Compressor voltage protection module enabled based on soft starter detection

Abstract

Disclosed is a heating ventilation and air conditioning system, and the heating ventilation and air conditioning system includes: at least one analog-to-digital converter configured to sample voltage signals on or between one or more power lines to provide samples, the one or more power lines supplying power to a compressor; a voltage-based protection module configured to execute one or more voltage-based protection algorithms to protect the compressor; and a soft starter detection module configured to detect i) a presence of a soft starter and ii) an activity of the soft starter to ramp up a current to the compressor based on the sample, and to detect a current to the compressor based on detecting the presence of the soft starter and the activity of the soft starter, the voltage-based protection provided by the voltage-based protection module is disabled.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit and priority of U.S. Patent Application No. 18 / 240,182 filed on August 30, 2023, which claims the benefit and priority of Indian Patent Application No. 202221050278 filed on September 2, 2022. The entire disclosure of the above application is incorporated herein by reference. Technical Field

[0003] The present disclosure relates to a voltage protection module for a compressor of a heating, ventilation, and air conditioning (HVAC) system. Background Art

[0004] The background description provided herein is for the purpose of generally presenting the context of the present disclosure. To the extent that the work is described in this background section, the work of the presently named inventors and aspects of the description that may not otherwise be qualified as prior art at the time of filing are neither explicitly nor implicitly admitted to be prior art against the present disclosure.

[0005] The compressor protection module in the HVAC system protects the compressor from various faults. Some example compressor protection modules include a motor protection module based on a positive temperature coefficient (PTC), a scroll over-temperature protection module based on a negative temperature coefficient (NTC), a phase reversal protection module, a single-phase protection module, an over-voltage and under-voltage protection module, a phase imbalance protection module, a frequency supply over- and under-range protection module, and a compressor short cycle protection module. The PTC-based motor protection module and the NTC-based scroll over-temperature protection module prevent compressor overheating events. The phase reversal protection module prevents the compressor from rotating in reverse.

[0006] The single-phase protection module prevents the compressor from operating when one phase of the compressor is lost. The overvoltage and undervoltage protection module prevents the compressor from operating when the voltage is above or below a predetermined safe voltage operating range. The phase imbalance protection module prevents the compressor from operating when the phase imbalance of the compressor causes one phase voltage to be less than the other phase voltage. The frequency supply over- and under-range protection module prevents the compressor from operating when the frequency of the power supplied to the compressor is not within a predetermined safe operating range. The compressor short cycle protection module prevents the compressor from operating when the cooling cycle of the compressor is shortened, causing the compressor to turn on and off more frequently, which may degrade the compressor. Summary of the invention

[0007] A heating, ventilation and air conditioning system is disclosed and includes: at least one analog-to-digital converter configured to sample a voltage signal on or between one or more power lines to provide samples, wherein the one or more power lines supply power to a compressor; a voltage-based protection module configured to execute one or more voltage-based protection algorithms to protect the compressor; and a soft starter detection module configured to detect i) the presence of a soft starter and ii) the activity of the soft starter to ramp up current to the compressor based on the samples, and based on detecting the presence of the soft starter and the activity of the soft starter, disable the voltage-based protection provided by the voltage-based protection module.

[0008] In other features, the soft starter detection module is configured to: disable voltage-based protection provided by the voltage-based protection module during the soft start ramp period; and enable voltage-based protection provided by the voltage-based protection module in response to detecting the end of the soft start ramp period.

[0009] In other features, the soft starter detection module is configured to: detect whether the voltage signal is a chopped voltage signal; in response to detecting that the voltage signal is a chopped voltage signal, determine that the soft starter is ramping up the current to the compressor; and in response to detecting that the voltage signal is not a chopped voltage signal, determine that the soft starter is not ramping up the current to the compressor.

[0010] In other features, the soft starter detection module is configured to: determine a first root mean square voltage of the voltage signal; determine a second root mean square voltage of the voltage signal; determine whether the soft starter is ramping up current to the compressor based on a difference between the first root mean square voltage and the second root mean square voltage; and in response to determining that the soft starter is ramping up current to the compressor, disable voltage-based protection provided by the voltage-based protection module.

[0011] In other features, the soft starter detection module is configured to: determine a first rms voltage based on a square root of an average sum of squares of samples of the voltage signal; and determine a second rms voltage based on a peak value of the samples of the voltage signal divided by a square root of two.

[0012] In other features, the soft starter detection module is configured to: track the amount of time that the soft starter ramps up the current to the compressor during startup of the compressor; compare the amount of time to a maximum ramp time; and enable voltage-based protection provided by the voltage-based protection module based on the comparison of the amount of time to the maximum ramp time.

[0013] In other features, the soft starter detection module is configured to: in response to the above-mentioned amount of time being greater than the maximum ramp time, enable voltage-based protection provided by the voltage-based protection module; and in response to the above-mentioned amount of time being less than or equal to the maximum ramp time, maintain the voltage-based protection module in a disabled state.

[0014] In other features, the soft starter detection module is configured to: determine a peak voltage of a sample; determine a current partial sum of the sample; determine a cumulative partial sum based on the current partial sum; determine a first voltage based on the cumulative partial sum; determine a second voltage based on the peak voltage; and based on the first voltage and the second voltage, detect at least one of: i) the presence of a soft starter, and ii) the activity of the soft starter to ramp up current to the compressor.

[0015] In other features, the soft starter detection module is configured to: determine a first voltage based on a square root of a sum of average squares of the samples; determine a second voltage based on a peak voltage of the samples; and based on the first voltage and the second voltage, detect at least one of: i) the presence of a soft starter, and ii) the activity of the soft starter to ramp up current to the compressor.

[0016] In other features, the HVAC system further includes: a soft starter; a compressor; a contactor connected between the soft starter and the compressor; and a control module configured to close the contactor to supply current from the soft starter to the compressor.

[0017] In other features, the control module is configured to enable at least one analog-to-digital converter to sample the voltage signal after closing the contactor.

[0018] In other features, the one or more power lines supply power i) from the soft starter to the contactor, or ii) from the contactor to the compressor.

[0019] In other features, a soft starter detection method for a heating, ventilation, and air conditioning system is disclosed. The heating, ventilation, and air conditioning system includes a voltage-based protection module configured to execute one or more voltage-based protection algorithms to protect a compressor. The method includes: sampling a voltage signal on or between one or more power lines to provide a sample, wherein the one or more power lines supply power to the compressor; based on the sample, i) detecting the presence of a soft starter supplying power to the compressor, and ii) detecting the activity of the soft starter to ramp up current to the compressor; and based on detecting the presence of the soft starter and the activity of the soft starter, disabling the voltage-based protection provided by the voltage-based protection module.

[0020] In other features, the soft starter detection method further includes: disabling voltage-based protection provided by the voltage-based protection module during the soft start ramp period; and enabling voltage-based protection provided by the voltage-based protection module in response to detecting an end of the soft start ramp period.

[0021] In other features, the soft starter detection method also includes: detecting whether the voltage signal is a chopped voltage signal; in response to detecting that the voltage signal is a chopped voltage signal, determining that the soft starter is causing the current to the compressor to increase; and in response to detecting that the voltage signal is not a chopped voltage signal, determining that the soft starter is not causing the current to the compressor to increase.

[0022] In other features, the soft starter detection method also includes: determining a first root mean square voltage of the voltage signal; determining a second root mean square voltage of the voltage signal; determining whether the soft starter is ramping up the current to the compressor based on the difference between the first root mean square voltage and the second root mean square voltage; and in response to determining that the soft starter is ramping up the current to the compressor, disabling voltage-based protection provided by the voltage-based protection module.

[0023] In other features, the soft starter detection method further includes determining a first rms voltage based on a square root of a sum of average squares of samples of the voltage signal; and determining a second rms voltage based on a peak value of the samples of the voltage signal divided by a square root of two.

[0024] In other features, the soft starter detection method also includes: tracking the amount of time that the soft starter causes the current to the compressor to rise during startup of the compressor; comparing the amount of time to a maximum ramp time; and based on the comparison of the amount of time to the maximum ramp time, enabling voltage-based protection provided by a voltage-based protection module.

[0025] In other features, the soft starter detection method further includes: in response to the amount of time being greater than a maximum ramp time, enabling voltage-based protection provided by a voltage-based protection module; and in response to the amount of time being less than or equal to the maximum ramp time, maintaining the voltage-based protection module in a disabled state.

[0026] In other features, the soft starter detection method also includes: determining a peak voltage of the sample; determining a current partial sum of the sample; determining a cumulative partial sum based on the current partial sum; determining a first voltage based on the cumulative partial sum; determining a second voltage based on the peak voltage; and based on the first voltage and the second voltage, detecting at least one of: i) the presence of a soft starter, and ii) the activity of the soft starter to ramp up current to the compressor.

[0027] In other features, the soft starter detection method further includes determining a first voltage based on a square root of a sum of average squares of the samples; determining a second voltage based on a peak voltage of the samples; and based on the first voltage and the second voltage, detecting at least one of: i) the presence of a soft starter, and ii) the activity of the soft starter to ramp up current to the compressor.

[0028] In other features, the soft starter detection method further includes closing a contactor to supply current from the soft starter to the compressor; and enabling sampling of the voltage signal after closing the contactor.

[0029] In other features, the one or more power lines supply power i) from the soft starter to the contactor, or ii) from the contactor to the compressor.

[0030] Further areas of applicability of the present disclosure will become apparent from the detailed description, the claims and the accompanying drawings.The detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The present disclosure will be more fully understood from the detailed description and accompanying drawings, in which:

[0032] Figure 1 is an example voltage signal output of the soft starter during the initial current ramp-up period of compressor startup;

[0033] Figure 2 is an example graph showing compressor on and off periods for ramp-up period, maximum ramp time, and voltage protection period;

[0034] Figure 3 is an example HVAC system including a soft starter detection module according to the present disclosure;

[0035] Figure 4 is an example graph showing compressor on and off periods of a ramp-up period, a maximum ramp time, and a voltage protection period coinciding with the ramp-up period in accordance with the present disclosure; and

[0036] Figure 5A and Figure 5B (collectively referred to as FIG. 5 ) illustrates a soft starter detection method according to the present disclosure.

[0037] Among the drawings, reference numerals may be repeated to identify similar and / or identical elements. DETAILED DESCRIPTION

[0038] In HVAC systems, a soft starter is often used to drive the compressor to minimize the amount of inrush current experienced by the compressor during startup. Soft starters are also used to minimize voltage flicker on the power lines that supply power to the compressor. Figure 1 As shown, the soft starter generates a chopped waveform while ramping up the current during startup of the compressor. Figure 1 A voltage signal 100 output from a soft starter is shown having a chopped waveform including an irregular portion 102. Depending on the type of compressor (i.e., a three-phase compressor or a single-phase compressor), the soft starter may provide a three-phase output having three voltage signals or a single-phase output having a single voltage signal. One or more of the voltage signals may have a chopped (or distorted) waveform. Figure 1 The voltage signal 100 may represent, for example, the output of a single-phase soft starter, one or more phases of a three-phase soft starter, or a voltage measured between two phases of the output of a three-phase soft starter.

[0039] Due to the chopped waveform of the voltage signal, the voltage-based protection module that monitors the voltage signal may generate one or more interfering faults. Example interfering faults (or false alarms) are phase loss faults, reverse phase faults, undervoltage faults, frequency supply out of range faults, etc. This is because different points of the voltage signal are sampled. Due to the chopping or irregular nature of the corresponding waveform of the voltage signal, the voltage-based protection module may behave inappropriately and generate interfering faults. As an example, a chopped voltage signal with an irregular portion may be sampled. The samples may then be evaluated by a voltage-based protection algorithm performed by a voltage-based protection module. The calculations performed by these algorithms are based on samples, which may lead to false alarms about detecting faults. For example, if there is a 25% phase-to-phase deviation between samples of different phase voltage signals, the corresponding voltage-based protection module may detect a fault due to sampling the chopped (or irregular) portion of the voltage signal. The voltage-based protection module may then cut off the corresponding compressor based on the fault.

[0040] Examples set forth herein include an HVAC system that includes a protection module that includes a voltage-based protection module and a soft starter detection module. The soft starter detection module detects the active presence (or ramping activity) of a soft starter and the absence of a soft starter during a startup period of the compressor. The soft starter detection module enables and disables the voltage-based protection module based on the active presence and absence of the soft starter. This prevents false alarms during startup. The soft starter detection module disables the voltage-based protection module during a time period when the soft starter ramps up the current to the compressor.

[0041] The ramp-up times of the compressors are not consistent and may therefore vary. Figure 2A staircase waveform illustrating example off and on periods for a compressor is shown, including an actual ramp-up period during startup of the compressor. A first compressor on period 200 is shown having a first ramp-up period 202. The compressor is turned off and then turned on again. A second compressor on period 204 is shown having a second ramp-up period 206. The second ramp-up period 206 is shorter than the first ramp-up period 202. In order to disable the voltage-based protection module for the duration of any ramp-up period, the voltage-based protection module may be disabled for a maximum ramp-up period during each startup, wherein the duration of each ramp-up period is the same as or shorter than the maximum ramp-up period. However, if the voltage-based protection is disabled for the maximum ramp-up period, as shown in FIG. Figure 2 As can be seen in FIG. 1 , there is an intermediate unprotected period 210, 212 during which the current of the compressor rises (e.g., is above a predetermined level) and / or no longer increases and voltage-based protection is disabled. This occurs between i) the current ramp-up period and ii) the point in time when the maximum ramp-up period ends and voltage-based protection is enabled. No voltage-based protection is provided during the intermediate unprotected period 210, 212.

[0042] Maintaining the disablement of the voltage-based protection for the maximum soft start ramp time may also result in erratic behavior of the protection module executing the voltage-based protection algorithm. For example, this may occur if the system operator sets the soft starter ramp time to be greater than the maximum soft start ramp time. In this case, there is a period when the current to the compressor is still ramping up and therefore the soft starter is still providing a chopped waveform while the voltage-based protection is enabled. As another example, due to load changes, the soft starter ramp time may be less than the maximum soft starter ramp time. As a result, the voltage-based protection algorithm remains inactive for the maximum soft starter ramp time and there are intermediate unprotected periods, which may have a negative impact on the life of the motor windings in the event of a voltage-based fault occurring during the unprotected intermediate period.

[0043] To eliminate the described intermediate unprotected periods 210, 212, the soft starter detection module may disable the voltage-based protection module not for a maximum amount of ramp time, but for a practical amount of ramp time. The soft starter detection module detects (i) when the soft starter is actively ramping up the current and thus providing a chopped voltage signal output, and (ii) when the soft starter stops actively ramping up the current and thus providing an un-chopped voltage signal output. The soft starter detection module disables the voltage protection during the ramp up period and enables the voltage protection at the end of the ramp up period.

[0044] Figure 3An HVAC system 300 including a soft starter module 302, a contactor 304, a compressor 306, and an HVAC control module 308 is shown. The soft starter module 302 may be referred to as a soft starter and receives mains power. The mains power may be in the form of three-phase power provided via lines L1, L2, and L3. The soft starter 302 supplies a three-phase voltage output signal represented by line 310 to the contactor 304. Although the soft starter 302 is shown as a three-phase soft starter, the soft starter 302 may also be implemented as a single-phase soft starter and output a single-phase voltage signal instead of a three-phase voltage signal. During the startup of the compressor 306, the soft starter 302 ramps up the current supplied to the contactor 304 via line 310. The startup of the compressor 306 refers to when the compressor 306 is turned on and the current to the compressor 306 ramps up from zero current to a predetermined current level.

[0045] The contactor 304 may be implemented as a relay and include a coil 320 that is energized to close the contactor 304 and transfer power from the line 310 to a line 322 that supplies power to the compressor 306. The power supplied via the line 322 may be provided to a motor 330 of the compressor 306. The compressor 306 may also include a sensor 332 and a compressor control module 334. The compressor control module 334 may operate the motor 330 based on the output of the sensor 332. The sensor 332 may include a voltage sensor, a current sensor, a temperature sensor, and / or other sensors.

[0046] The HVAC control module 308 controls the operation of the contactor 304 and the compressor 306. The HVAC control module 308 may include analog-to-digital (A / D) converters 340, 342, 344 and a protection module 346. The protection module 346 controls the state of the coil 320, and thus controls the on and off state of the contactor 304 and the on and off state of the motor 330 of the compressor 306. The protection module 346 may include a voltage-based protection module 350, a soft starter detection module 352, an NTC-based vortex protection module 354, and a PTC-based motor protection module 356. The A / D converters 340, 342, 344 convert analog voltage signals into digital voltage signals. The analog voltage signal may be a voltage signal on line 322, as shown, or may be a voltage signal on line 310. The A / D converters 340, 342, 344 sample the analog voltage signal and provide the samples to the modules 350, 352. Modules 354 , 356 may operate based on the output of sensor 332 .

[0047] The soft starter detection module 352 enables and disables the voltage-based protection module 350 based on detecting that the soft starter 302 actively ramps up the current to the compressor 306. The soft starter detection module 352 detects the installation (or presence) of the soft starter 302 and whether the soft starter 302 actively ramps up the current based on samples from the A / D converters 340, 342, 344. This enables the soft starter detection module 352 and the protection modules 350, 354, 356 to be compatible with HVAC systems that include soft starters and HVAC systems that do not include soft starters. The modules 350, 354, 356 implement corresponding protection algorithms 362 that can be stored in the memory 360, such as reverse phase protection algorithms, single phase protection algorithms, overvoltage and undervoltage protection algorithms, phase imbalance protection algorithms, frequency supply over and under range protection algorithms, compressor short cycle protection algorithms, PTC-based motor protection algorithms, and NTC-based scroll over temperature protection algorithms. The memory may also store a soft starter algorithm 364 implemented by the soft starter detection module 352 for detecting the ramp up of the current of the compressor 306 and disabling and enabling voltage based protection based on the detection. The soft starter algorithm 364 does not conflict with the protection algorithm 362, and therefore the protection module 346 does not perform erratically.

[0048] The protection module 346 and / or the soft starter detection module 352 may include a counter 370, such as a soft starter presence counter and a soft starter absence counter. The soft starter presence counter is used to confirm that the soft starter 302 is actively ramping up the current during the startup event of the compressor 306. The soft starter absence counter is used to confirm that the soft starter has completed the ramping up of the current during the startup event of the compressor 306. The protection module 346 and / or the soft starter detection module 352 may also include a soft starter ramp timer 372. The soft starter ramp timer 372 is used to determine the ramp time of the soft starter. If the ramp time exceeds a set amount of time (e.g., 0.5 seconds to 2.0 seconds), the soft starter detection module 352 and / or the protection module 346 can override the operation of the soft starter detection module 352 and enable the voltage-based protection module 350. This ensures that the voltage-based protection module 350 and the corresponding implementation of the algorithm will not be disabled for too long and / or for an indefinite amount of time.

[0049] When the protection module 346 detects a fault, for example, via one or more of the modules 350, 354, 356 and / or via one or more of the algorithms implemented by the modules 350, 354, 356, the protection module 346 de-energizes (or opens) the contactor 304. When voltage-based protection is disabled during the initial startup period, if one or more of the modules 354, 356 detects a fault, the protection module 346 may de-energize the contactor 304. If the voltage-based protection module 350 is not completely disabled and a fault is detected during the initial startup period when the voltage-based protection is disabled, the protection module 346 may not de-energize the contactor 304. If a soft starter is not included in the HVAC system 300, the voltage-based protection is enabled during startup of the compressor 306.

[0050] Figure 4 A graph of compressor on and off periods including an actual ramp-up period during the start-up of the compressor is shown. A first compressor on period 400 is shown as having a first ramp-up period 402. The compressor is turned off and then turned on again. A second compressor on period 404 is shown as having a second ramp-up period 406. The second ramp-up period 406 is shorter than the first ramp-up period 402. Voltage-based protection is disabled within the ramp-up periods 402, 406 and enabled when the ramp-up periods 402, 406 end. It can be seen that voltage-based protection is disabled within a period shorter than the maximum ramp-up time. If the actual ramp-up period extends to the end of the maximum ramp-up period, voltage-based protection can be disabled within the maximum ramp-up time. This minimizes the time period during which the compressor protection algorithm is disabled. The disabled period is the shorter of i) the period during which the soft starter ramps up activity and ii) the maximum ramp-up period.

[0051] Figure 3 The soft starter detection module 352 can monitor the three-phase voltage signal each time the compressor 306 is powered on. The three-phase voltage signal is collectively referred to as the voltage signal on the line 310 or 322, and the line 310 or 322 each carries a corresponding single-phase voltage signal. The soft starter 302 generates a chopped voltage signal waveform on one or more phases of the three-phase voltage signal to reduce the inrush current during the initial startup period of the compressor. Any voltage signal in the three-phase voltage signal can be monitored. The lines 310 can be referred to as L1', L2' and L3' respectively. Lines 322 may be referred to as L1", L2", and L3", respectively. Additionally or alternatively, the voltages between the three-phase voltage signals may be monitored and sampled by A / D converters 340, 342, 344. For example, the L1'-L2' voltage, the L2'-L3' voltage, the L1'-L3' voltage, the L1"-L2" voltage, the L2"-L3" voltage, and / or the L1"-L3" voltage may be monitored and sampled.

[0052] Figure 5A and Figure 5B (collectively referred to as FIG. 5 ) shows a soft starter detection method. The method can be performed by the HVAC control module 308 and its modules and devices. The method can be implemented each time the compressor is started (or turned on). Figure 3 The HVAC control module 308 can control the start of the compressor 306 and can send a signal to the soft starter when the compressor is about to start. The HVAC control module 308 can also control the timing of when the soft starter provides a chopped waveform to ramp up the current to the compressor. At 500, the HVAC control module 308 can turn on the protection module 346.

[0053] At 502, the protection module 346 can determine whether the contactor 304 is in a closed (or on) state (e.g., the coil 320 is energized). If the protection module 346 determines that the contactor 304 is in a closed (or on) state, operation 504 is performed. At power-up, the protection module 346 closes the contactor 304. At 504, the protection module 346 enables the soft starter detection module 352.

[0054] At 506, protection module 346 and / or soft starter detection module 352 initiates soft starter ramp timer 372. At 508, soft starter detection module 352 may initialize and / or set the partial sum, partial sum counter, current partial sum, soft starter present counter, and soft starter not present counter equal to zero.

[0055] At 510, the soft starter detection module 352 obtains a predetermined number of instantaneous voltage samples of one or more power line signals from one or more A / D converters (e.g., one or more of the A / D converters 340, 342, 344). In one embodiment, the voltage between a single phase or two phases is monitored. In another embodiment, two voltages between two phases or two pairs of phases are monitored. As an example, one of the voltage signals on one of the lines 322 can be monitored, and 25 microsecond (μs) samples of one of the voltage signals can be collected. This can include collecting 80 samples within a 25 μs period.

[0056] At 512, the soft starter detection module 352 can calculate the peak voltage of the voltage signal based on a predetermined number of samples and store the peak voltage in a memory (e.g., the memory 360) or other storage device (e.g., a register or buffer of the soft starter detection module 352). As an example, the peak voltage V P It can be determined according to Formula 1, where S1 to SN are samples, and N is the number of samples.

[0057] V P=MAX(S1,S2,...,SN) (1)

[0058] At 514 , the soft starter detection module 352 may calculate the current fraction and PPS. This may be calculated according to Eq. 2.

[0059]

[0060] At 516 , the soft starter detection module 352 may determine whether the fractional sum counter is equal to a predetermined value (eg, 50). If the soft starter detection module 352 determines that the fractional sum counter is not equal to the predetermined value, operation 518 may be performed, otherwise operation 522 may be performed.

[0061] At 518, the soft starter detection module 352 may calculate a cumulative partial sum, which may be equal to the sum of the current partial sum PPS and the partial sum PS (or the most recent cumulative partial sum value). At 520, the soft starter detection module 352 may increment the partial sum counter. For example, the partial sum counter value may be set equal to the partial sum counter value plus 1. Operation 510 may be performed after operation 520 is performed.

[0062] At 522 , the soft starter detection module 352 may calculate a first root mean square (RMS) voltage RMS1 based on the accumulated partial sum PS. For example, RMS1 may be calculated using Equation 3.

[0063]

[0064] By performing operations 510 , 512 , 514 , 516 , 518 , 520 , RMS1 is calculated every predetermined time period (eg, 100 milliseconds (ms)=80×50×25 μs), where 80 is the number of samples obtained for each of the 50 iterations.

[0065] At 524 , the soft starter detection module 352 may reset the partial sum (or cumulative partial sum), the partial sum counter, and the current partial sum to zero. Operation 526 is performed after operation 524 .

[0066] At 526, the soft starter detection module 352 can calculate a second RMS voltage RMS2 based on the peak voltage. The peak voltage can be the peak voltage determined during the most recent iteration of operation 512, or can be the peak value of the peak voltage determined during the most recent set of iterations of operations 510, 512, 514, 516, 518, 520. For example, when the predetermined iteration value is equal to 50, the peak voltage can be the maximum of 51 iterations of the peak voltage determined during the iterations of operations 510, 512, 514, 516, 518, 520. RMS2 can be calculated using Formula 4. In one embodiment, each time the compressor 306 is turned on, at least operations 512, 522, and 526 are repeated within a predetermined time period. The predetermined period can be 5 seconds or less. As an example, the predetermined time period can be 400ms.

[0067]

[0068] At 528, the soft starter detection module 352 may determine whether the absolute difference between RMS1 and RMS2 is less than a predefined value (e.g., 5V). The predefined value may be referred to as an empirical offset value. If the soft starter detection module 352 determines that the absolute difference between RMS1 and RMS2 is less than the predefined value, operation 530 may be performed, otherwise operation 540 may be performed. In an embodiment, when RMS2 is less than or equal to the sum of RMS1 and a predetermined empirical offset value, the absence of a soft starter is detected. These determinations may be made to determine whether the waveform of the monitored voltage signal is sinusoidal. When the voltage signal is sinusoidal and not chopped, the absence of a soft starter activity that ramps up the current is detected.

[0069] At 530, the soft starter detection module 352 may increment the soft starter not present counter. At 532, the soft starter detection module 352 may determine whether the soft starter not present counter is equal to a first predetermined threshold (e.g., 4) or other predetermined threshold. In an embodiment, the first predetermined threshold is greater than or equal to 1. If the soft starter detection module 352 determines that the soft starter not present counter is not equal to the first predetermined threshold, operation 510 may be performed, otherwise operation 534 may be performed.

[0070] At 534, the soft starter detection module 352 may set a flag in the memory indicating that the soft starter is confirmed to be absent. The soft starter not present may refer to the soft starter not being included in the HVAC system 300 and / or the soft starter 302 not ramping up the current to the compressor 306. This indicates that the soft starter 302 has completed ramping up the current to the compressor 306. In one embodiment, the soft starter is determined to be absent when RMS1 is equal to RMS2. In another embodiment, the soft starter is determined to be absent when the absolute difference between RMS1 and RMS2 is less than or equal to a predetermined empirical offset value. At 536, the soft starter detection module 352 may reset the soft starter not present counter to zero.

[0071] At 538, the soft starter detection module 352 may enable the voltage-based protection module 350 and / or implement voltage-based protection algorithms, such as a reverse phase protection algorithm, a single phase protection algorithm, an overvoltage and undervoltage protection algorithm, a phase imbalance protection algorithm, a frequency supply out-of-range and under-range protection algorithm, and a compressor short cycle protection algorithm. This may include allowing the voltage-based protection module 350 to shut down the compressor when one or more of the voltage-based protection algorithms detects a fault. In one embodiment, the soft starter detection module 352 enables the voltage-based protection once the soft start period of ramping up the current to the compressor 306 ends.

[0072] At 540, the soft starter detection module 352 may determine whether RMS2 is greater than the sum of RMS1 and a predefined value (e.g., 5V). If the soft starter detection module 352 determines that RMS2 is not greater than the sum of RMS1 and the predefined value, operation 542 may be performed, otherwise operation 546 may be performed. This determination is made to determine whether the waveform of the monitored voltage signal is chopped during the initial portion of the startup period. When the voltage signal is chopped, the presence of a soft starter activity that ramps up the current is detected.

[0073] At 542, the soft starter detection module 352 may determine whether RMS1 is greater than the sum of RMS2 and a predefined value (e.g., 5 V). In one embodiment, the predefined value is 0 V. In another embodiment, the predefined value is less than 5 V. If the soft starter detection module 352 determines that RMS1 is greater than the sum of RMS2 and the predefined value, operation 544 is performed.

[0074] At 544 , the soft starter detection module 352 may set a flag indicating that a calculation error has occurred. In the event of a calculation error, the values ​​of RMS1 and RMS2 may be discarded. Operation 554 may be performed after operation 544 .

[0075] At 546, the soft starter detection module 352 may increment the soft starter presence counter. At 548, the soft starter detection module 352 may determine whether the soft starter presence counter is equal to a second predetermined threshold (e.g., 4) or other predetermined threshold. In an embodiment, the second predetermined threshold is greater than or equal to 1. The second predetermined threshold may be the same as or different from the first predetermined threshold. If the soft starter detection module 352 determines that the soft starter presence counter is not equal to the second predetermined threshold or other predetermined threshold, operation 510 may be performed, otherwise operation 550 may be performed. By performing operations 532 and 548, RMS1 and RMS2 are confirmed every predetermined time period (e.g., 4×100ms or 400ms, where 4 is the first predetermined threshold and / or the second predetermined threshold). In an embodiment, the second predetermined threshold is different from the first predetermined threshold.

[0076] At 550, the soft starter detection module 352 may set a flag indicating that the soft starter presence has been confirmed and disable voltage-based protection. The soft starter presence may mean that the HVAC system 300 includes the soft starter 302 and the soft starter 302 ramps up the current to the compressor 306. This may include disabling the voltage-based protection module 350 and / or preventing the voltage-based protection operation from being performed. The voltage-based protection algorithm may be prevented from being executed. At 552, the soft starter detection module 352 may reset the soft starter presence counter to zero.

[0077] At 554, the soft starter detection module 352 can determine whether the soft starter ramp time is greater than the maximum ramp time. The maximum ramp time can be set based on the type of load and / or the size of the compressor 306. In one embodiment, the maximum ramp time does not exceed 10 seconds. If the soft starter detection module 352 determines that the soft starter ramp time is greater than the maximum ramp time, operation 556 can be performed, otherwise operation 510 can be performed. The soft starter ramp time is the current amount of time that the soft starter 302 has ramped up the current to the compressor 306 since the time when the compressor was last turned on.

[0078] At 556, the soft starter detection module 352 may set a flag indicating that a soft starter ramp timeout has occurred. Operation 538 may be performed after performing operation 554. The method may end after performing operation 538.

[0079] The above example includes enabling a protection module and implementing a protection algorithm at the end of a soft starter action that ramps up current to a compressor, thereby avoiding exposure of the compressor motor windings to high current levels due to a fault, such as the high current levels experienced during a single-phase fault. The soft starter algorithm implemented by executing the above method is used to detect the end of the ramp-up period independent of the length of the ramp-up period. The examples disclosed herein can be implemented independent of the soft starter rated current and independent of the soft starter brand or model. The disabling of voltage-based protection is independent of the maximum ramp period, which can be set by the system operator.

[0080] The foregoing description is essentially only illustrative, and is by no means intended to limit the present disclosure, its application or use. The broad teachings of the present disclosure can be implemented in various forms. Therefore, although the present disclosure includes specific examples, the true scope of the present disclosure should not be so limited, because after studying the drawings, the specification and the appended claims, other modifications will become apparent. It should be understood that one or more steps in the method can be performed in different orders (or simultaneously) without changing the principle of the present disclosure. In addition, although each embodiment is described above as having certain features, any one or more of those features described in any embodiment of the present disclosure can be implemented in any other embodiment and / or combined with the features of any other embodiment, even if the combination is not clearly described. In other words, the described embodiments are not mutually exclusive, but the replacement of one or more embodiments with each other is still within the scope of the present disclosure.

[0081] The spatial and functional relationships between elements (e.g., between modules, circuit elements, semiconductor layers, etc.) are described using various terms, including "connected", "engaged", "coupled", "adjacent", "immediately adjacent", "on top", "above", "below", and "set". Unless explicitly described as "directly", when describing the relationship between a first element and a second element in the above disclosure, the relationship can be a direct relationship between the first element and the second element without other intermediate elements, but can also be an indirect relationship between the first element and the second element with one or more intermediate elements (spatially or functionally). As used herein, the phrase at least one of A, B, and C should be interpreted to mean a logical (A or B or C) using a non-exclusive logical or, and should not be interpreted to mean "at least one of A, at least one of B, and at least one of C".

[0082] In the drawings, as indicated by the arrows, the direction of the arrows generally shows the flow of information (such as data or instructions) that the illustration is concerned with. For example, when element A and element B exchange various information but the information transmitted from element A to element B is relevant to the illustration, the arrow may point from element A to element B. This unidirectional arrow does not imply that no other information is transmitted from element B to element A. In addition, for information sent from element A to element B, element B may send a request for the information or a confirmation of receipt of the information to element A.

[0083] In this application, including the following definitions, the term "module" or the term "controller" may be replaced with the term "circuit". The term "module" may refer to, be part of, or include: an application specific integrated circuit (ASIC); a digital, analog, or mixed analog / digital discrete circuit; a digital, analog, or mixed analog / digital integrated circuit; a combinational logic circuit; a field programmable gate array (FPGA); a processor circuit (shared processor circuit, dedicated processor circuit, or group processor circuit) that executes code; a memory circuit (shared memory circuit, dedicated memory circuit, or group memory circuit) that stores code executed by the processor circuit; other suitable hardware components that provide the described functionality; or a combination of some or all of the above, such as in a system on a chip.

[0084] Module can include one or more interface circuits.In some examples, interface circuit can include the wired or wireless interface that is connected to local area network (LAN), Internet, wide area network (WAN) or its combination.The function of any given module of the present disclosure can be distributed between multiple modules connected via interface circuit.For example, multiple modules can make load balancing.In another example, server (also referred to as remote or cloud) module can realize some functions on behalf of client module.

[0085] As described above, the term code may include software, firmware, and / or microcode, and may refer to programs, routines, functions, classes, data structures, and / or objects. The term shared processor circuit encompasses a single processor circuit that executes some or all code from multiple modules. The term group processor circuit encompasses a processor circuit that executes some or all code from one or more modules in combination with additional processor circuits. References to multiple processor circuits encompass multiple processor circuits on discrete dies, multiple processor circuits on a single die, multiple cores of a single processor circuit, multiple threads of a single processor circuit, or a combination of the above. The term shared memory circuit encompasses a single memory circuit that stores some or all code from multiple modules. The term group memory circuit includes a memory circuit that stores some or all code from one or more modules in combination with additional memory.

[0086] The term memory circuit is a subset of the term computer-readable medium. As used herein, the term computer-readable medium does not encompass transient electrical or electromagnetic signals propagated through a medium (such as on a carrier wave); therefore, the term computer-readable medium may be considered to be tangible and non-transient. Non-limiting examples of non-transient tangible computer-readable media are non-volatile memory circuits (such as flash memory circuits, erasable programmable read-only memory circuits, or mask read-only memory circuits), volatile memory circuits (such as static random access memory circuits or dynamic random access memory circuits), magnetic storage media (such as analog or digital tapes or hard drives), and optical storage media (such as CDs, DVDs, or Blu-ray discs).

[0087] The apparatus and methods described in this application may be implemented in part or in whole by a special purpose computer created by configuring a general purpose computer to perform one or more specific functions embodied in a computer program. The above-mentioned function blocks, flow chart components and other elements act as software specifications that can be converted into computer programs by the routine work of a skilled technician or programmer.

[0088] The computer program includes processor executable instructions stored on at least one non-transitory tangible computer readable medium. The computer program may also include or rely on stored data. The computer program may include a basic input / output system (BIOS) that interacts with the hardware of the special-purpose computer, device drivers that interact with specific devices of the special-purpose computer, one or more operating systems, user applications, background services, background applications, etc.

[0089] A computer program may include: (i) descriptive text to be parsed, such as HTML (Hypertext Markup Language), XML (Extensible Markup Language), or JSON (JavaScript Object Notation), (ii) assembly code, (iii) object code generated by a compiler from source code, (iv) source code executed by an interpreter, (v) source code compiled and executed by a just-in-time compiler, etc. By way of example only, the source code may be written in C, C++, C#, Objective-C, Swift, Haskell, Go, SQL, R, Lisp, Fortran, Perl, Pascal, Curl, OCaml, HTML5 (Hypertext Markup Language Revision 5), Ada, ASP (Active Server Pages), PHP (PHP: Hypertext Preprocessor), Scala, Eiffel, Smalltalk, Erlang, Ruby, Visual Lua, MATLAB, SIMULINK, and The grammar of the language is used to write it.

Claims

1. A heating, ventilation and air conditioning system comprising: at least one analog-to-digital converter configured to sample a voltage signal on or between one or more power lines to provide a plurality of samples, the one or more power lines supplying power to the compressor; a voltage-based protection module configured to execute one or more voltage-based protection algorithms to protect the compressor; as well as a soft starter detection module configured to detect, based on the plurality of samples, i) the presence of a soft starter and ii) activity of the soft starter ramping up current to the compressor, and based on detecting the presence of the soft starter and the activity of the soft starter, disable voltage-based protection provided by the voltage-based protection module.

2. The heating, ventilation and air conditioning system of claim 1, wherein: The soft starter detection module is configured to: disabling voltage-based protection provided by the voltage-based protection module during a soft-start ramp-up period; as well as In response to detecting an end of the soft-start ramp-up period, voltage-based protection provided by the voltage-based protection module is enabled.

3. The heating, ventilation and air conditioning system of claim 2, wherein: The soft starter detection module is configured to: Detecting whether the voltage signal is a chopping voltage signal; In response to detecting that the voltage signal is a chopped voltage signal, determining that the soft starter is ramping up current to the compressor; as well as In response to detecting that the voltage signal is not a chopped voltage signal, it is determined that the soft starter is not ramping up current to the compressor.

4. The heating, ventilation and air conditioning system of claim 1, wherein: The soft starter detection module is configured to: determining a first root mean square voltage of the voltage signal; determining a second root mean square voltage of the voltage signal; determining whether the soft starter is ramping up current to the compressor based on a difference between the first rms voltage and the second rms voltage; as well as In response to determining that the soft starter is ramping up current to the compressor, voltage-based protection provided by the voltage-based protection module is disabled.

5. The heating, ventilation and air conditioning system of claim 4, wherein: The soft starter detection module is configured to: determining the first rms voltage based on a square root of a sum of average squares of the plurality of samples of the voltage signal; and The second rms voltage is determined based on a peak value of the plurality of samples of the voltage signal divided by a square root of two.

6. The heating, ventilation and air conditioning system of claim 1, wherein: The soft starter detection module is configured to: tracking an amount of time during startup of the compressor that the soft starter ramps up current to the compressor; comparing the amount of time to a maximum ramp time; as well as Based on a comparison of the amount of time to the maximum ramp time, voltage-based protection provided by the voltage-based protection module is enabled.

7. The heating, ventilation and air conditioning system of claim 6, wherein: The soft starter detection module is configured to: In response to the amount of time being greater than the maximum ramp time, enabling voltage-based protection provided by the voltage-based protection module; and In response to the amount of time being less than or equal to the maximum ramp time, maintaining the voltage-based protection module in a disabled state.

8. The heating, ventilation and air conditioning system of claim 1, wherein: The soft starter detection module is configured to: determining a peak voltage of the plurality of samples; determining a current partial sum of the plurality of samples; determining a cumulative partial sum based on the current partial sum; determining a first voltage based on the accumulated partial sum; determining a second voltage based on the peak voltage; as well as Based on the first voltage and the second voltage, at least one of: i) the presence of a soft starter, and ii) activity of the soft starter ramping up current to the compressor is detected.

9. The heating, ventilation and air conditioning system of claim 1, wherein: The soft starter detection module is configured to: determining a first voltage based on a square root of a sum of average squares of the plurality of samples; determining a second voltage based on a peak voltage of the plurality of samples; as well as Based on the first voltage and the second voltage, at least one of: i) the presence of a soft starter, and ii) activity of the soft starter ramping up current to the compressor is detected.

10. The HVAC system of claim 1, further comprising: The soft starter; the compressor; A contactor connected between the soft starter and the compressor; as well as A control module is configured to close the contactor to supply current from the soft starter to the compressor.

11. The heating, ventilation and air conditioning system of claim 10, wherein: The control module is configured to enable the at least one analog-to-digital converter to sample the voltage signal after closing the contactor.

12. The heating, ventilation and air conditioning system of claim 10, wherein: The one or more power lines supply power i) from the soft starter to the contactor, or ii) from the contactor to the compressor.

13. A soft starter detection method for a heating, ventilation and air conditioning system, the heating, ventilation and air conditioning system comprising a voltage-based protection module, the voltage-based protection module being configured to execute one or more voltage-based protection algorithms to protect a compressor, the method comprising: sampling a voltage signal on or between one or more power lines supplying power to the compressor to provide a plurality of samples; based on the plurality of samples, i) detecting the presence of a soft starter supplying power to the compressor, and ii) detecting activity of the soft starter ramping up current to the compressor; as well as Based on detecting the presence of the soft starter and the activity of the soft starter, voltage-based protection provided by the voltage-based protection module is disabled.

14. The soft starter detection method according to claim 13, further comprising: disabling voltage-based protection provided by the voltage-based protection module during a soft-start ramp-up period; as well as In response to detecting an end of the soft-start ramp-up period, voltage-based protection provided by the voltage-based protection module is enabled.

15. The soft starter detection method according to claim 14, further comprising: Detecting whether the voltage signal is a chopping voltage signal; In response to detecting that the voltage signal is a chopped voltage signal, determining that the soft starter is ramping up current to the compressor; as well as In response to detecting that the voltage signal is not a chopped voltage signal, it is determined that the soft starter is not ramping up current to the compressor.

16. The soft starter detection method according to claim 13, further comprising: determining a first root mean square voltage of the voltage signal; determining a second root mean square voltage of the voltage signal; determining whether the soft starter is ramping up current to the compressor based on a difference between the first rms voltage and the second rms voltage; as well as In response to determining that the soft starter is ramping up current to the compressor, voltage-based protection provided by the voltage-based protection module is disabled.

17. The soft starter detection method according to claim 16, further comprising: determining the first rms voltage based on a square root of a sum of average squares of the plurality of samples of the voltage signal; as well as The second rms voltage is determined based on a peak value of the plurality of samples of the voltage signal divided by a square root of two.

18. The soft starter detection method according to claim 13, further comprising: tracking an amount of time during startup of the compressor that the soft starter ramps up current to the compressor; comparing the amount of time to a maximum ramp time; as well as Based on a comparison of the amount of time to the maximum ramp time, voltage-based protection provided by the voltage-based protection module is enabled.

19. The soft starter detection method according to claim 18, further comprising: in response to the amount of time being greater than the maximum ramp time, enabling voltage-based protection provided by the voltage-based protection module; as well as In response to the amount of time being less than or equal to the maximum ramp time, maintaining the voltage-based protection module in a disabled state.

20. The soft starter detection method according to claim 19, further comprising: determining a peak voltage of the plurality of samples; determining a current partial sum of the plurality of samples; determining a cumulative partial sum based on the current partial sum; determining a first voltage based on the accumulated partial sum; determining a second voltage based on the peak voltage; as well as Based on the first voltage and the second voltage, at least one of: i) the presence of a soft starter, and ii) activity of the soft starter ramping up current to the compressor is detected.

21. The soft starter detection method according to claim 13, further comprising: determining a first voltage based on a square root of a sum of average squares of the plurality of samples; determining a second voltage based on a peak voltage of the plurality of samples; as well as Based on the first voltage and the second voltage, at least one of: i) the presence of a soft starter, and ii) activity of the soft starter ramping up current to the compressor is detected.

22. The soft starter detection method according to claim 13, further comprising: closing a contactor to supply current from the soft starter to the compressor; as well as Sampling of the voltage signal is enabled after closing the contactor.

23. The soft starter detection method according to claim 22, wherein: The one or more power lines supply power i) from the soft starter to the contactor, or ii) from the contactor to the compressor.

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