# US 10,500,972 B2 · Method and apparatus to dissipate recovered energy from a mechanical load within a connected motor during braking > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,500,972 B2 - Document ID: US10500972B2 - Status: Granted - Kind: B2 - Application number: 15/916,751 - Filed: 2018-03-09 - Published: 2018-09-13 - Granted: 2019-12-10 - Earliest claimed: 2017-03-09 - Applicants: Teknic, Inc. - Inventors: Thomas John Bucella; Scott Mayne; Warren God - Web page: https://patentgrep.com/patent/US10500972B2 ## CPC - H02J 7/60: including safety or protection arrangements - B60L 7/16: for vehicles comprising converters between the power source and the motor - B60L 15/2009: {for braking} - H02J 3/1892: the arrangements being an integral part of the loads or of their control circuits - H02J 7/14: for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle - H02J 7/82: Control of state of charge [SOC] - H02K 1/146: {consisting of a generally annular yoke with salient poles} - H02K 1/276: Magnets embedded in the magnetic core, e.g. interior permanent magnets [IPM] - H02K 49/104: {Magnetic couplings consisting of only two coaxial rotary elements, i.e. the driving element and the driven element} - H02P 3/18: for stopping or slowing an AC motor - H02P 6/18: without separate position detecting elements - H02P 6/24: Arrangements for stopping - H02P 25/026: thereby detecting the rotor position - H02P 25/03: with brushless excitation - H03B 5/1265: {switched capacitors} - B60L 1/20: {Energy regeneration from auxiliary equipment} - B60L 7/22: Dynamic electric resistor braking, combined with dynamic electric regenerative braking - B60L 15/025: {using field orientation; Vector control; Direct Torque Control [DTC]} - B60L 2210/40: DC to AC converters - H02J 7/64: against overvoltage - H02P 3/14: by regenerative braking - Y02T 10/64: Electric machine technologies in electromobility - Y02T 10/72: Electric energy management in electromobility - H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract In a permanent magnet synchronous motor drive system, phase currents can be used to calculate a current that produces no shaft torque and only motor losses and a current that only produces shaft torque. These currents can be controlled to be resupplied into the motor drive system to a desired amount on a continuous basis to maintain a DC energy storage device voltage at a desired safe level. The calculated currents are resupplied to the motor drive system such that voltage levels within the DC energy storage device that approach a voltage maximum limit are transferred to the motor in the form of current that is dissipated by the motor without losing efficiency and control of driving a load with the motor. ## Claims ### Claim 1 An electronic motor drive device to dissipate recovered energy from a mechanical load within a connected motor during braking, the device comprising: an energy storage device to store power received from an AC power line and to supply the stored power to operate a connected motor; an inverter to receive the power from the energy storage device and to provide a multi-phase power to the motor; a controller to detect and transform values of currents of the multi-phase power provided to the motor into a first new current (ID) and a second new current (IQ) corresponding to a rotor angle of the motor, ID producing only motor energy losses and IQ being directly proportional to the motor's shaft torque; and an energy dissipation controller to monitor the voltage across the energy storage device (Vbus) and to provide a calculated ID target current to the controller to increase the ID current of the multi-phase power, the provided ID target current being based on the value of the monitored Vbus. ### Claim 2 (depends on 1) The device according to claim 1, wherein the energy dissipation controller is configured to compare (Vbus) with a voltage limit (Vlim) of the energy storage device and to compare (Vbus) with a predetermined lower voltage set point lower than (Vlim), and to control the controller to add ID to the currents of the multi-phase power when (Vbus) exceeds (Vlim) and to stop adding ID to the currents of the multi-phase power when the (Vbus) is less than the predetermined lower voltage set point. ### Claim 3 (depends on 2) The device according to claim 2, wherein the energy dissipation controller sets a first target current (IDT) to a non-zero value when (Vbus) exceeds limit (Vlim), and sets IDT to zero when (Vbus) drops below the predetermined lower voltage set point, and controls the controller to add an amount of energy loss current equal to IDT. ### Claim 4 (depends on 2) The device according to claim 2, wherein the predetermined lower voltage set point is below (Vlim). ### Claim 5 (depends on 2) The device according to claim 2, wherein the energy dissipation controller sets IDT to a current value proportional to the square root of the product of the motor shaft velocity estimate and IQ. ### Claim 6 (depends on 5) The device according to claim 5, wherein the proportionality of IDT to the square root of the product of the motor shaft velocity estimate and IQ is adjusted for proper balance based upon the motor's electromagnetic parameters. ### Claim 7 (depends on 1) The device according to claim 1, wherein ID is proportional to the magnetic field that is aligned with the rotor's permanent magnet field and IQ is proportional to the magnetic field that is perpendicular to the rotor's permanent magnetic field. ### Claim 8 (depends on 3) The device according to claim 3, wherein the controller comprises: a direct-quadrature-zero transform to de-rotate the calculated ID and IQ currents; a summing circuit to subtract the de-rotated ID from the IDT; an independent proportional-integral controller to receive the subtracted de-rotated ID from the IDT to control this subtracted current based on modulated values of VD determined from ID; and a negative direct-quadrature-zero transform to rotate VD to form new three-phase power to be fed to the inverter. ### Claim 9 (depends on 5) The device according to claim 5, wherein the controller comprises: a direct-quadrature-zero transform to de-rotate the calculated ID and IQ currents; a summing circuit to subtract the de-rotated ID from the IDT; an independent proportional-integral controller to receive the subtracted de-rotated ID from the IDT to control this subtracted current based on modulated values of VD determined from ID; and a negative direct-quadrature-zero transform to rotate VD to form new three-phase power to be fed to the inverter. ### Claim 10 (depends on 1) The device according to claim 1, wherein the controller is a field oriented controller. ### Claim 11 (depends on 1) The device according to claim 1, wherein the energy storage device is a capacitor bank. ### Claim 12 A method of dissipating recovered energy from a mechanical load within a connected motor during braking, the method comprising: storing power received from an AC power line in a DC power storage device; inverting the stored DC power to a multi-phase power and providing the multi-phase power to the motor; calculating an (ID) current corresponding to a rotor angle of the motor from values of currents of the multi-phase power being provided to the motor, the ID current producing only motor energy losses and IQ current being directly proportional to the motor's shaft torque; calculating an ID target current based on monitoring the voltage across the DC power storage device (Vbus); and adding ID to the currents of the multi-phase power based on the monitored value of Vbus. ### Claim 13 (depends on 12) The method according to claim 12, further comprising: comparing Vbus with a voltage limit Vlim of the DC power storage device; comparing Vbus to with a predetermined lower voltage set point lower than Vlim; adding ID to the currents of the multi-phase power when Vbus exceeds Vlim; and preventing ID from being added to the currents of the multi-phase power when Vbus is less than the predetermined lower voltage set point. ### Claim 14 (depends on 12) The method according to claim 12, further comprising: setting a first target current (IDT) to a non-zero value when Vbus exceeds Vlim; setting IDT to zero when Vbus drops below the predetermined lower voltage set point; and adding an amount of IDT current to the currents of the multi-phase power to balance energy returned from the motor to the DC power storage device and energy flow from the DC power storage device to the motor as dissipated energy. ### Claim 15 (depends on 12) The method according to claim 12, wherein the predetermined lower voltage set point is equal to hlim subtracted from Vlim. ### Claim 16 (depends on 12) The method according to claim 12, further comprising: setting IDT to a current value proportional to the square root of the product of the motor shaft velocity estimate and IQ. ### Claim 17 (depends on 16) The method according to claim 16, wherein the proportionality of IDT to the square root of the product of the motor shaft velocity estimate and IQ is adjusted for proper balance based upon the motor's electromagnetic parameters. ### Claim 18 (depends on 12) The method according to claim 12, further comprising: applying first and second new voltages VD and VQ obtained from ID and IQ to modulate the DC stored power being converted based on a comparison of the first current with a received first target current and the second current with a received second target current. ### Claim 19 (depends on 14) The method according to claim 14, further comprising: generating IDT by: comparing Vbus to Vlim; comparing Vbus with a predetermined lower voltage value less than Vlim; and setting IDT to a non-zero value when Vbus exceeds Vlim, otherwise setting IDT to zero when Vbus is less than the predetermined lower voltage value. ### Claim 20 (depends on 12) The method according to claim 12, wherein ID is proportional to the magnetic field that is aligned with the rotor's permanent magnet field and IQ is proportional to the magnetic field that is perpendicular to the rotor's permanent magnetic field. ### Claim 21 (depends on 14) The method according to claim 14, further comprising: de-rotating the calculated ID and IQ currents; subtracting the de-rotated ID current from IDT; controlling the ID by changing values of VD; and rotating the VD values to modulate the stored DC power. ### Claim 22 An energy dissipation control circuit to dissipate energy stored in a DC storage device within a motor drive circuit, comprising: a first comparator to continuously monitor and compare a DC storage device voltage (Vbus) value to a voltage maximum limit (Vlim) of the DC storage device; a second comparator to continuously monitor and compare the DC storage device voltage Vbus value to a predetermined voltage value below the Vlim; and a controller to provide a target output current dissipation value to the motor drive circuit to decrease the Vbus value based on the monitored Vbus value, the target output current dissipation value being varied depending on the monitored Vbus value. ### Claim 23 (depends on 22) The energy dissipation control circuit according to claim 22, wherein the target output current dissipation value is set to a predetermined non-zero value when the first comparator value is high, and the target output current dissipation value is set to zero when the second comparator value is high. ### Claim 24 (depends on 22) The energy dissipation control circuit according to claim 22, wherein the controlled target output current dissipation value is dissipated through a motor.