# US 2014/0153308 A1 · Rectifier charge rate controller > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2014/0153308 A1 - Document ID: US20140153308A1 - Status: Published application - Kind: A1 - Application number: 14/091,775 - Filed: 2013-11-27 - Published: 2014-06-05 - Earliest claimed: 2012-11-30 - Assignees: Control Techniques Limited - Applicants: Control Techniques Limited - Inventors: Simon David Hart; Stephen Berry - Web page: https://patentgrep.com/patent/US20140153308A1 ## CPC - H02M 7/1626: {with automatic control of the output voltage or current} - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 1/0085: {Partially controlled bridges} - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) ## Abstract A rectifier circuit comprising an AC input, at least one thyristor coupled to the AC input, a DC bus driven by the at least one thyristor, a controller arranged to: derive a first current in the DC bus, derive a maximum current demand on the DC bus, and provide a trigger signal to the at least one thyristor based on the derived maximum current and the derived first current. ## Claims ### Claim 1 A rectifier circuit comprising: an AC input; at least one thyristor coupled to the AC input, the at least one thyristor arranged to drive a DC bus; a controller arranged to: derive a first current in the DC bus; derive a maximum current demand on the DC bus; provide a trigger signal to the at least one thyristor based on the derived maximum current and the derived first current. ### Claim 2 (depends on 1) The rectifier circuit of claim 1 wherein the trigger signal comprises a firing angle in relation to a voltage phase of the AC input. ### Claim 3 (depends on 1) The rectifier circuit of claim 1 comprising a plurality of thyristors coupled to the AC input and arranged to drive the DC bus and wherein the controller is arranged to provide a trigger signal to each thyristor, and optionally wherein the AC input comprises a three-phase input and wherein each thyristor is coupled to a single phase of the AC input. ### Claim 4 (depends on 1) The rectifier circuit of claim 1 wherein deriving the first current comprises measuring a voltage across a shunt resistor. ### Claim 5 (depends on 1) The rectifier circuit of claim 1 wherein deriving a maximum current demand on the bus comprises retrieving a pre-determined value from a memory associated with the controller. ### Claim 6 (depends on 2) The rectifier circuit of claim 2 wherein deriving a maximum current demand on the bus comprises retrieving a value from an external signal. ### Claim 7 (depends on 2) The rectifier circuit of claim 2 wherein providing a trigger signal comprises retrieving a pre-determined value for a firing angle from a memory associated with the controller. ### Claim 8 (depends on 2) The rectifier circuit of claim 2 wherein providing a trigger signal comprises calculating a value for a firing angle. ### Claim 9 (depends on 1) The rectifier circuit of claim 1 whereby the trigger signal causes the DC bus voltage to rise linearly thereby providing a constant DC bus current. ### Claim 10 (depends on 1) The rectifier circuit of claim 1 further comprising an over-current detection circuit operable to disable each thyristor, and optionally wherein the over-current detection circuit comprises a comparator arranged to compare the first current in the DC bus to a pre-determined over-current protection level and to disable the providing of a trigger signal to each thyristor if the first current exceeds the pre-determined over-current protection level. ### Claim 11 A method of controlling the current in a DC bus driven by a rectifier circuit comprising at least one thyristor coupled to an AC input and arranged to drive the DC bus, the method comprising the steps of: deriving a first current in the DC bus; deriving a maximum current demand on the DC bus; providing a trigger signal to the at least one thyristor based on the derived maximum current and the derived first current. ### Claim 12 (depends on 11) The method of claim 11 wherein the trigger signal comprises a firing angle in relation to a voltage phase of the AC input. ### Claim 13 (depends on 11) The method of claim 11 wherein the rectifier circuit comprises a plurality of thyristors coupled to the AC input and arranged to drive the DC bus and wherein a trigger signal is provided to each thyristor. ### Claim 14 (depends on 11) The method of claim 11 wherein the AC input comprises a three-phase input and wherein each thyristor is coupled to a single phase of the AC input. ### Claim 15 (depends on 11) The method of claim 11 wherein deriving the first current comprises measuring a voltage across a shunt resistor. ### Claim 16 (depends on 11) The method of claim 11 wherein deriving a maximum current demand on the bus comprises retrieving a pre-determined value from a memory associated with the controller, or retrieving a value from an external signal. ### Claim 17 (depends on 11) The method of claim 11 wherein providing a trigger signal comprises retrieving a pre-determined value for a firing angle from a memory, or calculating a value for a firing angle. ### Claim 18 (depends on 11) The method of claim 11 whereby providing a trigger signal causes the DC bus voltage to rise linearly thereby providing a constant DC bus current. ### Claim 19 (depends on 11) The method of claim 11 further comprising the steps of comparing the first current in the DC bus to a pre-determined over-current protection level and disabling the providing of a trigger signal to each thyristor if the first current exceeds the pre-determined over-current protection level. ### Claim 20 (depends on 11) The method of claim 11 wherein providing a trigger signal further comprises the step of comparing the derived maximum current demand with the derived first current. ### Claim 21 (depends on 20) The method of claim 20 further comprising the steps of: if the derived first current is less than the derived maximum current demand: converting the difference in current to a voltage demand signal indicative of a desired change in the DC bus voltage; retrieving a pre-determined firing angle value based on the voltage demand signal, or calculating a firing angle based on the voltage demand signal; providing an adjusted firing angle to at least one thyristor; and if the derived first current is greater than the derived maximum current demand: providing an unchanged firing angle to the at least one thyristor. ### Claim 22 (depends on 21) The method of claim 21 wherein the step of converting the difference in current to a voltage demand signal further comprises adding the voltage change demand signal to the previous voltage demand signal to obtain a new voltage demand signal, and optionally further comprises limiting the desired voltage change to a pre-determined voltage change increment before adding the voltage change demand signal to the previous voltage demand signal to obtain a new voltage demand signal.