AU2021269391A1 - An Alternator Stator Clamping Device - Google Patents
An Alternator Stator Clamping Device Download PDFInfo
- Publication number
- AU2021269391A1 AU2021269391A1 AU2021269391A AU2021269391A AU2021269391A1 AU 2021269391 A1 AU2021269391 A1 AU 2021269391A1 AU 2021269391 A AU2021269391 A AU 2021269391A AU 2021269391 A AU2021269391 A AU 2021269391A AU 2021269391 A1 AU2021269391 A1 AU 2021269391A1
- Authority
- AU
- Australia
- Prior art keywords
- alternator
- electronic switch
- circuit
- overvoltage
- clamping device
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/0833—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors for electric motors with control arrangements
- H02H7/0838—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors for electric motors with control arrangements with H-bridge circuit
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/06—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric generators; for synchronous capacitors
- H02H7/067—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric generators; for synchronous capacitors on occurrence of a load dump
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/085—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against excessive load
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H7/00—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions
- H02H7/08—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors
- H02H7/09—Emergency protective circuit arrangements specially adapted for specific types of electric machines or apparatus or for sectionalised protection of cable or line systems, and effecting automatic switching in the event of an undesired change from normal working conditions for dynamo-electric motors against over-voltage; against reduction of voltage; against phase interruption
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/10—Control effected upon generator excitation circuit to reduce harmful effects of overloads or transients, e.g. sudden application of load, sudden removal of load, sudden change of load
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H89/00—Combinations of two or more different basic types of electric switches, relays, selectors and emergency protective devices, not covered by any single one of the other main groups of this subclass
- H01H89/06—Combination of a manual reset circuit with a contactor, i.e. the same circuit controlled by both a protective and a remote control device
- H01H2089/065—Coordination between protection and remote control, e.g. protection job repartition, mutual assistance or monitoring
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01H—ELECTRIC SWITCHES; RELAYS; SELECTORS; EMERGENCY PROTECTIVE DEVICES
- H01H47/00—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current
- H01H47/22—Circuit arrangements not adapted to a particular application of the relay and designed to obtain desired operating characteristics or to provide energising current for supplying energising current for relay coil
- H01H47/36—Relay coil or coils forming part of a bridge circuit
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H3/00—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection
- H02H3/20—Emergency protective circuit arrangements for automatic disconnection directly responsive to an undesired change from normal electric working condition with or without subsequent reconnection ; integrated protection responsive to excess voltage
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02H—EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS
- H02H9/00—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection
- H02H9/04—Emergency protective circuit arrangements for limiting excess current or voltage without disconnection responsive to excess voltage
Abstract
Aa regulated DC alternator, the alternator including; a diode on each stator power line
connected to an electronic switch. The electronic switch connecting said diodes to a
negative output power line of the alternator. The alternator also including an overvoltage
detection circuit; a driver circuit; and a field coil enable/disable circuit. the overvoltage
detection circuit detecting a voltage spike and directing said driver circuit to drive and
thereby turn on the electronic switch and the field coil enable/disable circuit that receives
a signal from the overvoltage detection circuit and for enabling and disabling a field coil
control circuit.
1
8 Regulated DC Alternator
En/Dis
1
__ Field Coil Control Circuit
Diode
10 Bridge
5 12
+Po
Field Stator -La
Coil Coils - Neg La
13 31
7
Overvoltage Field Coil
Driver Detection I Enable/Disablel
4Circui Circuit Circuit
4~ |r |t
Description
8 Regulated DC Alternator En/Dis 1 Coil Field Circuit __ Control Diode 10 Bridge
5 12
+Po Field Stator -La Coil Coils - Neg La
13 31
7
Overvoltage Field Coil Driver Detection I Enable/Disablel Circuit Circuit 4Circui 4~ |r |t
[0001] The present invention relates to alternators and generators. An alternator is a device that converts mechanical energy into alternating current (AC) electrical energy. A generator is a device that converts mechanical energy into direct current (DC) electrical energy. The term 'alternator' is also commonly used to describe a device that is an alternator with circuitry to convert AC to DC, typically using a diode bridge, to deliver DC power. Alternators are commonly found in all types of vehicles; bicycles, motorbikes, cars, trucks, airplanes, tractors, earthmoving and mining equipment, boats, ships, spacecraft, etc. For devices that produce DC output the power can be measured at any point in time as the DC voltage times the current. The present invention relates to devices producing DC power.
[0002] Mechanical to electrical energy conversion occurs when a magnetic field and a coil are pushed past each other. This movement results in a mechanical force that resists the movement and the corresponding generation of an electrical current. The output power is a function of many parameters including the mechanical rotational speed, the strength and geometric shape of the magnetic field, the type of coil and the resistive, inductive and capacitive characteristics of the electrical load.
[0003] Commonly, alternators and generators are regulated by controlling the strength of the magnetic field using a field coil. A control circuit adjusts the current through the field coil to control the magnetic field which in turn controls the output power. Typically, the output voltage is monitored by the control circuit so as to deliver a relatively fixed output voltage for a wide range of loads. When there is a change of load, such as switching, for example, lights on or off the output voltage correspondingly goes down or up for a short period until the field strength can be adjusted to provide the regulated voltage for the new load. When the load suddenly drops there is a brief overvoltage surge and when the load suddenly increases there is a briefundervoltage droop.
[0004] Other, less common techniques may be employed to provide output voltage regulation, but these devices still exhibit overvoltage surge and undervoltage droop.
[0005] Devices being powered by the alternator or generator may require protective circuitry to handle the surge and droop that may occur as other devices are switched on and off A surge can readily generate voltage levels that damage unprotected circuitry. In the automotive industry, for example, an international standard, ISO 16750 Part 2, has been written to provide agreed upon surge and droop limits so both alternator and powered device manufacturers can seek to meet the specified limits at minimal cost. An electronic clamping device is often used with the alternator which quickly acts as a compensating load to limit the output voltage during the surge. These voltage clamping devices need to absorb the excess energy being delivered during the surge, converting this energy into heat. Notably, the voltage clamping device is placed in parallel with any other loads or as the only load. Often there is also a very fast transient overvoltage as the voltage clamping device begins to draw current. Even with surge protection the product life of loads, such as lights, may be reduced due to the overvoltage surges.
[0006] An overvoltage surge is typically known in the automotive industry as load dump and can occur frequently when the load to an alternator is disconnected or varied. The load dump surge is dependent on the variation of the load, from full load down to no load, and the RPM of the alternator.
[0007] There are surge protection devices specifically designed to clamp automotive load dump voltage spikes. They are commonly called voltage suppressors and can be electronic devices called TVS, MOV, transorb, etc. They are inherently fast operating and can absorb or withstand a large amount of power as they are primarily designed to dissipate the excess energy generated by the alternator in the instant of the load dump.
[0008] A major drawback of all these devices is the wide voltage range between the clamping voltage of a small current compared with the clamping voltage of the maximum current. For example, a 15V TVS will start to conduct in the region of 15V to 17V but when conducting the maximum surge current the voltage is over 23V. This poor clamping performance then requires powered devices to have secondary spike protection and filtering circuitry.
[0009] In hazardous environments, such as in mines, specialty flame-proof alternators are required to ensure the device will not cause mine explosions. These flame-proof alternators typically include circuitry to monitor the load and detect fault conditions and automatically shut off their output until they are manually reset by an operator.
[0010] The present invention is a stator clamp driven by a control circuit that responds to a voltage spike to rapidly clamp the stator power lines to each other to limit the voltage spike. The control circuit may optionally signal the field coil control circuitry to stop driving the field coil.
[0011] In its broadest from the present invention comprises:
an overvoltage stator clamping device comprising:
an overvoltage detection circuit for detecting an overvoltage condition in the output of an alternator having at least one load;
an electronic switch drive circuit,
an electronic switch,
an array of diodes,
the diodes forming a diode bridge, connecting stator connections to the electronic switch,
the electronic switch connected to the negative or positive terminal of the alternator,
wherein, stator coils are connected to each other via the diodes, the electronic switch and the diode bridge; the overvoltage detection circuit capable of actuating the electronic switch drive circuit to actuate the switch, once the output voltage of the alternator reaches specified thresholds.
[0012] In another broad from, the present invention comprises:
a regulated DC alternator, the alternator including;
a diode on each stator power line connected to an electronic switch, said electronic switch connecting said diodes to a negative output power line of the alternator;
an overvoltage detection circuit;
a driver circuit; and
a field coil enable/disable circuit;
the overvoltage detection circuit detecting a voltage spike and directing said driver circuit to drive and thereby turn on the electronic switch and the field coil enable/disable circuit that receives a signal from said overvoltage detection circuit and for enabling and disabling a field coil control circuit.
[0013] In another broad form the present invention comprises;
a regulated DC alternator, including overvoltage stator clamping device, the alternator further comprising;
a diode on each stator powerline connected to an electronic switch, said electronic switch connecting said diodes to a negative output power line of the alternator;
the clamping device comprising;
an overvoltage detection circuit for detecting an overvoltage condition in the output of an alternator having at least one load;
an electronic switch drive circuit, an electronic switch, an array of diodes, the diodes forming a diode bridge, connecting stator connections to the electronic switch, the electronic switch connected to the negative or positive terminal of the alternator, wherein, stator coils are connected to each other via the diodes, the electronic switch and the diode bridge; the overvoltage detection circuit capable of actuating the electronic switch drive circuit to actuate the switch, once the output voltage of the alternator reaches specified thresholds.
[0014] Preferably the electronic switch is an n-channel MOSFET. Alternatively, the switch is selected from one of the following: a transistor, insulated-gate bipolar transistor (IJBT), silicone controlled rectifier (SCR) or relay. Other suitable switches are contemplated.
[0015] When a surge overvoltage occurs, the overvoltage detection circuit detects the overvoltage and signals the electronic switch drive circuit to turn the electronic switch on. With the electronic switch on, the large currents generated in the stator coils pass through forward biased diodes, through the electronic switch, through the forward biased diodes in the diode bridge and back to the corresponding stator power lines. This has the effect of mechanically decoupling the stator and rotor as the rotating magnetic field derived from the field coil has no significant load to drive. From another perspective the large currents passing through the stator coils effectively generate an opposing magnetic field to the field coil's magnetic field resulting in a rapid collapse of the combined magnetic field.
[0016] There are many other forms of control circuitry that one versed in the art could devise to implement the current invention.
[0017] The present invention will now be described in broad detail according to preferred but non limiting embodiments wherein;
Figure 1 shows a block diagram of an embodiment of the invention.
[0018] DETAILED DESCRIPTION
Referring to figure 1 there is shown according to a preferred embodiment a regulated DC alternator 1 wherein three stator connections are additionally connected to the negative terminal 2 via three diodes 3 and a fast acting electronic power switch 4. The positive terminal 5 is connected to an overvoltage detection circuit 6 that signals a driver circuit 7 for controlling the electronic power switch 4. The overvoltage detection circuit 6 has a detection voltage threshold that is set at a voltage above the regulated voltage detected by the field coil control circuit 8. When the overvoltage detection circuit 6 detects an overvoltage on the positive terminal 5 it signals the driver circuit 7 to turn on the electronic power switch 4. When the electronic power switch 4 turns on, the three stator coils are connected to the negative terminal 2 which is connected to the three stator coils via three diodes 9 in the diode bridge 10. The voltage across any two stator coils is then limited to the voltage drop across the corresponding two conducting diodes and the electronic power switch 4.
[0019] Typically, when the electronic power switch 4 is turned on the three diodes 11 of the diode bridge 10 are reversed biased due to the capacitance of the load 12. The resistance and/or inductance of the load 12 drains the capacitance of the load 12 as the positive terminal no longer supplies power to the load 12 and the positive terminal 5 voltage drops. When the voltage drops sufficiently the overvoltage detection circuit 6 signals the driver circuit 7 to turn the electronic power switch 4 off When the electronic power switch 4 turns off the regulated alternator returns to normal operation and begins to supply power to the load 12. The turn on and turn off operation of the embodiment's circuits 7 and 8 and the electronic power switch 4 occur very rapidly in comparison to the change of the magnetic field generated by the field coil 13 which is driven by the field coil control circuit 8.
[0020] Typically, an overvoltage condition is initiated by a sudden reduction of power consumption in the load 12. In this case the turn off / turn on cycle described above occurs at a rate of hundreds of thousands of cycles per second until the field coil control circuit 8 is able to reduce the field coil's magnetic field to the correct strength for delivering correctly regulated power.
[0021] Optionally, the response time of the field coil control circuit 8 can be reduced by adding an enable/disable feature 14 to the field coil control circuit 8 and having the overvoltage detection circuit 6 additionally signal a field coil enable/disable control circuit 15 to disable the field coil control circuit 8 whenever the electronic power switch 4 is turned on. When the field coil control circuit 8 is disabled it stops driving the field coil 13 to increase the rate of collapse of the magnetic field generated by the field coil 13.
[0022] When the electronic power switch 4 is on the stator connections are effectively clamped to each other and large currents can flow through the stator coils but little power is being drawn because the effective load on the stator coils is only due to the voltage drop across the conducting diodes and the electronic power switch 4. In normal operation, when the electronic power switch 4 is off, the rotor and stator are magnetically coupled which induces a torque between the rotor and stator. The energy drain from the rotor due to this torque and the rotor's speed is delivered to the load 12 less any typical energy losses in the alternator. When the electronic power switch 4 is on the stator coil currents effectively decouple the rotor and stator causing the torque to rapidly drop to almost zero as the effective load, as described above, is almost zero compared to the load 12. The torque experienced by the rotor and stator therefore rapidly changes at the same rate as the operation of the electronic power switch 4. In this sense the operation of the present invention relies on the near zero capacitive nature of the stator coils and the rapid disconnection of the load 12 due to the reverse biasing of the three diodes connected to the positive terminal 5 thereby allowing for a rapid voltage drop across the stator connections.
[0023] Preferably the electronic power switch 4 is a MOSFET.
[0024] According to an alternative embodiment the circuit arrangements can be inverted whereby the voltages are inverted and the positive terminal 5 and the negative terminal 2 of the alternator 1 are swapped.
[0025] The present invention provides a useful alternative to the known devices and although the invention will be described with reference to its application in alternator and generator devices it will be recognised that the invention has a variety of applications not limited to that described.
[0026] It will be recognized by persons skilled in the art that numerous variations and modifications may be made to the invention as broadly described herein without departing from the overall spirit and scope of the invention.
Claims (21)
1. An overvoltage stator clamping device comprising:
an overvoltage detection circuit for detecting an overvoltage condition in the output of an alternator having at least one load;
an electronic switch drive circuit,
an electronic switch,
an array of diodes,
the diodes forming a diode bridge, connecting stator connections to the electronic switch,
the electronic switch connected to the negative or positive terminal of the alternator,
wherein, stator coils are connected to each other via the diodes, the electronic switch and the diode bridge;
the overvoltage detection circuit capable of actuating the electronic switch drive circuit to actuate the switch, once the output voltage of the alternator reaches specified thresholds.
2 A clamping device according to claim 1, wherein, once the output voltage of the alternator reaches a predetermined first specified threshold, the overvoltage detection circuit turns on the electronic switch; and once the output voltage of the alternator, drops below a pre -determined second threshold, the overvoltage detection circuit signals the electronic switch drive circuit to turn off the electronic switch.,
3. The clamping device according to claim 2 further comprising a field coil enable/disable circuit.
4 The clamping device according to claim, wherein the overvoltage detection circuit additionally signals the field coil enable/disable circuit to enable or disable the field coil control circuit.
The clamping device according to claim 4 wherein, when the output voltage exceeds a maximum threshold (surge overvoltage), the overvoltage circuit turns the electronic switch on.
6 The clamping device according to claim 4 wherein, when the output voltage drops below a minimum threshold, the overvoltage circuit turns the electronic switch off
7 The clamping device according to claim 6, wherein, when the electronic power switch is turned on, the three diodes of the diode bridge are reversed biased due to capacitance of a load on the alternator.
8 The clamping device according to claim 7, wherein when the voltage drops to a predetermined threshold, the overvoltage detection circuit signals the driver circuit to turn the electronic power switch off
9 The clamping device according to claim 8, wherein, when the electronic power switch is turned off, the alternator returns to normal operation and begins to supply power to the load .
The clamping device according to claim 9, wherein, the electronic switch is a MOSFET.
11. The clamping device according to claim 9, wherein the electronic switch is selected from one of the following: a transistor, insulated-gate bipolar transistor (IJBT), silicone controlled rectifier (SCR) or relay.
12 A regulated DC alternator, including overvoltage stator clamping device, the alternator further comprising;
a diode on each stator powerline connected to an electronic switch, said electronic switch connecting said diodes to a negative output power line of the alternator;
the clamping device comprising; an overvoltage detection circuit for detecting an overvoltage condition in the output of an alternator having at least one load; an electronic switch drive circuit, an electronic switch, an array of diodes, the diodes forming a diode bridge, connecting stator connections to the electronic switch, the electronic switch connected to the negative or positive terminal of the alternator, wherein, stator coils are connected to each other via the diodes, the electronic switch and the diode bridge; the overvoltage detection circuit capable of actuating the electronic switch drive circuit to actuate the switch, once the output voltage of the alternator reaches specified thresholds.
13 A regulated DC alternator according to claim 12, wherein, once the output voltage of the alternator reaches a predetermined first specified threshold, the overvoltage detection circuit turns on the electronic switch; and once the output voltage of the alternator, drops below a pre -determined second threshold, the overvoltage detection circuit signals the electronic switch drive circuit to turn off the electronic switch.,
13. A regulated DC alternator according to claim 12 further comprising a field coil enable/disable circuit.
14 A regulated DC alternator according to claim 13, wherein the overvoltage detection circuit additionally signals the field coil enable/disable circuit to enable or disable the field coil control circuit.
A regulated DC alternator according to claim 14 wherein, when the output voltage exceeds a maximum threshold (surge overvoltage), the overvoltage circuit turns the electronic switch on.
16 A regulated DC alternator according to claim 15 wherein, when the output voltage drops below a minimum threshold, the overvoltage circuit turns the electronic switch off
17 The clamping device according to claim 16, wherein, when the electronic power switch is turned on, the three diodes of the diode bridge are reversed biased due to capacitance of a load on the alternator.
18 The clamping device according to claim 17, wherein when the voltage drops to a predetermined threshold, the overvoltage detection circuit signals the driver circuit to turn the electronic power switch off
19 The clamping device according to claim 18, wherein, when the electronic power switch is turned ofl; the alternator returns to normal operation and begins to supply power to the load .
A regulated DC alternator according to claim 19, wherein, the electronic switch is a MOSFET.
21. The clamping device according to claim 10, wherein the electronic switch is selected from one of the following: a transistor, insulated-gate bipolar transistor (IJBT), silicone controlled rectifier(SCR) or relay.
8 Regulated DC Alternator En/Dis 14 Field Coil Control Circuit 11 2021269391
Diode 10 Bridge
5 12
+ Pos Field Stator Load Coil Coils - Neg
2
9
13 3 15 6 7
Overvoltage Field Coil Driver Detection Enable/Disable Circuit Circuit Circuit 4 1
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AU2020904263A AU2020904263A0 (en) | 2020-11-18 | An Alternator Stator Clamping Device | |
| AU2020904263 | 2020-11-18 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| AU2021269391A1 true AU2021269391A1 (en) | 2022-06-02 |
Family
ID=81753405
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| AU2021269391A Pending AU2021269391A1 (en) | 2020-11-18 | 2021-11-18 | An Alternator Stator Clamping Device |
Country Status (2)
| Country | Link |
|---|---|
| AU (1) | AU2021269391A1 (en) |
| ZA (1) | ZA202109206B (en) |
-
2021
- 2021-11-18 AU AU2021269391A patent/AU2021269391A1/en active Pending
- 2021-11-18 ZA ZA2021/09206A patent/ZA202109206B/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| ZA202109206B (en) | 2022-09-28 |
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