., compressor speed / time table or graph) associated with the first time period can define the operating speed of the compressor at a given instance. The speed profile can be continuous, discrete, or a combination of both. During the first time period, the speed profile can include an "on" sub-period in which the compressor 8 is operated at a non-zero speed that does not exceed the first compressor speed (i.e., compressor speed limit). During the first time period, the speed profile can include an "off sub-period in which the compressor speed is designated as 0 RPM (i.e., the compressor 8 is not supplied with power and / or is not operating).

[0153] The method can include providing, e.g., obtaining, measuring, or otherwise determining, information about the transport refrigeration system 1, such as the interior temperature of the refrigerated chamber 6. Other information can also be provided, such as a target interior temperature of the refrigerated chamber, a cooling capacity of the refrigeration unit, and a maximum speed of the compressor 8.

[0154] Generally, the refrigeration demand of the refrigerated chamber 6 is satisfied even if the compressor 8 is operated according to the compressor speed limit (i.e., the compressor 8 can be operated at a reduced speed for a longer period of time, e.g., the "on" sub-period of the first time period is longer). However, in some cases, the obtained information can indicate that the refrigeration demand is not satisfied when the compressor 8 is operated according to the first compressor speed (compressor speed limit). For example, the interior temperature of the refrigerated chamber 6 can be identified as being outside of a safe range of the setpoint of the refrigerated chamber 6. This can occur as a result of a malfunction in the transport refrigeration unit 7 or the refrigerated chamber 6 (e.g., in the case of a user inadvertently leaving the door of the refrigerated chamber 6 open). In such a case, the controller 10 of the transport refrigeration system 1 can be provided with an override mode that allows the compressor 8 to be operated at a speed that exceeds the compressor speed limit until the interior temperature of the refrigerated chamber 6 reaches the setpoint, or at least is within a safe range of the setpoint.

[0155] Figure 2 A plurality of transport refrigeration systems 1a, 1b are shown connected to the main power supply 2 and in communication with the remote server 100.

[0156] The transport refrigeration systems 1a, 1b operate in a similar manner as the transport refrigeration system 1 described above, but differ in the following respects.

[0157] The controllers 10a, 10b of each of the transport refrigeration systems 1a, 1b are in communication with the remote server 100. Such communication can be through a wireless connection as shown, or a wired connection. The wireless connection can be a wireless communication method such as, for example, radio, microwave, cellular, satellite, or another wireless communication method.

[0158] The remote server 100 can be located in a loading bay of a warehouse to coordinate operation of the transport refrigeration systems 1a, 1b. As such, the remote server 100 can be configured to only establish communication with the controllers 10a, 10b of the transport refrigeration systems 1a, 1b that are on site (i.e. within a particular range of the remote server 100).

[0159] The remote server 100 can also be in communication with the main power supply 2. Thereby, the remote server 100 can identify which of the transport refrigeration systems 1a, 1b is operating in the standby mode of operation based on which transport refrigeration system 1a, 1b is connected to the main power supply 2. Alternatively, the remote server 100 can obtain this information from the respective controllers 10a, 10b of the transport refrigeration systems 1a, 1b.

[0160] The method of controlling Figure 2 a system will now be described.

[0161] The remote server 100 is provided with information including the internal temperature and the target internal temperature of the refrigerated chamber of each of the transport refrigeration systems 1a, 1b.

[0162] The controller of each of the refrigeration systems 1a, 1b at least communicates the internal temperature of the corresponding refrigerated chamber 6a, 6b of each of the refrigeration systems 1a, 1b to the remote server 100. It can also communicate the target internal temperature of the corresponding refrigerated chamber 6a, 6b, or the remote server 100 can obtain the target internal temperature elsewhere (e.g. a loading schedule which dictates that perishable goods are to be loaded into the respective refrigerated chamber 6a, 6b which can require a particular temperature environment).

[0163] Upon receipt of this information, the remote server 100 determines a set of compressor speeds including a compressor speed for each compressor 8a, 8b of the transport refrigeration systems 1a, 1b.

[0164] The remote server 100 then sends the set of compressor speed limits to the controllers and instructs each controller to operate the respective compressor in accordance with the set of compressor speeds. The compressor speed acts as a compressor speed limit, i.e. operating the compressor in accordance with the assigned compressor speed includes running the compressor at any suitable speed less than or equal to the first speed, including non-zero speeds and 0 RPM (i.e. the compressor is off).

[0165] Thus, the remote server 100 can process information about the internal temperature conditions of the refrigerated chambers 6a, 6b of multiple transport refrigeration systems 1a, 1b to determine which compressors 8a, 8b can sustain their operating speeds being constrained in order to reduce the peak noise produced by the compressors 8a, 8b at any one time.

[0166] For example, in Figure 2In this case, the internal temperature of the refrigerated compartment 6a of the transport refrigeration system la can be further away from its target internal temperature than the internal temperature of the refrigerated compartment 6b of the transport refrigeration system lb. To ensure that the peak noise of the compressor operation does not exceed a certain threshold, the remote server 100 determines a compressor speed of the compressor 8a of the transport refrigeration system la (compressor speed limit) and a compressor speed of the compressor 8b of the transport refrigeration system lb (compressor speed limit). However, during this time period, the compressor speed of the compressor 8a is higher than the compressor speed 8b.

[0167] Similarly, the remote server 100 can calculate a speed profile for each compressor and each controller can thus operate the respective compressor according to the speed profile. The speed profile of each compressor defines how the compressor should be operated during a certain time period. Since the remote server has access to information of all transport refrigeration systems la, lb that are in standby, the remote server 100 can coordinate the speed profiles such that the peak noise of the operation of the compressors during a time period remains below a certain threshold. For example, with reference to Figure 2 Since the refrigeration unit will not necessarily need to be running all the time during standby mode, the “on” sub-periods of the compressor 8a can be coordinated to occur at the same time as the compressor 8b is in an “off” sub-period. Thus, the peak noise generated during this time remains reduced.

[0168] As briefly mentioned above, the remote server 100 can also have been provided with information such as (future) loading schedules of the plurality of transport refrigeration systems la, lb. This allows the remote server 100 to prioritize cooling of the refrigerated compartments 6a, 6b when necessary while maintaining the noise constraint.

[0169] For example, in case the transport refrigeration system la will be loaded one hour before the transport refrigeration system lb, the remote server 100 can prioritize cooling of the refrigerated compartment 6a before loading by increasing the associated compressor speed (compressor speed limit) and by correspondingly reducing the compressor speed (compressor speed limit) associated with the transport refrigeration system lb to balance the peak noise generated by the transport refrigeration systems la, lb.

[0170] The temperature information of one of the plurality of transport refrigeration systems 1a, 1b can further indicate that the transport refrigeration system 1a, 1b is malfunctioning or not operating correctly. Despite operating the respective refrigeration unit, the interior temperature of the refrigerated compartment 6a, 6b can be identified as not being within a safe range of a target interior temperature ("safe range" is a temperature range in which perishable goods can be stored without damage or other adverse effects). The refrigerated compartment 6a, 6b in question can have an interior temperature outside the safe range due to a defective component of the transport refrigeration system 1a, 1b, or can not be able to operate correctly because the transport refrigeration system 1a, 1b has been damaged, for example, the door of the refrigerated compartment has been inadvertently left open for a certain period of time.

[0171] In this case, the controller 10a, 10b of the damaged transport refrigeration system 1a, 1b is able to override the instructions from the remote server 100 and operate the compressor 8a, 8b at a speed greater than the compressor speed. Thus, the controller 10a, 10b of each transport refrigeration system 1a, 1b is able to operate its respective compressor 8a, 8b in an override mode in which the operating instructions from the remote server 100 are overridden. Each compressor 8a, 8b can run in the override mode until the information indicates that the compressor 8a, 8b can operate according to its compressor speed, i.e. the interior temperature of the refrigerated compartment 6a, 6b is within the safe range of the setpoint.

[0172] Thus, the system and method provide for peak noise reduction and control of a plurality of transport refrigeration systems 1a, 1b while maintaining effective temperature control of the refrigerated compartments 6a, 6b.

Claims

1. A method for controlling a transport refrigeration system, wherein the transport refrigeration system includes a plurality of cold storage compartments, each of the plurality of cold storage compartments being operatively coupled to a corresponding refrigeration unit including a compressor, and wherein the transport refrigeration system is operable in a standby mode, wherein in the standby mode the transport refrigeration system is connected to and powered by a main power supply, the method comprising: Obtain information including the internal temperature and / or target internal temperature of each of the plurality of cold storage compartments; Based on the information, a set of compressor speed curves is determined, including the compressor speed curve of each refrigeration unit. Determine when the transport refrigeration system is operating in the standby mode; Determine if the current time is within the first time period; as well as When it is determined that the transport refrigeration system is operating in the standby mode, and when it is determined that the current time is within the first time period, each compressor is operated according to the corresponding compressor speed curve in the set of compressor speed curves. Each compressor speed curve changes continuously and is complementary to at least one other compressor speed curve in the set of compressor speed curves.

2. The method as described in claim 1, wherein, One of the compressor speed curves in the set includes a closing sub-period that occurs simultaneously with the opening sub-period of one or more other compressor speed curves that are complementary to the compressor speed curve.

3. The method according to any one of claims 1-2, wherein, The step of determining the speed of the set of compressors is performed by a remote server, and the method further includes: Transmit at least some of the information to the remote server; and The remote server transmits the speed of each compressor in the set of compressor speeds to the corresponding transport refrigeration system.

4. The method according to any one of claims 1-2, wherein, The method further includes: Determine whether the internal temperature of the first refrigerator compartment in the plurality of refrigerator compartments is outside the range relative to the target internal temperature of the first refrigerator compartment; and When it is determined that the internal temperature of the first refrigerator compartment is outside the range, the first compressor of the first refrigeration unit operably coupled to the first refrigerator compartment is operated in overclocking mode, in which the first compressor operates independently of the corresponding compressor speed curve for the first compressor from the set of compressor speed curves.

5. The method of claim 4, wherein, The first compressor operates at a speed greater than the corresponding compressor speed curve for the first compressor.

6. A method for controlling multiple transport refrigeration systems, wherein, The method according to any one of claims 1-5 controls each of the plurality of transport refrigeration systems.

7. A transport refrigeration system operable in a standby mode, wherein the transport refrigeration system is connected to and powered by a main power supply in the standby mode, the transport refrigeration system comprising: Multiple cold storage compartments, each of which is operatively coupled to a corresponding refrigeration unit including a compressor; and Controller, wherein the controller is configured to: A set of compressor speed curves is obtained, including the compressor speed curves of the compressor of each refrigeration unit, wherein the set of compressor speed curves is based on information including the internal temperature and / or target internal temperature of each of the plurality of refrigeration compartments; Determine when the transport refrigeration system is operating in the standby mode; Determine if the current time is within the first time period; as well as When it is determined that the transport refrigeration system is operating in the standby mode, and when it is determined that the current time is within the first time period, each compressor is operated according to the corresponding compressor speed curve in the set of compressor speed curves. Each compressor speed curve changes continuously and is complementary to at least one other compressor speed curve in the set of compressor speed curves.

8. The transport refrigeration system of claim 7 further includes a power supply system configured to be connected to a main power source, wherein the controller is further configured to control the operation of the compressor of the refrigeration unit by adjusting the frequency and / or voltage of the AC power supplied to the compressor of the refrigeration unit.

9. The transport refrigeration system as described in any one of claims 7-8, wherein, The controller is also configured to: Determine whether the internal temperature of the first refrigerator compartment among the plurality of refrigerator compartments is outside the range relative to the target internal temperature of the first refrigerator compartment; and When it is determined that the internal temperature of the first refrigerator compartment is outside the range, the first compressor of the first refrigeration unit operably coupled to the first refrigerator compartment is operated in an override mode, in which the first compressor operates independently of the corresponding compressor speed curve for the first compressor from the set of compressor speed curves.

10. The transport refrigeration system as claimed in claim 9, wherein, The first compressor operates at a speed greater than the corresponding compressor speed curve for the first compressor.

11. A system comprising a plurality of transport refrigeration systems as claimed in any one of claims 7-10.

12. The system of claim 11, further comprising a server, the server being configured to: Obtain information including the internal temperature and / or target internal temperature of each refrigerated compartment of each transport refrigeration system; Based on the information, a set of compressor speed curves is determined for the corresponding transport refrigeration system; and The set of compressor speed curves are transmitted to the corresponding transport refrigeration system.

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